The forced response of the turbomachinery blade originates from unsteady fluid structure interactions due to the fluctuating aerodynamic load. As one of the primary unsteady issues, inlet distortion flow breaks the uniformity of airflow through the compressor channel which deteriorates the aerodynamic performance of the compressor and intensifies the pressure fluctuation on the blade surface. The work presented here arms to investigate the forced response of a centrifugal impeller induced by compressor inlet distortion. For this purpose, the unsteady flow computation was carried out to provide the temporal evolution of the distorted flow through the compressor and also to quantify the aerodynamic loads acting on the compressor blade due to inlet distortion flow compared with uniform inlet. Meanwhile, the experimental measurement was performed to obtain the transient pressure fluctuation on the blade surface and to validate the accuracy of numeric calculation. The forced response of the compressor impeller based on unsteady excitation was simulated in a finite element (FE) method to gain insight into vibration characteristic of each blade. Time-resolved blade pressure showed the drastic load fluctuation caused by distorted flow mainly located in the blade leading edge region due to the inlet airflow variation. Towards the impeller forced vibration, each blade shows individual response amplitude due to the phase angle difference among the blades. The effect of inlet distortion on the forced response of impeller increases significantly compared with that of the uniform inlet flow.

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