An improved cavitation model with thermodynamic effect and multiple cavitation regimes

Li, W., Yu, Z. and Kadam, S. (2023) An improved cavitation model with thermodynamic effect and multiple cavitation regimes. International Journal of Heat and Mass Transfer, 205, 123854. (doi: 10.1016/j.ijheatmasstransfer.2023.123854)

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Abstract

Mechanical feed pumps in organic Rankine cycle (ORC) power plants can suffer from cavitation to lose their normal feeding performance or even damage. Cavitation models for organic fluids in ORC systems are lacking presently. Hence, a new cavitation model with thermodynamic effect was proposed. Surface tension-controlled, inertia-controlled, intermediate and heat transfer-controlled cavitation regimes, and two key elements: vapour bubble growth rate and vapour bubble number density are included in the model. A known air or non-condensable gas concentration in the liquid was employed to determine cavitation nuclei number density. The model was coded in ANSYS CFX as user defined model and validated with cavitating flows of organic fluid R114 in a venturi, liquid nitrogen and liquid hydrogen on a tapered hydrofoil and warm water around a hydrofoil NACA 0015 in cavitation tunnels based on visualised cavity length. Two model constants, temperature depression, and minimal cavitation number were correlated to bulk liquid temperature, Reynolds number, and Jakob number. The temperature and pressure profiles of liquid nitrogen and hydrogen on hydrofoil surface were examined against the experimental data. The model was applied to simulate unsteady cavitating flows of organic fluid R245fa in a diaphragm pump. It was shown that the temperature depression and minimal cavitation number cannot be correlated to bulk liquid temperature, Reynolds number and Jakob number. Two model constants can be correlated fairly to Reynolds number. The model underestimates the thermodynamic effect by 43% for R114, 18.6% for liquid nitrogen and 32.6% for liquid hydrogen based on temperature depression. The predicted temperature and pressure profiles on hydrofoil surface agree with the experimental data for liquid nitrogen. The model can produce an expected curve of mean pump flow rate against net positive suction head available.

Item Type:Articles
Additional Information:This research benefited from the financial support provided by EPSRC (EP/T022701/1, EP/V042033/1, EP/P028829/1, EP/N020472/1, EP/N005228/1, EP/V030515/1) in the UK.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Li, Dr Wenguang and Kadam, Dr Sambhaji and Yu, Professor Zhibin
Authors: Li, W., Yu, Z., and Kadam, S.
College/School:College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:International Journal of Heat and Mass Transfer
Publisher:Elsevier
ISSN:0017-9310
ISSN (Online):1879-2189
Published Online:30 January 2023
Copyright Holders:Copyright © 2023 The Authors
First Published:First published in International Journal of Heat and Mass Transfer 205: 123854
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
312686Flexible Air Source Heat pump for domestic heating decarbonisation (FASHION)Zhibin YuEngineering and Physical Sciences Research Council (EPSRC)EP/V042033/1S&PS - Urban Studies
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309846Decentralised water technologiesWilliam SloanEngineering and Physical Sciences Research Council (EPSRC)EP/V030515/1ENG - Infrastructure & Environment