Numerical simulation of the effect of installation height on self-priming performance of a prototype self-priming pump.

To investigate the impact of installation height on the self-priming performance of a self-priming pump, this study established a circulating pipeline system incorporating the self-priming pump, a water tank, and other components. Clear water was placed in the lower part of the water tank and air in the upper part. The user-defined function (UDF) was employed to simulate the speed increase upon pump startup and subsequent constant-speed operation. Based on the Volume of Fluid (VOF) multiphase flow model, numerical simulations of the complete self-priming process were conducted for two different installation heights, focusing on gas-liquid two-phase flow. Additionally, vortex identification methods and entropy production theory were utilized to analyze the internal unsteady flow characteristics. The study revealed that as the installation height increases from 0.5 to 1.0 m, the self-priming time significantly prolongs by 6.260s, representing an 82% relative increase. During the oscillatory air discharge phase, the gas volume fraction within the volute remains consistently lower than that inside the impeller chamber. Throughout the self-priming process, the regions of significant hydraulic loss are primarily located at the outer edge of the impeller and the impeller inlet. This study is of great significance because it not only complements the understanding of how installation height affects pump performance but also provides practical guidance for optimizing the design and operational parameters of pumps, thereby improving efficiency and reducing energy consumption in real-world applications.