抛物线喷管型面参数对流动分离影响的数值模拟

Numerical simulation of effect of parabolic nozzle contour parameters on flow separation

为了研究抛物线喷管型面的3个参数——初始膨胀圆弧半径、入口角和出口角的变化对喷管流动分离过程的影响规律,模拟了不同参数组合下的抛物线喷管流场参数,获得了喷管流动位置、分离模态随集气室压强增加的变化过程.结果表明:这3个参数能够影响发动机起动过程中喷管流场的发展过程.在一定范围内分离模态转换喷管压比(NPR)与初始膨胀圆弧半径呈正相关;通过合理设定入口角和出口角,可以推迟和缩短受限激波分离过程,为解决彭冠侧向载荷问题提供了可能的方向.

To investigate how the parabolic nozzle flow separation process is affected by three contour parameters, namely initial expansion curve radius, inlet angle and exit angle, the flow field parameters under different contour parameter combinations were numerically simulated, the changing processes of the nozzle flow separation position and separation mode with the increases of gas chamber pressure were obtained. The flow separation mode varia- tion process with chamber pressure was gained. Results show that these three parameters can influence the development of nozzle flow field during engine starting, the flow separation mode transition nozzle pressure ratio （NPR） keeps a positive relationship with the initial ex- pansion curve radius within a certain range. Restricted shock separation can be put off and shortened by suitable design of inlet angle and exit angle. The conclusion provides a possible way to solve the side load problem.