A Hybrid Method for Flow-Induced Noise in Centrifugal Pumps Based on LES and FEM

A hybrid method is adopted for predicting flow induced noise within a centrifugal pump. The whole calculating domains are meshed with structured grids, and the inner flow analyses are accomplished with LES (Large Eddy Simulation) method, Smagorinsky model is selected as the sub-grid scale model. Flow induced noise is predicted based on simulating results of inner flow, the noise which generated by inlet and impeller are equivalently transformed to Lighthill surface, and volute is calculated as a direct acoustic source. Furthermore, the flow induced noise test bench is built up for test verification. The simulated results show that the blade pass frequency f_blade is predominant frequency of flow-induced noise, but the shaft rotation frequency f_rotating and 2f_blade cannot be neglected. The noise becomes more serious as the flow deviates from the best efficiency point. The maximum difference between simulated results and experimental data is less than 3dB. Hence, the hybrid method which based on LES and FEM (Finite Element Method) is an effective method to predict the flow induced noise in centrifugal pumps.