Optimization and Investigation on the Impact of Centrifugal Impeller Blade Thickness Distribution on Hydro-Induced Vibration

The vibration performance of centrifugal impellers is of great importance for pumps in some application areas such as automobiles and ships. Apart from mechanical excitations for instance, unbalanced rotor and misalignment, attentions should be concentrated on the hydraulic excitations. The complex internal secondary flow in the centrifugal impeller brings degradation on both hydraulic and vibration performances. On the purpose of repressing the internal secondary flow and alleviating vibration, an attempt of optimization by controlling the thickness distribution of centrifugal impeller blade is given. The vibration performances of the impellers are investigated numerically and experimentally. Meanwhile, further study on the mechanism of the influence of the thickness distribution optimization on vibration is conducted. There is a relative velocity gradient from suction side (SS) to pressure side (PS) due to the Coriolis force, which causes non-uniformity of energy distribution. By means of thickness distribution optimization, the impeller blade angle on the PS and SS along the blade-aligned (BA) streamwise location is respectively modified and therefore the flow field can be improved.