级间热分离条件下双级延伸喷管展开过程动力学耦合仿真研究

Coupling simulation of dynamics on the expansion process of double extendible nozzle under stage separation condition

对带有双级延伸喷管的固体火箭发动机级间热分离时延伸喷管的展开过程进行了动力学耦合仿真研究,获得了级间区的流场演化情况和延伸锥的展开特性,同时研究了气瓶压强、分离时刻和展开时刻对延伸喷管展开运动和结构受力的影响情况。结果表明:级间热分离时级间段流场产生复杂波系和漩涡流动,燃气的短时迴流使得延伸锥壁面瞬时温度高达3800 K左右,且延伸锥壁面气动力载荷波动剧烈;当气瓶初始压强低于(等于) 1.0 MPa时,延伸喷管无法展开到位;级间分离时刻较晚或延伸喷管展开时刻较早时,延伸喷管展开用时较短但延伸锥壁面气动力波动很大,适当提前级间分离时刻以及增加级间分离时刻和延伸喷管展开时刻的时间间隔,有利于提高延伸喷管展开过程和对接时的结构安全性。

The coupling simulation study of dynamics on the expansion process of double extendible nozzle was carried out and obtained the flow field evolution and deployment characteristic of extension cone,the influence of cylinder pressure,separation time and deployment time on the movement and structure of extension cone were also studied.The results show that a series of shock wave and vortex flow are generated in interstage area during thermal separation,and the backflow of gas makes the transient temperature of extension cone wall up to about 3800 K,and the aerodynamic load on extension cone wall fluctuates greatly;Extendible nozzle cannot expand to predetermined location when the initial pressure of cylinder is less than(equal to)1 MPa;Separation time later or deploy⁃ment time earlier will make extendible nozzle spend less time to expand but the aerodynamic load on extension cone will fluctuate more greatly,therefore taking separation time forward and increasing time interval between separation time and deployment time will make the deployment and docking process of extendible nozzle safer.