Investigation of energy loss characteristics of solid-liquid flow in centrifugal pumps under different flow conditions

Abstract

This study aims to investigate the behavior of solid-liquid flow in a centrifugal pump under different flow conditions and address the challenge of low accuracy in solid-liquid flow simulations. To achieve a more precise analysis of the solid-liquid flow field within the pump, an advanced Computational fluid dynamics-discerete element method (CFD-DEM), previously developed by the author, is employed. Furthermore, using entropy generation theory, a comprehensive analysis is conducted on the effects of particle aggregation (including phenomena such as inlet swirl, particle wake, particle settling, etc.) and the associated energy losses in the centrifugal pump. The results reveal that, under low-flow conditions, a vortex develops at the pump’s inlet, which is associated with the expansion of the transverse vortex within the liquid phase flow field. As the flow rate rises, the particle translational velocity increases significantly, while the rotational velocity decreases. From the viewpoint of energy loss in the liquid phase flow field, both high and low flow conditions experience greater energy losses compared to the design condition, with the energy loss in the volute being the primary contributor to the overall energy loss in the centrifugal pump. Under varying flow conditions, the regions of high entropy generation loss within the impeller and volute are distributed differently. Additionally, the wall entropy generation loss rises as the flow rate increases, with most of the loss concentrated on the impeller wall. The results provide ponderable insights for optimizing the centrifugal pump structure and improving its service life.