【摘要】 数值模拟的控制方程为雷诺平均的可压缩纳维尔 斯托克斯 (Navier Stokes)方程 ,湍流模型采用k ε两方程模型 ,数值格式为二阶迎风格式 .数值模拟了喷管在高反压环境下的流场 ,得到了流场结构变化规律 ,研究表明 :喷管在非设计工况下工作 ,产生了较大推力损失 ,该损失主要由静推力损失造成 .通过合理设计发动机工作压强和喷管扩张比 ,使其与外界反压相匹配 ,可以降低推力损失 .最后给出了基于喷管的一维理论与数值方法的推力计算对比 ,结果显示 :反压越高两者之间计算误差越大 .更多还原

【Abstract】 The governing equations are the Reynolels averaged Navier Stokes equations, k ε model is adopted for turbulence flow. The numerical scheme is second order windward scheme. The characteristics of flow field in nozzle which were surrounded with high environment pressure are simulated by a numerical method, and the change rule of flow field in nozzle is gained . Results suggest that rocket lost obvious thrust when the nozzle worked under unconventionality working condition, and this losing account for lesser static thrust. Our study indicated that thrust loss could be reduced, if the working pressure of rocket and the nozzle expansion ratio were rationalization designed and adapted well to environment pressure. In the end, thrust computation results are list and compare with numerical simulation and one dimension theoretic methods, the conclusion suggest that computation error become more and more bigger as the environment pressure raise.更多还原