Numerical Simulation of Internal Flow Characteristics and Pressure Fluctuation in Deceleration Process of Bulb Tubular Pump

In order to explore the change in internal and external characteristics pressure fluctuation of large bulb tubular pump unit during deceleration, a transient steady three-dimensional (3D) numerical simulation is executed, based on standard k-? turbulence model boundary conditions such as flow rate. Finally, data are analyzed by wavelet method. There good agreement between experimental results. During deceleration process unit, head decreases linearly while efficiency remains stable. Meanwhile, shock phenomenon hysteresis effect appear before after deceleration. Although there vortex backflow outlet conduit distribution suction surface impeller blades changes uniformly significantly. The inlet more obvious deceleration: closer hub, greater pressure, this with decreasing radius. energy mainly concentrated high-frequency region 100–120 Hz rotational speed. This paper provides reference for utilization safe operation water adjusting speeds variable frequency.