Investigation of Self-Priming Process of a Centrifugal Pump with Double Blades

The gas-liquid two-phase flow patterns of a centrifugal pump during the self-priming process were investigated numerically and experimentally. The Euler-Euler multiphase model and SST k-ω turbulence model were applied for simulating the self-priming process. Meanwhile, the change of motor speed and self-priming height were considered in the simulation. The overall transient two-phase flow features and water level distributions were mapped. Results showed that the self-priming process was divided into three stages. The liquid level in inlet-pipe rose in oscillation during self-priming process. The variations of water level during self-priming process of numerical simulation and test result agreed well. The inlet-pipe (Ver) was filled at 22 s and 24 s respectively numerically and experimentally. The bubble cloud circulated in the volute during middle stage of self-priming process, and breakup into smaller bubbles by shear force and tongue, and then discharged into chamber. The bubbles in the outlet-pipe mainly included bubbly flow and slug flow at the last stage of self-priming process, which is morphologically consistent with the test results. Also, during the self-priming process, the reflux liquid was pressed by blades and fully mixed with gas; that is the way to realizing the function of self-priming.