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Accurately determining the calorific value of aviation kerosene is crucial for optimizing aircraft engine efficiency and design testing. However, current measurement methods exhibit significant uncertainties, necessitating an assessment of the uncertainty associated with measuring the calorific value of aviation kerosene to establish precise results. The present paper introduces the oxygen bomb calorific value measurement method and the probability box model, proposing an improved aviation kerosene calorific value uncertainty evaluation method by combining it with the MCM method. An uncertainty evaluation model based on GUM method, MCM method, and improved MCM method is established in conjunction with experimental data. The analysis of different models demonstrates that the improved MCM method effectively considers the uncertainty of corresponding distribution parameters of variables based on their own uncertainties, providing a reliable approach for calculating the heating value uncertainty of aviation kerosene. [ABSTRACT FROM AUTHOR]

In order to solve the problem of combustion cycle variation in two-stroke aviation kerosene piston engines under idle conditions, experiments were conducted to investigate the influence of intake air temperature on combustion cycle variation and output work. The coefficient of variation of the indicated mean effective pressure was used to characterize combustion cycle variation. The results showed that there is a negative correlation between the engine combustion work and the combustion cycle variation. In the lower range, increasing the intake air temperature has a greater effect on reducing the combustion cycle variation, while in the higher range, the combustion cycle variation has a greater impact on the output work. At the same time, the influence of intake air temperature on the fuel evaporation rate is related to engine speed, and this relationship weakens as the engine speed increases. In the range of 0~40 °C, the higher the intake air temperature, the larger the stable combustion range. [ABSTRACT FROM AUTHOR]

In recent years, the Chinese government has proposed the “dual carbon” goal of achieving a carbon peak by 2030 and carbon neutrality by 2060. In achieving this goal, the petrochemical industry is experiencing the urgent challenge regarding its development and transformation vis energy conservation and emission reduction. Biobased aviation kerosene is a sustainable and environmentally friendly alternative for reducing carbon emissions in the aviation industry, offering a notable promise for widespread adoption. This study comprehensively reviews the process for producing aviation kerosene from biomass. Vegetable oil, oil from inedible oil crops, pyrolysis oil, lignocellulosic residues, sugar, and starch biomass can be used as raw materials for the production of bioaviation kerosene. Biobased aviation kerosene can be classified into the following types according to its production technology: oil to jet (OTJ), gas to jet (GTJ), alcohol to jet (ATJ), and sugar to jet (STJ) fuels. With the rapid development of China’s bioethanol industry and abundant production, the energy supply-diversification strategy represented by ethanol and other alternative energy sources has become a guide for energy policies in various countries. The use of bioethanol as a raw material for preparing aviation kerosene is important for the environment, economy, and sustainability. This study focuses on the process of converting bioethanol into aviation fuel. It analyzes and summarizes the reaction conditions and catalysts involved in the three main reactions: ethanol dehydration to ethylene, olefin oligomerization, and hydrogenation. Currently, the ATJ process still suffers several disadvantages, such as long process flow and low conversion efficiency. The conversion route from ethanol to jet kerosene is complex and requires three different catalysts. We must develop a catalyst that can catalyze both the dehydration reaction and oligomerization hydrogenation reaction, increase the conversion efficiency, and reduce the production cost. This study introduces the carbon–carbon coupling of ethanol and hydrodeoxidation for the production of aviation kerosene, including discussions on reaction mechanisms and catalysts for the preparation of high-carbon alcohol. The Guerbet condensation reaction of ethanol is hindered by the presence of water as a by-product. Therefore, a catalyst is proposed for carbon–carbon coupling reaction of aqueous ethanol to produce high-carbon alcohols. The catalyst, with its satisfactory water resistance, can retain its activity and selectivity for high-carbon alcohols even in the presence of water and effectively inhibit the interference of water molecules, thereby increasing the efficiency and stability of the catalytic reaction. Jet kerosene is obtained via hydrodeoxidation of high-carbon alcohols, in which noble metal- and molybdenum-based catalysts exhibit satisfactory catalytic performance. Transition metals combined with Mo2C catalysts can selectively break the C–O bonds in polyols and avoid C–C bond breakage. Research and development of efficient hydrodeoxidation catalysts can facilitate the conversion of high-carbon alcohols into hydrocarbons, providing important support for the development of alternative aviation fuels. This study highlights the current challenges facing the production of ethanol-based jet fuel, such as the high production cost and the need for new catalysts. Furthermore, it proposes future development directions, offering valuable insights for the industrialization of bioethanol-based aviation kerosene production.

This paper examines the safety of aero-engine pipelines under different heating conditions. Based on the fire test standard documents, a model of an aero-engine oil pipe was constructed, and its safety under heating conditions that meet the standard was analyzed using fluid–solid thermal coupling. The pipe material was stainless steel 1Cr18Ni9Ti, and the oil inside the pipeline was China RP-3 kerosene. To simulate the different working conditions or pump failure scenarios, various kerosene inlet flow rates were used for the calculations. The results indicate that the pipe wall exhibits an uneven temperature distribution under standard heating conditions. As the kerosene flow rate decreases, the pipe wall temperature rises, and heat transfer deterioration occurs. The increase in the pipe wall temperature reduces the material's strength, while the uneven temperature distribution generates thermal stress, further increasing the safety risk. When the kerosene flow rate is reduced to a certain level, the equivalent stress in the pipe wall exceeds the material's yield strength, leading to a high risk of rupture. [ABSTRACT FROM AUTHOR]

Copyright of Chemical Engineering (China) / Huaxue Gongcheng is the property of Hualu Engineering Science & Technology Co Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Advances in New & Renewable Energy is the property of Editorial Office of Advances in New & Renewable Energy and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to study the blast damage effects of aviation kerosene storage tanks, the out-field explosion experiments of 8 m3 fixed-roof tanks were carried out. The fragments, shock wave and fireball thermal radiation of the tank in the presence of bottom oil, half oil and full oil, as well as empty tank, were investigated under internal explosion by various TNT charge contents (1.8 kg, 3.5 kg and 6.2 kg). The results showed that the tank roof was the only fragment produced, and the damage forms could be divided into three types. The increase of TNT charge content and oil volume enlarged the deformation of the tank, while the hole ratio presented a trend of increase first and then decrease. The Hr, max and Vmax values positively increased as increasing the TNT charge content and oil volume (from empty to half oil), but decreased in full oil. The Pmax values had a progressive increase with the increment of TNT charge content, but not the case with the increase in oil volumes. The development of fireball was divided into three stages: tank roof 'towed' flame, jet flow flame tumbling and rising, and jet flow flame extinguishing. The Dmax and Hf, max values both increased as increasing TNT charge content and oil volumes. The oscillation phenomenon of fireball temperature was observed in the cooling process. The average temperature of fireball surface was positively correlated with TNT charge content, and negatively correlated with oil volumes. [ABSTRACT FROM AUTHOR]

With the depletion of petroleum resources, more and more attention has been paid to the production route of non-oil-based aviation kerosene. Among them, to produce aviation kerosene from synthesis gas (CO and H2) is one of the most promising industrial alternative fuel production routes. The traditional catalyst for making aviation kerosene from syngas is based on iron and cobalt. The process is complicated and cost is high. In this paper, a novel Co/Al-SBA-15-La metal-zeolite catalyst prepared by melt infiltration method has been reported for the direct and highly selective production of aviation kerosene components from syngas (CO and H2). Compared with the catalyst prepared by impregnation method, the Co/Al-SBA-15-La catalyst prepared by melt infiltration method has smaller, highly dispersed CoOx and LaOx nanoparticle size and suitable acidity. Under the optimal loading amount, the conversion of CO can reach 45.8%, and the selectivity of C8–C16 aviation kerosene component can reach 54.0%, which provides a new idea for the industrial production of aviation kerosene. [ABSTRACT FROM AUTHOR]

Regimes of detonation burning of a two-phase mixture consisting of TS-1 aviation kerosene and air in a radial vortex chamber 500 mm in diameter with exhaustion toward the center and geometry variations at the combustor entrance and exit are obtained and studied. Air is injected into the combustor through a vortex injector, and kerosene bubbled with air is injected through oppositely directed channels. Optical registration of the process is performed through transparent windows in the combustor by a high-speed camera with a frequency of 420 000 fps. The flow pattern observed in the combustor with free exhaustion and an expanding nozzle is continuous spin detonation with one detonation wave rotating with a velocity of 1.68–2.17 km/s close to the Chapman–Jouguet detonation velocity or pulsed detonation with radial waves with a frequency of 0.14–0.26 kHz. Mounting of radial partitions yields pulsed detonation or combustion. In continuous spin detonation, the air flow rate is 3.6–11.7 kg/s, the kerosene flow rate is 0.2–0.77 kg/s, and the equivalence ratio varies from 0.63 to 2.5. [ABSTRACT FROM AUTHOR]

This paper aims to explore the spontaneous combustion characteristics and engine performance of kerosene under traditional compression ignition mode, providing a reference for further optimizing the performance of kerosene compression ignition engines and the application of advanced combustion mode. The ignition visualization tests of kerosene under marine and vehicle engine conditions are carried out, and the characteristics under 0.3 mm nozzle diameter are compared with that of diesel. Then, the engine performance of the two fuels under medium load and ultra-high injection pressures is compared. The experimental results show that the ignition and combustion characteristics of kerosene and diesel are very similar, indicating that kerosene has a strong universality in diesel engine application. The long ignition delay time of kerosene leads to its lagging combustion and heat release. Compared with diesel, kerosene has lower CO, particulate emissions and indicated thermal efficiency, while higher HC and NOx emissions. The emission characteristics of kerosene RP-3 are different from previous studies, especially under ultra-high injection pressure. The combustion process and engine emissions of kerosene may be optimized with advanced combustion models and strategies. [ABSTRACT FROM AUTHOR]

An air-kerosene thermal mass coupled turbine blade with kerosene micro-channels added to the traditional laminated structure turbine blade is proposed, and numerical simulations are carried out. The enhanced heat transfer mechanism of the air-kerosene thermal mass coupled turbine blade is studied, and the influence of different kerosene temperatures, blowing ratios, and solid thermal conductivity on the heat transfer of the laminated turbine blades is analyzed. The results show that adding kerosene micro-channels can significantly reduce the blade temperature and change the cooling gas heat transfer direction inside the laminate cooling structure. Compared with the traditional laminate cooling structure, adding kerosene micro-channels can significantly improve the heat transfer performance of the blades, and the integrated cooling efficiency increases by 31.7%. Moreover, when the kerosene temperature decreases from 400-300 K, the cooling efficiency increases by 3.9%. Similar conclusions can be obtained by studying the increases in the blowing ratio and the solid thermal conductivity, respectively. [ABSTRACT FROM AUTHOR]

Due to the increasing depletion of petroleum resources, the production route of non-oil-based aviation kerosene has been paid more and more attention. In this regard, the process of preparing aviation kerosene from syngas (CO and H2) is one of the most promising industrial alternative fuel production routes. The traditional syngas-to-aviation kerosene catalyst uses iron-based and cobalt-based catalysts, which is a complex process with a high cost. In this work, a hierarchical Co/Beta metal-zeolite bifunctional catalyst prepared via the melting method is reported, which can directly and highly selectively produce an aviation kerosene component from syngas (CO and H2). Compared with the catalyst prepared via the impregnation method, the Co/Beta catalyst prepared via the melting method has smaller, more highly dispersed Co metal active species and more suitable acid properties, the conversion of CO can reach 34.6%, and the selectivity of the C8-C16 aviation kerosene component can reach 40.2%, which provides a new idea for the industrial production of aviation kerosene. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• The rod-less opposed-piston spark-ignition kerosene engine was studied. • The swirl-wall-guided combustion system was designed and optimized. • The pit structure has a relatively small impact on the indicated power. • The ISFC decreases as the pit diameter decreases. • The knock intensity increases as the pit diameter decreases. Spark-ignited direct-injection opposed-piston rod-less kerosene engines are highly suitable for small and medium-size unmanned aerial vehicles (UAVs) because of the high power-to-weight ratio, self-balancing ability, and safety of such engines. The design and optimization of combustion systems are crucial for power, fuel economy, and knock control. To meet the increasing demand for UAV power systems and fill the research void in this area, reported here for the first time are the design and optimization of a swirl-wall-guided combustion system including the spray pattern and pit structure on the top surface of the piston, with the dynamic, fuel economy, and knock intensity as the evaluation indicators. The results indicate that the spray pattern mainly affects the fuel escape rate and inhomogeneity. After it is injected into the pit, the fuel is guided to the combustion chamber by the steering role of the guide arc. If the spray drop point is located away from the pit, it leads to increased fuel escape rate and inhomogeneity. The turbulent kinetic energy in the spark-plug zone decreases as the pit diameter decreases, fluctuating by 48 %, while the average value remains relatively constant. The distribution is influenced primarily by the enveloping effect of the pit structure on the airflow. Under low-speed conditions, as the pit diameter decreases, the ignition delay period increases and then decreases, and the combustion duration decreases monotonically. The fluctuation of indicated power is relatively small (2.64 %), and the fuel escape rate decreases monotonically, resulting in the same variation pattern of indicated specific fuel consumption (ISFC). When the pit diameter is 43 mm, the fuel escape rate and ISFC reach their lowest values. Knock combustion near the wall is influenced mainly by two factors: the temperature rise rate and the flame propagation speed. The temperature rise rate increases significantly with decreasing pit diameter. When the pit diameter is less than 50 mm, knock combustion begins to occur. Under high-speed equivalent combustion conditions, as the pit diameter decreases, the indicated power changes by 5.21 %, and the ISFC decreases monotonically. [ABSTRACT FROM AUTHOR]

For security and logistical convenience, the single fuel forward policy hopes to use a single kerosene fuel to replace a variety of military fuels, especially the unsafe gasoline. However, the performance of kerosene-fueled spark ignition (SI) engines is severely restricted by knock, slow combustion rate, and poor combustion stability. This work innovatively applies cooled exhaust gas recirculation (EGR) combined with prechamber jet ignition (PJI) to a kerosene-fueled engine to suppress knock and improve performance. The results show that applying cooled EGR at a fixed throttle opening can suppress knock and improve fuel economy. However, the power decreased due to the decreased intake of energy. While applying EGR with constant fresh air mass flow makes the knock more prominent because of the microboosting effect caused by the increased throttle opening. This indicates that cooled EGR alone cannot improve the power output. Moreover, combustion instability was also caused due to the slower combustion rate. Therefore, PJI was introduced to compensate for the negative impact of EGR. As a result, a synergistic effect of cooled EGR and PJI was discovered, improving the IMEP by 5% and reducing the ISFC by 4.9% compared to the baseline. The PJI can shorten the combustion duration and improve the combustion stability because of the high kinetic energy jet and high turbulence flame. In addition, a novel two-stage heat release process which includes the unusual first-stage low-temperature heat release was discovered. Overall, EGR dominates the knock suppression, and PJI contributes to the combustion rate improvement. [ABSTRACT FROM AUTHOR]

In realistic industrial scenarios, the leakage of aviation kerosene (RP-5) under forced airflow easily leads to fire spread, which seriously threatens the safety of human life and causes enormous economic losses. Therefore, it is necessary to study the characteristic parameters of flame spread over RP-5 aviation kerosene under forced airflow, such as flame tilt angle (θ), flame height (H), and flame spread rate (V). In this paper, the RP-5 flame spread experiments were carried out by varying the speed (u = 0–6 m/s) and direction (concurrent, opposed, and perpendicular airflows) of the forced airflow. The results show that the flame tilt angle increases as the airflow speed increases and finally tends to be stable, while the flame height decreases monotonically with airflow speed. The special behaviors of flame bifurcation and fire spread rate induced by the critical airflow speed are observed. The phenomenon of "flame bifurcation" will occur due to the influence of differential pressure resistance under high concurrent airflow conditions (u > 1 m/s). When the airflow is relatively small (u ≤ 1 m/s), the mean flame spread rate varies slightly with increasing airflow speed. With further increasing the airflow speed (u > 1 m/s), the mean flame spread rate increases with an increase in the concurrent airflow speed while decreasing as the opposed airflow speed increases. By contrast, the mean flame spread rate remains essentially unchanged under all perpendicular airflows. [ABSTRACT FROM AUTHOR]

This study reports the adsorption of the naphthenic acids (NA) presents in an aviation kerosene (AVK) model mix using adsorbents prepared from peanut shell (PS). Both carbonization and the CO 2 activation of the PS favored the adsorptive process. In the factorial design, the activated carbon prepared presented the highest adsorptive capacity for the lowest levels of the variables studied (<0.09 mm and without agitation). The adsorption equilibrium after 360 min, and the process is not only controlled by the intraparticle diffusion step. The adsorption isotherm was best fitted to Langmuir model with a maximum adsorbed amount of 884 mg g−1, whose heat of adsorption indicated that the process was of the physisorption. In the continuous adsorption study, it was verified that the increase of the flow and the concentration of NA decreased the rupture time. The breakthrough time and adsorptive capacity were reduced at each adsorption/desorption cycle. Given the shortage of works on this topic in literature, this study contributes with new findings that describe naphthenic acid adsorption in AVK. [Display omitted] • Characterization of adsorbents prepared for naphthenic acid adsorption. • Adsorption of naphthenic acid in an aviation kerosene model mixture. • Parameters evaluation using factorial design for the adsorptive process. • Model application to predict the naphthenic acid adsorption process. • Study of continuous adsorption of naphthenic acid in a fixed-bed column. [ABSTRACT FROM AUTHOR]

A one-step continuous catalyzed hydrogenation preparation of bioaviation kerosene was prepared from castor oil with a molecular probe in a high-pressure microfixed bed. The catalyst was Pt-La/SAPO-11, which was synthesized by the impregnation of Pt, as the active metal component, and metal auxiliaries. The effect of adding metal auxiliaries into the bifunctional metal was evaluated by XRD, XRF, BET, TEM, and Py-IR techniques, and it was confirmed that the hydrodeoxygenation performance, the selectivity of C8–C16 alkanes, the selectivity of C8–C16 isoalkanes, and the selectivity of C8–C16 arenes were all improved. Combined with a Box-Behnken central composite design, the reaction temperature, pressure, liquid hourly space velocity (LHSV), and hydrogen/oil ratio (hydrogen volume/castor oil volume) were selected as the four critical factors for the three levels of selectivity. The response surface method (RSM) was selected to establish a mathematical model with a second-order quadratic equation and optimize the process parameters for enhancing the selectivity of C8–C16 alkanes. The optimization conditions of the four process parameters were found to be a temperature of 405 °C, a pressure of 3.9 MPa, an LHSV of 0.93 h−1, and a hydrogen/oil ratio of 990 NmL mL−1. Three verification experiments showed that the selectivity of C8–C16 alkanes was 58.76%. [ABSTRACT FROM AUTHOR]

The fuel concentration distribution in an afterburner is a critical factor that affects its ignition, flameout, stability, and combustion efficiency. Additionally, the trajectory of the fuel jet directly affects the distribution of the downstream fuel. Hence, this paper studied the factors that affect a jet's trajectory and fuel concentration distribution through numerical calculations. The change law of the fuel jet trajectory under various parameters was studied, and the jet penetration depth change rate was analyzed. Moreover, the empirical formula of the spanwise distribution range of the liquid fuel in front of the stabilizer was fitted. Furthermore, this study investigated fuel concentration distribution experimentally in the afterburner under normal temperature and pressure. The paper obtained the variation law of fuel concentration in the spanwise and radial directions, and the proportion of the gaseous fuel in the flow section under the influence of different parameters. Additionally, the spatial distribution of the droplet concentration was obtained, revealing that it increased initially, and then decreased in the flow direction, reaching a peak at the end of the recirculation zone. In the radial direction, two concentration peaks were found in the boundary of the recirculation zone and in the main flow region. [ABSTRACT FROM AUTHOR]

Due to the increasing depletion of petroleum resources, the production route of non-oil-based aviation kerosene has been paid more and more attention. In this regard, the process of preparing aviation kerosene from syngas (CO and H2) is one of the most promising industrial alternative fuel production routes. The traditional syngas-to-aviation kerosene catalyst uses iron-based and cobalt-based catalysts, which is a complex process with a high cost. In this work, a hierarchical Co/Beta metal-zeolite bifunctional catalyst prepared via the melting method is reported, which can directly and highly selectively produce an aviation kerosene component from syngas (CO and H2). Compared with the catalyst prepared via the impregnation method, the Co/Beta catalyst prepared via the melting method has smaller, more highly dispersed Co metal active species and more suitable acid properties, the conversion of CO can reach 34.6%, and the selectivity of the C8-C16 aviation kerosene component can reach 40.2%, which provides a new idea for the industrial production of aviation kerosene.

• Impact of air-assisted nozzle shape on shock wave formation is studied. • Effect of shock wave type on spray flow field is investigated. • Vortex identification method is used to study vortex distribution. • Turbulent and shear breakup of liquid in air-assisted spray field are discussed. • Conical nozzle to promote fuel diffusion, arc nozzle atomization ability is strong. Due to its physical characteristics of large viscosity and non-volatilization, aviation kerosene has a poor atomization effect in aeroengine cylinder, and is inappropriate for aviation piston engine unless high pressure injection is used. Air-assisted injection can effectively solve this problem. In the paper, the CFD software is used to establish a 3-D numerical model of the air-assisted injector, and the influence of the nozzle shape on the airflow movement and interaction between gas and liquid is investigated. The accuracy of the simulation model is confirmed by the comparison of the simulation results with the spray morphology and penetration of the spray experiments in the constant volume bomb. Based on this, three nozzle shape models are established to simulate the air-assisted spray flow field of aviation kerosene RP-3 under various ambient back pressures. The influence of nozzle shape on the flow state of compressed air and spray characteristics is compared and analyzed. The results show that when the back pressure is 0.09 MPa, the oblique shock waves can be observed near both large and small circular arc nozzle exits, and the attenuation degree of airflow velocity by the oblique shock wave is relatively small. The stronger interaction between the gas-liquid two phases is beneficial to fuel atomization. Moreover, the normal shock wave appears in the conical nozzle where the injected nitrogen has less kinetic energy. Several large-scale vortices are generated in the near field of the spray, which promotes the mixing of fuel and surrounding nitrogen. Therefore, for aviation kerosene which is difficult to atomize, a large and small circular arc shaped nozzle with strong atomizing ability should be used. When the mixture is required to be evenly distributed in the combustion chamber, the conical nozzle should be preferred. [ABSTRACT FROM AUTHOR]

As a way of energy saving and emission reduction, the blended fuel strategy can effectively reduce the dependence on fossil energy. In this paper, a long-chain alcohol—n-butanol was selected and blended with aviation kerosene to study the spray characteristics of the blended fuel in a constant volume environment. The results show that at a blending ratio of 10%, the blended fuel and pure aviation kerosene show similar spray characteristics. As the blending ratio increased, the spray tip penetration and spray cone angle of the blended fuel were more different from those of aviation kerosene. The spray volume and mass of entrained gas of AKB10 and aviation kerosene were larger, showing a better fuel-gas mixing degree. [ABSTRACT FROM AUTHOR]

Aviation kerosene will go through numerous storage and transportation links from production to use. As the fuel of jet aircrafts, the aviation kerosene will follow the high requirements on the quality index specified in national standards. All aviation kerosene production and transportation entities attach great importance to the inspection of oil quality changes. In this paper, typical storage and transportation process of aviation kerosene from production to use was introduced, quality and safety accidents of aviation kerosene occurred in China and abroad in recent years were presented, and quality problems including foreign pollutants, mixed oil transported in sequence, quality attenuation of oil products, etc. that may occur in aviation kerosene storage and transportation were reviewed. The quality and safety assurance measures in aviation kerosene storage and transportation were additionally summarized, so as to provide reference for engineers and researchers committed to assuring the aviation kerosene quality and reducing the cost of aviation kerosene transportation.

Aero-engine combustors may experience extreme low pressures in the case of an in-flight shutdown, which makes the study of aviation kerosene flame propagation characteristics at low pressures important. The present work examined flame propagation during the combustion of aviation kerosene over the pressure range from 25 to 100 kPa using a constant-volume bomb apparatus. The laminar burning speeds at different initial pressures, temperatures and equivalence ratios were measured and compared. In addition, numerical simulations were used to examine the reaction sensitivity of the laminar burning speed at low pressure. In trials at the lean flammability limit, the data indicated that it was more difficult to ignite the fuel under a lower pressure condition of 25 kPa and a lower temperature condition of 420 K. The experimental results of laminar burning speed were fitted to an equation providing the laminar burning speeds expected at different pressures (25–100 kPa), temperatures (400–480 K) and equivalence ratios (0.8–1.5). The temperature index ( α = 1.76 ) and pressure index ( β = − 0.15 ) of the fitting equation were obtained. Both hydrodynamic and diffusional thermal flame instabilities were found to be suppressed at low pressures. The negative effects of two specific reactions on laminar burning speed were greatly reduced at these same low pressures of 25 kPa. [ABSTRACT FROM AUTHOR]

In this research, n-dodecane and world-average jet fuel (JW) are selected as single and multicomponent surrogate fuel of aviation kerosene to study the Jet-A spray combustion characteristics. The spray combustion phenomena are simulated using large eddy simulation coupled with detailed chemical reaction mechanism. Proper orthogonal decomposition method is applied to analyze the flow field characteristics, and the instantaneous velocity field is decomposed into four parts, namely, the mean part, coherent part, transition part, and turbulent part, respectively. The four parts have their own characteristics. In terms of different fuels, JW has a higher intensity of coherent structures and local vortices than n-dodecane, which promotes the fuel-air mixing and improves the combustion characteristics, and the soot formation is significantly reduced. In addition, with the increase of initial temperature, the combustion is more intense, the ignition delay time is advanced, the flame liftoff length is reduced, and soot formation is increased accordingly. [ABSTRACT FROM AUTHOR]

Regimes of detonation burning of TS-1 aviation kerosene in an air flow in a flow-type radial vortex combustor 500 mm in diameter with exhaustion toward the center are obtained. The parameters varied in experiments are the diameter of the combustor exit cross section (from 250 to 125 mm) and the shape of one of the combustor walls. The air flow rate in detonation burning regimes is 5.23–23.85 kg/s, and the kerosene flow rate is 0.49–1.2 kg/s. The fuel-to-air equivalence ratio is varied in the interval from 0.58 to 2.24. Kerosene is bubbled with air before its injection into the combustor. Pulsed detonation with radial waves and continuous spin detonation with one rotating detonation wave with a velocity close to the Chapman–Jouguet detonation velocity are observed. The structure of detonation waves and the flow in their vicinity display no principal differences from those observed previously in a plane–radial combustor with a smaller diameter (204 mm). A strong effect of detonation waves in the combustor on the air and kerosene injection systems is detected. Centrifugal forces acting on the mixture flow and detonation products are enhanced as the combustor exit diameter decreases (as the combustor length increases). For identical specific flow rates of kerosene–air mixtures, the pressure near the cylindrical surface of the combustor in idle runs is found to be higher than that in the case of detonation. [ABSTRACT FROM AUTHOR]

• A surrogate and its compact reaction kinetics model were developed for aviation kerosene fuel through decoupling methodology. • The developed mechanism covers both low and high temperature regions. • The model showed a close emulation of the experimental data for the simulation of ignition delay. • The surrogate model could provide a close simulation for the flame speed of jet A fuel. • A generally good agreement was observed for modelling of the main oxidation products of jet A fuel compared to the experimental results. In spite of the great advances in surrogate development for conventional jet fuels, it is still a big challenge to allocate the appropriate components and proportion which accurately emulate the real fuel specifications. So, this study aims to investigate the development of a well-validated surrogate with a simplified chemical kinetics mechanism that delivers a good prediction ability for the key combustion parameters of aviation kerosene in a wide range of conditions for temperature, pressure and equivalence ratio. A surrogate consisting of 4 components including 30% (by mass) tetradecane, 30% iso -dodecane, 24% n-propylcyclohexane, and 16% toluene was developed based on the major components of the real fuel and the similar property targets to the target fuel. Then, a simplified compact mechanism was developed for the proposed surrogate. The model was used for the simulation of ignition delay, flame speed, and species concentration. In general, the results showed a good agreement compared to the experimental data, and a closer emulation of the empirical data for ignition delay and flame speed, in comparison to previously developed models for jet A. Considering the compact size and the predictive ability of the proposed surrogate, the model can be used as a tool for the combustion investigation of kerosene to improve engine designs, efficiency and reduce emissions. [ABSTRACT FROM AUTHOR]

To address the environmental issues caused by traditional aviation fuels, the use of new alternative jet fuels (AJF) is emerging. C1 fuel, due to its excellent performance, is used as a blended fuel with traditional aviation kerosene. In this study, the pyrolysis pathways of C1 fuel are examined from molecular simulations. Furthermore, C1 fuel is blended with traditional aviation kerosene fuel RP-3 in a 1:4 vol ratio, and the potential coupling effects between two fuels are addressed under both pyrolysis and combustion conditions. In the process of fuel pyrolysis, it is observed that the composition of the fuel has a significant impact on the pyrolysis products. The decomposition process of C1 fuel is mainly dominated by branched-chain alkanes, while the pyrolysis of RP-3 primarily involves β-scission reactions of straight-chain alkanes. By comparing the combustion and pyrolysis processes of fuels, it is found that the combustion of fuel first involves the decomposition of fuel molecules, followed by the oxidation of pyrolysis products. Moreover, it is found that the reaction kinetics of blended fuel can be approximated using the additivity of two neat fuels, indicating a minor chemical coupling. Based on the proportion of C1 and RP-3 in the blended fuel, the mass fractions of key hydrocarbon products, including CH 4 , C 2 H 2 , C 2 H 4 , C 2 H 6 , C 3 H 6 , C 4 H 6 , C 6 H 6 , and C 7 H 8 , can be computed from the simulations of neat fuels. From a molecular perspective, the additivity of the HyChem model in describing the combustion behavior of blended fuels is verified. [Display omitted] • The detailed pyrolysis reaction mechanism of C1 fuel is discussed. • The potential coupling effect between C1 and RP-3 is investigated. • The HyChem approach is verified from molecular perspective. [ABSTRACT FROM AUTHOR]

In order to meet the requirements of Sustainable Aviation Fuel (SAF) to achieve the imperatives of energy conservation and emission reduction. This paper compares the combustion characteristics of diesel, RP-3/n-butanol blends in terms of heat release rate, in-cylinder pressure, temperature and fuel economy in a compression ignition engine, taking into account the advantages of lightweight structure, low fuel consumption and wide range of applications of aviation piston engines. The results certified the viability of applying RP-3 and RP-3/n-butanol blends in diesel engines. Adding n-butanol prolonged the ignition delay and shorten the combustion duration. Moreover, the peak of the pressure, temperature and apparent heat release rate (AHRR) increased. In addition, the blended fuel showed obvious diffusion combustion characteristics at high load. With the n-butanol increased, the combustion instability of the blended fuels decreased significantly, at low load. At n = 2400r/min, pme = 0.53 MPa, compared with diesel, the maximum heat release rate (MHRR) of R70B30 increased by 76.6 %, improving the combustion characteristics of the blended fuel. Moreover, the equivalent specific fuel consumption (ESFC) of RP-3 is 5.56–14.83 % lower than that of diesel, and the effective thermal efficiency (ETE) of RP-3 is 2.8–13.46 % higher than that of diesel under most working conditions. • The n-butanol/RP-3 blended fuels can replace diesel fuels in compression ignition engines. • The n-butanol improves the combustion difficulties at low load. • The blended fuel shows obvious diffusion combustion characteristics at high load. • Using n-butanol as blended fuel can shorten the combustion duration. [ABSTRACT FROM AUTHOR]

Modern trends of civil aviation development indicate the need to improve fuel efficiency and environmental friendliness of the utilized fuels. The use of conventional jet fuel is meeting to a lesser degree the promising requirements concerning environmental friendliness at a constantly rising price for it. Apart from that, oil reserves are limited. According to many experts, the solution to the growing problems with oil fuels can be application of alternative types of aviation fuel. A number of companies around the world, together with aircraft manufacturers under the significant state support, are actively developing new types of fuel. At the moment the most widespread biofuels consisting of bioethanol are obtained from various plant and animal sources. Alternative fuels should not be inferior to petroleum fuels in its operational properties. A possible transition to them should not require significant costs for the modernization of aircraft and facilities of ground aviation fuel supply. Therefore, an urgent task is to compare the main indicators of the quality of oil fuels, biofuels and their mixtures to assess the possibility of using biofuels on aircraft. A comparative analysis was carried out on some quality indicators. Afterwards the comments were given on the impact of changes of these quality indicators on the performance properties of the fuels. It is shown that according to some quality indicators, biofuels under research have the advantages over oil ones. The relevance of comprehensive study of the performance properties of biofuels is obvious. The improvement of oil fuels and their comprehensive study have been under way for more than 60 years. Biofuels are just beginning their life, so it is reasonable to conduct thorough research on their use in aviation.

The fuel concentration distribution in an afterburner is a critical factor that affects its ignition, flameout, stability, and combustion efficiency. Additionally, the trajectory of the fuel jet directly affects the distribution of the downstream fuel. Hence, this paper studied the factors that affect a jet’s trajectory and fuel concentration distribution through numerical calculations. The change law of the fuel jet trajectory under various parameters was studied, and the jet penetration depth change rate was analyzed. Moreover, the empirical formula of the spanwise distribution range of the liquid fuel in front of the stabilizer was fitted. Furthermore, this study investigated fuel concentration distribution experimentally in the afterburner under normal temperature and pressure. The paper obtained the variation law of fuel concentration in the spanwise and radial directions, and the proportion of the gaseous fuel in the flow section under the influence of different parameters. Additionally, the spatial distribution of the droplet concentration was obtained, revealing that it increased initially, and then decreased in the flow direction, reaching a peak at the end of the recirculation zone. In the radial direction, two concentration peaks were found in the boundary of the recirculation zone and in the main flow region.

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The ignition behavior of the polytetrafluoroethylene/aluminum/tungsten reactive projectile impacting a fuel-filled tank is experimentally investigated. In ballistic experiments, the reactive projectiles and the steel projectiles are launched from a smooth bore powder gun barrel to impact fuel-filled tanks at different velocities. The processes are recorded by a high-speed video camera. The result of the ignition-enhanced behavior of the reactive projectile relative to the steel projectile is presented. When the reactive projectile impacts the fuel-filled tank, the combined effects of the kinetic energy impact and the chemical energy release are achieved to improve the ignition probability. Especially, the flame (ignition kernel of the fuel) caused by the reactive projectile has a longer duration and a greater expansion region. [ABSTRACT FROM AUTHOR]

There is individual droplet burning phenomenon in spray flames but the ignition prediction and criteria are lack of both experimental and theoretical study. In this paper, firstly based on the energy balance analysis method, two new droplet ignition models are proposed by analyzing the single droplet evaporation and ignition process in relatively static high temperature air environment. These new models can be used to predict the droplet ignition phenomenon in spray flames. Then, single droplets of RP3 aviation kerosene, common kerosene and diesel were suspended in static air environment with ambient temperature from 845 ​K to 1085 ​K to test the ignition limits of the fuel droplet. The experimental ignition boundary was obtained by measuring and recording the minimum ignitable initial diameters of the experimental droplet in every temperature condition. The experimental results show that the ignitable minimum initial diameter of the fuel droplet decreases along with the increase of ambient temperature. And at the same ambient temperature, the minimum ignitable initial diameter of common kerosene droplet is the biggest, then is diesel and RP3 aviation kerosene is the smallest. Finally, the predicted ignition boundaries of the two new models are compared with the experimental data. And the comparison results show that the models’ predictions are in good agreement with the experimental data, whose error is within 10%.

To get reliable computational results, the RNG k-ε turbulence model with enhanced wall treatment was validated to solve the heat transfer of supercritical RP-3 in a helically coiled tube, and models of the thermo-physical properties of RP-3 were optimally chosen. Most significantly, the grid independence was validated by two-step procedure, and the effect of boundary grids of the supercritical-temperature wall on the computational accuracy was well studied. Through adjusting boundary-layer girds' size, four regions (increased, pseudo-convergence, decreased and convergence) of the outlet temperature Tout were obtained and analyzed. The results showed that the maximum computation errors of Tout and the pressure differential between the inlet and outlet ΔP reached 20.65% and 98.15%, respectively, indicating that boundary grids have a significant influence on computation of flow and heat transfer. Based on this, a dimensionless distance from the wall-adjacent cell to the wall y+ = Prw−1/1.78 (Prw denotes Wall Prandtl number) was recommended as a convergence point. The variation laws of viscous length scale y were discussed under different structural parameters, operation parameters, and helical lengths. An explicit model of y* was proposed to calculate the height (y) of the first boundary layer grids and refine boundary grids efficiently. A modified model for coefficient of friction factor Cf was proposed based on Rogers's, and Nusselt number Nu was proposed based on an analogy of momentum and heat transfer. The above models about y*, Cf and Nu could apply to both the entrance region and the whole tube length, and showed good performance when Reynolds number was extended to above 70 000, or whenever the outlet temperature is below or above the critical point. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Petrochemical Universities / Shiyou Huagong Gaodeng Xuexiao Xuebao is the property of Journal Editorial Department Of Liaoning Shihua University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The use of mathematical experiment planning is proposed to optimize test conditions providing the maximum resolution of the method for assessing the anti-wear properties of aviation kerosene. The absolute difference between the values of the determined indicator "wear-track width" for fuels with different levels of anti-wear properties is selected as the optimization criterion. [ABSTRACT FROM AUTHOR]

In order to study the effect of rolling amplitude on the heat release of aviation kerosene, an experimental oil pool was designed. The rolling frequency of the oil pool was used as a fixed amount. The rolling amplitudes were 0, 15°, 30° and 45°, respectively. The initial thickness of aviation kerosene was 0.646 mm, 1.291 mm and 1.940 mm, respectively. The results show that the heat release rate of aviation kerosene increases significantly with the increase of rolling amplitude, and the total heat release of aviation kerosene increases with the increase of swing amplitude. When the initial aviation kerosene was relatively thin, the upward trend was not obvious, with only slight changes; the thicker the oil pool is, the more obvious the upward trend is and the greater the total heat released is.

For the first time, a detonation afterburner (DA) for continuous detonation combustion of TS-1 aviation kerosene was developed, manufactured, and tested. Test fires of the DA in combination with a TJ100S-125 small-sized single-circuit turbojet engine were carried out on a ground test bench. In the test fires, stable modes of continuous detonation combustion of aviation kerosene were registered: a near-limit mode of longitudinally pulsating detonation (LPD) and a spin detonation (SD) mode with one detonation wave. Compared to a conventional afterburner, at the same in-chamber pressure, the specific fuel consumption in the DA was 30% lower and the specific thrust and thrust boosting coefficient were 30% higher. It is shown that, when operating in the LPD mode, the average heat flux to the DA walls is about 0.5 MW/m2 and, in the SD mode, 0.86 MW/m2. These values indicate the high potentiality of the DA when used in advanced jet engines. [ABSTRACT FROM AUTHOR]

This research work studies the impact of the mixture concentration, spark timing, and ignition energy on the knock suppression of a two-stroke spark ignition aviation kerosene-fueled engine. Bench tests on different working conditions were conducted and some related data including in-cylinder pressure, cylinder head temperature, exhaust temperature, engine power, and torque were collected to analyze the influence of different control parameters on the knock characteristics of the engine. The results show that the knock can be suppressed at leaner and richer (than the stoichiometric) mixtures, and the richer mixture has a more obvious effect on suppressing knock. Retarding the ignition advanced angle will reduce the knock intensity but will make the exhausted temperature exceed and the output power decrease. The use of a rich mixture with early spark timing has a better effect on the knock suppression as compared to the use of a lean mixture with late spark timing. Reducing the ignition energy can suppress the knock slightly, but experimental results show that it is not an effective way. [ABSTRACT FROM AUTHOR]