Abstract: To accurately obtain the parameters of different species in a nozzle, the direct simulation Monte Carlo (DSMC) method in combination with the variable soft sphere (VSS) model was employed in the analysis of a low-density gas flow in a small nozzle. Comparison of the present results for simple gas with those of previous work in reference shows that the results are believable. Based on this, the mixed gas flow in the bell-shaped nozzle of a bipropellant engine was simulated. The results show the integrated effect of the pressure and thermal diffusion caused the heavy gases to move towards boundary layer.

Key words: Bipropellant rocket engine;Attitude control rocket engine;Monte Carlo method;Nozzle flow;Numerical simula- tion

摘要： 为了准确获得喷管内不同燃气成分的参数,采用直接模拟蒙特卡罗(DSMC)方法结合可变软球(VSS)模型模拟喷管流动。单组分的计算结果与文献比较表明,所采用的程序和计算结果可信。对真空双组元钟形喷管内流动的模拟结果表明,压强扩散和热扩散的综合效应导致质量越大的分子越趋向于向边界层内扩散。

关键词: 双元推进剂火箭发动机;姿控火箭发动机;蒙特卡罗法;喷管气流;数值仿真