涉及HO2的中间反应对火箭羽流后燃流场数值模拟的影响

Effects of Intermediate Reaction Involving HO2 on Simulation of Rocket Plume Afterburning

关键词:  火箭羽流  后燃  反应机理  HO₂

Key words:  Rocket plume  Afterburning  Reaction mechanism  HO₂

摘要:

针对火箭羽流的后燃现象，建立了考虑涉及中间产物HO₂的基元反应的反应机理，并通过CFD方法应用此反应机理，对一个轴对称喷管模型在4个不同的飞行高度下进行数值模拟。同时，在相同的条件下，分别计算并获得了采用典型的不含HO₂的反应机理的后燃流场，以及采用建立在化学平衡假设基础上的反应机理的后燃流场。通过对比发现，化学平衡的假设不适合后燃流场的计算；利用包含HO₂的反应机理会得到较高的羽流温度，温度差别最大可达100K，CO和CO₂质量分数分布结果与其他反应机理近似，在O和OH质量分数分布上与不考虑HO₂的反应机理差别很大，尤其是O的质量分数，在5～35km的飞行高度内，仅为后者的10%～73%；从而综合证明了在计算羽流后燃流场时考虑HO₂是有必要的。

Abstract:

A reaction mechanism involving intermediate reaction product HO₂ was established for flow field simulation of afterburning of rocket plume. The mechanism was applied in CFD method to simulate the afterburning plume from an axisymmetric nozzle model at four altitudes. For comparison，a common mechanism without HO₂ and a mechanism based on chemical equilibrium were used for the mentioned calculation. The results show that the hypothesis of chemical equilibrium was not appropriate for afterburning course. And compared with the common one，mechanism taking HO₂ into account caused similar CO/CO₂ mass fraction but higher temperature which had a maximum increasing of 100K. As for the mass fraction of O/OH，there were huge disagreements，especially for the mass fraction of O whose value from the mechanism with HO₂ various from 10% to 73% of that from the common mechanism，within the flight altitude from 5km to 35km. And it was concluded that HO₂ was necessary to be involved into the simulation of afterburning plume.