迷宫气封三维非定常流场及转子动特性数值仿真

SIMULATION OF 3D UNSTEADY FLOW AND PREDICT OF ROTORDYNAMIC COEFFICIENTS FOR ROTOR WITH LABYRINTH GAS SEALS

通过计算流体力学方法,采用近似的解析变换网格,以及混合有限分析格式,对迷宫气封流场进行三维非定常数值求解,进而求得密封气流对转子的气流激振力,获得转子的动特性系数。将计算结果与试验结果以及双控制体计算结果相比较,结果令人满意,说明了该计算程序是正确可靠的。该方法精度较高,适用范围广,可以应用于各种复杂的涡动情况及各种齿型,对气封转子的深入研究有重要意义。计算结果还显示了主刚度、主阻尼对气流进口周向速度不敏感,而交叉刚度对气流进口周向速度非常敏感。由于交叉刚度对转子的稳定性影响相当大,这一点是值得注意和利用的。

By the method of computational fluid dynamics, the three-dimensional unsteady flow field in labyrinth gas seals is predicted and the rotordynamic coefficients of the rotor are studied with approximate analytical transformation and scheme of hybrid finite analytical method. The reliability of the code is confirmed by comparing with the results of experiment and rwo-control-volume model. This code has the powers of studying the complex 3D unsteady flow field in complicated gas seal with arbitrary whirl of rotor. The results also show that the direct stiffness and the direct damping change small and the cross-coupled stiffness changes large if inlet tangential velocity changes large. Because the cross-coupled stiffness has the important effect on the stability of rotor, this phenomenon is uti-lizable.