高原工况压气机叶轮振动失效特征分析

Vibration Failure Characteristic Analysis of Compressor Impeller UnderPlateau Conditions

针对高原工况下离心压气机叶轮振动失效问题,以某增压发动机压气机叶轮为研究对象建立仿真模型,使用非定常计算流体动力学方法分析高原共振工况下叶轮受到的气流激励时域与频域特征,并基于单向流固耦合,使用瞬态动力学与谐响应方法研究气流激励作用下叶轮共振响应特征,得出高原工况叶轮振动失效原因。结果表明,高原工况叶轮在4阶气流激励作用下发生共振,激励主要来源于叶片与蜗舌间的动静干涉作用,叶顶间隙泄漏流增大了吸力面20%弦长位置的压力波动。气流激励下叶轮共振导致叶片前缘振动应力升高,振动应力幅值达101.5 MPa,与实际叶片振动失效情况一致。

A turbocharged engine centrifugal compressor impeller simulation model was established to analyze the reasons for vibration failure under plateau conditions.The unsteady computational fluid dynamics method was used to study the time domain and frequency domain characteristics of aerodynamic excitation on the impeller under plateau resonance conditions.Based on one-way fluid-solid coupling,transient dynamics and harmonic response methods were used to research the dynamic characteristics of the resonant impeller under the action of aerodynamic excitation.Finally,the reason for impeller vibration failure in plateau conditions was obtained.The results show that the fourth-order aerodynamic excitation affects the resonance of the impeller under plateau conditions,which is caused by the dynamic and static interferences between the blade and the volute tongue.The blade tip clearance leakage flow increases the pressure fluctuation at 20%chord length of the suction surface.Impeller resonance under aerodynamic excitation leads to an increase in vibration stress at the leading edge of the blade.The vibration stress amplitude reaches 101.5 MPa at the blade’s leading edge,which is consistent with the actual blade vibration failure.