Numerical and experimental investigation of flow-induced noise in centrifugal pump as turbine

In order to improve internal flow-induced noise of pump as turbine, the performance and noise test systems for pump as turbine were established. Experimental investigation of flow noise was performed under different flow rates. Boundary element method (BEM) and finite element method/boundary element method (FEM/BEM) were adopted to study the interior and external noise fields caused by hydrodynamic forces, and two methods were validated and verified by experimental results. The results show that the characteristic frequencies and low broadband frequencies are contained in the frequency spectrum, especially under small flow rate. The error of FEM/BEM coupling method with the test results is smaller than that of BEM at blade frequency. The trend of FEM/BEM coupling method is more reasonable. Under different flow conditions, the radiated noise of bladefrequency(150.2 Hz) under the optimal working condition flow is the lowest, showing the close relationship between the flow-induced noise and efficiency.