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Instabilities of blow-down type Venturi cavitation considering thermodynamic effect

Instabilities of blow-down type Venturi cavitation considering thermodynamic effect It is known that thermodynamic effect of cavitation could not be ignored in liquids such as cryogenic liquids, refrigerants, and high temperature water. This effect could delay and suppress the further development of cavitation, thus improve the suction performance in cases of hydraulic machinery. However, the influence of thermodynamic effect on cavitation instabilities has not been adequately discussed. For this purpose, a series of systematically designed experiments of Venturi cavitation in a blow-down type cavitation tunnel have been carried out, using water as the working liquid at different temperatures. For the first time, the cavitation instabilities were analyzed and identified with controlled degrees of thermodynamic effect Σ*. The mean cavitation length Lcav∗\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$L_{{\rm{cav}}}^ \ast$$\end{document} and three types of cavitation instabilities were recognized through an image post-processing method. A decrease of Lcav∗\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$L_{{\rm{cav}}}^ \ast$$\end{document} is observed with an increasing Σ*. For all Σ* conditions, cavitation surge (system instability), cloud shedding, and oscillations of the attached cavitation length occur at small, middle, and large pressure recovery number (κ) conditions, respectively. The thermodynamic effect mainly influences the range of κ for different cavitation instabilities. Cavitation surge and transition from cloud shedding to oscillations of attached cavitation length shift to a lower κ with an increasing Σ*. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Thermophysics and Aeromechanics Springer Journals

Instabilities of blow-down type Venturi cavitation considering thermodynamic effect

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Publisher
Springer Journals
Copyright
Copyright © H.C. Zhang, H. Chen, L. Xiang, Z.G. Zuo, and S.H. Liu 2021
ISSN
0869-8643
eISSN
1531-8699
DOI
10.1134/s0869864321040107
Publisher site
See Article on Publisher Site

Abstract

It is known that thermodynamic effect of cavitation could not be ignored in liquids such as cryogenic liquids, refrigerants, and high temperature water. This effect could delay and suppress the further development of cavitation, thus improve the suction performance in cases of hydraulic machinery. However, the influence of thermodynamic effect on cavitation instabilities has not been adequately discussed. For this purpose, a series of systematically designed experiments of Venturi cavitation in a blow-down type cavitation tunnel have been carried out, using water as the working liquid at different temperatures. For the first time, the cavitation instabilities were analyzed and identified with controlled degrees of thermodynamic effect Σ*. The mean cavitation length Lcav∗\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$L_{{\rm{cav}}}^ \ast$$\end{document} and three types of cavitation instabilities were recognized through an image post-processing method. A decrease of Lcav∗\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$L_{{\rm{cav}}}^ \ast$$\end{document} is observed with an increasing Σ*. For all Σ* conditions, cavitation surge (system instability), cloud shedding, and oscillations of the attached cavitation length occur at small, middle, and large pressure recovery number (κ) conditions, respectively. The thermodynamic effect mainly influences the range of κ for different cavitation instabilities. Cavitation surge and transition from cloud shedding to oscillations of attached cavitation length shift to a lower κ with an increasing Σ*.

Journal

Thermophysics and AeromechanicsSpringer Journals

Published: Jul 1, 2021

Keywords: cavitation instabilities; thermodynamic effect; Venturi pipe with cavitation

References