隔舱式双脉冲发动机内流场数值分析

Numerical Analysis of the Internal Flow Field of Compartment Dual-pulse Motor

由于级间隔板的存在,双脉冲发动机Ⅱ脉冲药柱工作时,其燃烧室内部流场与常规固体火箭发动机内流场有较大的差别。为探究Ⅱ脉冲药柱内孔半径和颗粒粒径对流场特征的影响,采用k-ε模型和离散相模型对发动机Ⅱ脉冲稳态工作过程进行了数值仿真。结果表明,随着Ⅱ脉冲药柱内孔半径的增大,燃气再附着点的位置和最大回流速度的位置向Ⅰ脉冲燃烧室下游移动;当药柱内孔半径为20 mm时,在级间孔前,粒子会在涡流区存在沉积;经过级间孔后,一部分粒子会随着气流进入燃气涡流区域,形成对Ⅰ脉冲燃烧室冲蚀,另一部分粒子则随气流不断加速,撞击喷管收敛段;当药柱内孔半径达到30 mm后,回流区消失,粒子只撞击喷管收敛段。颗粒的粒径大小对Ⅰ脉冲燃烧室轴线上的燃气温度和马赫数没有影响,但对喷管轴线上的燃气温度和马赫数影响较大。

Due to the existence of inter-stage partition, the internal flow field in the combustion chamber of a dual-pulse motor is different from that of a conventional solid rocket motor when the second pulse propellant burns. In order to explore the influence of second pulse grain inner-hole radius and particle size on flow field, the second pulse steady state operation process of compartment dual-pulse motor is simulated numerically using k-epsilon model and discrete phase model. The results show that with inner hole radius increasing, the location of the attachment point and the location of the maximum return velocity moves downstream of the first chamber. When the radius of the inner hole of the second pulse grain is 20 mm, the particles will deposit in the vortex area before the inter-stage hole. After passing through the inter-stage hole,some particles enter the gas vortex region and scour the wall of first chamber, the other particles are accelerated with the airflow, and hit nozzle convergence section. When the radius reaches to 30 mm, the vortex area disappears and the particles only hit the convergence section of the nozzle. The particle size has no effect on the temperature and Mach number of gas on the axis of the first chamber, but has a great influence on the temperature and Mach number of gas on the axis of the nozzle.