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Pressure fluctuation characteristics in the sidewall gaps of a centrifugal dredging pump

Lei Cao (State Key Laboratory of Hydroscience and Engineering, Department of Thermal Engineering, Tsinghua University, Beijing, China)
Yexiang Xiao (Department of Thermal Engineering, Tsinghua University, Beijing, China)
Zhengwei Wang (Department of Thermal Engineering, Tsinghua University, Beijing, China)
Yongyao Luo (Department of Thermal Engineering, Tsinghua University, Beijing, China)
Xiaoran Zhao (Department of Thermal Engineering, Tsinghua University, Beijing, China)

Engineering Computations

ISSN: 0264-4401

Article publication date: 12 June 2017

Abstract

Purpose

The purpose of this paper is to study the pressure fluctuation characteristics in the sidewall gaps of a centrifugal dredging pump in detail and discover the excitation sources.

Design/methodology/approach

An unsteady numerical simulation with shear–stress transport–scale-adaptive simulation (SAS-SST) model was conducted for a centrifugal pump considering the sidewall gaps. The numerical codes were validated by a model test carried out in China Water Resources Beifang Investigation, Design and Research Co., Ltd. Fast Fourier transform was used to obtain the frequency components of the pressure fluctuation.

Findings

Pressure fluctuation characteristics inside the pump were analyzed for a condition near the design point. In the sidewall gaps, the circumferential, radial and axial distribution of the pressure fluctuation amplitude follow different laws. The non-axisymmetrical distribution of pressure fluctuation in the sidewall gaps shows that the unsteady flow in the volute casing which has a non-axisymmetrical geometry imposes an evident effect on the flow field in the sidewall gaps and the interaction between the main flow and the clearance flow cannot be neglected. There are several frequency components appearing as the dominant frequencies at different locations in the sidewall gaps, but the relatively stronger pressure fluctuations are all dominated by the rotating frequency. It indicates that the rotating impeller, which originally makes the shrouds rotate, is the primarily excitation source of the pressure fluctuations in the sidewall gaps.

Originality/value

The pressure fluctuation characteristics in the sidewall gaps of centrifugal pumps were first comprehensively analyzed. Unsteady flows in the sidewall gaps should be considered during the design and operation of centrifugal pumps.

Keywords

Acknowledgements

The authors thank the financial support given by the State Key Program of National Science of China (Grant No. 51439002), National Natural Science Foundation of China under Contract (No. 51479093), Special Funds for Marine Renewable Energy Projects (Grant No. GHME2012GC02), and State Key Laboratory of Hydroscience and Engineering (Grant No. 2014-KY-05).

Citation

Cao, L., Xiao, Y., Wang, Z., Luo, Y. and Zhao, X. (2017), "Pressure fluctuation characteristics in the sidewall gaps of a centrifugal dredging pump", Engineering Computations, Vol. 34 No. 4, pp. 1054-1069. https://doi.org/10.1108/EC-12-2015-0383

Publisher

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Emerald Publishing Limited

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