Improving air-water two-phase flow pumping in centrifugal pumps using novel grooved front shrouds

The present investigations aim to improve the gas-liquid two-phase transport in centrifugal pumps using a novel front shroud design with macroscopic grooves. This increases the secondary flow strength and the two-phase mixing, boosting the performance. A total of 23 different circumferential and radial groove profiles were numerically investigated to identify the best configuration leading to the highest mixing efficiency. Three different loads were considered, i.e., part load, optimal point, and overload. Additionally, the performance of the novel designs was compared with that of the established alternatives, involving two different clearance gaps and/or an inducer. While circumferential grooves already lead to a slightly improved specific delivery work, radial grooves improve noticeably the pump efficiency and deliver a very high two-phase mixing compared to other traditional pump configurations. Under conditions of optimal loading, the utilization of circumferential grooves led to a phase mixing enhancement of approximately 19.5%, whereas the implementation of radial grooves exhibited a notable improvement in mixing efficiency by 64.8% compared to the standard gap. The radial design R14 is superior to all other designs regarding efficiency and phase mixing. It is therefore recommended for transporting gas-liquid two-phase flows. & COPY; 2023 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.