基于动网格技术的双脉冲发动机内流场仿真

Simulation on the Transient Working Process of a Small Double-pulse Motor based on Dynamic Mesh

为获得隔层式小型双脉冲发动机瞬态工作特性,采用FLUENT计算平台和动网格模型,综合考虑压强变化率和速度效应对燃速的影响,对发动机进行了二维非稳态仿真。获得了移动边界条件下瞬态内流场分布。计算结果表明:燃气流经隔板后在Ⅰ脉冲燃烧室空腔形成回流涡旋,级间孔直径越小,回流涡旋越大,燃气再附着点位置越靠近喷管收敛段下游。级间孔直径的改变对侵蚀压强峰出现时间无影响,但是对侵蚀压强峰的峰值存在影响,即级间孔直径越小,峰值越大。

ABSTRACT：In order to obtain the transient performance of the small double-pulse motor, FLUENT calculation plat- form and a dynamic grid model were applied to simulate the effect of pressure change rate and velocity effect on the burning rate. The transient internal flow field distribution under moving boundary condition was obtained. The results show that as the gas flows into the cavity of the first pulse combustion chamber, the smaller the interstice, the larger the vortex, and the position of the reattachment point is closer to the downstream of the convergent section of the noz- zle. The interstage port diameter has no effect on the pressure peak time, but can affect the peak of the erosion pres- sure peak, the smaller the interstage port diameter, the greater the peak.