Detonation development inside spark ignition engines can result in the so called super-knock with extremely high pressure oscillation above 200 atm. In this study, numerical simulations of autoignitive reaction front propagation in hydrogen/air mixtures are conducted and the detonation development regime is investigated. A hot spot with linear temperature distribution is used to induce autoignitive reaction front propagation. With the change of temperature gradient or hot spot size, three typical autoignition reaction front modes are identified: supersonic reaction front; detonation development and subsonic reaction front. The effects of initial pressure, initial temperature, fuel type and equivalence ratio on detonation development regime are examined. It is found that the detonation development regime strongly depends on mixture composition (fuel and equivalence ratio) and thermal conditions (initial pressure and temperature). Therefore, to achieve the quantitative prediction of super-knock in engines, we need use the detonation development regime for specific fuel at specific initial temperature, initial pressure, and equivalence ratio.

中文翻译：

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氢/空气混合物中热点自燃和爆轰发展的数值研究

火花点火发动机内部的爆震发展会导致所谓的超爆震，在 200 个大气压以上具有极高的压力振荡。在这项研究中，进行了氢气/空气混合物中自燃反应前沿传播的数值模拟，并研究了爆轰发展机制。具有线性温度分布的热点用于诱导自燃反应前沿传播。随着温度梯度或热点尺寸的变化，确定了三种典型的自燃反应前沿模式：超音速反应前沿；爆轰发展和亚音速反应前沿。考察了初始压力、初始温度、燃料类型和当量比对爆轰发展机制的影响。发现爆轰发展机制强烈依赖于混合物成分（燃料和当量比）和热条件（初始压力和温度）。因此，要实现对发动机超爆震的定量预测，需要利用特定燃料在特定初始温度、初始压力和当量比下的爆震发展机制。