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Ammonia/hydrogen fuel mixture is considered to be a new type of sustainable and environmentally friendly energy. However, their explosive properties are not well understood. This study investigated the explosion of NH 3 /H 2 /air fuel mixture in a 1.67-litre constant-volume combustion chamber using hydrogen ratios (H 2 = 15, 20, 25, and 30%), equivalence ratios (ϕ = 0.8–1.4), starting temperatures (T i = 298, 363, and 428 K), and pressures (P i = 1, 2, and 3 bar). The explosivity of NH 3 /H 2 /air was characterized using the maximum explosion pressure (P max), maximum pressure rise rate (dP/dt max), and deflagration index (K G). Also, the maximum heat release rate (HRR max) and heat loss were used to account for variations in heat generated by the explosion. The findings indicate that P max decreases with increasing temperature but P max , dP/dt max , and K G increase with an increase in pressure. Overall, an increase in pressures, hydrogen ratios, and equivalence ratio enhances the explosion severity, but the pressure has a significant effect on the explosion severity. Furthermore, a cubic polynomial provides a superior match to the correlations between the P max , dP/dt max , K G , and HRR max and equivalence ratio. This study deeply explores the safe use mechanism of NH 3 /H 2 mixed fuel and provides an essential reference for the safe application of NH 3 /H 2 mixed fuel. • Studied confined explosion of NH 3 /H 2 mixed fuel under different initial conditions. • K p shows max explosion pressure sensitivity decreases then slightly increases with higher equivalence ratio. • Hydrogen content's impact on explosion parameters is more significant in lean fuel than rich fuel. • Deflagration index shows H 2 makes NH 3 more flammable with little increase in hazard. [ABSTRACT FROM AUTHOR]

In this work, the explosion of hydrogen/nitrous oxide/carbon dioxide mixtures with various equivalence ratios (0.6–1.0), initial pressures (40–100 kPa), and carbon dioxide fractions (20%–40 %) at ambient temperature (298 K) was conducted inside a normative 15.625-L cubic container. The maximum explosion pressure and pressure rise speed were obtained and analyzed. The results show that carbon dioxide plays a crucial role in weakening H 2 /N 2 O explosion intensity, flame instabilities, as well as the tendency of deflagration to detonation. In addition, the addition of carbon dioxide has affected the two competitive effects between adiabatic temperature and molecular number. The variations of maximum explosion pressure and pressure rise speed with equivalence ratios depend on the carbon dioxide fraction. Only a linear dependence was found between maximum pressure rise speed and original pressure. These results would be useful in developing explosion-proof devices in the event of potential fire and explosion hazards. • Highlights (for review). • Carbon dioxide plays a significant role in weakening H 2 /N 2 O explosion intensity. • The variations of (d p /d t) max - φ depend on the carbon dioxide fraction. • The competitive effects between adiabatic temperature and molecular number are affected by CO 2. • The addition of CO2 effectively suppresses the tendency of deflagration to detonation. [ABSTRACT FROM AUTHOR]

As a representative renewable biofuel, ethanol can reduce mankind's dependence on petroleum resources and the emission of greenhouse gases and other pollutants. In recent years, the application of ethanol in the aviation field has begun to be a concern of scholars. As ethanol is a flammable liquid, it is significant to study its explosion characteristics in aviation conditions from a safety perspective. In this work, at 20 kPa, the explosion characteristics of ethanol–air mixtures (concentration 6~12%) were experimentally and numerically studied under an initial temperature range of 303 K~363 K. The effects of the initial temperature and concentration on the maximum explosion pressure, maximum rate of pressure rise, explosion time, and fast burning time were analyzed. In addition, the heat loss fraction and sensitivity analysis were examined and discussed. The main conclusions are as follows: A linear relationship exists between the maximum explosion pressure and the reciprocal of the initial temperature. The maximum rate of a pressure rise appears to decrease or at least approach a constant value as the initial temperature increases. The explosion time is significantly dependent on the concentration. At a constant concentration, the proportions of heat loss are approximately constant except for 12%. In our sensitivity analysis, R1 (H + O2 <=> O + OH) was the dominant elementary reaction. [ABSTRACT FROM AUTHOR]

Prevention and mitigation of unwanted explosions require knowledge of explosion characteristics. Available explosion data are not always adequate for use in a particular application. For example, predicting the behavior of gas explosions at a lower temperature should be based on the explosion data obtained at these temperatures and not atmospheric. Basic knowledge of the methane explosions at low temperatures is desirable for a thorough understanding of this gas that cannot be found in the literature. In the presented research, the methane/air deflagrations were studied in the millisecond time domain. The standard 20-L deflagration chamber was adopted to produce consistent and reproducible data for the comparison of atmospheric and low initial temperature measurements. Methane/air mixtures were studied experimentally for concentrations between 4.6 vol.% and 16.6 vol.% and two initial temperatures of 20 and −5 °C. More than three hundred and fifty pressure–time curves were recorded and analyzed. Twenty-five deflagration curves of the methane/air mixtures were studied in 20-L volume for the first time, including thirteen pressure–time curves at −5 °C. The effects of temperature on the maximum rate of pressure rise and deflagration index were investigated. The evaluated experiments’ results are the maximum pressure rise rate of 261 bar/s at −5 °C. This work allowed potential hazards involving the handling and storing of fuels. Many pieces of knowledge must be collected to advance the phenomenological understanding of low-temperature deflagrations to make realistic theoretical predictions and correlations.

This work aims to is to study the flame propagation characteristics of the hydrogen/liquefied petroleum gas (LPG) premixed gas in a closed tube. With the aid of a self-developed square glass explosion tube and a high-speed camera, the characteristic parameters (i.e., flame structure, flame tip speed, maximum explosion overpressure, maximum rate of explosion pressure rise, deflagration index) were obtained and analyzed the explosion characteristics of the premixed gas. The results show that the time for the flame to reach the end of the pipe decreased, and the maximum explosion overpressure increases as the hydrogen addition ratio increases. However, the explosion overpressure and flame propagation velocity increased slowly when the hydrogen addition ratio was less than 40%, While the explosion overpressure and flame propagation velocity increased drastically in the range of hydrogen addition ratio 40–80%. Therefore, the key turning point for LPG hydrogenation is when the hydrogen volume fraction is 40%. The peak explosion flame propagation velocity and the peak explosion pressure showed the change law of increasing first and then decreasing with the equivalent ratio increasing. The P max and V max are 6.4 bar and 71.2 m/s respectively. The explosive flame structure of the premixed gas formed a "multiple tulip" structure after the typical tulip flame structure due to the influence of hydrodynamic. In addition, the propagation law of H 2 -LPG-Air premixed flame in the pipeline was influenced by the interaction of pressure wave and flame front velocity, and P max trajectory and V max curve showed similar oscillation law. Hence, the study provides crucial data for the prevention and control of H 2 -LPG-Air gas mixture combustion and explosion accidents. [ABSTRACT FROM AUTHOR]

The aim of the article is to point out the dangers arising from the properties of plastic dust and what influence its properties have on the origin and course of the explosion. The present study deals with a sample of polyethylene dust, by-product of granulate production and storage. The explosion tests are performed on containers of a similar shape to those found in plants. The volumes of the closed vessels are 1.35 m3 (N1) and 5.45 m3 (N2). The tests are conducted in vessel N1 with a venting area DN 250 on the top of the vessel, in vessel N2 with a venting area DN 585 or DN 775 installed on the upper flanges of the vessels, and in vessels interconnected by pipes with a diameter DN 150 and length of 3, 6, and 10 m. The experiments show that the pressure of the explosion in technological equipment may reach higher values than those obtained in laboratory tests. During the explosion propagation in the connected vessels, the effect of overpressure appears due to precompression; as a result, the measured pressure and the rate of pressure rise are many times higher than the values measured only in the vessel itself with a venting area. As the explosion propagates from a larger volume vessel to a smaller volume vessel, the effect of precompression of the mixture increases the explosion parameters in the smaller vessel despite the opening areas of both vessels. Other elements can be also used to ensure sufficient explosion protection. The results also describe the effect of the length of the pipeline route by which the vessels are connected. [ABSTRACT FROM AUTHOR]

Low-concentration methane accounts for the most massive percent of coal mine methane (CMM). Reasonable utilization of low-concentration methane, especially the ultra-low concentration methane (less than 5%), is of great significance for resource conservation and environmental protection. Therefore, a reasonable utilization method of ultra-low concentration methane (ULCM) was proposed. The main idea is to add combustible substances, such as dimethyl ether (DME), into ULCM to promote its combustion and explosion. The experimental investigations on the explosion parameters of ULCM mixed with DME were conducted in a horizontal explosion pipeline. The results suggested that the addition of DME can promote the combustion and explosion of ULCM. The maximum values of v and Pmax appear in the equivalence ratio of 1.1–1.3, which are slightly higher than the values at stoichiometric concentration because of the transient effect of the explosion pipeline. The results provide a reference for selecting optimum mixing concentration in the utilization process of ULCM mixed with combustion supporting agent. The researches offer a feasible method for the utilization of ULCM, which is of great significance for energy conservation and emission reduction of CMM. [ABSTRACT FROM AUTHOR]

The characteristics of methane-air explosion in interconnected containers with different dimensions are studied in this paper, and the prediction models are established. The explosion apparatus consists of two cylindrical containers and a connecting pipe, and three structure parameters are selected as influencing factors for the experiments. The explosion pressure, the maximum rate of pressure rise and pressure growth index under different conditions are compared by changing the volume ratio (V1/V2), the length of the pipe, and the inner diameter of the pipe. During the experiment, the combustion and explosion of gas developed from the main container to the auxiliary container. Under different size effect conditions, the maximum explosion pressure in the secondary container was always higher than the maximum explosion pressure in the primary container. The maximum explosion pressure and the maximum rate of pressure rise in the primary and secondary containers both increase with increasing pipe length. With an increase in the pipe diameter, the maximum explosion pressure and the maximum rate of pressure rise both decrease gradually. When the volume ratio changes, the parameters such as the maximum explosion pressure are also affected by the volume changes of the containers at both ends. Therefore, the explosion parameters in both connected containers do not show a single development trend with the increase of the volume ratio. For practical application, in order to reduce the explosion intensity and protect the device, large-diameter pipes should be used and the volume ratio should be reduced.

• Effects of hydrogen content on pressure development in H2/ethanol are studied. • Explosion parameters are obtained from the experiment and analyzed. • The deflagration index of mixture has been experimentally measured. With the anticipated widespread integration of biofuels and hydrogen fuels within the future energy landscape, the potential explosion hazards after their release within confined spaces under the atmospheric are deserving of heightened attention. The present work takes the mixtures of ethanol and hydrogen as the objects and experimentally studies the impacts of hydrogen fraction and equivalence ratio on the explosion characteristics in a constant-volume explosion vessel at 0.10 MPa and 400 K. The data reveals that an increase in the hydrogen fraction leads to a rise in the maximum explosion pressure during lean explosions but causes a decrease during rich explosions. Nonetheless, the duration of the explosion decreases with the increase of hydrogen fraction in all the explosions. In consideration of explosion pressure, the maximum pressure rise is found to be exponential in relation to the maximum explosion pressure. However, the confidence level diminishes significantly with an increase in the hydrogen fraction. Conversely, the maximum rate of pressure rise during an explosion appears to be a function of the duration of the explosion, suggesting that the reaction rate plays a more pivotal role in determining the hazardous level. Meanwhile, the duration of fast combustion steadily occupies approximately 83 % of the explosion duration. Furthermore, the deflagration index is no more than 30 MPa*m/s, namely, ethanol/hydrogen mixture is a promising fuel with mild hazardous potential. [ABSTRACT FROM AUTHOR]

As a representative renewable biofuel, ethanol can reduce mankind’s dependence on petroleum resources and the emission of greenhouse gases and other pollutants. In recent years, the application of ethanol in the aviation field has begun to be a concern of scholars. As ethanol is a flammable liquid, it is significant to study its explosion characteristics in aviation conditions from a safety perspective. In this work, at 20 kPa, the explosion characteristics of ethanol–air mixtures (concentration 6~12%) were experimentally and numerically studied under an initial temperature range of 303 K~363 K. The effects of the initial temperature and concentration on the maximum explosion pressure, maximum rate of pressure rise, explosion time, and fast burning time were analyzed. In addition, the heat loss fraction and sensitivity analysis were examined and discussed. The main conclusions are as follows: A linear relationship exists between the maximum explosion pressure and the reciprocal of the initial temperature. The maximum rate of a pressure rise appears to decrease or at least approach a constant value as the initial temperature increases. The explosion time is significantly dependent on the concentration. At a constant concentration, the proportions of heat loss are approximately constant except for 12%. In our sensitivity analysis, R1 (H + O2 O + OH) was the dominant elementary reaction.

The study here presents data from the literature regarding the characteristic parameters of explosion propagation in gaseous ethane–air mixtures. The maximum explosion pressures, maximum explosion times, maximum rates of pressure increase, and deflagration indices from experimental measurements are discussed and analyzed against the initial pressure, initial temperature, and equivalence ratio, as well as the explosion vessel characteristics. Ethane is used for ethylene production, as a refrigerant in cryogenic systems, as an alternative clean fuel in the power generation industry and automotive propulsion, and for many other applications. Therefore, the explosion characteristics of its mixtures with air are of great interest for explosions occurring after accidentally forming flammable mixtures, as well as for the prediction of combustors' performances and/or engines that work in different conditions. [ABSTRACT FROM AUTHOR]

The explosion characteristics of H 2 –N 2 O over a wide range of equivalence ratio (φ) at a reduced pressure were studied experimentally in a cylindrical explosion vessel. Two orifice plates with the blockage ratios of 0.4 and 0.6 were employed to characterize the influence of an obstacle on the explosion behaviors. The experimental results showed that maximum explosion pressure could be higher than the adiabatic value due to the potential of flame acceleration and deflagration to detonation transition (DDT). The maximum explosion pressure was increased by the orifice plate at the fuel-lean side due to the flame instability while decreased at the fuel-rich side. This means that the roles played by the orifice plate are different for affecting the maximum pressure. The maximum pressure rise rate ( (d p / d t) max) was increased by introduction of an orifice plate due to the turbulence-generator effect. The maximum (d p / d t) max was obtained at φ = 0.6, indicating that the flame instability rather than the adiabatic explosion pressure or laminar burning velocity plays a leading role. • Effects of an orifice plate on the explosion behaviors of H 2 –N 2 O were studied. • The orifice plate plays a dual role on the maximum explosion pressure. • The orifice plate acts as a turbulence-generator on the maximum pressure rise rate. • The flame instability dominates the evolution of the maximum pressure rise rate. [ABSTRACT FROM AUTHOR]

In order to evaluate the effect of mixing hydrogen on the explosive characteristics of ammonia, this work explored the evolution of explosion overpressure and flame propagation characteristics of ammonia/hydrogen/air mixture under different hydrogen blending ratios in closed pipelines through experimental research. Experimental results show that as the hydrogen blending ratio increase, the instability of flame increases, and flame surface changes from smooth to wrinkled. Flame propagation undergoes the evolution of jellyfish-shaped/near-spherical, finger-shaped, plane-shaped, irregularly protruding flame and tulip flame. Flame surface area is constantly changing, accompanied by violent flame tip velocity pulsations. The maximum explosion pressure and the maximum explosion pressure rise rate are consistent with the evolution law of adiabatic flame temperature. They first increase and then decrease with increase of the equivalence ratio, and their peak value appears near the equivalence ratio of 1.1. On the contrary, the explosion duration and rapid combustion period first decrease and then increase with increase of equivalence ratio, and decrease monotonically with increase of hydrogen blending ratio. The conclusions obtained in this work will contribute to the structural design of flame arresters and the formulation of explosion venting strategies during the preparation, transportation and utilization of ammonia/hydrogen mixtures. • The effects of equivalence ratio and hydrogen blending ratio on the explosion characteristics of ammonia/air mixtures were investigated. • Hydrogen blending significantly increased the explosion intensity and flame instability. • The formation of concave flames has a significant dependence on equivalence ratio and the composition of the mixture. • The flame tip speed evolution can be divided into acceleration stage, deceleration stage and velocity pulsation stage. [ABSTRACT FROM AUTHOR]

• The length of duct has a great influence on the flame development of LPG/H 2 blended fuel. • There is a direct proportional relationship between the maximum explosion pressure and the length of duct. • The longer the duct, the greater the depth of the tip of the "tulip-flame" at the later stage of flame propagation. • When R H is under 40%, the duct length more significantly influences the flame propagation time than hydrogen does. The search for an efficient and clean alternative fuel is one of the research hotspots in the world's major energy countries, and the blending of different levels of hydrogen in LPG is likely to become a promising alternative energy source in the future. Therefore, this paper investigates the effects of different duct lengths and R H on the explosion characteristics of LPG/H 2 blended clean fuels under closed conditions. It reveals that the development stages of the flame and the emergence of its characteristic structures vary with duct lengths. The longer the duct, the greater the absolute position of the "plane-flame", in the late stage of flame propagation "tulip flame" tip depth, the longest tip depth of 305 mm. Hydrogenation increases the flame front speed in ducts of identical length, yet it doesn't alter the location of the characteristic "plane-flame". When R H is under 40 %, the duct length more significantly influences the flame propagation time of the LPG/H 2 blended clean fuel than hydrogen does. However, this effect reverses when R H exceeds 40 %. The P max correlates directly with duct length, the longer the length of the duct, the larger the P max. When Ф=1.0 and R H = 0.8, the P max of LPG/H 2 blended clean fuel in a 1500 mm duct is 1.51 times that of 500 mm. [ABSTRACT FROM AUTHOR]

This study experimentally and numerically determined the effect of FM-200 on H 2 /air explosion. Firstly, the explosion pressure was investigated to evaluate the suppression efficiency. The results indicated that the effect of FM-200 on H 2 /air explosion was quite different for various equivalence ratios. FM-200 could enhance the explosion at lean mixture, but suppress the explosion at rich mixture. Then, the burning velocity, heat production and temperature free radicals were investigated. The results also demonstrated that FM-200 exhibited stronger suppression effect in rich explosion. In addition, the increase of free radicals indicated the enhancement effect of FM-200 at lean explosion. Last, the analysis of sensitivity and reaction path was performed to understand the suppression kinetics. It was shown that R1466 and R1468 could suppress explosion at Φ = 1.3 and 1.6, however, they changed into promoting explosion at Φ = 0.8 and 1.0. Moreover, the reaction path analysis indicated that CHF:CF 2 →CHF:O→CO could enhance explosion at Φ = 0.8. For CHF:CF 2 →CH 2 F→HF, it played an important role in scavenging H to suppress explosion at Φ = 1.6. Furthermore, it was indicated that there was a competition between the enhancement and suppression effect at Φ = 1.3. • Several characteristic parameters of hydrogen explosion with FM-200 addition were analyzed. • The explosion was enhanced with small volume fraction FM-200 addition at lean explosion. • Reaction R1466 and R1468 could suppress explosion at rich mixtures; but promote explosion at lean mixtures. • The analysis of reaction path was performed to understand the suppression kinetics. [ABSTRACT FROM AUTHOR]

Incense is an indispensable material with religion and life in Asia. It is also a bridge of cultural expression and inheritance. Because the operating environment concentration of dust generated during the production process is considerable, most of the research pertaining to the hazard of incense factories has investigated air pollution, such as PM2.5, PM10, and VOCs. However, the production of incense causes dust dispersion, high temperature from ovens, and static electricity generated by friction. It can all possibly lead a dust explosion. To prevent and alleviate hazard from re-occurring, we used sandalwood dust at an incense factory in Taiwan, measured the effect of moisture content on the explosion parameters under normal conditions by 20-L apparatus, and used the oven to diminish its moisture content to 0%, 10.0%, and 15.0% as a control group to analyze the explosion characteristics at the different moisture contents, such as maximum explosion pressure and explosion limit. The results showed that the minimum ignition energy of dry dust was 30 mJ. Beyond doubt, incense factories face potential explosion hazards. The above results could be evaluated by the most dangerous range to avoid incense dust in this range at the workplace, lessening hazards caused by a dust explosion. The effect of moisture content on the suppression of the dust explosion was explored. [ABSTRACT FROM AUTHOR]

The effects of hydrogen addition on the explosion characteristics of liquefied petroleum gas (LPG)-air mixtures were experimentally investigated under initial conditions of 1 atm and 298 K. Furthermore, with reference to the detailed USC-Mech II mechanism, sensitivity and the rate of production (ROP) analyses were conducted. When the hydrogen proportion is constant, the maximum explosion pressure and the maximum rate of pressure rise first increase and then decrease, reaching peaks at an equivalence ratio of 1.3. The experimentally measured maximum explosion pressure is lower than the numerically calculated adiabatic pressure. The calculated adiabatic pressure decreases slightly with an increase in the hydrogen proportion. However, under the experimental conditions, owing to the high reactivity of hydrogen, the LPG-H 2 -air mixtures experience a small heat loss in the early stage of the explosion, and the maximum explosion pressure and maximum rate of pressure increase considerably, with the arrival time of the pressure peak is advanced. The addition of hydrogen promotes the sensitivity coefficient of reactants C 3 H 8 and C 4 H 10 and increases the maximum ROP of free radicals H, O, and OH. Meanwhile, the addition of hydrogen significantly influences the maximum ROP of the elementary reaction R2. • H 2 addition increases the explosion risk of liquefied petroleum gas. • Hydrogen promotes the sensitivity coefficient of reactants C 3 H 8 and C 4 H 10. • Hydrogen increases the maximum ROP values of free radicals H, O and OH. • Hydrogen has a great influence on the maximum ROP value of elementary reaction R2. [ABSTRACT FROM AUTHOR]

The aim of the article is to point out the dangers arising from the properties of plastic dust and what influence its properties have on the origin and course of the explosion. The present project analyzed the sample of polyethylene dust,by-product of granulate production and storage. The explosion tests were performed on containers of a similar shape to those found in a plants. By examining the properties of plastic dust and its behavior in the event of an explosion we have observed that the risk of explosion in technological equipment can not be underestimated. Knowledge about explosiveness of dust samples will be used in comprehensive safety solution of a particular technological node.

To further explore the propagation law of gas coal dust explosion with different coal species involved, 3 kinds of representative coal dust were tested in a self-made semi-enclosed pipe, and the flame propagation speed, flame surface luminescence intensity and maximum explosion pressure of gas coal dust explosion were studied. The results show that the maximum explosion pressure and flame propagation velocity of gas coal dust explosion rise first and then decrease with the increase of coal dust concentration, and there is an optimal gas concentration and coal dust concentration, which makes the flame propagation speed reach the maximum and the luminous intensity reach the maximum; flame propagation speed, the maximum explosion pressure and the luminous intensity produced by the explosion are reduced by lignite, bituminous coal and anthracite in turn.

To study the influence of common combustible gas produced in spontaneous combustion of underground coal on methane explosion, the effects of the mixture of C2H4, C2H6, H2 and CO on the maximum explosion pressure and temperature of methane were simulated by FLACS software at 5 initial temperatures (25, 60, 100, 140 and 180 ℃). The results show that, with the increase of initial temperature, the maximum explosion temperature of methane and the maximum explosion pressure show an upward trend, while the maximum explosion pressure shows a downward trend. With the increase of the volume fraction of the four combustible gases from 0.4% to 2.0%, the maximum explosion temperature and the maximum explosion pressure of methane increased even more when the initial temperature was lower.

In this study, we report the explosion characteristics of H 2 /N 2 O mixtures at fuel-lean side and stoichiometric condition in a 113 L cylindrical vessel. Experiments were performed at different sub-atmospherical pressures (P 0 =10 kPa–40 kPa). Explosion pressure traces were obtained by a pressure transducer mounted on the wall. Meanwhile, the flame morphology was recorded using schlieren visualization. The maximum explosion pressure (P max) and maximum pressure rise rate ( (d p / d t) max) were derived and discussed. Results show that two competitive effects (i.e., the adiabatic flame temperature and the molecular number) make the maximum P max occurring at φ =0.5—0.6. Linear correlations were found between P max and P 0. Except the adiabatic flame temperature and flame propagation speed, the flame instability was found to participate in dominating the maximum pressure rise rate. For increased initial pressure, the equivalence ratio of the maximum (d p / d t) max switches to the lean side due to the enhanced flame instability. Depending on different equivalence ratios, both linear and quadratic correlations were found between (d p / d t) max and P 0. [ABSTRACT FROM AUTHOR]

The study here presents data from the literature regarding the characteristic parameters of explosion propagation in gaseous ethane–air mixtures. The maximum explosion pressures, maximum explosion times, maximum rates of pressure increase, and deflagration indices from experimental measurements are discussed and analyzed against the initial pressure, initial temperature, and equivalence ratio, as well as the explosion vessel characteristics. Ethane is used for ethylene production, as a refrigerant in cryogenic systems, as an alternative clean fuel in the power generation industry and automotive propulsion, and for many other applications. Therefore, the explosion characteristics of its mixtures with air are of great interest for explosions occurring after accidentally forming flammable mixtures, as well as for the prediction of combustors’ performances and/or engines that work in different conditions.

The experimental parameters that significantly affect the gas explosion process were determined, investigating the pressure, temperature, and velocity in the methane‐air explosion process under quiescent and turbulent conditions. Experiments and computational fluid dynamics simulations were integrated to optimize the experimental parameters and elucidate the impact of the initial turbulence on the explosion behavior of methane‐air mixtures. Good agreement was achieved between the computed results and experimental data. For a certain CH4 concentration within the explosive limit range, an initial turbulence can increase the maximum explosion pressure and the maximum rate of the pressure rise, shorten the time to reach the maximum explosion pressure and enhance the explosion strength and destructive power of CH4‐air mixtures. Turbulent flow can significantly broaden the explosive limits of CH4‐air mixtures. The ignition delay time affects the distribution of the initial turbulence and thus the extent and severity of the explosions. [ABSTRACT FROM AUTHOR]

Premixed gas explosion pipe system was established to study the change rule of explosion pressure and pressure rise rate of 10% methane/ air premixed gas under four condition that no material was filled, used material was filled, new materials was filled and cleaned materials was filled in explosive pipe. The results show that compared with the used material and cleaned material, the average maximum explosion pressure was reduced by 21.62% and the average pressure rise rate decreased by 84.80%. The results show that the suppression performance of used aluminum alloy explosion-proof materials improved greatly after the used materials is cleaned.

It is well-known that the calorific value and heat transfer speed of coal are closely related to the coal quality index, and affect the explosion intensity and the maximum explosion pressure of coal dust explosion. In this paper, the pressure for different coal quality indexes is studied experimentally, and the main parameters affecting the pressure are elucidated by the principal component analysis of multivariate statistical analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] The main task of this work is to study the hydrogen-ammonia-air cloud explosion characteristics. The flame behavior and explosion pressure are obtained experimentally by changing equivalence ratio (ER) and ammonia fraction (AF). Then the correlation between flame behavior and maximum explosion pressure is revealed. Finally, the thermal, diffusion and chemical factors affecting laminar burning velocity (LBV) are analyzed. The results indicated that averaged flame propagation velocity (AFPV) and maximum explosion pressure (MEP), become decreased continuously with increasing AF, become increased firstly and then decreased with increasing ER. Maximum value of both AFPV and MEP of AF = 0.1, AF = 0.3, AF = 0.5 and AF = 0.7 is reached at ER = 1.4, ER = 1.2, ER = 1.0 and ER = 1.0. the MEP could be underestimated and overestimated by laminar and turbulent flame model. The MEP is largely affected by LBV especially when the flame instabilities are ignored. With increasing AF, the reduction of adiabatic flame temperature and thermal diffusivilty contributes to the LBV reduction. With increasing ER, the main factor affecting LBV is the generation and consumption of H radical. [ABSTRACT FROM AUTHOR]

Gas explosions are major disasters in coal mining, and they typically cause a large number of deaths, injuries and property losses. An appropriate understanding of the effects of combustible gases on the characteristics of methane explosions is essential to prevent and control methane explosions. FLACS software was used to simulate an explosion of a mixture of CH4 and combustible gases (C2H4, C2H6, H2, and CO) at various mixing concentrations and different temperatures (25, 60, 100, 140 and 180°C). After adding combustible gases to methane at a constant volume and atmospheric pressure, the adiabatic flame temperature linearly increases as the initial temperature increases. Under stoichiometric conditions (9.5% CH4-air mixture), the addition of C2H4 and C2H6 has a greater effect on the adiabatic flame temperature of methane than H2 and CO at different initial temperatures. Under the fuel-lean CH4-air mixture (7% CH4-air mixture) and fuel-rich mixture (11% CH4-air mixture), the addition of H2 and CO has a greater effect on the adiabatic flame temperature of methane. In contrast, the addition of combustible gases negatively affected the maximum explosion pressure of the CH4-air mixture, exhibiting a linearly decreasing trend with increasing initial temperature. As the volume fraction of the mixed gas increases, the adiabatic flame temperature and maximum explosion pressure of the stoichiometric conditions increase. In contrast, under the fuel-rich mixture, the combustible gas slightly lowered the adiabatic flame temperature and the maximum explosion pressure. When the initial temperature was 140°C, the fuel consumption time was approximately 8-10 ms earlier than that at the initial temperature of 25°C. When the volume fraction of the combustible gas was 2.0%, the consumption time of fuel reduced by approximately 10 ms compared with that observed when the volume fraction of flammable gas was 0.4%. [ABSTRACT FROM AUTHOR]

To explore the propagation of gas explosions in roadways, test pipes with circular, square, rectangular, and trapezoidal cross-sections were used to monitor the temperature and pressure changes. The results showed the longest time was required for the flame to fill the roadway with a trapezoidal cross-section. The highest temperature was observed for the square cross-section. The maximum explosion pressures in the roadways was about 0.6 MPa, but the longest time was required in the roadway with a trapezoidal cross-section, while the gas explosion temperature was the lowest, and the time to reach the maximum explosion pressure was the longest. [ABSTRACT FROM AUTHOR]

This work is aimed at evaluating unrestricted duct-vented explosion of hydrogen-air mixture and hydrogen-methane-air mixture. The flame behavior in the venting zone and explosion pressure inside explosion chamber are obtained in the experiments. On the assumption of only fresh mixture venting or only combustion product venting, a mathematical model of unrestricted duct-vented explosion is established by considering chocked venting. The results indicated that the chocked venting could be achieved for unrestricted hydrogen and hydrogen-methane explosion venting due to the fact that the Mach disc structure is appeared in venting zone. Maximum explosion pressure and maximum pressure rise rate could be reduced significantly by unrestricted duct-venting. For the unrestricted hydrogen explosion venting, maximum explosion pressure and maximum pressure rise rate increases until Φ = 1.5, then decreases monotonously with the increase of equivalence ratio. For the unrestricted hydrogen-methane explosion, maximum explosion pressure and maximum pressure rise rate continue to decrease with the increase of methane addition. Maximum explosion pressure in the experiment is between theoretical values of fresh mixture venting and combustion product venting. Maximum explosion pressure and pressure rise rate are increased with increasing burning velocity whether it is fresh mixture venting or combustion product venting. Maximum explosion pressure is increased linearly with increasing nondimensional vent coefficient. • Flame behavior and explosion pressure of duct-vented explosion are analyzed. • The mathematical model of duct-vented explosion is established. • Maximum explosion pressure of duct-vented explosion is evaluated. [ABSTRACT FROM AUTHOR]

A dust explosion occurs when an airborne combustible dust cloud encounters an effective ignition source. The resulting pressure and temperature increase can severely injure people and damage surrounding equipment and buildings, and therefore needs to be prevented or controlled (Taveau, 2016). The article deals with the measurement of maximum explosion pressure and maximum rate of explosion pressure rise of sugar dust cloud. The measurements were carried out according to STN EN 14034-1+A1:2011 Determination of explosion characteristics of dust clouds. Part 1: Determination of the maximum explosion pressure pmax of dust clouds, the maximum rate of explosion pressure rise according to STN EN 14034-2+A1:2012 Determination of explosion characteristics of dust clouds - Part 2: Determination of the maximum rate of explosion pressure rise (dp/dt) max of dust clouds and Determination of explosion characteristics of dust clouds. Part 3:Determination of the lower explosion limit LEL of dust clouds. The sugar dust cloud in the chamber is achieved mechanically. The testing of explosions of sugar dust clouds showed that the maximum value of the pressure was reached at concentrations of 1000 g / m3 and its value is 6,89 bars.

Zirconium powder, a main potential dangerous source in nuclear industry, has been focused on its explosion characteristics in this paper. Experiments were performed in a 20 L cylindrical explosion vessel with the influences of initial ignition energy, ignition delay time and zirconium concentration. Results showed that the maximum explosion pressure of zirconium-air mixture rose with the increase of the initial ignition energy, and a peak value was obtained with the variation of the ignition delay time. Lower explosion limit with the initial ignition energy of 10 kJ is 10 g/m³. Furthermore, explosion severity parameters, including maximum explosion pressure, maximum rate of pressure rise and maximum explosion index of zirconium-air mixture, were also obtained with the coupling variation between initial ignition energy and dust concentration. Research results and data obtained are a supplement to the utilization and safety operation of zirconium powders. [ABSTRACT FROM AUTHOR]

In order to explore the effect of gas explosion on the refuge chamber of coal mine, this paper carried out a numerical simulation on the process of gas explosion under the closed and open condition respectively. The physical model of the refuge chamber was established by means of applying the software of ICEM, and then Fluent software was used to carry out the numerical simulation on the pressure and temperature variation of gas explosion under different boundaries. In addition, The Origin software was used to carry out the curve fitting of the pressure as well as the temperature variation during the process of the gas explosion. The results show that under the sealing condition, the refuge chamber need withstand the high pressure of 0.61 MPa and the high temperature of 2269 K; under the condition of opening, the refuge chamber only need withstand the overpressure of 12.39 KPa and the high temperature of 1773 K respectively. Considering comprehensively the explosion overpressure and the high temperature, the position of the refuge chamber should be far away from the dead end roadway. [ABSTRACT FROM AUTHOR]

• MPe maximum rate of pressure rise was insensitive to the initial temperature. • MPe experimental and adiabatic deflagration indices showed satisfactory agreement. • MPe explosions were hazardous at high pressures and in rich mixtures. • MPe unstable flame crack lengths and cell numbers were more sensitive to pressure. Combustible fuels like methyl pentanoate (MPe) could cause accidental explosions and fire. Therefore, MPe explosion characteristics have to be well characterized and understood for its safe and reliable use in industries and combustion devices. Considering this, MPe's explosion pressure, maximum explosion pressure, rate of pressure rise, maximum rate of pressure rise, heat release rate, etc., were investigated in this study at the initial conditions of 1, 2, and 4 bar and 423 K, 453 K, and 483 K using the equivalence ratios of 0.7–1.4. The maximum explosion pressures and maximum rate of pressure rise of MPe increased as the initial pressures increased but the maximum rate of pressure rise was insignificantly affected by the initial temperature. The explosion duration decreased with a decrease in the initial pressure. The maximum heat release rate and deflagration index increased with increasing initial pressure. The MPe maximum deflagration index was 224.8 bar•m/s, which occurred at a higher initial pressure and fuel-rich mixture. Therefore, the explosion severity of MPe was enhanced at higher initial pressures and fuel-rich mixtures. Moreover, the flame cellularity study showed that MPe unstable flame crack length and cell number were more affected by increments in the initial pressure and equivalence ratio. Therefore, flame instability and cellularity would significantly influence explosion severity at higher pressures and equivalence ratios. This study's findings provide first-hand data that could be used to further investigate and characterize MPe's explosion risk. [ABSTRACT FROM AUTHOR]

[Display omitted] • Explosion characteristic parameters of raw and oil-immersed coals were determined. • The explosive intensity of oil immersed coal dust was increased. • The MEC for finer coal dust was lower, whereas the MEC for the coarser dust was higher. • The 6 wt% oil concentration obviously increased the explosion risk of coal dust. • The pre-post explosion microstructure for the coals was analysed. To investigate the explosion hazards of oil-immersed coal dust in co-existing mine areas, the explosion characteristic parameters of coal dust under different particle dimensions, coal dust concentration, and oil-immersed concentration were studied in a 20-L explosion chamber. The maximum explosion pressure of oil-immersed coal dust first decreases and then increases as coal dust particle size increases. For oil-immersed concentration samples between 2 and10 wt.%, the K st value, and maximum explosion pressure of the oil-immersed samples were higher than those of the raw coal counterpart. The maximum explosion pressure of oil-immersed samples was 7.49%, 4.10%, 5.7%, 7.13%, and 4.10% higher than the raw samples. Moreover, when the oil-immersed concentration was 6 wt%, the minimum explosion concentration (MEC) of finer particles was the lowest, while the MEC for large particles was the highest. The impact mechanism of coal dust concentration on maximum explosion pressure is that the number of coal dust particles affects the distance between particles and heat transfer efficiency. The influence mechanism of particle size on the explosion of oil-immersed coal is that the particle size can reflect the specific surface area size, which affects the diffusion of oxygen in particles and the rate of combustible volatiles released by particles. Hydrocarbons released from the crude oil via heating and the complex organic molecules generated during high-temperature pyrolysis produced simpler hydrocarbons, generating hydrogen and higher temperatures that accelerated the onset of explosions and increased coal dust explosion intensity. These experimental results were of use to process safety working and can help prevent coal dust explosion accidents in underground coal mines. [ABSTRACT FROM AUTHOR]

• The explosion behaviors of gaseous binary fuel (H 2 /C 3 H 8) at N 2 O atmosphere were firstly investigated. • The presence of N 2 O makes explosion extremely unstable due to its heat release during decomposition. • A spot of propane can dramatically alter the explosion characteristics of H 2 -N 2 O mixtures. • The maximum explosion pressure and maximum pressure rise rate both present three characteristic trends with propane fraction. • The effect of initial pressure on flame acceleration and heat loss was found and analyzed. In the present work, the explosion of hydrogen-propane-nitrous oxide mixtures with various equivalence ratios (ϕ = 0.2 - 2.4), propane fractions (ω C = 0 - 1.0) and initial pressures (P 0 = 50 - 100 kPa) at ambient temperature (288 K, room temperature) was experimentally performed in a standard 3.375-L cubic vessel. The maximum explosion pressure (P max), maximum pressure rise rate ((d p / d t) max) and explosion time (t e) were obtained in light of pressure–time curves, and the normalized maximum explosion pressure (P max / P 0) and normalized explosion time (t d / t e) were analyzed as well. Moreover, the adiabatic pressure (P ad) and laminar burning velocity (S L) were also calculated for argumentation. The results indicate that with the increase of ω C , P max and (d p / d t) max both present three characteristic variation trends for different ϕ , while the inflections of P max - ϕ and (d p / d t) max - ϕ transient gradually from lean to rich mixtures. Besides, t e and t d / t e are monotonously rising with ω C , illustrating that propane addition can remarkably decelerate the explosion process. In addition, with the increase of P 0 , P max / P 0 raises monotonously and is asymptotic to P ad / P 0 at ω C ⩽ 0.2 , demonstrating that heat loss decreases under higher P 0. Linear dependence is also found between (d p / d t) max and P 0 for any composition. Furthermore, t e monotonically decreases with P 0 , due to the flame acceleration occurring in the combustion period. In general, the presence of nitrous oxide (N 2 O) with a large content makes the explosion extremely unstable, and a spot of propane can dramatically alter the explosion characteristics of H 2 -N 2 O mixtures. These results will be meaningful for the development of explosion-mitigation devices and technology in case of underlying explosion and fire hazards. [ABSTRACT FROM AUTHOR]

The aim of this paper is to approximate danger of dust clouds normally occur by determining their explosion characteristics. Nowadays, dusty environment is phenomenon in the industry. In general, about 70% of dust produced is explosive. Dust reduction in companies is the main purpose of the national and European legislative. Early identification and characterization of dust in companies may reduce the risk of explosion. It could be used to identify hazards in industrial production where an explosive dust is produced. For this purpose several standards for identification and characterization of explosion characteristics of industrial dust are being used.

The explosion characteristics of a hydrogen–propane mixture under different initial temperatures and at different hydrogen addition, equivalence, and dilution ratios were studied using a 20-L apparatus. First, the effects of hydrogen addition and equivalence ratio were studied. The results showed that the maximum explosion pressure and the maximum rate of pressure rise first increased, then decreased from lean to an equivalence ratio of 1.6, and reached the maximum value at the equivalence ratio of 1.2. The maximum explosion pressure and the maximum rate of pressure rise increased with the increasing hydrogen proportion of the mixtures, and the time to the maximum explosion pressure decreased. Furthermore, the mixed fuel with the equivalence and hydrogen addition ratios of 1.0 and 0.4, respectively, was explored under nitrogen or carbon dioxide dilution. Carbon dioxide exhibited a stronger dilution effect than nitrogen. For the mixed fuel with the equivalence and hydrogen addition ratios of 1.0 and 0.4, respectively, the maximum explosion pressure saliently decreased with the increasing initial temperature in the range of 25 °C-120 °C. The variation trend of experimental results was consistent with theoretical predictions. • P max , (d P /d t) max , K G and S L reached the maximum value at φ = 1.2. • P max , (d P /d t) max , K G and S L increased with increased H 2 content in the mixed fuel. • CO 2 had a stronger dilution effect than N 2 at the same dilution ratio. • P max decreased with increased initial temperature, and t 1 was reduced. [ABSTRACT FROM AUTHOR]

• Explosion pressure and rate of explosion pressure rise determined for Li-ion battery electrolyte solvents. • Upper and Lower explosive limit determine for Li-ion electrolyte battery solvents. • All Li-ion battery electrolyte solvents have similar explosion characteristics. • The Li-ion battery electrolytes have similar explosion characteristics has propane. Li-ion batteries are used in electronic devices and electric cars, yet they create safety concerns due to the possibility of the release of combustible materials. The electrolyte, one of the main components in a Li-ion cell, consists of organic carbonates. Venting and thermal runaway release organic carbonates and when mixed with air, it can result in fires and explosions. A 20-liter explosion sphere was used to determine the explosion characteristics for three typical carbonates used in electrolytes, at 373 K, and 100 kPa absolute pressure. The explosion pressure and the maximum rate of explosion pressure rise are presented for the carbonates and for hydrogen, methane, and propane, and the explosive limits for the carbonates are also identified at the same conditions. This allowed a comparison of the explosion characteristics for the carbonates with those for hydrogen, methane, and propane. Theoretical calculations gave a higher explosion pressure than that from the experimental results most likely due to losses in the hydrocarbon experiments. The carbonates analyzed have very similar explosion pressures and rate of explosion pressure rise as propane. The explosion characteristics found for the three carbonates can be used in future consequence and risk assessments for Li-ion battery installations. [ABSTRACT FROM AUTHOR]

Wood dust samples with different particle sizes were used to investigate the explosion characteristics of wood dust. The dust samples came from Populus alba L., Pinus massoniana Lamb., and Cinnamonum camphora (L.) Pres., species that are commonly utilized in medium density fiberboard production in China. The thermogravimetric characteristics, element composition, and morphology of dust samples were analyzed to help explain the explosion phenomena in a 20 L sphere. The analysis showed that both the maximum explosion pressure and explosion index of wood dust presented a decreasing trend with increasing particle size, and the maximum explosion pressure values were in the range of 7 to 9 bar, regardless of species. For both explosion pressure and explosion index values, the wood dust with similar particle sizes were different, which are ranked as Populus alba > Cinnamonum camphora > Pinus massoniana. In addition, for the explosion pressure of wood dust with similar particle size, the dust concentration had threshold values. Additionally, the particle size and dust concentration had a synergistic effect on the explosion pressure and explosion index. Wood dust with a smaller particle size is more likely to explode at the threshold of concentration. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Effect of a single orifice on methane-air explosions are studied. • Maximum explosion pressure decreases with the presence of orifice plates. • Maximum pressure rise rate was anomalous compared with that obtained without orifice plate. Abstract In this study, the explosion behaviors of methane-air mixtures were investigated experimentally in a cylinder vessel (210 mm inner diameter and 210 mm height) filled with a single orifice plate at atmospheric pressure (1 atm) and room temperature (298 K). The equivalence ratios of the test mixtures ranged from 0.7 to 1.3. The blockage ratios of the orifice plates were from 0.49 to 0.94, and the distance between the orifice plates and the ignition point (S) were 25 mm, 50 mm and 75 mm. The results show that the maximum explosion pressure in the presence of an orifice plate. However, the effects of the orifice plate on the maximum rate of pressure rise are various. At the fuel-lean side, the maximum pressure rise rate is increased significantly (larger than that of the stoichiometric condition). As the distance between the orifice plate and ignitor increases, the maximum pressure rise rate increases. In the case of the fuel-rich conditions, the maximum pressure rise rate is the smallest for S = 25 mm, followed by the no plate condition, S = 50 mm and S = 75 mm. The mechanisms are left for further study. [ABSTRACT FROM AUTHOR]

The properties of an ethane-ethylene mixture were analyzed under varying equivalence ratios (ranging from 0.58 to 1.4) and ethylene volume fractions (ranging from 0% to 100%) with varying dilution ratios, using a 20-liter apparatus. The study aimed to understand the explosion characteristics of the mixture and to identify the elementary reactions that have the most significant impact on the rise in pressure and ethylene consumption during the explosion process. The results showed that adding ethylene increases the maximum explosion pressure and broadens the flammability limit range. In addition, the work investigated the effects of diluting the mixture with either nitrogen or carbon dioxide. It was found that carbon dioxide has a higher specific heat capacity compared to nitrogen, which enhances the heat absorption capacity of the mixture. The collision of carbon dioxide molecules with the activated radicals in the reaction transfers energy from the radicals to carbon dioxide, reducing the radicals' activity and causing a more significant dilution effect than nitrogen. Finally, a chemical kinetics analysis of the premixed gas using the UC San Diego mechanism revealed that the production rate of key free radicals gradually increases with the addition of ethylene, enhancing the explosion reaction intensity. • Ethylene addition broadens flammability limit & increases max explosion pressure. • Carbon dioxide dilution enhances heat absorption & reduces radicals' activity. • Carbon dioxide dilution causes a more significant dilution effect than nitrogen. • Sensitivity analysis using UC San Diego mechanism enhances explosion reaction intensity. • Study provides insights into explosion characteristics of ethane-ethylene mixtures. [ABSTRACT FROM AUTHOR]

In this work, explosion characteristics of stoichiometric shale gas were studied employing a standard 20-L explosion bomb. Shale gas was represented by methane/ethane, methane/propane, and methane/ethane/propane mixtures, and the effect of fuel compositions, the volume fraction of ethane (or propane) increases from 0 to 0.42, on explosion parameters was examined. Results show that the maximum explosion pressure, the maximum explosion pressure rising rate, and the laminar flame speed increase with the volume fraction of ethane (or propane). The reason is that the increment of ethane (or propane) volume fraction increases the mole fraction of [H + O + OH] max. For a given volume fraction, propane provides more heat and H, O, and OH radicals, and consequently, propane shows a more robust incentive function on explosion parameters. Finally, the CH ratio, which is defined as the ratio of total carbon atoms and hydrogen atoms, is used to further study the explosion characteristics of various fuel compositions. There is a robust linear relationship between the CH ratio and explosion parameters. For laminar flame speed, however, the global fit curve provides poor accuracy while the local fitting curves coincide well with the data. This indicates that the laminar flame speed is more sensitive to the gas species. • The increment of ethane (or propane) in shale gas increases the explosion intensity. • Propane shows a stronger incentive effect on explosion because it releases more key radicals. • There is a robust linear relationships between CH ratio and P max (or (dP/dt) max). • Gas species significantly affect the linear relationship of CH ratio and S uL. [ABSTRACT FROM AUTHOR]

Abstract Explosion characteristics of syngas/air mixtures was investigated numerically in a 3-D cylindrical geometric model, using ANSYS Fluent. The results showed that the maximum explosion pressure increased from lean to an equivalence ratio of 1.2, then decreased significantly with richer mixtures, indicating that maximum explosion pressure occurred at the equivalence ratio of 1.2, while explosion time was shortest at an equivalence ratio of 1.6. Increasing H 2 content in the fuel blends raised maximum explosion pressure and significantly shortened the explosion time. Normalized peak pressure was sensitive to the initial pressure of the mixture, showing that they significantly changed with increased initial pressure. [ABSTRACT FROM AUTHOR]

In the present article, the evolution of explosion pressure for 50%H2-50%CO syngas-air mixtures with a wide range of equivalence ratio in various turbulent ambience had been experimentally studied in a 28.73-L fan-stirred explosion vessel. Equivalence ratio varied from 0.4 to 3.0, and the turbulent intensity varied from 0 to 1.309 m/s. The results indicated that explosion indices (including maximum explosion pressure, explosion duration, and the maximum rate of pressure rise) were not monotonous to equivalence ratio, and the inflection equivalence ratio for different indices was different. The maximum explosion pressure was attained at the equivalence ratio of 1.2 for the reasons about maximum adiabatic flame temperature, the minimum explosion duration was attained at the equivalence ratio of 2.0 for the reasons about fastest laminar burning velocity, and the maximum rate of pressure rise was attained at the equivalence ratio of 1.6 for the competition effects of laminar burning velocity and adiabatic flame temperature. With the increase of turbulent intensity, the maximum explosion pressure and the maximum rate of pressure rise were raised albeit the growth tendencies were different for different ranges of equivalence ratio; the major reason to the growths was the heat transferred the wall during explosion had been reduced. Furthermore, with the increase of turbulent intensity, the value of deflagration index significantly rose even the values were higher than 30 MPa m/s for most cases in a weaker turbulent ambience; the results indicated that keeping the ambience quiescent is one better safety protection to syngas. [ABSTRACT FROM AUTHOR]

This paper aims at exploring the explosion characteristics of -10# and -35# diesels experimentally. The diesel gas in the explosion chamber is obtained by heating the diesel at various temperatures. The results demonstrate that the maximum explosion pressure of -10# and -35# diesels increases firstly and then decreases as the diesel temperature increases. More premixed gas of -10# and -35# diesel is vaporized at 130℃ and 86℃, respectively. Besides, the higher temperature of -10# diesel is needed to reach the same volume concentration and maximum explosion pressure compared with -35# diesel. [ABSTRACT FROM AUTHOR]

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