STUDY ON PRESSURE PULSATION IN THE VOLUTE OF A CENTRIFUGAL PUMP BY LARGE EDDY SIMULATION

Pressure pulsation caused by unsteady flow plays one of the most important roles in the stable operation of centrifugal pumps. Numerical simulation method of LES (Large Eddy Simulation) with WALE model has been used to calculate the unsteady flow in IS150-125-250 centrifugal pump passages. Three groups monitoring points distributed on 8 cross sections in different radial, circumferential, axial directions were set. And pressure pulsation in volute with different flow rates, radial distance, circumferential angles and axial distance was studied. Changing of the maximal pressure pulsation amplitude on monitoring points has been obtained by time and frequency domain analysis. The research demonstrated the maximum amplitude of pressure pulsation is located at the volute tongue, and its magnitude changes with flow rates at each monitoring point. The dominant frequency of pressure pulsation in the volute is equal to the blade passing frequency and the subdominant frequencies are also related to the blade passing frequency. The periodicities of circumferential pressure pulsations at different monitoring points in the volute are similar. More deviation of design flow rate results in larger pressure pulsation amplitude. Increasing radius will weaken pressure pulsation amplitude while closing to the wall of volute can strengthen the pressure pulsation. The research of pressure pulsation in volute will show great help in hydraulic design of centrifugal pump to realize longer component life, less vibration and more stable operation.