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Investigation of rotating stall characteristics in a centrifugal pump impeller at low flow rates

Peijian Zhou (College of Water Resources and Civil Engineering, China Agricultural University, Beijing, China and College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou, China)
Fujun Wang (College of Water Conservancy and Civil Engineering, China Agricultural University, Beijing, China)
Jiegang Mou (College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou, China)

Engineering Computations

ISSN: 0264-4401

Article publication date: 7 August 2017

Abstract

Purpose

Rotating stall is an unsteady flow phenomenon that causes instabilities and low efficiency in pumps. The purpose of this paper is to investigate the rotating stall characteristics and unsteady behavior of stall cells in a centrifugal pump impeller at low flow rates.

Design/methodology/approach

A developed large eddy simulation with dynamic mixed nonlinear model is performed to evaluate the unsteady flow in a centrifugal pump impeller. The rotating stall flow field through the centrifugal pump impeller is analyzed under three typical flow rates. Frequency spectrum analysis are carried out on the series of pressure fluctuation to get the rotating stall characteristics. The size and intensity of stall cells are also analyzed using time-averaged vorticity and static pressure.

Findings

The rotating stall cell first occurs in the suction side of the blade and exhibits an obvious life cycle including decay mergence, shedding, growing and development with a low frequency. With the decrease of flow rate, the amplitude of pressure fluctuations in the impeller tends to be larger, the propagated speed of stall cells and rotating stall frequency tends to be smaller, but the number of cells remains unchanged. The size of stall cells increases as the flow rate decreases, but intensity changes is very little.

Originality/value

The rotating stall characteristics in a centrifugal pump impeller under low flow rates are presented first using a developed large eddy simulation approach.

Keywords

Acknowledgements

The authors gratefully acknowledge the financial supports given by the National Nature Science Foundation of China (51139007, 51321001) and the National Science & Technology Support Project of China (2015BAD20B01).

Citation

Zhou, P., Wang, F. and Mou, J. (2017), "Investigation of rotating stall characteristics in a centrifugal pump impeller at low flow rates", Engineering Computations, Vol. 34 No. 6, pp. 1989-2000. https://doi.org/10.1108/EC-05-2016-0167

Publisher

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Emerald Publishing Limited

Copyright © 2017, Emerald Publishing Limited