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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。
Aiming at the post-combustion phenomenon of rocket plume, a reaction mechanism considering the elementary reaction involving the intermediate product HO2 was established. By applying this reaction mechanism by CFD method, a model of axisymmetric nozzle was set up at four different flight levels simulation. At the same time, under the same conditions, the post-combustion field with typical HO2-free reaction mechanism and the post-combustion field using the reaction mechanism based on the chemical equilibrium assumption were calculated and obtained respectively. By comparison, it is found that the assumption of chemical equilibrium is not suitable for the calculation of afterburning flow field. Using the reaction mechanism including HO2, higher plume temperature can be obtained with the temperature difference up to 100K. The results of CO and CO2 mass fraction distribution are in good agreement with other reaction mechanisms Approximately, there are great differences in the O and OH mass fraction distributions with respect to the reaction mechanism without considering HO2. In particular, the mass fraction of O is only 10% ~ 73% of the latter at flight altitudes of 5 ~ 35km; It is proved that it is necessary to consider HO2 when calculating the post-plume flow field.