1,908 results on '"*HEAT of combustion"'
Search Results
2. Carbon footprint reduction potential for diesel-fuelled generators through periodic maintenance using EXORIN treatment.
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Alimin, Ahmad Jais, Asmat, Fatina, Yin, Clement Lee Nyuk, Subramaniyan, S. Kanna, Osman, Shahrul Azmir, and Razali, Mohd Azahari
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ECOLOGICAL impact , *GREENHOUSE gases , *DIESEL motors , *REDUCTION potential , *HEAT of combustion , *COMBUSTION efficiency - Abstract
Climate change and greenhouse gas emissions are among the most pressing global issues, with reduction of carbon footprint has been identified as one of the main indicators in this battle. In the effort to reduce carbon footprint generation, a local power utility company, located in East Malaysia that operates diesel-fuelled generators had conducted a periodic maintenance program using EXORIN treatment. EXORIN treatment program focused on improving the fuelling capability of the diesel-fuelled generators. Using comparative tests from untreated and treated operations, the carbon footprint emission levels were determined by comparing data obtained from gaseous emission sampling method, dark smoke observation and data of stationary source from the utility powerplant. From analysed data, CO and CO2 emissions were successfully reduced by around 7%. The combustion and energy efficiencies had also improved within the range of 9% to 21%. Fuel economy, which is dependent on the consumers electricity demands, also showed significant trend. These results outlined the potential of reducing carbon footprint using the dedicated EXORIN treatment program. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Mathematical modeling of ways to improve the efficiency of fuel combustion in combustion devices.
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Kovalnogov, Vladislav N., Fedorov, Ruslan V., Bysigin, Sergey V., and Generalov, Dmitry A.
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COMBUSTION efficiency , *ENERGY consumption , *COMBUSTION , *HEAT of combustion , *COMBUSTION chambers - Abstract
One of the key directions in the energy sector at present is the most economical combustion of fuel and the reduction of pollutant emissions. This can be achieved in many respects with the most efficient organization of processes in furnace devices. Turbulent combustion of a pre-mixed air-fuel mixture is currently receiving much attention, since aerodynamic processes in gas flows inside the combustion chambers determine the conditions for heat exchange and combustion. Mathematical modeling of combustion processes makes it possible to provide optimal conditions for fuel combustion. The article presents graphs of the distribution of NOx content in the active combustion zone with a change in the proportion of flue gas recirculation from 0 to 8%. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Thermal performance of gasoline engine with the use of water ammonia solution: Numerical study.
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Flaih, Duaa S. and Al-Dawody, Mohamed F.
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SPARK ignition engines , *HEAT release rates , *ANTIKNOCK gasoline , *WATER use , *HEAT of combustion , *ENERGY consumption , *DIESEL motors - Abstract
This study examines numerically the effects of using various volumetric blends water ammonia solution (WAS) and gasoline fuel (GF) on the combustion and engine performance of spark ignition (SI) engines. The Russian simulation software Diesel-RK is used for numerical investigation. Four blends are selected for the study starts with pure gasoline for comparison base line case, followed by 5% WAS, 10% WAS, 15% WAS then ends with 20% WAS. The results obtained showed a slight decrease in the combustion pressure and heat release rate for all WAS blends. The burning combustion temperature is reduced by 1.22%, 1.68%, 2.51%, and 3.47% for the operation with 5% WAS, 10% WAS, 15% WAS and 20% WAS respectively. Considerable increase in knock resistance is achieved with the use of WAS blends. Compared to neat gasoline. The minimum octane number (ONmin) required to prevent knock is dropped by 1.5%, 2.33%, 3.28%, 5.18% for 5% WAS, 10% WAS, 15% WAS and 20% WAS respectively. Significant reduction is observed in the exhaust gas temperature is noticed. The operation with 20% WAS reported higher increase in brake thermal efficiency (BTE) (2.34%) as well as lower decrease in the exhaust gas temperature (5.46%) compared to other blends of WAS. The brake-specific fuel consumption (BSFC) for all blends considered is higher than neat gasoline. The results of other investigations are used to check the ones that were acquired. [ABSTRACT FROM AUTHOR]
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- 2024
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5. The effect of secondary boundary layer combustion of hydrogen on rocket plume heat release characteristics.
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Wang, Limin, Cheng, Qunli, Wang, Jiannan, Zhang, Yongwei, Zhang, Weimeng, Liu, Shuyuan, and Xia, Zhixun
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BOUNDARY layer (Aerodynamics) , *HEAT release rates , *COMBUSTION kinetics , *HEAT of combustion , *PARTIAL pressure , *COMBUSTION , *ROCKETS (Aeronautics) - Abstract
The secondary combustion between unburnt fuel in rocket plume and ambient air significantly affects the stealth characteristics of rocket motors. In order to reveal the effect of secondary boundary layer combustion of hydrogen on rocket plume heat release characteristics, a two-dimensional axisymmetric model for boundary layer combustion between the rocket plume and air is established. The results identifies significant exothermic effect due to secondary combustion reaction between the plume and air. Compared to the nozzle plume without considering secondary combustion, the average temperature of the plume with secondary combustion increases by 47%. As hydrogen content in the nozzle plume increases from 2.7% to 4.2%, the average temperature of the nozzle plume increases by 17.2% due to enhanced combustion heat release. The secondary combustion process is weakened with the increase of flight altitude. The average temperature of the nozzle plume decreases by 11.8% from 2 km to 8 km of flight altitude. This is because both the pressure and temperature of the ambient air decrease when the flying altitude rises, which leads to lower secondary combustion reaction and heat release rate. Moreover, as the ambient pressure decreases, the hydrogen concentration in the plume decreases due to plume expansion effect. The results indicate that hydrogen content and flight altitude affect secondary combustion by different mechanisms. The hydrogen content directly affects the concentration term of the reaction rate of secondary combustion. However, the flight altitude affects the kinetic rate of secondary combustion by changing both the temperature and partial pressure of oxygen. The present study provides better insight into the interaction mechanism between nozzle plume and ambient air. • Established numerical model for secondary combustion of rocket plume. • Higher hydrogen content enhances secondary combustion process. • Secondary combustion heat release is weakened as flight altitude increases. • Secondary combustion is controlled by shear mixing and heat transfer. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Transient spray combustion characteristics in a gas–liquid pintle rocket engine under acoustic excitation.
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Jin, Xuan, Zhu, Chao, Chen, Dejiang, and Zhang, Zhongpei
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ROCKET engines , *ACOUSTIC excitation , *HEAT of combustion , *TEMPERATURE distribution , *FIRE testing , *SPRAY combustion , *SOUND pressure , *FLAME temperature - Abstract
In order to investigate the acoustic oscillation characteristics of gas–liquid pintle rocket engines and elucidate the path by which spray combustion process provides energy to the combustor pressure oscillation, a LOX/GCH4 pintle engine with rectangular combustor was designed. By adding transverse velocity disturbance for the first time, the acoustic response of spray combustion process was simulated, and the effect of excitation amplitude on acoustic response was researched. Numerical results show that the adopted transverse velocity disturbance can excite the first-order transverse acoustic oscillation with same excitation frequency in the engine combustor. The acoustic response maintenance mechanism under extrinsic excitation is summarized for pintle engines. Besides, the temperature distribution inside the engine combustor tends to be uniform, and the low-frequency oscillation caused by the flame transverse swing gradually disappears. The amplitude of combustor pressure oscillation is dominated by excitement amplitude and phase difference between the pressure and heat release in combustion reaction region. In addition, the time-averaged combustor pressure can be amplified mainly by transverse velocity disturbance. The research work can provide a reference for related fire tests on the acoustic response of a subscale gas–liquid pintle engine. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Soil Enzyme Response and Calorific Value of Zea mays Used for the Phytoremediation of Soils Contaminated with Diesel Oil.
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Borowik, Agata, Wyszkowska, Jadwiga, Zaborowska, Magdalena, and Kucharski, Jan
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DIESEL fuels , *CORN , *SOIL enzymology , *PHYTOREMEDIATION , *SOIL remediation - Abstract
Ensuring a stable and cost-effective energy supply is a major challenge for the International Energy Agency (IEA). Additionally, the effectiveness of vermiculite and dolomite in mitigating the adverse effects of diesel oil, a petroleum-derived product, on plant growth and development, and on the biochemical activity of the soil, were assessed. Therefore, an attempt was made in the study to determine the energy properties of Zea mays, which is suitable for cultivation in contaminated areas. For these purposes, several parameters were analyzed in its biomass, including calorific value (Q), heating value (Hv), energy yield (Yep), ash content, and the presence of carbon (C), hydrogen (H), sulfur (S), nitrogen (N), and oxygen (O). Biochemical activity was measured through the evaluation of soil enzymes serving as indicators for the carbon (dehydrogenases, catalase, β-glucosidase), nitrogen (urease), sulfur (arylsulfatase), and phosphorus (acid and alkaline phosphatase) cycles. The plant greenness index was also determined. It has been demonstrated that diesel oil does not alter the calorific value of Zea mays biomass but significantly reduces the biomass quantity and destabilizes the biochemical properties of the soil. Zea mays contained an average of 6.84% ash, 49.88% C, 5.65% H, 0.17% S, 2.90% N, and 34.57% O. The calorific value of Zea mays ranged from 15.02 to 15.54 MJ kg−1 d.m. of plants, and the heating value ranged from 18.25 to 19.21 MJ kg−1 d.m. of plants. The biomass obtained from contaminated soil is recommended for energy purposes. The sorbents used—vermiculite and dolomite—proved to be less effective in the remediation of soil contaminated with diesel oil. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Effect of Composted Organic Waste on Miscanthus sinensis Andersson Energy Value.
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Zając, Mariola and Skrajna, Teresa
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MISCANTHUS , *RENEWABLE energy sources , *ORGANIC wastes , *FIELD research , *SUSTAINABLE development - Abstract
At the time of rising urbanization and population growth, the search for renewable energy sources to ensure sustainable development is of extreme importance. The aim of this research was to determine the effects of different proportions of composted organic materials, i.e., mushroom substrate and municipal waste, on Chinese silver grass (Miscanthus sinensis Andersson) energy value. A three-year field experiment was established on experimental plots in the east-central part of Poland. Various treatment combinations, each introducing 170 kg N·ha−1 to the soil, had a positive effect on the energy parameters of Chinese silver grass biomass. The highest calorific value (17,964 kJ·kg−1) was noted for plants treated with mushroom compost on its own (MSC100%). [ABSTRACT FROM AUTHOR]
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- 2024
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9. Characteristic of Premixed Hydrogen/Air Tubular Flames in Microcombustor: Effects of Stimulated and Unstimulated Inlet Conditions on Flame Dynamics.
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Alipoor, Alireza and Abbaspour, Pouyan
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HYDROGEN flames , *FLAME , *HEAT of combustion , *FLAME temperature , *INLETS , *HIGH temperatures - Abstract
The present study investigates the characteristics and periodic behavior of H2/air tubular flames in a 1 mm diameter microtube under exciting and nonexciting inlet conditions. Under unstimulated inlet conditions, increasing inlet velocity positively impacted flow stratification and self-sustaining of the tubular flames, leading to higher maximum temperatures within the flame kernel due to reduced flow temperature gradients near the wall. Conversely, under stimulated conditions, varying excitation amplitudes resulted in two flame propagation modes: flame with semi-repetitive extinction/ignition (FSREI) and pulsating flame, observed across different exciting amplitude ranges. It was found that the formation of recirculation fields generated by negative propagation speed temporarily stored the released heat of combustion and prevented it from extinguishing in the flowing phase. From the kinetics point of view, the maximum reaction rate during the pulsating mode belongs to H + O2 = HO2, while competition between H + O2 = HO2 and H2 + OH = H2O + H occurred in the FSREI mode. Results revealed that in the pulsating mode, fluctuations in mass fractions of the heavier species are more considerable near the outlets. However, radical mass fraction fluctuations were significant near the inlet slot in pulsating mode. [ABSTRACT FROM AUTHOR]
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- 2024
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10. Transitioning from low-emission dry micro-mix hydrogen-air combustion to zero-emission wet micro-mix hydrogen-oxygen combustion in hydrogen energy storage systems.
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Boretti, Alberto
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HEAT of combustion , *ENERGY storage , *HYDROGEN as fuel , *HYDROGEN storage , *COMBUSTION , *COMBUSTION kinetics - Abstract
This study explores the transition in combustion technologies from dry micro-mix hydrogen-air to wet micro-mix hydrogen-oxygen configurations. The investigation involves a comprehensive analysis of the combustion processes currently being considered for converting methane gas turbines to methane-hydrogen mixtures and hydrogen, including wet premixed, dry low emission, sequential combustion, and micro-mix, examining key parameters such as efficiency, emissions, and overall performance. Then, the work considers the shift from utilizing air as an oxidizer to oxygen. Wet micro-mix hydrogen-oxygen combustion is then discussed for its impact on combustion dynamics and the potential for achieving zero emissions, cancelling NOx emissions in addition to CO 2 emissions. The findings contribute valuable insights into the feasibility and advantages of transitioning from conventional hydrogen-air combustion to innovative wet hydrogen-oxygen combustion, paving the way for more sustainable and environmentally friendly combustion technologies. Scheme of a hydrogen energy storage system comprising one electrolyser, two tanks for the hydrogen and the oxygen, and an O 2 /H 2 /H 2 O gas turbine power system. The system could be able to receive non-dispatchable electricity and release dispatchable electricity working as a battery but without any limitation on the amount of energy storable, or the time of the storage. [Display omitted] [ABSTRACT FROM AUTHOR]
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- 2024
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11. Enhanced ignition and combustion performance of boron-based energetic materials through surface modification and titanium dioxides coating.
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Mondal, Jayanta, Singh, Sumit Kumar, and Shin, Weon Gyu
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TITANIUM dioxide surfaces , *SURFACE coatings , *SURFACES (Technology) , *HEAT of combustion , *COMBUSTION , *CATALYSIS - Abstract
The present study focuses on the removal of ineffective hydroxyl surface (B–OH) of the shell of pristine boron (B) particles, followed by its modification using a low-cost, eco-friendly, and non-hazardous ethylene glycol (EG). Subsequently, very small-sized titanium dioxide (TiO 2) particles are coated onto the boron surface by adding titanium tetraisopropoxide (TTIP) precursors at room temperature. Characterization techniques were employed to investigate the structure and morphology of these materials. FTIR, XPS, and TEM analysis reveal that EG effectively removes ineffective boron hydroxyl surfaces and modifies the surface through passivation by its surface functionalities. Furthermore, EG assists in the coating very small-sized TiO 2 particles on the boron surface. Thermal stability tests show that the modified boron surface and TiO 2 -coated boron surface exhibit earlier oxidation of the core boron compared to pristine boron. This enhanced capability for earlier oxidation of core boron was further investigated in the shock tube and bomb calorimeter for measurement of ignition delay time and heat of combustion. The findings demonstrate that room temperature synthesized TiO 2 -coated B particles (ignition delay time of ∼181 μs and heat of combustion of ∼17.3 kJ/g) outperform pristine B particles (ignition delay time of ∼284 μs and heat of combustion of ∼13.2 kJ/g). This improvement is attributed to the removal of ineffective boron hydroxyl surfaces, surface modification, uniform coating with very small TiO 2 particles, the catalytic effect of TiO 2 on oxygen diffusion, and effective oxidation of core boron. This study suggests that efficient energetic material can be achieved at room temperature with no potential harm to the environment. [ABSTRACT FROM AUTHOR]
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- 2024
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12. Influence of natural aging on wood combustion heat release.
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Zhao, Jingyu, Jiang, Xinrong, Song, Jiajia, Lu, Shiping, Xiao, Yueyan, and Shu, Chi-Min
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WOOD combustion , *HEAT of combustion , *HEAT release rates , *WOOD , *DIFFERENTIAL scanning calorimetry , *FIRE prevention , *FLAME spread , *FIREPROOFING agents - Abstract
Wood is a primary building tool for ancient buildings and structures, but for those that survive to date, naturally aged wood may pose a noteworthy fire hazard. There are potential risks to health, safety, and substantial cultural loss if fire risks in such buildings are not mitigated. We obtained several samples of aged wood commonly used in ancient structures (elm, pine, and aspen), and compared the kinetic and thermal characteristics to fresh wood examples to determine potential methods of enhancing safety. Differential scanning calorimetry was used to establish the heat release characteristics of the fresh and aged samples, and the characteristics of the thermal reaction stages were characterized using the temperature range and heat release laws for each reaction stage. The heat release characteristics during combustion were investigated for different heating rates, and the influence of aging on temperature change and heat release rate characteristics during different exothermic stages was assessed. Finally, using heat flow data, the apparent activation energy (AAE) of the samples and their distributions during different exothermic stages were calculated and analyzed via the Friedman differential iso-conversion method. Results showed that the exothermic energy of the aged samples was higher than that of the fresh samples, indicating that aging does impact the thermal reaction process. The aged samples in this study had a greater heat diffusion capacity, transmitted more heat, were more susceptible to burning (by spreading that heat), and generally posed a greater fire hazard. During the rapid exothermic phase, the AAE of aged wood increased as the reaction progressed, and exhibited lower AAE with a greater sensitivity to fire than fresh samples. A sound linear relationship between pre-exponential factor and AAE and the kinetic compensation effect was obvious. This study provided a rudimentary theoretical basis for the prevention of fires in timber-framed ancient buildings. [ABSTRACT FROM AUTHOR]
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- 2024
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13. DOPO-based derivatives with different phosphorous oxidation states as highly efficient flame retardants for epoxy resins.
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Tang, Gang, Tao, Yi, Wu, Qiang, Shen, Haifeng, Sun, Junjie, Deng, Dan, and Liu, Xiuyu
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FIREPROOFING agents , *OXIDATION states , *EPOXY resins , *HEAT release rates , *HEAT of combustion , *MOLECULAR structure - Abstract
Over the past few decades, the development of highly efficient phosphorus-based flame retardants has become one of the research focuses in the field of halogen-free flame-retardant polymer technology. In this work, three kinds of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-based derivatives were synthesized through integrating multiple phosphorous oxidation states into one molecular structure. The influence of DOPO-based derivatives on the thermal decomposition and flame-retardant properties of EP composites were investigated. DOPO-based derivatives promoted the slightly earlier decomposition of the epoxy matrix, resulting in better thermal stability at high temperatures and higher char yield. The unmodified EP showed a LOI value of 27.0% and no UL-94 rating, while all the EP composites containing 2 wt.% DOPO-based derivatives passed the UL-94 V-0 rating and achieved a LOI value of higher than 30.0%. Among the three DOPO-based derivatives, TDCA-DOPO-2 behaved the best flame-retardant efficiency owing to the highest synergistic effect. Specifically, the peak of heat release rate, total heat release and average effective heat combustion (av-EHC) of EP/TDCA-DOPO-2 was 62.0%, 54.2% and 39.9% lower than those of the unmodified EP, respectively. The high flame-retardant efficiency of DOPO-based derivatives was ascribed to the synergism between the barrier effect in the condensed phase (proved by the high yield and stability of char residues) and the flame inhibition effect in the gaseous phase (proved by the decreased av-EHC values). [ABSTRACT FROM AUTHOR]
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- 2024
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14. Estimation of Fuel Properties for the Heavy Fraction of Biomass Pyrolysis Oil Consisting of Proposed Structures for Pyrolytic Lignin and Humins.
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Terrell, Evan
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THERMODYNAMICS , *LIGNINS , *LIGNIN structure , *HEAT of combustion , *PYROLYSIS , *HEATS of vaporization , *COAL liquefaction - Abstract
The organic component of biomass pyrolysis oils is composed of a light fraction (C2–C4 volatiles, sugar- and lignin-derived monomers) and a less polar heavy fraction (pyrolytic lignin/humins, greater than approximately 200 g/mol). Importantly, this heavy fraction can account for roughly one-third to one-half of the total pyrolysis oil. While the composition and characteristics of the light fraction are generally well understood, research is still needed for the characterization of the heavy fraction. Some important thermodynamic fuel properties of this fraction are the heat of combustion, normal boiling point, heat of vaporization, and flash point, which are (computationally) estimated in this work with regularized regression and empirical correlations. The quantification of these properties has implications on downstream utilization, particularly in the context of co-processing bio-oils with plastic and coal liquefaction products and/or crude petroleum. Finally, challenges and opportunities for (experimental) work are discussed for the advancement of sustainable valorization of biomass pyrolysis oils. [ABSTRACT FROM AUTHOR]
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- 2024
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15. Toxicity of particles derived from combustion of Ethiopian traditional biomass fuels in human bronchial and macrophage-like cells.
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McCarrick, Sarah, Delaval, Mathilde N., Dauter, Ulrike M., Krais, Annette M., Snigireva, Anastasiia, Abera, Asmamaw, Broberg, Karin, Eriksson, Axel C., Isaxon, Christina, and Gliga, Anda R.
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INDOOR air pollution , *GENETIC toxicology , *BIOMASS , *HEAT of combustion , *WOOD chemistry , *POLYCYCLIC aromatic hydrocarbons , *COMBUSTION , *WOOD - Abstract
The combustion of traditional fuels in low-income countries, including those in sub-Saharan Africa, leads to extensive indoor particle exposure. Yet, the related health consequences in this context are understudied. This study aimed to evaluate the in vitro toxicity of combustion-derived particles relevant for Sub-Saharan household environments. Particles (< 2.5 µm) were collected using a high-volume sampler during combustion of traditional Ethiopian biomass fuels: cow dung, eucalyptus wood and eucalyptus charcoal. Diesel exhaust particles (DEP, NIST 2975) served as reference particles. The highest levels of particle-bound polycyclic aromatic hydrocarbons (PAHs) were found in wood (3219 ng/mg), followed by dung (618 ng/mg), charcoal (136 ng/mg) and DEP (118 ng/mg) (GC–MS). BEAS-2B bronchial epithelial cells and THP-1 derived macrophages were exposed to particle suspensions (1–150 µg/mL) for 24 h. All particles induced concentration-dependent genotoxicity (comet assay) but no pro-inflammatory cytokine release in epithelial cells, whereas dung and wood particles also induced concentration-dependent cytotoxicity (Alamar Blue). Only wood particles induced concentration-dependent cytotoxicity and genotoxicity in macrophage-like cells, while dung particles were unique at increasing secretion of pro-inflammatory cytokines (IL-6, IL-8, TNF-α). In summary, particles derived from combustion of less energy dense fuels like dung and wood had a higher PAH content and were more cytotoxic in epithelial cells. In addition, the least energy dense and cheapest fuel, dung, also induced pro-inflammatory effects in macrophage-like cells. These findings highlight the influence of fuel type on the toxic profile of the emitted particles and warrant further research to understand and mitigate health effects of indoor air pollution. [ABSTRACT FROM AUTHOR]
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- 2024
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16. On the Impact of Non‐CHO Elements on Fuel Properties in Waste Incineration.
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Förtsch, Dieter
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HEAT of combustion , *WASTE products as fuel , *HAZARDOUS wastes , *HAZARDOUS substances , *INCINERATORS , *INCINERATION - Abstract
Incineration is and will remain a proven technology for the safe and sustainable destruction of environmentally hazardous substances. The behavior of non‐CHO elements during combustion plays an important role in the design of incinerators for hazardous waste since they drive the selection and design of the process sequence and of the single equipment. This contribution presents an overview on impacts of the presence of non‐CHO compounds in waste incinerators and provides correlations to estimate the product distribution of sulfur‐ and halogen‐containing compounds as well as for the important fuel properties oxygen demand and heat of combustion of material containing non‐CHO elements. [ABSTRACT FROM AUTHOR]
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- 2024
- Full Text
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17. Effect of NPAH Exposure on Lung Function of Children in Indoor Coal Combustion Environment.
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Wang, Beibei, Huang, He, Qin, Ning, Zhao, Wenjing, Wang, Qin, Cao, Suzhen, Chen, Xing, Xu, Xiangyu, and Duan, Xiaoli
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BIOMASS burning , *HEAT of combustion , *LUNGS , *MONTE Carlo method , *TOBACCO smoke , *PRINCIPAL components analysis , *COAL combustion - Abstract
Nitropolycyclic aromatic hydrocarbon (NPAH) emissions from the combustion of household solid fuel may cause great harm to public health. Children are one of the most susceptible population groups at risk of indoor air pollutants due to their immature respiratory and immune systems. In this study, a primary school using household coal combustion for heating in winter was selected and forty participants were randomly recruited among schoolchildren. Fine particulate matter samples were collected by both individual portable samplers and fixed middle-flow samplers during the heating and nonheating seasons. The NPAH concentrations in PM2.5 samples were analyzed by a gas chromatograph coupled to a mass spectrometer. Potential sources of NPAHs were identified by NPAH ratios as well as principal component analysis. Lung function of children was tested by an electronic spirometer. The relationship between NPAH exposure level and children's lung function was studied. Finally, the cancer risk caused by NPAH inhalation was assessed. The results showed significantly higher individual NPAH exposure level in heating season (0.901 ± 0.396 ng·m-3) than that in nonheating season (0.094 ± 0.107 ng·m-3). Coal/biomass combustion and secondary formation were the potential NPAH sources in heating season. Significantly lower lung function of children was also found in heating season compared with that in nonheating season. As a result of the Monte Carlo simulation, the averaged incremental lifetime cancer risk (ILCR) values from the inhalation of NPAHs in the heating and nonheating seasons were 3.50 × 10 − 8 and 2.13 × 10 − 8 , respectively. Our research revealed the association between NPAH exposure and children's lung function and confirmed the adverse effect of indoor coal combustion. The results also indicated that further control strategies on indoor coal combustion are needed to reduce the risk of NPAH exposure and protect children's health. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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18. Secondary Atomization and Micro-Explosion Effect Induced by Surfactant and Nanoparticles on Enhancing the Combustion Performance of Al/JP-10/OA Nanofluid Fuel.
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Li, Shengji, Liu, Zixuan, Yang, Qianmei, Wang, Zhangtao, Huang, Xuefeng, and Luo, Dan
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FLAME , *NANOFLUIDS , *ATOMIZATION , *COMBUSTION , *HEAT of combustion , *NANOPARTICLES - Abstract
Aluminum/tetrahydrodicyclopentadiene/oleic acid (Al/JP-10/OA) nanofluid fuel is considered a potential fuel for aircraft powered by aviation turbine engines. However, an optimized formula for an Al/JP-10/OA system inducing a secondary atomization and micro-explosion effect and improving the burning performance needs to be developed. With this aim, in this work, the combustion characteristics of pure JP-10, JP-10/OA, JP-10/Al, and Al/JP-10/OA were experimentally tested, and a comparative analysis was conducted. Specifically, the influence of the surfactant and nanoparticle concentrations on the combustion characteristics of Al/JP-10/OA nanofluid fuel, including the flame structure, the flame temperature, the burning rate, the secondary atomization and micro-explosion effect, etc., were evaluated in detail. The results demonstrate that the addition of OA surfactant and Al nanoparticles had a significant effect on the burning rate of fuel droplets. The OA had an inhibition effect, while the Al nanoparticles had a promotion effect. As both OA and Al nanoparticles were added to the JP-10, the synergetic effect had to be considered. At the optimum ratio of OA to Al for the best suspension stability, there is a critical Al concentration of 1.0 wt.% from promotion to inhibition with increases in the Al concentration. The addition of OA and Al nanoparticles induced the secondary atomization and micro-explosion, resulting in an unsteady combustion and chaotic flame structure. The transient flame temperature of hundreds of Kelvins increased, the high-temperature flame zone widened, and thus, the energy release was elevated. Therefore, the combustion performance and energy release of Al/JP-10/OA nanofluid fuel can be improved through the secondary atomization and micro-explosion effect induced by the surfactant and nanoparticles. [ABSTRACT FROM AUTHOR]
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- 2024
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19. Comparative investigation on fuel characteristics of different parts of corn stover considering particle size and pelletizing pressure based on macro-TGA.
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Nie, Yazhou, Deng, Mengsi, Shan, Ming, and Yang, Xudong
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CORN stover , *PELLETIZING , *WOOD pellets , *HEAT of combustion , *RAW materials , *CARBON emissions - Abstract
Biomass fuel is considered a favorable fuel for reducing carbon emissions. The combustion performance of different biomass differs considerably. Even in the same plant, the contents of the main components in different tissues or fractions are significantly different. The corn stover was divided into four fractions (stalk, leaf, bract, and cob), and the effects of the sample fraction, particle size, and pelletizing pressure on combustion performance were investigated using an orthogonal experiment based on a custom-designed macro-thermogravimetric analyzer (macro-TGA). The sample fraction made a significant difference to the results of elemental analysis and industrial analysis (p < 0.01), while the particle size also resulted in extremely significant differences in the measured values of C, N, and S (p < 0.01). According to the classification standard for non-woody biomass pellet fuel, all four fractions of corn stover reached level 1 in terms of moisture, density, and calorific value. The three factors of sample fraction, particle size, and pelletizing pressure have different effects on the characteristic parameters of combustion process (ignition index, burnout index, etc.). The comprehensive combustion indices of leaves, bracts, and cobs were significantly higher than that of straw (p < 0.05). The pelletizing process significantly reduced the activation energy during combustion compared with that of the raw biomass material (p < 0.05). The results of this study can provide guidance for better utilization of corn stover, and strengthen the understanding of differentiation in the thermal degradation process of biomass. [ABSTRACT FROM AUTHOR]
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- 2024
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20. An experimental study of the flow structure in arrays of cold bidirectional swirling jets.
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Evdokimov, Oleg A., Guryanov, Alexander I., and Veretennikov, Sergey V.
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SWIRLING flow , *PARTICLE image velocimetry , *HEAT of combustion , *HEAT transfer - Abstract
Jets arrays have become a promising technology for industrial applications, including heat transfer and combustion processes. This paper presents the first experimental results of arrays of bidirectional swirling jets, including their flow structures and specific turbulent interactions. Particle image velocimetry of non-reacting linear arrays showed the formation of recirculation zones within each jet of the array. These regions are the most stable, with fluctuations less than 0.002 of the bulk inlet velocity Vin. In addition, jets merging locations also show a significant decrease in velocity fluctuations, with values V′/Vin < 0.005, which is most clearly seen at a smaller pitch distance. However, the highest turbulent fluctuations occur in shear layers, reaching values of V'/Vin ≈ 0.02 for linear arrays and V'/Vin ≈ 0.03 for planar configurations. The flow structure of planar arrays is more complex, leading to the formation of secondary vortex structures at locations of jet interaction. This results in a significant decrease in the flow swirl number, from an initial value of Sin = 2.1 in the vortex chamber, to S1 = 0.36–0.49 at z/dout2 = 1 and S2 = 0.19–0.27 at z/dout2 = 2 beyond the outlet nozzle. Strong cross-sectional motions are observed in planar arrangements, leading to the development of additional regions of negative axial velocity between the outlet nozzles. The boundaries of these regions have nearly zero axial velocity values and can provide reliable ignition and flame stabilization in the case of reactive bidirectional jets. Therefore, the flow structure in planar arrays forms a large stabilization zone, and the obtained results can be used to develop a new multipoint combustion technique. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
21. Properties and detonation performance of tetraamminecopper(II) nitrate (TACN) – a prospective green explosive.
- Author
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Trzciński, Waldemar A., Hara, Marcin, and Szymańczyk, Leszek
- Subjects
- *
DIFFERENTIAL thermal analysis , *HEAT of combustion , *ELECTRIC charge , *COORDINATE covalent bond , *EQUATIONS of state , *CHEMOTAXONOMY - Abstract
The simplest ligand that can be present in energetic complex compounds is ammonia. It has a lone pair of electrons on the nitrogen atom that can form a coordinate bond with the metal cation. An example of such a compound is tetraamminecopper(II) nitrate (TACN). TACN is considered in the literature as an energy material with potential use in ammunition and civil applications. In the work, the physicochemical properties and detonation performance of TACN were investigated. The compound was identified using differential thermal analysis coupled with thermogravimetry (DTA/TG) and infrared spectroscopy (IR). The sensitivity of TACN to mechanical stimuli (friction and impact) was determined. The thermal stability was tested. The critical diameter of the charge with bulk density and the ability to detonation for charges of different densities initiated by an electric detonator were determined. The velocity of detonation was also measured for various diameters and densities of charges and the method of their initiation. The cylinder expansion tests were performed for TACN charges of various densities, and the acceleration ability, detonation pressure and energy as well as the equation of state of detonation products were determined. The calorimetric heats of combustion and detonation were also measured. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
22. Experimental study on the influence of trifluoroiodomethane on the flammability of 1,1-difluoroethane, isobutane and propylene.
- Author
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Zhong, Quan, Huang, Yujie, Li, Huajie, and Zhao, Huan
- Subjects
- *
FLAMMABLE limits , *TRIFLUOROIODOMETHANE , *FLAMMABILITY , *GAS as fuel , *HEAT of combustion , *FIREPROOFING agents , *FIRE resistant polymers - Abstract
• The flammability limits of R13I1 + R152a/R600a/R1270 binary mixtures were measured. • The critical flammable volumetric ratios of R13I1 + R152a/R600a/R1270 were obtained. • A generalized equation for the LFL of R13I1 mixtures was provided. • F -number and HOC were calculated and the inhibitory effects of R13I1 were analyzed. Trifluoroiodomethane (R13I1) is a flame retardant with an extremely low global warming potential (GWP) and can be used as a component to improve the flammable characteristics of most promising low-GWP refrigerants. In this paper, the flammability limits of R13I1 + 1,1-Difluoroethane (R152a), R13I1 + isobutane (R600a) and R13I1 + propylene (R1270) binary mixtures were measured at 60 °C and atmospheric pressure with a 12 L flask according to ASHRAE standards. The critical suppression ratios of R13I1 + R152a, R13I1 + R600a and R13I1 + R1270 are 0.45, 2.24 and 0.99, respectively. A generalized equation for the lower flammability limit (LFL) of R13I1 mixtures was provided. With the LFL of the fuel gas in air and the ratio of R13I1 to the fuel gas, the developed generalized equation can calculated the LFL of R13I1 mixtures with a reasonable accuracy. The influence of R13I1 on the flammability of R152a, R600a and R1270 were studied. The LFL increases and heat of combustion (HOC) decreases significantly with the increase of the R13I1 concentration. The flammability inhibition effects of R13I1 decrease in the order: R152a > R1270 > R600a. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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23. Effects of Humic Acids on Calorific Value and Chemical Composition of Maize Biomass in Iron-Contaminated Soil Phytostabilisation.
- Author
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Wyszkowski, Mirosław and Kordala, Natalia
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- *
HUMIC acid , *HEAT of combustion , *BIOMASS , *PLANT biomass , *ENERGY crops , *CORN , *IRON fertilizers , *PLANT nutrients - Abstract
An interesting feedstock for energy purposes is plant biomass due to its renewability, widespread availability and relatively low cost. One plant with a high and versatile use potential is maize. Plants used for energy production can be grown in polluted areas, e.g., with iron. The aim of the study was to determine the effect of humic acids (HAs) on the yield, calorific value and other energy parameters and chemical composition of maize biomass applied as a phytostabiliser on iron-contaminated soil. The soil was contaminated with iron at 0, 250, 500 and 750 mg kg−1. The HAs were added to the soil in the following amounts: 0, 0.3, 0.6 and 0.9 g kg−1 of soil. Soil contamination with iron had relatively little effect on the heat of combustion and calorific value of biomass and very strongly reduced plant height (42%), dry matter yield (95%) and energy production of maize biomass (90%), the SPAD index at the fifth leaf unfolded stage (44%) (as opposed to the stem elongation stage), sodium, magnesium and phosphorus contents, and increased calcium, potassium and nitrogen contents of maize. The application of HAs to the soil had a positive and very large effect on both the height and biomass parameters studied, resulting in an increase in plant height (22%), dry matter yield (67%) and energy production from maize biomass (62%). Changes in the heat of combustion and calorific value of the biomass were minimal but positive. HAs contributed to a decrease in the value of the SPAD index during the stem elongation phase of maize and in the content of all macronutrients in maize biomass as a result of a reduction in the effect of iron on macronutrient content and to a significant increase in maize dry matter yield in plots with their application. The application of HAs appears to be an effective adjunct in the phytostabilisation of iron-contaminated soils by growing crops for energy purposes. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
24. Optimizing the Recovery of Latent Heat of Condensation from the Flue Gas Stream through the Combustion of Solid Biomass with a High Moisture Content.
- Author
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Kabiesz, Jarosław and Kubica, Robert
- Subjects
- *
HEAT recovery , *BIOMASS burning , *LATENT heat , *RENEWABLE energy sources , *HEAT of combustion , *FLUE gases - Abstract
This study focuses on a specific method of heat recovery in combustion systems especially dedicated to wet biomass. Solid biofuels such as woodchips or bark are sources of renewable energy, a substitute of fossil fuels, of dynamically growing importance due to the energy transformation towards a zero-emission economy. Various solutions are generally known, in particular those based on absorption and compressor heat pumps. The solution presented here eliminates the need for such expensive equipment while maintaining very high efficiency. It involves a system of several suitably configured scrubbers. Chemcad 8 simulation shows how the fluid flow rates affect the efficiency of the proposed solution. Optimal configuration of the system and adjustment of the process parameters (flow rates of water in scrubbers circuits) result in a thermal efficiency as high as 108.2%, close to the maximum theoretically achievable efficiency (111%). The system was compared with other existing solutions for efficiency. The performance of the system was examined under different operating conditions to determine the optimum. The effect of an increased fuel moisture content on efficiency was determined. It was shown that the key to achieving significant cost benefits for such a solution is to optimise the flow rates of the circulating fluids. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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25. Effect of the Addition of Elderberry Waste to Sawdust on the Process of Pelletization and the Quality of Fuel Pellets.
- Author
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Obidziński, Sławomir, Cwalina, Paweł, Kowczyk-Sadowy, Małgorzata, Sienkiewicz, Aneta, Krasowska, Małgorzata, Szyszlak-Bargłowicz, Joanna, Zając, Grzegorz, and Kryński, Rafał
- Subjects
- *
WOOD pellets , *WOOD waste , *FUEL quality , *PELLETIZING , *HEAT of combustion , *WASTE management - Abstract
This paper presents the results of a study on the process of the pelletization of pine sawdust with the addition of herbaceous waste from elderberry, in the working system of a pellet press with a flat matrix, in the context of producing fuel pellets. Based on the research, the impact of the addition of herbal waste in the form of elderberry waste on the granulation process of pine sawdust and the assessment of the quality of the obtained pellets were determined. The addition of herbaceous waste from elderberry to pine sawdust had a beneficial effect on the kinetic durability of the obtained fuel pellets, with an increase of up to approximately 1.3% (from 98.03 to 99.31%). Based on the obtained results, it can be concluded that the mechanical strength of all the tested pellets is higher than 97.5%, which is consistent with the ISO 17225-1:2021-11 standard. The bulk density of pellets with the addition of herbaceous waste from elderberry increased (from 649.34 to 658.50 kg∙m−3) as did their density (from 1231.38 to 1263.90 kg∙m−3). The addition of herbaceous waste from elderberry in amounts ranging from 10% to 20% did not have a significant effect on the power requirements of the pelletizer, which decreased compared to the pelletization process of pure pine sawdust. The percentage of this decrease compared to the pelleting process with pure pine sawdust was approximately 10%. The addition of herbaceous waste from elderberry to pine sawdust slightly reduces the energy value (i.e., the heat of combustion and the calorific value) of the obtained pellets. The addition of 30% elderberry waste resulted in a decrease in the heat of combustion from 20.27 to 19.96 MJ·kgd.m.−1, while the calorific value of the pellets decreased from 19.98 to 18.69 MJ·kgd.m.−1 compared to pine sawdust pellets. Hence, adding herbaceous waste from elderberry seems to be a good way of managing large amounts of waste of this kind generated in herbal processing plants. This method of waste management opens new perspectives towards more sustainable and economically effective energy production. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
26. Fabrication and energy release study of metastable intermolecular composite microspheres with enhanced combustion performance.
- Author
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Chen, Chong, Zhang, Bobo, Lu, Jiaxin, Yang, Yongxia, Liang, Taixin, and Xiao, Fei
- Subjects
- *
METALLIC oxides , *EXOTHERMIC reactions , *FIELD emission electron microscopes , *HEAT of combustion , *COMBUSTION , *FOURIER transform infrared spectroscopy - Abstract
Metastable intermolecular composites (MICs) are often used in military and aerospace applications because of their high energy density. However, the traditional preparation methods are either complicated and unsafe, or the prepared composites have incomplete combustion and low energy release rates. In this paper, a series of aluminum/metal oxide/nitrocellulose (AM x N) composite microspheres were prepared by spray drying technique. The field emission scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) results show that the prepared AM x N composite microspheres have regular morphology and uniform particle size, and nitrocellulose (NC) is successfully coated between fuel (Al) and oxidizers (CuO, MoO 3 , and Bi 2 O 3). The thermal reactivity, energy, and combustion properties of AM x N were investigated and compared with physically mixed aluminum/metal oxide (AM x). The explosion heat of AM x N is higher than AM x , while the thermal reaction exothermic peak temperature is lower. Among them, the composite containing copper oxide has the highest explosive heat value (5034 J/g), and the composite containing bismuth oxide has the shortest burning time (2.8 ms). These results prove that NC as a binder shortens the reaction distance between the oxidizer and the fuel in the presence of spray drying. Different oxidizers can modulate the energy release rate of AM x N composites, which is beneficial for applying MICs in energetic materials. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
27. Large Eddy simulation of the effects of radiative heat loss on combustion instability prediction.
- Author
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Lee, Jongkwon, Jun, Daeyoung, Chun, Byoungjoo, Mousavi, S Mahmood, Lee, Bok Jik, and Faroughi, Salah A.
- Subjects
- *
HEAT losses , *LARGE eddy simulation models , *HEAT of combustion , *ADIABATIC temperature , *ISOTHERMAL temperature , *ISOTHERMAL flows - Abstract
This study examined the influence of various chemical reaction mechanisms and heat loss conditions on the prediction of longitudinal combustion instability in the Continuous Variable Resonance Combustor (CVRC). To assess the impact of chemical reaction mechanisms on the prediction of longitudinal combustion instability modes, both global and skeletal mechanisms were used, while adiabatic wall conditions were employed to eliminate the effects of heat loss. To evaluate the effect of heat loss conditions on the prediction of combustion instability modes, investigations were conducted under three different conditions: adiabatic wall, isothermal wall, and considering thermal radiation using the simple P1 model and the gray gas model. Radiative heat loss was calculated using a radiative convection boundary condition, while heat loss through wall convection was ignored. The dominant frequency, temperature field, pressure field, and combustion instability development mechanism were analyzed based on the numerical results and compared with experimental data and previous numerical studies. The use of a skeletal mechanism and the consideration of heat loss were found to reduce the difference in combustion instability mode frequency compared to experimental data. The results showed that maintaining an isothermal wall temperature effectively decreased the difference in the dominant frequency compared to experiments, but had limitations in reducing pressure fluctuation amplitudes. Additionally, incorporating thermal radiation did not significantly decrease the difference in the first mode frequency compared to experimental data, although it kept the range of pressure fluctuations within a reasonable level. Therefore, this study underscores the importance of accurate temperature prediction for evaluating thermal-acoustic instability frequencies and highlights the necessity of using a chemical reaction mechanism that accurately predicts the adiabatic flame temperature and heat loss conditions. • We investigated the impact of modeling choices on the prediction of instability. • Global and skeletal reaction mechanisms overestimated instability frequencies. • Radiative heat loss was found negligible for temperatures under 2500 K. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
28. Feasibility of Using Combustion-Based Methods to Quantify Saline-Based Anti-Stripping Agent in Modified Asphalt Binders.
- Author
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Riyad, Riyadul Hashem, Wu, Ji, and Shen, Junan
- Subjects
- *
HEAT of combustion , *ASPHALT , *TEST methods , *SELF-propagating high-temperature synthesis - Abstract
"Anti-stripping Agents" or "adhesion promoters" can enhance the chemical affinity between asphalt and aggregate by increasing their mutual attraction. Various forms of anti-stripping agents have been proposed to mitigate pavement stripping, and siloxane-based Zychotherm is one of them. Choosing the appropriate type and dose of anti-stripping additives is no doubt vital to the intended performance. Therefore, it is critically important to determine the dose of the additives used in the modification of asphalt binders. This research developed a feasible detection method that can closely measure the dose (0.05% and 0.1%) of siloxane-based anti-stripping liquid agents. Related test methods, including heat combustion test, residue visualization, burning, and ignition, were implemented. The heat combustion results showed that with the addition of the Zychotherm anti-stripping additive, the average heat combustion value decreased by 1.34% and 1.72% for 0.05% and 0.1% Zychotherm-modified binder, respectively. In the burning and ignition process, the modified binder left yellowish substances in the residue, which is an indication of the presence of Zychotherm. The weight of the yellowish residue related more to the quantity of Zychotherm in the asphalt binder. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
29. EXPERIMENTAL INVESTIGATION OF THE EFFECT OF ALTITUDE ON EFFICIENCY AND EMISSIONS OF A DIESEL ENGINE.
- Author
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Zhipeng LI, Qiang ZHANG, Fujun ZHANG, and Hongbo LIANG
- Subjects
- *
DIESEL motors , *DIESEL motor exhaust gas , *EXHAUST gas recirculation , *DIESEL motor combustion , *HEAT release rates , *COMBUSTION efficiency , *HEAT of combustion - Abstract
The Diesel engine is expected to be available for operation at high altitude. However, power loss and emission deterioration have been plaguing highland Diesel engines. Therefore, this study aimed to investigate the impact of altitude on the performance and combustion characteristics of Diesel engines that is limited discussed in existing studies. The research was conducted by varying the altitude from 0-4500 m using a research Diesel engine and analyzing the combustion characteristics at different combustion phases with the help of triple Wiebe function. The results indicated a noticeable drop in power output with increasing altitude, and the deterioration of performance and emissions became significant when the altitude exceeded 3000 m. Specifically, the indicated specific CO, unburned hydrocarbon, and soot emissions increased while nitrogen NOx showed a reverse trend. Additionally, it was found that the lower cylinder pressure at high altitude extended the ignition delay and caused a higher heat release rate in the premixed combustion stage. Moreover, the high altitude condition shortened the duration of combustion and reduced the energy release fraction in the diffusion phase. Furthermore, the late combustion phase occurred earlier and lasted longer at high altitude, which consequently reduced the combustion and thermal efficiency. The most important finding is that the engine performance, especially the combustion efficiency, shows an abrupt degradation with altitudes above 3000 m. As a result, engines operating at extremely high altitudes require multi-stage turbocharging to compensate for combustion deterioration. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
30. Use of hydrogen fuel for mobile internal combustion engines.
- Author
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Parlyuk, Ekaterina, Zanko, Mikhail, and Guzalov, Artembek
- Subjects
- *
INTERNAL combustion engines , *HEAT of combustion , *ALTERNATIVE fuels , *SPECIFIC heat , *ENGINE testing , *HYDROGEN as fuel - Abstract
The article deals with the issue of using hydrogen fuel for an internal combustion engine. Interest in this alternative fuel is due not only to environmental friendliness, availability and renewability of the resource, but also to the specific heat of combustion of hydrogen. A list of the main optimization problems solved in the process of research based on the methods of statistical processing of the results of the experiment and modeling of the workflow is formulated. The results of computational studies are presented, based on the main design parameters of the engine (cycle, type, working volume, number of cylinders), as well as on regime parameters (power, speed). To ensure the required characteristics of the hydrogen-air mixture based on a commercially available carburetor, a developed engine power system is presented, which provides the ability to operate the engine on hydrogen. The results of comparative tests of the VAZ-2101 engine when running on hydrogen are also presented. In conclusion the main conclusions of the study are given as well as prospects for further research. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
31. Influences of ambient temperature, injection pressure and spray characteristics on ignition delay and combustion process of palm oil and waste cooking oil.
- Author
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Nursal, Ridwan Saputra, Jaat, Norrizam, Khalid, Amir, Ishak, Izuan Amin, Abidin, Shaiful Fadzil Zainal, Manshoor, Bukhari, and Samion, Syahrullail
- Subjects
- *
EDIBLE fats & oils , *HEAT of combustion , *COMBUSTION , *BIODIESEL fuels , *ALTERNATIVE fuels , *POLLUTION , *SPRAYING & dusting in agriculture - Abstract
Alternative fuels have been explored for the substitution of diesel to lessen dependence on fossil fuel and to mitigate environmental pollution. Opted on biodiesel seem like promising due to its availability and regenerability, as well as ability to lower emissions. The objective of this research is to investigate the effects of ambient temperature, injection characterirics and spray characteristics on ignition delay and combustion process of biodiesel blends derived from palm oil and waste cooking oil. The ignition delay and combustion were observed using a rapid compression machine with ambient temperatures ranging from 850 K to 1050 K and injection pressure ranging from 80 MPa to 130 MPa. Palm and waste cooking oil biodiesel blends fuel were produced by blending these oils with Euro5 pure diesel at concentration of 5vol%, 10vol% and 15vol% correspondingly. Higher injection pressure and higher ambient temperature have been found to significantly reduce the ignition delay and influences to the heat recovery of combustion, while the higher biodiesel blending concentration of biodiesel promotes the reduction of CO emissions. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
32. Techno-economic analysis of coal leaching processes to produce ultra clean coal.
- Author
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Karim, Abdul Rahman Marwis, Nurani, Indah, Lestari, Tiva Putri Tri, Wintoko, Joko, and Azis, Muhammad Mufti
- Subjects
- *
CLEAN coal technologies , *LEACHING , *HEAT of combustion , *COAL , *COAL combustion , *FLY ash - Abstract
Coal is the largest energy source in the world. However, coal combustion is also the largest source of CO2 emission that is the main cause of global warming. Indonesia consumed 1 million terajoule of energy from coal in 2020. There are no energy sources that consumed more than coal except light petroleum products. Coal combustion to produce energy emitted SOX, NOX, COX, and fly ashes to the environment and also cause corrosion and clogging to industrial equipment. Sulfur content in the coal produces SOX, meanwhile mineral content becomes fly ashes. Therefore, sulfur and mineral content should be reduced before combustion. Chemical leaching is the way to demineralize and desulfurize coal. Numerous researchers have studied the process to produce ultra clean coal (UCC) that limited the mineral content and sulfur content to less than 1 wt.% so it can decrease the adverse effects when it is used as an energy resource in combustion. Various processes such as acid leaching, alkali leaching, peroxide leaching or even acid-alkali leaching have been studied by several researchers. These methods are considered high-cost in regards to the high price of chemicals despite their technical feasibility to produce UCC. Therefore, it is important to conduct economic analysis of the processes. This paper presents techno-economic analysis to compare several leaching processes in order to study their technical and economic feasibility. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. Modeling of physico-chemical processes in the combustion chamber of gas diesel.
- Author
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Lopatin, O. P.
- Subjects
- *
COMBUSTION chambers , *COMBUSTION gases , *GAS chambers , *HEAT of combustion , *CHEMICAL kinetics , *DIFFUSION , *TURBULENT shear flow - Abstract
The mixing processes obey the laws of molecular and turbulent diffusion. It is obvious that the total duration of the kinetic combustion process (CP) is determined by a combination of thermal and chemical factors and obeys, with known limitations, the laws of chemical kinetics. Consideration of the basic laws of the diffusion processes and the establishment of ways to intensify or inhibit them makes it possible to purposefully influence the conditions of mixing gas with air. The brief information given in the paper about the features of the emission of gas flares is not intended to equip readers with methods for calculating heat transfer in the combustion chamber (CC) of gas diesel (GD), but only help to correctly understand and evaluate the factors that determine the radiation characteristics of the torch. It is shown that the intensity of turbulent diffusion is immeasurably higher than that of molecular diffusion, since the scale of turbulence is tens and hundreds of thousands of times greater than the path length of the molecule. The final mixing process in turbulent diffusion is molecular diffusion. The determining values of these processes are revealed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
34. In situ growth of Ag nanoparticles on the surface of MXene by γ -ray irradiation to fabricate EVA composite: the improvement of flame retardancy, smoke suppression, and mechanical properties.
- Author
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Xu, Siyi, Li, Danyi, Wang, Wenrui, Lin, Lin, Sun, Ying, Li, Jihao, and Li, Linfan
- Subjects
- *
FLAMMABILITY , *FIREPROOFING , *ENTHALPY , *VINYL acetate , *HEAT of combustion , *SMOKE , *ETHYLENE-vinyl acetate , *FIRE resistant polymers - Abstract
A large amount of toxic smoke and heat generated by the combustion of ethylene vinyl acetate copolymer (EVA) poses a significant threat to human fire escape evacuation. This work aims to use γ -ray to prepare e-MXene@Ag hybrid flame-retardant materials by the method of in-situ reduction, and EVA composites are prepared by melt blending to reduce the smoke and toxic gases produced during combustion significantly. Compared with pure EVA, the total heat release, total smoke release, and the production rate of CO and CO2 produced by the combustion of EVA composite with 1 wt% e-MXene@Ag1.0 decreased by 30.3%, 33.3%, 18.2%, and 20.1% respectively. The fire hazard reduction of EVA composite materials was due to the physical barrier, catalytic carbonization and adsorption of the e-MXene@Ag1.0 hybrid. In addition, e-MXene@Ag1.0 can also further increase the mechanical properties of EVA composites due to its own 'multi-contact point limit structure'. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
35. Carbon emission efficiency of China's construction industry based on super-efficiency SBM and Tobit model.
- Author
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Xu, Yebiao
- Subjects
- *
CARBON emissions , *TOBITS , *ENERGY consumption , *CONSTRUCTION industry , *GLOBAL warming , *HEAT of combustion - Abstract
Global warming is one of the key issues attracting international concern. The carbon dioxide emission produced by energy combustion is the main cause of the greenhouse effect, and reducing carbon emissions is considered the most effective way to deal with the greenhouse effect. The extensive production mode characterized by high energy consumption, high emission, and low efficiency in China's construction industry intensifies the contradiction between economic development and resources and the environment, and the growth under this mode is at the expense of consuming a lot of resources and energy. The improvement of carbon emission efficiency is an effective means of achieving the goal of economic growth and carbon emission reduction simultaneously, making it necessary to accurately measure the carbon emission efficiency of the construction industry in each province, determine the influencing factors, and formulate reasonable emission reduction policies for this industry. In this study, an input-output index system of carbon emission efficiency of China's construction industry was constructed, the carbon emission efficiency of the construction industry in each province was evaluated using the super-efficiency SBM model, and the factors affecting the carbon emission efficiency of this industry were analyzed via the Tobit model. The results showed that the average value of carbon emission efficiency of the construction industry generally showed a rising trend in a fluctuating way during the study period. From 2014 to 2022, the average carbon emission efficiency of the national construction industry presented an upward trend, from 1.122 in 2014 to 1.148 in 2022; the regional economic level (p = 0.020 < 0.05) and human capital level (p = 0.000 < 0.01) exerted obvious promoting effects on the carbon emission efficiency of China's construction industry, while the urbanization development (p = 0.049 < 0.05) generated evident negative effects on carbon emission efficiency of this industry. The research results have important reference values for making cross-provincial emission reduction plans for the construction industry, promoting its carbon emission efficiency, and driving the research and development of green building materials and clean energy. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
36. A comprehensive study of melt foaming in E‐glass batch‐to‐melt conversion process: Effects of sulfate content and chemistry of raw materials.
- Author
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Demirok, Gülin, Li, Hong, and Solak, Nuri
- Subjects
- *
FOAM , *RAW materials , *SULFATE pulping process , *HEAT of combustion , *FUSED silica , *ANALYTICAL chemistry - Abstract
Control of sulfate‐induced melt fining without excessive foaming is one of the critical steps in maintaining the stability of E‐glass fiber manufacturing processes. Besides, the efficiency of combustion or energy utilization is directly affected by the extent of the melt‐foaming. A fundamental understanding of key factors affecting melt foaming under the simulated oxy‐fuel combustion environment will enable commercial E‐glass fiber production to optimize both batch chemistry and operation conditions to achieve adequate furnace control. In this study, six types of E‐glass batches with the same target glass composition were prepared by using four different CaO sources; calcined limes with different SO3 contents, limestone, limestone with sodium sulfate, and a mixture of limestone and calcined lime. All batch samples were examined by HTMOS‐EGA system (high temperature melting observation system with evolved gas analysis). HTMOS enables monitoring batch‐to‐melt conversation steps by using a high‐resolution camera and EGA detects the evolved reaction gaseous, such as CO, CO2, and SO2 via an Fourier transform infrared (FTIR) gas analyzer. Gases of water vapor, N2, and O2 were introduced accordingly into the fused quartz crucible to simulate similar oxy‐fuel atmosphere of the furnace operation. This study aimed to investigate the effects of different SO3 contents in batches and different raw material chemistries on the foam formation in E‐glass melts under the oxy‐fuel atmosphere. Different raw materials were characterized by mineralogical analysis, chemical analysis, particle size distribution, chemical oxygen demanding (COD) level, and Brunauer–Emmett–Teller (BET) analysis. Although some of the batches contained the same SO3 content, different foam formations resulted from the effect of the batch chemistry. Our detailed HTMOS‐EGA investigations show that not only SO3 content in the batch affects foam formation in E‐glass melts, but also raw material chemistry and particle size have strong effects on the melt foaming in E‐glass batch melting, especially for those of ingredients having hydroxide phases and/or finer particles with higher specific areas. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. Improving the energy effectivity of biomass drying for utilisation in energy systems by combining convective and contact drying.
- Author
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Havlík, Jan and Dlouhý, Tomáš
- Subjects
- *
BIOMASS energy , *WOOD chips , *BIOMASS burning , *HEAT of combustion , *ENERGY consumption , *WASTE heat - Abstract
The article deals with reducing the energy consumption of biomass drying before combustion in energy plants. The combination of traditionally used convective hot air drying and less applies contact drying is analyzed. To determine the basic drying characteristics, the experiments on a contact dryer and a convective hot air dryer were carried out with wet wood chips. A heat balance model of a system with serial connection of a convective air dryer and a contact dryer was compiled. In the model, the utilization of condensation heat from the waste vapor leaving contact drying to preheat the drying air for convective drying was considered. Based on these results, the system could be optimized to achieve the lowest energy consumption, drying time, and dryer sizing. This solution can significantly improve the energy efficiency of drying moist biomass before combustion from 3.29 and 2.76 MJ per kg of evaporated water for only convective drying and only contact drying, respectively, to 1.48 or 1.33 MJ per kg of evaporated water, depending on the order of the dryers in their connection. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
38. Heat release and flame scale effects on turbulence dynamics in confined premixed flows.
- Author
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Fortin, Max K., Morales, Anthony J., Tonarely, Michael E., Genova, Tommy, and Ahmed, Kareem A.
- Subjects
- *
FLAME , *PLANAR laser-induced fluorescence , *TURBULENCE , *PARTICLE image velocimetry , *HEAT of combustion , *RENEWABLE energy transition (Government policy) - Abstract
As industry transitions to a net-zero carbon future, turbulent premixed combustion will remain an integral process for power generating gas turbines, aviation engines, and high-speed propulsion due to their ability to minimize pollutant emissions. However, accurately predicting the behavior of a turbulent reacting flow field remains a challenge. To better understand the dynamics of premixed reacting flows, this study experimentally investigates the effects of combustion heat release and flame scales on the evolution of turbulence in a high-speed, confined bluff-body combustor. The combustor is operated across a range of equivalence ratios from 0.7 to 1 to isolate the role of chemical heat release, flame speed, and flame thickness on the evolution of turbulence as the flow progresses from reactants to products. High-speed particle image velocimetry and CH* chemiluminescence imaging systems are simultaneously employed to quantify turbulent flame and flow dynamics. The results notably demonstrate that the flame augments turbulence fluctuations as the flow evolves from reactants to products for all cases, which opposes most simulations of premixed turbulent reactions. Notably, turbulence fluctuations increase monotonically with the heat of combustion and corresponding turbulent flame speed. Spatial profiles of turbulence statistics are conditioned on the mean flame front, and nondimensionalizing the turbulence profiles using laminar flame properties is shown to collapse all conditions onto a single curve. The resulting nondimensional profile confirms that turbulence dynamics scales with the heat of combustion and was used to develop a novel correlation to predict the increase in turbulent fluctuations across the premixed flame. A Reynolds averaged Navier Stokes decomposition is also explored to further characterize the effects of combustion heat release on the dominant mechanisms of turbulent energy transport. The cumulative results can guide modeling capabilities to better predict flame and flow dynamics and accelerate design strategies for premixed turbines with carbon-free fuels. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
39. The Impact of Soil Contamination with Lead on the Biomass of Maize Intended for Energy Purposes, and the Biochemical and Physicochemical Properties of the Soil.
- Author
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Wyszkowska, Jadwiga, Boros-Lajszner, Edyta, and Kucharski, Jan
- Subjects
- *
SOIL pollution , *LEAD in soils , *HEAT of combustion , *SOILS , *BIOMASS , *CORN - Abstract
The subject of our research was to assess the suitability of maize grown in lead-contaminated soil for energy purposes. Lead is toxic to the natural environment. Therefore, the recultivation of soil polluted with this element is very important in stabilizing the natural environment. In the present research, maize was used as a remediating plant, and its effects were enhanced by soil fertilization with biocompost and biochar. The aim of the research was to determine the influence of Pb2+ on maize biomass, its combustion heat and heating value, and the biochemical and physicochemical properties of the soil. It was accomplished in a pot experiment by testing the effects of 800 mg Pb2+ kg−1 d.m. soil and biocompost and biochar applied of 20 g kg−1 d.m. soil. Lead was found to drastically deteriorate soil quality, which reduced the biomass of maize. Lead negatively affected the activity of the soil enzymes tested and modified the physicochemical properties of the soil. Fertilization with biocompost and biochar mitigated lead-induced interference with soil enzymatic activity. The applied biocomponents also had positive effects on the chemical and physicochemical properties of the soil. Maize cultivated on lead-polluted soil did not lose its energetic properties. The heating value of maize was stable, which shows its potential in the recultivation of lead-contaminated soils. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. The Research and Development of a Jet Disturbance Combustion System for Heavy-Duty Diesel Engines.
- Author
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Liu, Yize, Su, Wanhua, Wu, Binyang, and Wang, Jiayong
- Subjects
- *
DIESEL motors , *HEAT release rates , *HEAT of combustion , *COMBUSTION , *COMBUSTION chambers , *THERMAL efficiency - Abstract
Herein, a diesel engine jet disturbance combustion system was proposed to achieve efficient and clean combustion under heavy load conditions in heavy-duty diesel engines. The key components of the combustion system were designed, and a research platform was constructed. Focusing on the internal combustion conditions of the disturbance chamber and the developmental path of high-speed jets, the design and comprehensive optimization of the jet disturbance combustion system were carried out. Following optimization, the peak internal heat release rate increased from 86 J/deg to 269 J/deg, and the cumulative heat release increased by 112 J, significantly enhancing the energy of the disturbance chamber jet. Then, considering combustion optimization and the heat transfer loss from the piston, it was determined that the optimal configuration for the disturbance chamber jet channel angles was 60 deg inter-channel angle and 10 deg channel incidence angle. This configuration allowed the disturbance chamber jet to precisely disturb the concentrated mixture area in the middle and late stages of combustion. The intervention of the disturbance chamber jet provided sufficient energy for the fuel–air mixing process and complicated the gas flow state in the main combustion chamber. Despite its low-momentum density, the residual mixture in the cylinder maintained a high mixing rate after the end of the fuel injection process. Single-cylinder engine test results showed that a diesel engine using this jet disturbance system and a 180 MPa common rail pressure fuel system achieved 52.12% thermal efficiency. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. Study on the evolution of thermal behaviour of dry and wet ageing wood with ageing degrees.
- Author
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Song, Jia-jia, Zhao, Jing-yu, Deng, Jun, Lu, Shi-ping, Hang, Gai, Ming, Han-qi, Zhang, Yan-ni, and Shu, Chi-Min
- Subjects
- *
WOOD chemistry , *WOOD , *WOOD combustion , *HEAT of combustion , *SCANNING electron microscopy , *ACTIVATION energy - Abstract
Owing to the serious natural ageing phenomenon of ancient wooden buildings, to better explore the effect of drying and wet ageing degree on the exothermic behaviour of wood combustion, firstly, wood treated with different degrees of dry and wet ageings was obtained by artificially accelerating the dry and wet ageing method. The pore characteristics, along with the capacity of the heat transport of wood treated and wood combustion heat flow with different dry and wet ageing degrees, were analysed by scanning electron microscopy, thermophysical property, and thermal analysis test. Finally, according to Friedman's differential equivalent conversion method, the reaction process of the distribution of apparent activation energy of wood in various exothermic stages was computed and appraised, revealing the mechanism of the effect of the wood treated with dry and wet ageings on thermal reaction process. In the accelerated exothermic stage, the initial dry and wet ageing process (10 to 30 times) led to the opposite change in the trend of the apparent activation energy of wood and the fresh wood as a whole. The effect of the dry and wet ageings on the energy demand of the oxidation reaction at the end of prompt exothermic stage could decrease with the deepening of the ageing degree. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
42. Experimental investigation on the combustion phenomena and heat transfer mechanism of ethanol spill fire with different initial fuel temperatures.
- Author
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Ye, Chenghao, Hu, Xuejing, Xia, Meiqing, Li, Jiaxing, and Zhang, Peihong
- Subjects
- *
HEAT of combustion , *HEAT transfer , *ETHANOL , *FLAME temperature , *FREQUENCIES of oscillating systems , *TEMPERATURE , *HIGH temperatures - Abstract
The process of fluid diffusion and fire dynamics in spill fires at different initial temperatures is unstable and complex, potentially leading to severe consequences. Through a series of experiments, the effects of initial fuel temperature on the combustion mechanism of ethanol spill fire were investigated. The results show that in the liquid-phase control stage, the propagation of the spill fire is greatly affected by the liquid spread, and the increasing rate of combustion area (IRCA) and the maximum combustion area (MCA) gradually increase with the increase in the initial temperature. In the gas-phase control stage, the propagation of spill fire is greatly affected by the combustion of liquid, as initial temperature increase, the IRCA and MCA gradually decrease. The increase in the initial temperature will lead to the attenuation of the pulsation phenomenon during the propagation of the flame, but will lead to the frequency of flame oscillation increases. The prediction equations of burning rate at different initial fuel temperatures are established, which show that there is a significant difference in burning rate in the liquid-phase control stage, the maximum increase in the burning rate was only 2.3%, while in the gas-phase control stage, this value is about 50%. The convective feedback is the main heat feedback mechanism of small spillage fires, and the convective feedback accounts for more than 62.5%. The higher the initial temperature, the stronger the convective feedback mechanism. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. Exergy destruction behavior of chemical reactions during the auto-ignition of methane doped with hydrogen.
- Author
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Wu, Honghuan, Liu, Yuncong, Sun, Wuchuan, Huang, Zuohua, and Zhang, Yingjia
- Subjects
- *
ENDOTHERMIC reactions , *CHEMICAL reactions , *EXERGY , *HEAT of combustion , *COMBUSTION kinetics , *METHANE - Abstract
Chemical reaction is the major source of combustion irreversibility in premixed conditions, and revealing the details of exergy destruction can provide a more essential perspective on exploring high-efficiency combustion strategies. The present study focuses on the homogeneous combustion process of CH 4 /H 2 /air mixtures, aiming to reveal the exergy destruction behavior of chemical reactions from the viewpoint of different combustion stages and oxidation paths. Results indicate that exergy destruction is mainly accumulated in the ignition delay stage, and the exergy destruction caused by different elementary reactions depends on the temperature at which the reaction takes place and the resulting change of free energy. By dividing the chemical reactions into four groups, the main reaction channels that contribute to the change in exergy destruction with combustion boundaries have been identified. Global reaction flux analysis reveals the effect mechanism of different oxidation paths on exergy destruction. Furthermore, the staged combustion concept with endothermic reactions reacting firstly at lower temperatures followed by dilute combustion in the high-temperature heat release stage is discussed from the point of the exergy destruction evolution, which offers the potential to simultaneously reduce exergy destruction and suppress NO x formation. • Exergy destruction depends on the reaction temperature and free energy change. • The chemical reactions are classified into four groups. • Exergy destruction is significantly affected by the reaction paths. • H 2 addition effectively broadens the area of low exergy destruction. • A staged combustion concept for reducing combustion irreversibility is explored. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Enhancing soot oxidation using microtextured surfaces.
- Author
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Oren, Oz, McTaggart-Cowan, Gordon, and Khan, Sami
- Subjects
- *
SOOT , *BIOMASS burning , *X-ray photoelectron spectroscopy , *HEAT of combustion , *LASER ablation - Abstract
Biomass combustion provides energy needs for millions of people worldwide. However, soot accumulation on the combustors' walls significantly reduces heat transfer efficiency. Herein, we demonstrate how microtextured surfaces minimize soot accumulation by enhancing soot oxidation. We investigate soot layers from the combustion of paraffin wax as a model for wood-based soot, and find that randomly microtextured glass obtained by sandblasting shows a 71% reduction in the time taken to oxidize 90% of surface soot coverage when compared to smooth glass at 530 °C. We also study grooved microtextures fabricated via laser ablation and find that grooves with widths between 15 and 50 µm enhance soot oxidation, while the expedited advantage is lost when the groove width is 85 µm. X-ray photoelectron spectroscopy validates the superior extent of soot removal on microtextures down to a sub-nanometer length-scale. The high density of sharp features such as peaks and edges on microtextures, and the conformality of the soot layer to the microtextures contribute to increased soot oxidation. We also demonstrate enhanced soot oxidation on microtextured stainless steel, the principal material of construction in biomass combustors. Microtextured surfaces that facilitate soot oxidation upon contact could significantly improve performance and longevity in various combustion applications. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
45. Biological production of hydrogen: From basic principles to the latest advances in process improvement.
- Author
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Ivanenko, A.A., Laikova, A.A., Zhuravleva, E.A., Shekhurdina, S.V., Vishnyakova, A.V., Kovalev, A.A., Kovalev, D.A., Trchounian, K.A., and Litti, Y.V.
- Subjects
- *
HYDROGEN production , *HEAT of combustion , *ORGANIC wastes , *HYDROGEN as fuel , *SOLAR energy , *FOSSIL fuels - Abstract
The development of net-zero emission fuels is a priority area of modern research due to the imminent reduction of fossil fuel reserves and environmental problems caused by their combustion. One of the promising fuels is hydrogen, which has a high heat of combustion and is eco-friendly, forms water as the only byproduct. Recently, methods of hydrogen production by microorganisms, which use directly the solar energy or utilize the organic waste during fermentation, have been intensively developed and applied. In this review, the basic principles of the main light-dependent (biophotolysis, photofermentation) and light-independent (dark fermentation and microbial electrolysis) methods of biological hydrogen production are discussed. Particular attention is paid to the advantages and disadvantages of these methods, the possibility of combining them into a single system, as well as various strategies for improving biohydrogen production aimed at transition from laboratory research to full-scale application. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. An Opportunity for Coal Thermal Power Plants Facing Phase-Out: Case of the Power Plant Vojany (Slovakia).
- Author
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Stričík, Michal, Kuhnová, Lenka, Variny, Miroslav, Szaryszová, Petra, Kršák, Branislav, and Štrba, Ľubomír
- Subjects
- *
POWER plants , *STEAM power plants , *ALTERNATIVE fuels , *THERMAL coal , *CLEAN energy , *HEAT of combustion , *ECONOMIC efficiency - Abstract
The study deals with the possibilities of using alternative types of fuels to produce electricity. Power Plant Vojany (PPV) is a thermal power plant (TPP) in eastern Slovakia, which is part of the company Slovenské elektrárne, a. s. (SE). PPV primarily used black coal to produce electricity, which had to be imported from abroad (the Russian Federation). This activity has become inefficient both economically and environmentally, due to the high price of CO2 permits and the high emission factor of this type of fuel. PPV decided to co-combust biomass and refuse-derived fuel (RDF), which resulted in much better economic conditions due to their price, economic efficiency, and partly closed CO2 cycle. The aim of the paper is to explore the possibilities related to the production of energy in the cleanest possible way and with the least possible damage to the environment in coal thermal power plants using the example of operating Power Plant Vojany located in eastern part of Slovakia and to inspire each other for the modern transformation. For the purposes of hypothesis verification, analytical methods focused on overview studies of average fuel prices, comparisons, and the balance of fuels in connection with eliminated CO2 emissions, as well as municipal waste (MW) management in the EU and V4 countries, were used. The authors also focused on the energy recovery and combustion of MW and tracking the achieved CO2 savings in connection with the development of fuel sources in PPV. The results point to the fact that PPV is one of the power plants that could use biomass and RDF as fuel, which confirms the economic advantages of this procedure. The results confirm that the potential of RDF production in Slovakia is sufficient to ensure the operation of PPV at planned, even higher volumes of electricity production. The transformation to cleaner operation of coal thermal power plants represents a significant contribution of this study. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
47. Characteristics of spray and combustion in gas-centered swirl coaxial injector with varying gas nozzle diameter.
- Author
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Lee, Jungho, Woo, Seongphil, Lee, Ingyu, Han, Yeoungmin, and Yoon, Youngbin
- Subjects
- *
SPRAY combustion , *PROPELLANTS , *COMBUSTION chambers , *HEAT of combustion , *INJECTORS , *ROCKET engines - Abstract
Gas-centered swirl coaxial (GCSC) injectors, a type used in the combustion chamber of liquid rocket engines, have been widely investigated because their characteristics are key parameters for the performance of the engine. This study investigated the spray and combustion characteristics of GCSC injectors used in the combustion chamber of oxidizer-rich staged-combustion cycle engines. When the propellant mass flow rate and oxidizer-to-fuel mass flow ratio (O/F ratio) were identical, the diameter of the gas nozzle was changed such that the ratio of the gas-to-liquid momentum could be changed; thus, the swirl strength of the liquid also changed because of the increase in the injector diameter. In the spray experiments, the spray characteristics were identified in accordance with changes in the diameter of the gas nozzle through the spray angle, droplet mean velocity, and droplet size by using backlight photography and the ParticleMaster imaging system. For combustion tests, four types of reduced combustion chambers were designed to spray propellants through the same two injectors used in the spray experiments. To generate an oxidizer-rich combustion gas, combustion tests were performed using a pre-burner. The changes in combustion characteristics according to the change in the injector shape under the same combustion chamber shape, propellant flow rate, and O/F ratio were identified through the characteristic velocity and heat flux of the combustion chamber. As the gas–liquid momentum flux ratio increased in accordance with the change in diameter of the gas nozzle, the characteristic velocity increased from at least 1700 m/s to a maximum of 1721 m/s, which was related to the decrease in the Sauter mean diameter observed in the spray experiments. Few studies have investigated GCSC shape variables by simultaneously conducting atmospheric spray experiments and high-pressure combustion tests on GCSC injectors using kerosene and oxidizer-rich combustion gases as propellants. This study observed the changes in spray characteristics according to the change in the diameter of the injector gas nozzle through atmospheric spray experiments of the GCSC injector and compared and analyzed the combustion characteristics through combustion tests using the same injector. The results of this study will potentially aid the design optimization of GCSC injectors and facilitate future developments. • Gas-centered swirl coaxial (GCSC) injector spray, combustion characteristics studied. • These are used in oxidizer-rich staged combustion cycle engine combustion chambers. • Atmospheric spray experiments and combustion performed. • Results can aid design optimization of GCSC injectors and future developments. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
48. Activation Energy of Hydrogen–Methane Mixtures.
- Author
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Moroshkina, Anastasia, Ponomareva, Alina, Mislavskii, Vladimir, Sereshchenko, Evgeniy, Gubernov, Vladimir, Bykov, Viatcheslav, and Minaev, Sergey
- Subjects
- *
BURNING velocity , *LEAN combustion , *HEAT of combustion , *MIXTURES , *DEBYE temperatures , *COMBUSTION kinetics , *ACTIVATION energy - Abstract
In this work, the overall activation energy of the combustion of lean hydrogen–methane–air mixtures (equivalence ratio φ = 0.7−1.0 and hydrogen fraction in methane α = 0 , 2, 4) is experimentally determined using thin-filament pyrometry of flames stabilised on a flat porous burner under normal conditions ( p = 1 bar, T = 20 °C). The experimental data are compared with numerical calculations within the detailed reaction mechanism GRI3.0 and both approaches confirm the linear correlation between mass flow rate and inverse flame temperature predicted in the theory. An analysis of the numerical and experimental data shows that, in the limit of lean hydrogen–methane–air mixtures, the activation energy approaches a constant value, which is not sensitive to the addition of hydrogen to methane. The mass flow rate for a freely propagating flame and, thus, the laminar burning velocity, are measured for mixtures with different hydrogen contents. This mass flow rate, scaled over the characteristic temperature dependence of the laminar burning velocity for a one-step reaction mechanism, is found and it can also be used in order to estimate the parameters of the overall reaction mechanisms. Such reaction mechanisms will find implementation in the numerical simulation of practical combustion devices with complex flows and geometries. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
49. Comparison of three arrangements of internal combustion engine-driven energy systems boosted with PEM fuel cell towards net-zero energy systems.
- Author
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Mansir, Ibrahim B., Ali, Amjad, Musharavati, Farayi, Farouk, Naeim, Hadj-Taieb, Lamjed, and Nguyen, Din Duc
- Subjects
- *
PROTON exchange membrane fuel cells , *HEAT of combustion , *FUEL cells , *THERMOELECTRIC generators , *INTERNAL combustion engines , *KALINA cycle , *HIGH performance computing - Abstract
The current works aim is performance improvement of different integrated energy systems towards net-zero energy which is driven by a set of Internal Combustion Engine (ICE) through adding some components like fuel cell and thermoelectric generator (TEG) in new arrangements introduced and analyzed. The novelty of the present work is the proposal of the new arrangement of energy conversion systems. In this study the basic cycle (cycle 1) is including an ICE, Kalina cycle, Humidification and Dehumidification (HDH) unit, in cycle 2, the HDH is eliminated while a fuel cell is added to the system and in the cycle 3, in addition to fuel cell and having HDH unit in the system, a thermoelectric generator (TEG) has been used instead of condenser to recover more wasted thermal energy. The performance of all proposed systems is analyzed from energy, exergy, and exergo-economic aspects. It is demonstrated that from an energetic viewpoint, cycle 3 has the better performance with an energy efficiency, and net output power of 37% and 391.7 kW, respectively. That is while from an exergetic viewpoint cycle 2 with exergy destruction of 257.1 kW has superior exergetic performance. The results of current work can provide a precise basis for designing an efficient energy system with a higher thermal performance. • Performance of different integrated energy systems towards net-zero energy. • Cycle components are ICE, HDH unit, Fuel cell, Thermoelectric generator. • From energetic viewpoint, cycle 3 has the better performance. • From exergetic viewpoint, cycle 2 has superior exergetic performance. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
50. Numerical investigation of the effect of reactive gas jets on the flame acceleration and DDT process.
- Author
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Wang, Jiabao, Zhao, Xinyu, Pan, Jianfeng, and Zhu, Yuejin
- Subjects
- *
HEAT of combustion , *FLAME , *DUST explosions , *RADIO jets (Astrophysics) , *GASES - Abstract
Jet obstacles can quickly induce the deflagration to detonation transition (DDT) process and reduce the thrust loss of an engine. However, there are few studies on the use of combustible premixed gases as the reactive jet obstacle. Based on the OpenFOAM platform, a detailed numerical investigation of the flame acceleration and DDT process is carried out with different initial jet velocities and the number of jet obstacles. The results show that, although the stronger flame generated by the reactive jet obstacles will reduce the virtual blockage ratio to a greater extent, the turbulence and combustion heat release effect generated by them still significantly promote the flame acceleration. In terms of flame acceleration, initially, increasing the initial jet velocity has no obvious effect on the flame acceleration. Later, turbulence and combustion heat release begin to dominate the flame acceleration and significantly promote the flame acceleration. Since the jets in this study adopt the same combustible premixed gases, increasing the number of reactive jet obstacles downstream does not improve the upstream flame acceleration. In DDT, increasing the initial velocity of the reactive jet can improve the detonation initiation, but the effect of the obstacle number on DDT is greatly affected by the initial jet velocity. Specifically, at a low initial jet velocity, more jet obstacles can significantly promote the detonation initiation, while at a high initial jet velocity, the enhanced turbulence caused by the jet is the dominant factor for the flame acceleration. Therefore, compared with the number of jet obstacles, the detonation initiation process of the premixed gases is more sensitive to the change in the initial jet velocity. • Reactive jet enhances turbulence effect and provide extra heat for DDT. • Jet velocity variations have different influences in different stages. • The number of downstream jets barely affects the upstream flame evolution. • The DDT process is more sensitive to the change in the initial jet velocity. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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