0
Research Papers: Multiphase Flows

Experimental Study of a Cavitating Centrifugal Pump During Fast Startups

[+] Author and Article Information
S. Duplaa

 Ecole Navale IRENav, BCRM Brest CC 600, 29240 BREST Cedex 9, Francesebastien.duplaa@ecole-navale.fr

O. Coutier-Delgosha

 Arts et Métiers ParisTech/LML Laboratory, 8 Boulevard Louis XIV, 59046 Lille Cedex, Franceolivier.coutier@lille.ensam.fr

A. Dazin

 Arts et Métiers ParisTech/LML Laboratory, 8 Boulevard Louis XIV, 59046 Lille Cedex, Franceantoine.dazin@lille.ensam.fr

O. Roussette

 Arts et Métiers ParisTech/LML Laboratory, 8 Boulevard Louis XIV, 59046 Lille Cedex, Franceroussette@ensam.fr

G. Bois

 Arts et Métiers ParisTech/LML Laboratory, 8 Boulevard Louis XIV, 59046 Lille Cedex, Francegerard.bois@lille.ensam.fr

G. Caignaert

 Arts et Métiers ParisTech/LML Laboratory, 8 Boulevard Louis XIV, 59046 Lille Cedex, Franceguy.caignaert@lille.ensam.fr

J. Fluids Eng 132(2), 021301 (Jan 28, 2010) (12 pages) doi:10.1115/1.4000845 History: Received April 04, 2008; Revised December 04, 2009; Published January 28, 2010; Online January 28, 2010

The startup of rocket engine turbopumps is generally performed only in a few seconds. It implies that these pumps reach their nominal operating conditions after only a few rotations. During these first rotations of the blades, the flow evolution in the pump is governed by transient phenomena, based mainly on the flow rate and rotation speed evolution. These phenomena progressively become negligible when the steady behavior is reached. The pump transient behavior induces significant pressure fluctuations, which may result in partial flow vaporization, i.e., cavitation. An existing experimental test rig has been updated in the LML Laboratory (Lille, France) for the startups of a centrifugal pump. The study focuses on the cavitation induced during the pump startup. Instantaneous measurement of torque, flow rate, inlet and outlet unsteady pressures, and pump rotation velocity enable to characterize the pump behavior during rapid starting periods. Three different types of fast startup behaviors have been identified. According to the final operating point, the startup is characterized either by a single drop of the delivery static pressure, by several low-frequency drops, or by a water hammer phenomenon that can be observed in both the inlet and outlet of the pump. A physical analysis is proposed to explain these three different types of transient flow behavior.

Copyright © 2010 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 17

Evolution of the pump head, inlet and outlet pressures, and inlet flow rate (case 1) (τ=0.091, Qf=1.1Qn, and ωf=3000 rpm)

Grahic Jump Location
Figure 19

Dimensionless torque evolutions in cavitating conditions

Grahic Jump Location
Figure 20

Classification of the startups

Grahic Jump Location
Figure 21

Comparison between the present set of data and the previous results reported in Ref. 3: (a) data from Tanaka and Tsukamoto; (b) present experiments

Grahic Jump Location
Figure 22

Final operating points reported on the head drop curves

Grahic Jump Location
Figure 23

Evolution of τ according to δ for case 2: (a) full scale; (b) zoom

Grahic Jump Location
Figure 24

Evolution of τ according to δ for case 1: (a) full scale; (b) zoom

Grahic Jump Location
Figure 25

Evolution of τ according to δ for case 3: (a) full scale; (b) zoom

Grahic Jump Location
Figure 26

Correlation between the impeller cavitation and τ evolution (case 2): (a) t=0.308 s; (b) t=0.422 s; (c) t=0.520 s; and (d) t=0.728 s

Grahic Jump Location
Figure 1

Photography and scheme of the test rig

Grahic Jump Location
Figure 2

Picture of the impeller

Grahic Jump Location
Figure 3

Evolution of the pump elevation according to the inlet flow rate coefficient (ΔΨ/Ψ=0.5% and Δδ/δ=4%)

Grahic Jump Location
Figure 4

Evolution of (a) χ according to δ at 3000 rpm (Δχ/χ=5% and Δδ/δ=4%), (b) η according to δ at 3000 rpm (Δη/η=9,5%), (c) χ according to ω/ωn for Q=Qn(Δχ/χ=5%), and (d) the dimensionless amplitude of the radial vibrations according to δ(Δδ/δ=4%)

Grahic Jump Location
Figure 5

Head drop charts at 2500 rpm and 3000 rpm at nominal flow rate (ΔΨ/Ψ=0.5% and Δτ/τ=0.5%)

Grahic Jump Location
Figure 6

Head drop charts for six inlet flow rates at 3000 rpm (ΔΨ/Ψ=0.5%, Δτ/τ=0.5%, and Δδ/δ=4%)

Grahic Jump Location
Figure 7

Evolution of τ according to δ for 3%, 10%, and 20% head drop (3000 rpm) (Δτ/τ=0.5% and Δδ/δ=4%)

Grahic Jump Location
Figure 8

Evolution of the head drop according to δ at constant value of τ (ΔΨ/Ψ=0.5, Δδ/δ=4%, and Δτ/τ=0.5%)

Grahic Jump Location
Figure 9

Evolution of the efficiency according to τ for six values of the inlet flow rate coefficient (3000 rpm) (Δη/η=9.5% and Δτ/τ=0.5%)

Grahic Jump Location
Figure 10

(a) Evolution of the pump head, and the inlet and outlet pressures; (b) inlet flow rate evolution in the suction pipe (Qf=Qn, ωf=3000 rpm, no cavitation)

Grahic Jump Location
Figure 11

Evolution of the rotation speed (Qf=Qn, ωf=3000 rpm, no cavitation)

Grahic Jump Location
Figure 12

Evolution of the dimensionless torque (Qf=Qn, ωf=3000 rpm, no cavitation)

Grahic Jump Location
Figure 16

Amplitude of the radial vibrations on the pump casing for ωf=3000 rpm: (a) noncavitating conditions Qf=Qn; (b) τ=0.091 and Qf=0.9Qn

Grahic Jump Location
Figure 18

Evolution of the pump head, inlet and outlet pressures, and inlet flow rate (case 3) (τ=0.111, Qf=0.7Qn, and ωf=3000 rpm)

Grahic Jump Location
Figure 13

Comparison between the measured and calculated dimensionless torques (Qf=Qn and ωf=2000 rpm)

Grahic Jump Location
Figure 15

Evolution of the pump head, inlet and outlet pressures, and inlet flow rate (case 2) (τ=0.091, Qf=0.9Qn, and ωf=3000 rpm)

Grahic Jump Location
Figure 14

Comparison between the measured and calculated values of Cmax/Cst(Qf=Qn)

Tables

Errata

Discussions

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.

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