Numerical simulations of one-dimensional pulsating detonation in off-stoichiometric n-heptane/air mixtures are conducted by solving the reactive Navier–Stokes equations with a skeletal chemical mechanism. The effects of mixture equivalence ratio, initial pressure and temperature on pulsating detonations are studied. The results show that the pulsating instabilities in n-heptane/air mixtures are strongly affected by equivalence ratio. It is seen that pulsating instability only occurs in the fuel-lean or fuel-rich cases, whereas stable detonation is obtained for near-stoichiometric mixtures. Low-frequency pulsating detonations with single mode are observed, and decoupling / coupling of the reaction front and leading shock front occur periodically during the pulsating detonation propagation. The heat release and flame structure at the reaction front of the fuel-lean case differ from those in the fuel-rich case, and thus affects the DDT process of the reaction front. The pulsating detonation frequency is considerably influenced by equivalence ratio, initial pressure and temperature. The results of chemical explosive mode analysis and budget analysis of energy equation reveal that the mixture between the reaction front and shock front is highly explosive and thermal diffusion would promote the periodic dynamics of the reaction front and shock front. It is also found that the chemical explosion mode in the induction zone consists of two parts, i.e. the autoignition dominated reaction immediately behind the leading shock front and a following propagating reaction front.

非化学计量正庚烷/空气混合物中一维脉动爆轰的数值模拟是通过求解具有骨架化学机理的反应性Navier–Stokes方程进行的。研究了混合当量比，初始压力和温度对脉冲爆轰的影响。结果表明，n中的脉动不稳定性庚烷/空气混合物受当量比的影响很大。可以看出，脉动不稳定性仅发生在燃料稀薄或燃料丰富的情况下，而对于接近化学计量的混合物，则获得了稳定的爆震。观察到具有单模的低频脉动爆震，并且在脉动爆震传播期间周期性地发生反应前沿和前冲激震前沿的解耦/耦合。贫燃料箱反应前沿的放热和火焰结构与富燃料箱反应壳的不同，因此影响了反应前沿的DDT过程。脉冲爆震频率受当量比，初始压力和温度的影响很大。化学爆炸模式分析和能量方程预算分析的结果表明，反应前沿和激波前沿之间的混合具有很高的爆炸性，热扩散将促进反应前沿和激波前沿的周期性动力学。还发现感应区中的化学爆炸模式由两部分组成，即在前冲激波前沿之后的自燃主导反应和在随后的传播反应前沿。