Numerical Calculation of the Influence of Reflux Hole Area on the Self-Priming Performance of a Prototype Self-Priming Pump

Abstract

To investigate the impact of the reflux hole area on the self-priming performance of a self-priming pump, this study innovatively established a circulating pipeline system that includes the self-priming pump, water tank, and other components. Additionally, the influence of increasing rotational speed was taken into account to ultimately simulate accurate self-priming performance. The upper parts of the water tank, the self-priming pump, and the initial part of the pipeline were set to contain air, while the rest was filled with clear water. Additionally, the acceleration phase of the rotational speed was also included in the calculation through user-defined functions. Therefore, the computational physical model established closely matches the actual situation, effectively reflecting the real and complete self-priming process. Based on the VOF (volume of fluid) multiphase flow model, the numerical study analyzed the effects of three different initial water storage volumes on the self-priming performance of the pump. The study found that the largest reflux hole area does not result in the shortest time for a complete self-priming process; instead, there exists an optimal value. When the reflux hole area is small, it takes longer during the oscillatory gas discharge stage, with an extended time of up to 4 s, indicating that the size of the reflux hole mainly affects this stage of the self-priming process. The influence of the reflux hole area on the head and the time required to reach a stable value is relatively minor, with differences within approximately 1 s and a head difference of around 0.1 m. The “internal leakage” phenomenon during the early stages of the self-priming process results in a slightly lower stable flow rate at the pump outlet compared to the stable flow rate at the pump inlet. The article reveals the impact of the size of the reflux hole area on the efficiency and stability of the self-priming process in a self-priming pump, which provides crucial guidance for optimizing the design and operating conditions of the pump.