高空飞行环境中液体运载火箭底部热环境研究

采用数值模拟和飞行测试验证相结合的方法对液体运载火箭高空对流/辐射耦合换热问题开展系统深入研究。基于燃气多组分输运Navier-Stokes方程、热辐射方程、Realizable k-ε两方程湍流模型，建立了高空含自由流的运载火箭燃气喷流流动模型。辐射模型采用离散坐标法(DOM)，空间离散采用二阶迎风TVD格式，对多个典型飞行高度火箭底部热流进行大型并行计算，将数值结果与试验数据进行广泛对比，验证了计算模型的精度和有效性。数值研究表明，火箭底部辐射热流在刚起飞阶段达到最大值，随着飞行高度上升，辐射热流逐渐降低，火箭底部对流热流表现为先升高后降低的趋势，并在20 km高空达到峰值。本文的预测分析方法对液体运载火箭底部热防护设计具有重要的理论意义和工程应用价值。

Studies on Thermal Environment of Liquid Launch Vehicle Tail Compartmentat High Altitude

 The coupled convective and radiative heat transfer of a liquid launch vehicle is studied by employing a method which combines the experimental tests and the numerical simulations. The multiphase Navier-Stokes equations, radiative transfer equations and realizable k-ε turbulence model are used to establish the rocket plumes flow model with free stream at high altitude. By using the discrete-ordinates methods and the second order TVD upwind scheme in the spatial discretization, the heat flux in different typical altitude is calculated. The accuracy and effectiveness of this established model is verified by presenting the comparative experimental data and the results show that the radiation heatflux of the afterbody reaches the maximum at the beginning of launch, and the radiation heat flux becomes small with an increase in altitude. The convection heat flux of the afterbody increases firstly and then decreases, the peak of the convection heat flux occurs at high altitude, approximately 20 km. The study results provide the theory foundation and engineering guidance for the thermal protection system of the liquid launch vehicle.