Multidimensional Diagnostics of Turbine Cavitation

[+] Author and Article Information
Branko Bajic

Korto Cavitation Services–Korto GmbH, 12, rue Ste Zithe, L-2763 Luxembourg, Luxembourge-mail: korto@cavitation.de

J. Fluids Eng 124(4), 943-950 (Dec 04, 2002) (8 pages) doi:10.1115/1.1511162 History: Received December 01, 2000; Revised May 06, 2002; Online December 04, 2002
Copyright © 2002 by ASME
Your Session has timed out. Please sign back in to continue.



Grahic Jump Location
The sensors placed on the 20 guide vanes react to cavitation in various locations around the spiral
Grahic Jump Location
Typical power density spectra of noise picked up at different power values. There is no noticeable line at the revolution frequency, but the blade-passage frequency (BPF) lines are rather strong. The background noise, recorded in the turbine at rest while the other machinery in the plant was operating, is low enough to enable reliable estimation of the continuous spectrum component between 0.3 and 800 kHz.
Grahic Jump Location
Overview of the normalized power spectra. The v=1 power density spectra recorded at different turbine power values are compared to the one recorded at 13.3 MW. The spectrum related to this reference value is thus represented by the zero-dB line.
Grahic Jump Location
An example of modulation curves: M1(θ,f,P) in an octave band centered at f=125 kHz measured at different turbine power values
Grahic Jump Location
Normalized spectra of Fig. 3(Po=13.3 MW) presented two dimensionally, seen from two perspectives
Grahic Jump Location
Noise decomposition: contribution of the three cavitation mechanisms to the total noise
Grahic Jump Location
The way used to determine the range of prevalence of a mechanism m,(f,P)m, in the total noise is illustrated here by the m=2 case. At the P-values between the pairs of curves the m=2 intensity is equal resp. 2, 5, or 10 times stronger than the rest of the intensity. There from the (f,P)2 denoted; the ratio 5 is assumed sufficiently high.
Grahic Jump Location
Typical cases of noise modulation
Grahic Jump Location
The fine-structure cavitation characteristics of the turbine: the most detailed description of cavitation that can be obtained by the multidimensional method. For each tested turbine-power value, P, there are 380 (number-of-runner-blades×number-of-guide-vanes) dimensionless values, Cvb, that stand for the intensity of cavitation caused by the interaction of a pair consisting of the runner blade b, and the guide vane v. The Cvb-values specify the relative intensity of cavitation. Their use in cavitation erosion estimation is discussed elsewhere (Bajic 1417). The data presented in the figure describe total cavitation. The method also enables identification of different segments of a cavitating flow—cavitation mechanisms—and yields data like this for each of them.
Grahic Jump Location
Runner and wicket gate cavitation characteristics
Grahic Jump Location
Global turbine characteristics without and with resolution with respect to cavitation mechanisms
Grahic Jump Location
Check of (in)stationarity: variation of cavitation intensity at the (f,P)-values characteristic of the mechanisms




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