预旋系统稳态和非稳态计算对比研究

A Comparative Study on Steady and Unsteady Calculations of a Pre-Swirl System

关键词:  预旋系统  对比  非稳态  转子相位  时均

Key words:  Pre-swirl system  Comparison  Unsteady-state  Rotor phase  Time-averaged

摘要:

针对预旋系统由于旋转引起流场和温度场参数周期性瞬态变化的问题，分别采用滑移网格的瞬态法和固定转子相位的稳态法进行数值求解，并在稳态计算中通过改变转子相位来近似模拟非稳态问题的时空变化特性。通过稳态空间平均结果与非稳态时均结果的对比，以期为预旋系统非稳态问题的低成本求解提供方法依据。结果表明：稳态计算结果与非稳态计算结果相比，周期性波动频率一致，接受孔进口处，稳态计算的压力波动幅度小39%左右，温度波动幅度小15%左右；多个相位的稳态空间平均结果与非稳态时均结果相比，压力高0.2%，温度低0.1%；采用多个计算周期数与单个周期的非稳态计算结果差异微小。当采用喷嘴出口气流中心正对接受孔迎风面前缘的转子相位时，稳态计算结果与非稳态计算时均结果最接近。

Abstract:

In order to solve the problem of periodic transient changes of flow parameters and temperature caused by rotation in a pre-swirl system, the transient method with sliding mesh and the steady-state method with frozen rotor approach were used， respectively. The time-space characteristics of unsteady problems were approximated by changing rotor phase in the steady-state calculation. To find a low cost solving method for the unsteady-state problem in a pre-swirl system, the steady-state space-averaged results and the unsteady-state time-averaged results were compared extensively. The results show that the periodic fluctuation frequency of steady-state calculation is consistent with that of unsteady-state calculation. At the inlet of the receiving hole, the pressure fluctuation amplitude calculated by steady-state method is about 39% smaller than that calculated by unsteady-state method, and the temperature fluctuation amplitude is about 15% smaller. Compared with the unsteady-state time-averaged results, the steady-state space-average results of multiple rotor positions show that the pressure is 0.2% higher and the temperature is 0.1% lower. There is little difference between the unsteady calculation results with multiple calculation periods and those with single period. When the rotor is located at this position where the nozzle outlet air flow is opposite to the front edge of the receiving hole windward side, the steady-state calculation results are the closest to the unsteady-state calculation results.