复燃对液体火箭返回阶段底部热环境的影响

为了研究垂直起降液体火箭在返回阶段发动机反向喷流及复燃对箭体着陆支腿和底部热环境的影响,建立了尾焰复燃、流场及光谱辐射计算模型。在国内率先对垂直起降液体火箭在返回阶段的箭体底部热环境进行了数值计算,流场计算采用商业软件,复燃反应使用有限速率化学反应模型;采用HITRAN数据库获得喷流气体组分的光谱吸收系数、正反光线踪迹法求解辐射传递方程。利用文献实验结果,对计算进行了验证并考察了复燃对底部热环境的影响。结果表明:复燃反应对包括箭体底面、侧壁面及着陆支腿的对流和辐射热流密度均会明显升高,最高可达80%以上。因此,研究成果适用于液体火箭返回阶段底部精细化热设计,且在设计过程中有必要考虑复燃的影响。

Effects of Recrudescence on the Thermal Environment of the Bottom of a Liquid Rocket during Its Return Stage

In order to study the effects of opposing jet and recrudescence of the engine of a vertical take-off and landing liquid rocket on the landing legs and the thermal environment of the bottom of the rocket body during its return stage, the calculation models for the tail flame recrudescence, flow field, and spectral radiation are established. The thermal environment of the bottom of a vertical take-off and landing liquid rocket during its return stage is numerically calculated for the first time in China. The flow field is calculated by using the FLUENT software, and the recrudescence reaction is obtained by the finite-rate chemical reaction model. The spectral absorption coefficient of the jet gas components is obtained by the HITRAN database, and the radiative transfer equation is solved by the positive and negative ray tracing method. The experimental results in literature are used to verify the results obtained in this paper, and the effects of recrudescence on the thermal environment of the bottom of the rocket are also investigated. The results show that the recrudescence reaction increases the convective and radiant heat flux densities of the bottom, side wall, and landing legs of the rocket body, and the maximum increase amplitude is up to 80%. Therefore, the research results of this paper are applicable to the fine thermal design of the bottom of the liquid rocket during its return stage, and it is also necessary to consider the effects of recrudescence in the design process.