Flammability limits are important safety parameters of each flammable material. Thermal theory of flame propagation suggests existence of a threshold temperature above which a flame propagates. Density theory of flame propagation suggests existence of a threshold density factor above which a flame propagates; density factor is defined as the ratio of before ignition to after ignition density. Based on a general version of thermal theory of flame propagation, constancy of values of adiabatic flame temperature at each flammability limit can be used to predict flammability limits. Similarly, based on a general version of the density theory of flame propagation, constancy of values of density factor at each flammability limit can be used to predict flammability limits. This work reports and compares predictions of general versions of both thermal theory and density theory of flame propagation for lower flammability limits and for upper flammability limits. This work shows that thermal theory and density theory both perform well at predicting the lower flammability limit while density theory performs far better than thermal theory at predicting the upper explosive limit.

中文翻译：

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通过火焰传播的热理论和密度理论预测可燃性极限

可燃性极限是每种易燃材料的重要安全参数。火焰传播的热理论表明存在一个阈值温度，高于该阈值温度火焰传播。火焰传播的密度理论表明存在一个阈值密度因子，高于该阈值密度因子火焰传播；密度因子定义为点火前与点火后密度的比值。基于火焰传播的热理论的一般版本，可以使用在每个可燃性极限处的绝热火焰温度值的恒定性来预测可燃性极限。类似地，基于火焰传播的密度理论的一般版本，每个可燃性极限处的密度因子值的恒定性可用于预测可燃性极限。这项工作报告并比较了对火焰传播的热理论和密度理论的一般版本的预测，以用于较低的可燃性极限和较高的可燃性极限。这项工作表明，热理论和密度理论在预测可燃性下限方面都表现良好，而密度理论在预测爆炸上限方面的表现要好于热理论。