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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。
The unsteady numerical simulation of the flow field of a third-stage axial-flow compressor of a gas turbine is carried out to study the effect of second-order CLOCKING on the aerodynamic loads of the blades in the middle stage. The calculation uses the Harmonic-based frequency domain change method to solve the full three-dimensional Navier-Stokes (N-S) equation. The time-domain and frequency-domain analysis of the unsteady aerodynamic loads on each row of blades shows that when the mid-stage rotor blades R2 of the rotor blade are in different CLOCKING positions, the airflow excitation force of R2 blades itself and downstream intermediate stator vanes S2 are significantly changed . In the position of CLK0 (the installation positions of the moving blades are the same) in the circumferential direction, the forces of the middle-level stator blades are opposite to the normal direction in some moments, and the fluctuation of aerodynamic force and torque is the largest. The stability of the aerodynamic loads on both R2 and S2 blades is improved at CLK2 (rotor blades are circumferentially offset by 1/2 pitch). S2 static aerodynamic, aerodynamic torque amplitude was significantly smaller than other locations, and the direction of the number of changes is also smaller. At the same time, S2 has the least response to the double frequency of its upstream and downstream moving blades, so it has a relatively stable aerodynamic load.