压气机叶片非同步振动机理及气动布局优化研究

Non-Synchronous Vibration Mechanism and Aerodynamic Layout Optimization of Compressor Blades

关键词:  压气机  非同步振动  气动布局优化  流固双向耦合  导叶偏转角  栅距非谐

Key words:  Compressor  Non-synchronous vibration  Aerodynamic layout optimization  Two-way fluid-structure interaction  Deflection angle of guide vane  Blade spacing mistuning

摘要:

针对航空发动机叶片中的非同步振动诱发叶片断裂失效问题，基于时域推进的方法建立了压气机全周物理域的流固双向耦合模型，旨在对周向非定常扰流和叶片气动弹性特征进行更合理的描述。通过该模型揭示了叶片非同步振动的发生机理，并通过一定的气动布局手段优化了叶片表面气动力和振动幅值。研究表明：叶尖泄漏流与主流掺混后形成的通道涡是诱发叶片产生非同步振动的根本原因，而掺混流的周向传播强度仅在一适中的范围内时才具有产生明显通道涡的能力，并提出以通道前缘截面上的流动相对周向动量W_mix为判断通道涡和振动幅度强弱的依据。导叶偏转角或导叶栅距非谐程度的增大，均会对掺混流的周向强度有一定的加强作用，使得通道涡强度和非同步振动幅值呈现先增大后减小的趋势。

Abstract:

Aiming at approaching the fracture failure of blades induced by non-synchronous vibration （NSV） in aeroengine， a fluid-structure interaction model of the whole domain of the compressor was established based on the time domain propulsion method. The purpose is to describe the circumferential unsteady turbulence and blade aeroelastic characteristics reasonably. Through this model， the mechanism of NSV was revealed， and the aerodynamic force on the blade surface and vibration amplitude were optimized by certain aerodynamic layout. Results show that the channel separation vortex formed by the mixing of tip leakage flow and mainstream is the fundamental reason for the NSV， but the significant separation vortex only occurs when the circumferential propagation intensity of mixed flow is moderate. In addition， the normalized circumferential momentum （W_mix） in front of the channel is taken as the basis to judge the strength of the channel vortex and vibration amplitude. With the increase of guide vane deflection angle or blade spacing mistuning degree， the W_mix will also increase to a certain extent， which makes the channel vortex intensity and the NSV amplitude increase to a peak and then decrease.