Correction of cavitation with thermodynamic effect for a diaphragm pump in organic rankine cycle systems

Li, W., Mckeown, A. and Yu, Z. (2020) Correction of cavitation with thermodynamic effect for a diaphragm pump in organic rankine cycle systems. Energy Reports, 6, pp. 2956-2972. (doi: 10.1016/j.egyr.2020.10.013)

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Abstract

Diaphragm pumps are a sort of leakage-proof reciprocating pumps with low flow rate but high head and better efficiency, and can potentially find their applications in organic Rankine cycle (ORC) systems as the feed-pump of organic fluid to the evaporator. A diaphragm pump in an ORC system may suffer from cavitation in the pump suction chamber inevitably when the pump delivers an organic fluid. However, the cavitation performance of the pump has been a little known for organic fluids so far. In the article, the performance of a specific diaphragm pump was determined based on the existing performance charts provided by the pump manufactory in terms of pump rotating speed and inlet liquid pressure for cold water. The net positive suction head required (NPSHr) was predicted by involving thermodynamic effect in cavitation when the pump feeds the organic liquid R245fa to the evaporator in an ORC system at 480rpm rotational speed. The net positive suction head available (NPSHa) was calculated at 100 kPa and 141 kPa inlet liquid pressures, and the corresponding cavitation safety margins were addressed. The subcooling for the NPSHr and NPSHa as well as the safety margin were figured out. Two one-dimensional (1D) mechanical models for motion of the suction valve were built and solved at 480rpm and 100 kPa and 141 kPa inlet pressures. A preliminary experiment was performed to verify the analytical results. It turned out that the NPSHr is reduced to 2.02m from 3.02m NPSHr of cold water due to the thermodynamic effect in cavitation, and the corresponding subcooling is lowered to 8.28 C from 12.38 C. 100 kPa but 141 kPa inlet pressure can result in cavitation in the pump. The 1D mechanical models are subject to a rough spatial resolution for the flow field in the suction chamber, hence three-dimensional(3D) numerical simulations of the flow field are desirable.

Item Type:Articles
Additional Information:The work was supported by EPSRC in the UK in terms of grants such as EP/N020472/1, EP/N005228/1, EP/P028829/1 and EP/R003122/1, the support was acknowledged indeed.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:McKeown, Mr Andrew and Li, Dr Wenguang and Yu, Professor Zhibin
Creator Roles:
Li, W.Investigation, Methodology, Formal analysis, Visualization, Writing – original draft
Mckeown, A.Investigation, Writing – review and editing
Yu, Z.Funding acquisition, Project administration, Writing – review and editing
Authors: Li, W., Mckeown, A., and Yu, Z.
College/School:College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:Energy Reports
Publisher:Elsevier
ISSN:2352-4847
ISSN (Online):2352-4847
Published Online:26 October 2020
Copyright Holders:Copyright © 2020 The Authors
First Published:First published in Energy Reports 6: 2956-2972
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
172394Thermally Driven Heat Pump Based on an Integrated Thermodynamic Cycle for Low Carbon Domestic Heating (Therma-Pump)Zhibin YuEngineering and Physical Sciences Research Council (EPSRC)EP/N020472/1ENG - Systems Power & Energy
171763Dynamic Organic Rankine Cycle for Recovering Industrial Waste HeatZhibin YuEngineering and Physical Sciences Research Council (EPSRC)EP/N005228/1ENG - Systems Power & Energy
300663Geothermally Sourced Power and Freshwater Generation for Eastern AfricaZhibin YuEngineering and Physical Sciences Research Council (EPSRC)EP/P028829/1ENG - Systems Power & Energy
300273An ORC power plant integrated with thermal energy storage to utilise renewable heat sources for distributed H&PProject Number; 102883Zhibin YuEngineering and Physical Sciences Research Council (EPSRC)EP/R003122/1ENG - Systems Power & Energy