Research Papers: Multiphase Flows

Analysis of the Staggered and Fixed Cavitation Phenomenon Observed in Centrifugal Pumps Employing a Gap Drainage Impeller

[+] Author and Article Information
Bing Zhu

School of Energy and Power Engineering,
University of Shanghai for
Science and Technology,
Shanghai 200093, China
e-mail: zbing@usst.edu.cn

Hongxun Chen

Shanghai Institute of Applied
Mathematics and Mechanics,
Shanghai University,
Shanghai 200072, China
e-mail: chenhx@shu.edu.cn

1Corresponding author.

Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received April 11, 2016; final manuscript received October 3, 2016; published online January 19, 2017. Assoc. Editor: Matevz Dular.

J. Fluids Eng 139(3), 031301 (Jan 19, 2017) (11 pages) Paper No: FE-16-1229; doi: 10.1115/1.4034952 History: Received April 11, 2016; Revised October 03, 2016

Previous work has shown that the employment of a gap drainage impeller in a centrifugal pump can improve the pump's hydraulic performance and cavitation resistance. However, during experiments, an unconventional cavitation phenomenon has been observed in the form of a staggered pair of fixed impeller flow tunnels. For the purpose of understanding the factors involved with this unconventional phenomenon, the present study analyzes the cavitation formation and evolution processes using numerical and experimental methods. A scalable detached eddy simulation (SDES) method was employed to address unsteady turbulent flow. First, the method was validated by comparing the performance data and liquid water velocity distributions obtained by calculation and experiment in the absence of cavitation. Then, numerical simulations of the cavitation flow field were conducted under a flow discharge condition one-half that of the optimum value. Within a particular range of cavitation numbers, the calculated results are found to reproduce the unconventional cavitation phenomenon observed in the experiments. The formation mechanism involves a combination of many factors such as impeller geometry, inflow discharge condition, and cavitation number. As for a certain geometry, the formation and evolution processes can generally be analyzed and explained according to the influence of the attack angle, which is affected by variations in the allocated flow discharge and cavitation volume in each impeller tunnel. The jet flow through the gap between the main and vice blades also contributes to the formation of this phenomenon.

Copyright © 2017 by ASME
Your Session has timed out. Please sign back in to continue.



Grahic Jump Location
Fig. 1

Experimental centrifugal pump test rig

Grahic Jump Location
Fig. 2

Experimental setup for cavitation visualization

Grahic Jump Location
Fig. 3

Schematic representation of the physical pump including the gap drainage impeller (a) and the computational region (b)

Grahic Jump Location
Fig. 4

Grid distributions: (a) global mesh and (b) impeller mesh

Grahic Jump Location
Fig. 5

Comparison of the predicted hydraulic performance with that of the experimental data given according to the water head coefficient ψ and the efficiency η with respect to the pump flow discharge coefficient φ

Grahic Jump Location
Fig. 6

Comparisons of the predicted average velocity distributions with PIV data for flow rates 0.5Q (top), Q (middle), and 1.5Q (bottom): (a) PIV and (b) CFD

Grahic Jump Location
Fig. 7

Cavitation evolution with time (T5 = 5/3000 s, flow rate 0.5Q, and cavitation number σ = 0.42): (top) by high-speed camera and (bottom) by PIV camera

Grahic Jump Location
Fig. 8

Comparison of the predicted performance with that of the experimentally obtained according to the water head coefficient ψ with respect to the cavitation number σ

Grahic Jump Location
Fig. 9

Circumferential evolution of cavitation at σ=0.37 with respect to time intervals TB = 60/(4 × 1000) s: (a) water vapor volume fraction distributions and (b) liquid water velocity streamline distributions

Grahic Jump Location
Fig. 10

Velocity distribution and water vapor volume fraction (σ=0.37, 5TB, and 0.5Q): (a) global velocity, (b) water vapor volume fraction, and (c) local velocity at the blade-to-blade plane

Grahic Jump Location
Fig. 11

Cavitation evolution with respect to the cavitation number at the locked phase location (4.1TB): (a) water vapor volume fractions and (b) liquid water velocity streamline distributions




Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In