微喷管过渡区流动的DSMC模拟研究

On micro nozzle transition area flow by DSMC method

微喷管性能的好坏关系到微推进器能否提供所需的准确推力及能否具有较高的推力效率,因此微喷管的研究对提高微型推进器的性能起重要作用.针对高温气流的特点,在运用直接模拟蒙特卡罗方法模拟微喷管流动过程中,考虑由于非平衡性而发生的内能松弛等问题,引入分子内能激发和松弛概率,对不同入口压力及温度下高温流体的拉伐尔喷管流场进行了数值模拟,模拟结果表明随着入口流体温度的升高,微喷管的推力效率也随之增长,在低压下入口压力的增大有助于提高微喷管的工作效率,而高压下入口压力的变化对微喷管性能的影响并不显著.

Micro nozzle is a key element whose performance influences the thrust accuracy and thrust efficiency, so research on micro nozzle will make significant influences in improving performance of micro thruster. Focusing on the characteristic of high temperature airflow, the DSMC method is employed in the simulation of flow in micro nozzle, and the molecular internal energy explode and laxation probability was introduced on considering the internal taxation arose by non-equability, the flow model set up and ultra-temperature airflow in the micro nozzle under different inlet pressure and temperature simulated. Results show that when the temperature of inlet flow increases, the thrust efficiency will increase accordingly, while the influence of inlet pressure variation on the nozzle performance under high pressure is insignificant.