Abstract: To study the influence and mechanism of plasma chemical kinetics on the combustion flow fieldof hydrogen/air in a scramjet combustor，different concentrations of active particles has been added in hydrogenfuel jet to simulate the chemical kinetic effects of plasma. Under the different active particles concentrations，the formation of product water，the pressure distribution around the rear wall and the mechanism of plasma chemical kinetics in combustion chamber are numerically studied. The results show that，in the early stage of combustion，the higher concentration of active particles，the faster formation of combustion products and the wider the distri.bution in combustor. The effect of plasma heightens the pressure peak value near the end point of the rear edge center domain of cavity，the maximum increase of peak value is 9.4%，and also weakens the pressure peak value near the side region of rear edge，the maximum damping of peak value is 7.7%. The plasma chemical kinetics ac.celerates the reaction of the original core reaction of hydrogen and oxygen，so that the O，OH and the other inter. mediate particles needed for subsequent combustion are rapidly accumulated，thus speeding up the overall reac. tion and shortening the formation time of the products.

Key words: Scramjet engine；Chemical kinetic effects；Plasma；Numerical simulation

摘要： 为探究等离子体化学动力学对超燃燃烧室中氢氧燃烧流场的影响及其相关机理，在氢气燃料喷流中添加不同浓度的活性粒子以模拟等离子体化学动力学效应。利用数值模拟手段，分析了不同活性粒子浓度下，超燃燃烧室中产物水的生成、凹腔后缘近壁面处压力分布以及等离子体化学动力学相关作用机理。研究结果表明:在燃烧反应建立初期，活性粒子浓度越高，燃烧产物形成越快、分布范围越广。等离子体的作用使得凹腔后缘近壁面中心区终点处压力峰值增大，峰值最大增幅 9.4%，同时也削弱了侧壁面区域压力峰值，峰值最大减幅 7.7%。等离子体化学动力学通过加快氢氧原有核心反应的正向进行，使得后续燃烧所需要的 O，OH等粒子被快速积累，从而加快了反应的总体进行，缩短了产物生成时间。

关键词: 超燃冲压发动机；化学动力学效应；等离子体；数值计算