Numerical Investigation of Pressure Fluctuation and Rotor-Stator Interaction in a Multistage Centrifugal Pump

The unsteady flow field in a multistage centrifugal pump was simulated with ANSYS-CFX code based on transient rotor-stator method, and Shear Stress Transport (SST) turbulence model to investigate the pressure fluctuations in the three stages passages. With the Fast Fourier Transform (FFT) analysis, the pressure fluctuations and frequency domains are analyzed and compared between stages. The numerical results show that the pressure fluctuates at the blade passage frequency, and the maximum amplitude of blade passage frequency occurs in the region from the rotor to the stator when the impeller blade gets close to the diffuser vane leading edge. The pressure pulsation period mainly associated with the number of impeller blades, but the influence gradually reduce when the fluids flow into the diffuser. The flow patterns and pressure fluctuation between stags are similar.