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利用商业软件CFX对某液体火箭大面积比喷管地面条件下的分离流动进行了三维数值模拟.计算获得了喷管入口总压从8MPa减小到1MPa时的流场参数分布和侧向力载荷情况.结果表明,随着入口总压的降低,喷管内流场会依次经历自由激波分离和受限激波分离两种分离激波模态.受限激波分离模态下喷管壁面压强具有较大波动,再附着点压强甚至高于环境压强.流动分离情况下,喷管将受到一定侧向载荷作用,载荷方向随机分布.入口总压为4MPa时计算得到的侧向载荷最大,实际侧向载荷峰值可能出现在自由激波分离与受限激波分离转换瞬间.
A three-dimensional numerical simulation of the separation flow of a liquid rocket with a large area ratio of nozzles over the ground was carried out by using the commercial software CFX.The flow field parameter distribution and the lateral force load were obtained when the total pressure at the nozzle inlet was reduced from 8MPa to 1MPa .The results show that with the decrease of inlet total pressure, the flow field in the nozzle undergoes two kinds of separate shock modes: free shock separation and limited shock separation, And the pressure at the reattachment point is even higher than the ambient pressure.When the flow is separated, the nozzle will be subjected to a certain lateral load and the load direction will be randomly distributed.The maximum lateral load calculated when the total inlet pressure is 4MPa is the maximum, Lateral load peaks may occur at the moment of free shock separation and limited shock separation.