多级压气机动叶片时序效应数值研究

对某型燃气轮机中间三级轴流压气机流场进行了非定常数值模拟,研究第二级动叶时序(CLOCKING)效应对中间级各列叶片气动负荷的影响。计算过程采用基于谐函数(Harmonic)的频域变化方法对全三维Navier-Stokes(N-S)方程进行求解。通过对各列叶片非定常气动负荷进行时域和频域分析,指出转子叶片中间级动叶R2处于不同的CLOCKING位置时,会引起R2叶片本身以及下游中间级静叶S2气流激振力显著变化。在CLK0(各列动叶片在周向上安装位置相同)位置,中间级静叶片在部分时刻内受力与常规方向相反,且气动力和力矩波动幅度最大。在CLK2(动叶片在周向上错开1/2节距安装)位置上,R2叶片和S2叶片气动负荷的稳定性都得到改善。静叶S2气动力、气动力矩波动幅值明显较其他位置小,且方向的改变次数也较小。同时,S2对其上下游动叶一倍通过频率的响应也最小,因此具有比较稳定的气动负荷。

Numerical Study of Influence of Rotor Blades' CLOCKING Effect on Aerodynamic Performance of a Multistage Compressor

The unsteady flow fields of a three-stage axial compressor were simulated,and the CLOCKING effect of the second rotor blades(R2) on the aerodynamic loading of the second stator vane S2 was mainly studied.The 3D N-S equations was solved by using frequency domain transformed method based on Harmonic function.The aerodynamic force and torque of each blade rows were studied by time and frequency domain analysis.The results show that the flow excited forces of the second rotor blade R2 and S2 would be significantly changed when R2 at different CLOCKING positions.When at CLK0 position(all rotor row at the same circumferential position),the aerodynamic force direction of S2 is opposite to conventional in some moments.The fluctuation of aerodynamic force and torque also reach the maximum.When at CLK2 position(the second rotor blade located at the circumferential position after rotating half pitch),the aerodynamic force stability of R2 and S2 are both improved.The aerodynamic force direction of S2 is always positive and its fluctuation is obviously smaller than those at other CLOCKING positions.The fluctuation of aerodynamic torque and times of variation in directions are also lower than others.Furthermore,the response of the first-order blade passing frequency(BPF) on the rotor blades upstream and downstream reaches the minimum.