Two-phase flow investigation of sewage pumps with different tip clearance via computational fluid dynamics and multi-factor ANOVA

Abstract

Sewage pumps are widely utilized in various applications, including municipal wastewater treatment plants, industrial processes, and residential sewage systems. These pumps are specifically designed to handle the transportation of mixtures consisting of solid and liquid components, commonly observed as two-phase flow. In this study, semi-open sewage pumps with varying clearance sizes have been examined through adjustment of the geometrical model. Multi-factor analysis of variance is employed to investigate the combined influence of different two-phase flow conditions and tip clearance sizes on the performance of sewage pumps. The results show that the performance of the pump decreases significantly as the clearance size increases. Also, the sensitivity of pump efficiency to variations in tip clearance size is contingent upon the flow rate. Under part-load conditions, both particle concentration and clearance size exhibit a notable effect on efficiency. The two-phase flow will greatly enhance the intensity of the unsteady flow near the inlet and outlet of the semi-open impeller, which is the main reason for the performance degradation of the sewage pump. The findings of this research provide valuable insights for enhancing the hydraulic performance and operational stability of semi-open sewage pumps operating under two-phase flow conditions.