Multifactor response-based optimization for enhancing cavitation performance of short injection self-priming pumps

As the heart of the water supply systems, the energy conversion efficiency of the self-priming pumps with built-in injection system under overload conditions is extremely affected by cavitation problems. This study focuses on a typical short-type injection self-priming pump devoted to improve the pump performance, especially to solve the cavitation problem under overload conditions. Through a two-factor, five-level orthogonal test that combines numerical simulation and experimental validation, the influence of key structural parameters within the ejector on cavitation performance and energy characteristics are analyzed. The results demonstrate the high level accuracy of numerical simulation, as indicated by the consistency and small error between the numerical results and the experimental results for head, efficiency, and power under full flow conditions. Regression analysis based on the orthogonal test results reveals significant correlations between the hydraulic performance of the pump and the nozzle throat diameter and nozzle outlet diameter. Under overload conditions, the high-speed jet generated by the injector induces a negative pressure at the effuser and nozzle, leading to cavitation at the effuser throat and nozzle outlet. Employing appropriate structural parameters, particularly the effuser throat diameter and nozzle outlet diameter, proves effective in increasing the operating flow range. This in turn improves the energy characteristics of the entire hydraulic system. The optimal combination identified for the ejector's structural parameters in this study is a nozzle outlet diameter of 8.2 mm and a throat diameter of 18 mm. This provides theoretical insights for the optimal design of short-type jet self-priming pumps, holding practical significance in engineering applications.