Title: Value of blade number in centrifugal flow pumps in both turbine and pump mode through experimental and numerical means

Authors: Sun Sheng Yang; Tian Fang; Tao Wang; Punit Singh

Addresses: Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang, Jiangsu, 212013, China ' Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang, Jiangsu, 212013, China ' Key Laboratory of Fluid and Power Machinery, Ministry of Education, School of Energy and Power Engineering, Xihua University, Chengdu, 610039, China ' Centre for Sustainable Technologies, Indian Institute of Science, CV Raman Road, Bangalore, 560012, India

Abstract: The hydraulic significance of blade number of pump impellers is experimentally and numerically investigated in turbine mode and pump mode respectively for three different specific speeds and validated using the classical theoretical approach of streamline shape (angular momentum of fluid) and loss gradient. The results indicate that for both pump and turbine mode operation, the effect of streamline shape is dominating over the change in hydraulic loss with increase in blade number. The frictional component of losses for blade passage using an existing empirical model is compared with computational results. While the flow line shapes markedly improved, yet the losses could not be reduced. The study finds an optimum number of blades different for turbine (more blades) and pump (fewer blades) operation. It recommends systematic adaption of increased blade number particularly for 'pump as turbine' users.

Keywords: centrifugal pump; pump as turbine; PAT; blade number; angular momentum; streamline; hydraulic losses; Euler velocity vectors.

DOI: 10.1504/PCFD.2022.124605

Progress in Computational Fluid Dynamics, An International Journal, 2022 Vol.22 No.4, pp.197 - 218

Received: 28 May 2021
Accepted: 17 Oct 2021

Published online: 29 Jul 2022 *

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