Abstract

The nonmonotonic boundary of the “three pressure limits” region experimentally obtained by N.N. Semenov and coworkers in a wide pressure range of ~20–600 Torr was reproduced for the first time by two numerical kinetic methods for stoichiometric methane–oxygen mixtures. The self-ignition delays were modeled in the same range of parameters in which three pressure limits were also found experimentally from delays. A nonlinear scheme of methane oxidation (150 reactions) was used to calculate the ignition delays. From the linear part of the same scheme (~20 reactions of the methyl peroxide cycle), formulas for the corresponding Jacobian matrix determinant were obtained, and three roots with respect to pressure were found for each given temperature from the equation for zero determinant, which were used to construct the nonmonotonic (according to pressure) boundary line of the self-ignition region. Satisfactory convergence of the experimental and calculated data was obtained both in terms of delay times and position of the limits in the P–T space.

中文翻译：

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СН4 + 2О2 混合物压力着火极限对温度的非单调依赖性的本质

摘要

NN Semenov 及其同事在约 20-600 Torr 的宽压力范围内实验获得的“三压力极限”区域的非单调边界，首次通过化学计量甲烷-氧气混合物的两种数值动力学方法重现。自燃延迟是在相同的参数范围内建模的，其中还通过延迟实验发现了三个压力限制。使用甲烷氧化的非线性方案（150 个反应）来计算点火延迟。从同一方案的线性部分（甲基过氧化氢循环的〜20个反应），获得了相应的雅可比矩阵行列式的公式，并从零行列式的方程中找到了每个给定温度的三个关于压力的根，用于构建自燃区域的非单调（根据压力）边界线。在延迟时间和极限位置方面，实验数据和计算数据都得到了令人满意的收敛。P-T空间。