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A series of experiments were conducted to study the thermal failure hazard of large-format commercial lithium-ion batteries with typical states of charge in a calorimeter apparatus. The results indicate that the thermal failure penetration of the lithium-ion battery with 70% state of charge is faster than the lithium-ion battery with 50% state of charge. Two typical thermal failure modes, ''Gas-driven mode'' and ''Flame-driven mode,'' were also observed, corresponding to lithium-ion battery with 70% state of charge and 50% state of charge, respectively. Significant heat release, accompanied by large amount of carbon dioxide (CO 2) release, took place for lithium-ion battery with 50% state of charge. Inversely, lithium-ion battery with 70% state of charge presented a lower heat release while more carbon monoxide (CO) generation and obvious mass loss trend. This study may serve as a reference for safe storage, application, and transportation in lithium-ion batteries.

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In this work, the explosive combustion of NH3/CH3OH/air mixtures covering wide ranges of equivalence ratios (0.7–1.7) and CH3OH mole fractions (0.2–1.0) was investigated experimentally and theoretically at ambient temperature and pressure. Results showed that the addition of CH3OH increases the maximum explosion pressure and maximum pressure rise rate. The empirical correlations for the maximum explosion pressure and maximum pressure rise rate are proposed, respectively. Furthermore, the heat loss of the explosion decreases significantly with the increasing CH3OH mole fraction. According to the instability analysis, the tendency of flame instability is enhanced with the enrichment of CH3OH due to the promoted hydrodynamic instability. Besides, the maximum pressure rise rate is augmented by flame instability. Kinetic analysis indicates that the CH3OH addition enhances the net heat release rate and active radicals. The total heat release of the NH3/CH3OH/air explosion is mainly attributed to the reactions R3: OH + H2 ⇔ H + H2O, R11: HO2 + H ⇔ 2OH, R24: CO + OH ⇔ CO2 + H, and R284: NH3 + H = NH2 + H2, while the predominant endothermal reaction is R1: H + O2 ⇔ O + OH. With the addition of CH3OH, the chemical effect has the largest contributions to the accelerated flame propagation on the lean and stoichiometric side, while the contributions of thermal and transport effects are dominant on the rich side.

The effect of initial temperature and initial pressure on lower explosion limit (LEL) of RP-3 aviation kerosene vapor was investigated experimentally. The experiments were conducted in an explosion limit equipment at initial temperature of 40-160 °C and initial pressure 100-160 kPa. In the temperature-pressure range studied, the LEL decreases with the increase of the initial temperature, while increases as the initial pressure increases. A correlation formula established in the present study can predict the experimental data well. A comparison of the temperature dependence and pressure dependence indicates that the LEL of RP-3 aviation kerosene vapor is mainly affected by the initial temperature. This guides people to pay more attention to the aspect of the heat transfer in the fuel tank of aircrafts avoiding the explosion risk caused by high temperature.

The blend of ammonia (NH3) and dimethyl ether (DME) is a promising renewable and clean fuel. This work studies the basic explosion characteristics of NH3/DME/air with varying equivalence ratios (from 0.6 to 1.8) and DME fractions (from 0.2 to 1). Three essential parameters, i.e., explosion pressure (P max), explosion time (t c), and maximum pressure rise rate ((dP/dt)max), were experimentally obtained, and the heat loss during the explosion was quantitatively analyzed. Besides, the heat release characteristics and critical flame radius of destabilization in the explosion process were analyzed using the detailed NH3/DME reaction mechanism. The results showed that adding DME to the mixture can significantly increase the P max, increase the (dP/dt)max, and shorten the t c. The heat loss during the NH3/DME/air explosion mainly presents a negative correlation with the explosion intensity, as reflected by (dP/dt)max and t c. In addition, at stoichiometric ratios, the elementary reaction R12: H + OH + M = H2O + M contributes most to the total heat release of the NH3/DME/air explosion, while the NH3- or DME-related reactions subdominate the total heat production. Adding DME reduces the critical flame radius, causing the flame to enter an unstable state earlier, which is mainly dominated by the hydrodynamic effect.