Kinetics of physicochemical processes occurring during combustion of a hydrogen–air mixture initiated by a shock wave was studied using state-to-state and mode models that take into account nonequilibrium vibrational excitation of N2, O2, H2, and OH molecules. The effect of vibrational–translational relaxation on the induction time was considered: it was shown that the delay in establishing thermodynamic equilibrium between vibrational and translational degrees of freedom slows down the initiation of combustion, while the intensity of this effect depends on the temperature and pressure of the gas behind the shock front. An analysis of the peculiarities of vibrational distributions showed that populations of the lower vibrational levels of molecules in the course of chain reactions of combustion behind the shock wave are close to the Boltzmann ones. Therefore, it is sufficient to use the mode approximation. Calculations of the induction time using models of mode approximation showed a significant dependence of the results on the choice of the nonequilibrium factor model. If the nonequilibrium factors are calculated based on the summation of level rate constants of physicochemical processes, the accuracy of the mode model is not inferior to the accuracy of the state-to-state approximation.

中文翻译：

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在状态到状态和模式近似下冲击波条件下对 H2-空气混合物点火的振动非平衡影响建模

使用考虑 N2、O2、H2 和 OH 分子的非平衡振动激发的状态到状态和模式模型研究了由冲击波引发的氢-空气混合物燃烧期间发生的物理化学过程的动力学。考虑了振动-平移弛豫对诱导时间的影响：结果表明，在振动和平移自由度之间建立热力学平衡的延迟会减慢燃烧的开始，而这种影响的强度取决于温度和压力冲击波前的气体。对振动分布特性的分析表明，在冲击波后面的燃烧链反应过程中，分子的较低振动能级的群体接近玻尔兹曼的群体。因此，使用模式近似就足够了。使用模式近似模型计算诱导时间显示结果对非平衡因子模型的选择有显着依赖性。如果基于物理化学过程的水平速率常数的总和计算非平衡因子，则模式模型的精度不亚于状态到状态近似的精度。