固体火箭发动机工作末期的内流场数值计算

Simulation of Inner Flow Fields at end of burning in a SRM

针对固体火箭发动机(SRM)绝热结构设计中的气固两相内流场数值计算问题,基于Euler-Lagrange方法,应用SSTk-ω湍流模型和颗粒轨道模型(PTM),并用PSIC方法进行气固耦合计算,仿真研究了某型SRM工作末期复合过载条件下的三维两相内流场特性。揭示了两个典型工况下的SRM内部压强和温度场、燃气和粒子速度场、粒子沉积分布及其运动规律,重点分析了SRM不同部位的颗粒沉积浓度变化。结果表明:在复合过载条件下,颗粒沿横向过载的反方向偏移,滞后效应明显,容易撞击喷管收敛段;两种工况下的SRM内部压强、温度及速度场分布规律相近;最高粒子沉积浓度产生于SRM后封头的绝热层内壁,并形成粒子聚集流及其两侧尺度较大的低速旋涡流动现象;随着推进剂的燃面不断推移,在贴近绝热层壁面处的平均粒子沉积浓度呈升高趋势。

According to the problems of the numerical calculation of the gas-solid two-phase flow field in the design adiabatic structure of the solid rocket motor(SRM), the 3-D two-phase inner flow field at end of burning in a SRM under overload conditions with the method of Euler-Lagrange, the SST(shear-stress-transport)k-ω turbulence model and the particle trajectory model(PTM)were used, and PSIC method were employed to solve equation sets. The internal pressure and temperature fields, gas and particle velocity fields, solid-phase particle deposition concentration and particle trajectory of the SRM under two cases were calculated. The concentration of particles in different parts of SRM was analyzed emphatically. The results demonstrate that the particles move in the opposite direction of the transverse overload, and the hysteresis effect is evident, so is likely to hit the nozzle convergence. The change of pressure, temperature and the flow velocity fields of SRM in two cases are very close. The highest particle deposition concentration is generated in the inner wall of the insulating layer of the SRM rear head, resulting in the particle congregation and the low velocity vortex flow phenomenon. With the constantly burning propellant, the average particle deposition concentration near the wall of the adiabatic layer shows an upward trend.