TRANSACTIONS OF THE KRYLOV STATE RESEARCH CENTRE

Science journal

 
ISSN (print) 2542-2324 /(online) 2618-8244


Articles of The Transactions of KSRC








Cavitation inception calculation for pumpjet impeller



Full text article ( in russian)

Year

 
2019

Issue

 
389

Volume

 
3

Pages

 
63-72

Caption

 
Cavitation inception calculation for pumpjet impeller

Authors

 
63-72

Keywords

 
impeller, pumpjet, cavitation, Reynolds equations, numerical simulation

DOI

 
10.24937/2542-2324-2019-3-389-63-72

Summary

 
Object and purpose of research. This paper studies pumpjets with short ducts to develop a calculation procedure for cavitation inception in model test conditions.
Subject matter and methods.The moment of cavitation inception is determined visually, by observation of the cavitation tunnel test. The conditions of physical test have been thoroughly replicated in a computer-based simulation by means of state-of-the-art numerical methods and high-end hardware.
Main results. This paper suggests a method of cavitation inception determination that relies on the results of numerical pumpjet flow simulation based on Reynolds equations. Two variants of this method are discussed: the first one tackles depressurization areas (without calculating the vaporization process, i.e. cavitation itself), whereas the second one does calculate cavitation by means of Schnerr and Sauer model. Simulation results are compared versus the test data where cavitation inception is determined visually. The criteria of cavitation inception suggested in this paper are, in the first variant, the volume of depressurization domains or, in the second variant, the volume of cavities defined as the areas with 5% vapour content. For standard conditions of model tests (impeller diameter 200–250 mm) this volume is 1 mm3.
Conclusion. The method of cavitation inception determination suggested in this paper is sufficiently accurate for practical purposes. For impellers with blade geometry close to the one discussed in this paper, the method can predict cavitation inception without calculation of vaporization itself, which gives four-fold gain in the hardware resources required for calculation. Both variants of this method will be especially helpful for studies on the effect of local changes in impeller blade geometry upon cavitation inception.

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ISSN (print) 2542-2324 / ISSN (online) 2618-8244

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