半开式离心叶轮气动阻尼的影响规律研究

Influence Rule of Aerodynamic Damping of Semi-open Centrifugal Impellers

离心压缩机半开式叶轮的阻尼是影响叶轮振动应力水平的重要因素,主要包括材料阻尼和气动阻尼。其中,气动阻尼的准确计算是叶轮动应力分析的前提。本文通过流固弱耦合方法研究了压缩机运行工况以及叶片振幅对气动阻尼的影响,并对影响规律进行了理论分析。研究结果表明,进口温度一定时,叶片气动阻尼比随进口流量的增大而增大;进口质量流量一定时,气动阻尼比随进口温度的减小而增大;对同一工况,气动阻尼比基本与振幅无关。研究结果对叶轮结构在实际运行工况条件下的强度校核具有重要的参考意义。

The damping of impeller is an important factor affecting the dynamic stress level of the impeller which include material dampings and aerodynamic dampings. Aerodynamic damping prediction is crucial for the dynamic stress estimation of impeller. Therefore, the aerodynamic damping of a semi-open centrifugal impeller at different operational conditions and vibration amplitudes is studied by weakly fluid-structure coupled method in this paper. The results indicate that the aerodynamic damping ratio increases with the mass flow rate increascing at a certain inlet temperature, the aerodynamic damping ratio increase with the temperature decreasing at a certain inlet mass flow rate.Nevertheless, for a given operational condition, the aerodynamic damping is nearly independent of the vibration amplitude of the blade. The result would be valuable to the strength check of the impeller structure at practical operational condition.