Numerical investigation of the unsteady fluctuate performance for the internal flow-field within a centrifugal pump

In order to study the unsteady phenomena and to uncover the rules on how pumps' performance are effected by relative positions of their volutes and impellers, the internal flow-field of a low specific speed centrifugal pump was simulated by numerical method on a parallel distributed computer cluster. Simulation results show that the unsteady fluctuations of the internal flow-field is very strongly; the unsteady fluctuation frequency is determined by the number of blades and the rotational speed of its impeller; all parameters' instantaneous result are determined by relative positions of its volute and impeller. Results also show that rotor-stator interaction between volute inlet and impeller exit is the fundamental cause of the unsteady phenomena. For the purpose of improving the performances and fatigue capabilities of pump, the running noise and vibration must be controlled under special level, optimizing the matching of impeller and volute must be an effective method. So, the study on the unsteady fluctuation of the pump is very important and useful.