Research Papers: Flows in Complex Systems

Numerical Analysis of the Fluid Flow in the First Stage of a Two-Stage Centrifugal Pump With a Vaned Diffuser

[+] Author and Article Information
H. Stel, C. O. R. Negrão

Federal University of Technology - Paraná,
UTFPR, 80230-901 Curitiba, PR, Brazil

G. D. L. Amaral

Macaé, RJ, 27913 350 Brazil

S. Chiva

Universitat Jaume I,
Castellón de la Plana, E 12071 Spain

V. Estevam

Rio de Janeiro, RJ, 20035-900 Brazil

R. E. M. Morales

Federal University of Technology - Paraná,
UTFPR, 80230-901 Curitiba, PR, Brazil
e-mail: rmorales@utfpr.edu.br

1Corresponding author.

Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received July 16, 2012; final manuscript received October 23, 2012; published online May 15, 2013. Assoc. Editor: Chunill Hah.

J. Fluids Eng 135(7), 071104 (May 15, 2013) (9 pages) Paper No: FE-12-1331; doi: 10.1115/1.4023956 History: Received July 16, 2012; Revised October 23, 2012

This work presents a numerical investigation of the fluid flow in the first stage of a two-stage centrifugal pump with a vaned diffuser. A computational fluid dynamics (CFD) analysis is performed by using the ANSYS-CFX software for a wide range of volumetric flow rates and also for different rotor speeds. The numerical results are validated against measured values of pressure rise through the impeller and diffuser of the first stage with an overall good agreement. Nevertheless, not only the best efficiency point evaluated numerically is overestimated in comparison with the measured two-stage pump values but also the computed hydraulic efficiency of the first stage. Investigation of the flow pattern for different flow rates reveals that the flow becomes badly oriented for part-load conditions. In such cases, significant levels of turbulence and blade orientation effects are observed, mainly in the diffuser. In spite of different flow rates or rotor speeds, the flow pattern is quite similar if the flow dimensionless coefficient is kept constant, showing that classical similarity rules can be applied in this case. By using such rules, it was also possible to derive a single equation for the pump head to represent the whole operational range of the pump.

Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.



Grahic Jump Location
Fig. 6

Experimental setup

Grahic Jump Location
Fig. 5

Influence of the initial condition. (a) Time evolution of pressure at the leading edge of a diffuser vane; and (b) azimuthal pressure calculation at the impeller-diffuser interface after half impeller revolution.

Grahic Jump Location
Fig. 4

Computational grid

Grahic Jump Location
Fig. 3

Schematics of the subdomains and boundary conditions adopted in the numerical simulations

Grahic Jump Location
Fig. 11

Hydraulic efficiency for the rotor speed of 1150 rpm. Comparison of the numerical results for the single-stage model, experimental data and manufacturer's curve for the two-stage pump.

Grahic Jump Location
Fig. 2

Schematics of the pump under analysis. (a) Section view of the two-stage pump; and (b) top view of the first stage (without the shroud and the pump casing).

Grahic Jump Location
Fig. 1

Pictures of the two-stage centrifugal pump under analysis: (a) Full mounted; (b) first stage and return channel; (c) first impeller without the hub; and (d) diffuser

Grahic Jump Location
Fig. 7

Positions of the pressure taps in the two-stage pump

Grahic Jump Location
Fig. 8

Pictures of the test rig. (a) Overview of the setup and (b) pump with a Plexiglas cover to show the pressure taps and the internal parts.

Grahic Jump Location
Fig. 9

Comparison of the numerical and experimental head curves for the first stage of the pump

Grahic Jump Location
Fig. 10

Comparison of the numerical and experimental pressure rises through the first impeller (a) and the diffuser (b)

Grahic Jump Location
Fig. 12

2D streamline paths and velocity magnitude contours at a plane located in the middle height of the impeller-diffuser interface for four selected flow rates and a rotor speed of 1150 rpm: (a) 20 m3/h, (b) 35 m3/h, (c) 45 m3/h, and (d) 55 m3/h

Grahic Jump Location
Fig. 13

2D streamline paths and velocity magnitude contours at a plane located in the middle height of the impeller-diffuser interface for four rotor speeds and a fixed flow coefficient (φ=0.132)

Grahic Jump Location
Fig. 15

Volume average of Ti and Ui inside the diffuser as a function of the flow coefficient for the four different rotor speeds. (Dashed lines are fourth-order polynomial fittings for each data set.)

Grahic Jump Location
Fig. 16

Numerical results of the head coefficient ψ versus flow coefficient φ for four different rotor speeds

Grahic Jump Location
Fig. 17

Numerical head values compared with the fitted curve

Grahic Jump Location
Fig. 14

Contour plots of the instantaneous turbulence and unsteady intensity at a plane located in the middle height of the impeller-diffuser interface for a part-load condition and the best efficiency flow coefficient: (a) Ti for ϕ = 0.059, (b) Ui for ϕ = 0.059, (c) Ti for ϕ = 0.132, and (d) Ui for ϕ = 0.132




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