Mechanism of the impact of sediment particles on energy loss in mixed-flow pumps

Abstract

Numerical simulations were performed on the fluid domain of the mixed-flow pump with different solid-phase volume fractions to examine the influence of the sediment particles on internal energy dissipation. The energy properties of the mixed-flow pump were analyzed using the entropy production theory, considering the various flow rates and the solid particle conditions. The research examined the impact of the proportion of the solid particles in the flow on the performance and effectiveness, uncovering the complexities of the energy dissipation in the channel. The results showed that incorporating solid particle media resulted in the decrease in both the performance and effectiveness of the mixed-flow pump compared to water conditions. The mixed-flow pump's head decreased by 0.56 % and its efficiency declined by 2.74 % due to the change in particle volume fraction (Cv) from 5 % to 7.5 %. Upon transitioning from Cv = 7.5 % to Cv = 10 %, the head exhibited a 2.54 % decrease, coupled with a 7.22 % efficiency reduction, signifying pronounced energy loss. The findings highlight that the increase in the quantity of the solid particles enhances the pump's energy dissipation. Solid particles tend to be mainly concentrated in the impeller inlet, blade outer edge, guide vane inlet, and guide vane outer edge regions at varying solid-phase volume fractions. The main dissipation in the fluid region of the mixed flow pump mainly occurs in the impeller and the guide vane, the total energy loss in the guide vane is more than 500 W under the three volume fractions, the total energy loss in the impeller is also about 500 W, and the inlet and outlet losses are small. These research outcomes lay the groundwork for further enhancements in the energy characteristics of mixed-flow pumps.