Nucleate boiling heat transfer coefficients of halogenated refrigerants up to critical heat fluxes

• Published in: Proceedings of the Institution of Mechanical Engineers. Part C, Journal of mechanical engineering science Journal of mechanical engineering science, 2009-06, Vol.223 (6), p.1415-1424
• Main Authors: Park, K-J, Jung, D, Shim, S E
• Format: Article
• Language: English
• Subjects: Boilers; Chemical engineering; Cooling; Copper; Correlation; Deviation; Halogenation; Heat flux; Heat transfer; Heat transfer coefficients; Mechanical engineering; Nucleate boiling; Refrigerants; Refrigeration; Thermocouples; Vapor pressure; Vapors
• ISSN: 0954-4062; 2041-2983
• DOI: 10.1243/09544062JMES1356

Abstract In this work, nucleate pool boiling heat transfer coefficients (HTCs) of five refrigerants of differing vapour pressures are measured on a horizontal, smooth copper surface of 9.53×9.53 mm. The tested refrigerants are R123, R152a, R134a, R22, and R32 and HTCs are taken from 10 kW/m2 to the critical heat flux (CHF) of each refrigerant. Wall and fluid temperatures are measured directly by thermocouples located underneath the test surface and in the liquid pool, respectively. Test results show that nucleate pool boiling HTCs of halogenated refrigerants increase as the heat flux and vapour pressure increase. This typical trend is maintained even at high heat fluxes above 200 kW/m2. Zuber's prediction equation for CHF is quite accurate showing a maximum deviation of 21 per cent for all refrigerants tested. For all refrigerants, Stephan and Abdelsalam's well-known correlation underpredicted nucleate boiling HTC data up to the CHF with an average deviation of 21.3 per cent, while Cooper's correlation overpredicted the data with an average deviation of 14.2 per cent. On the other hand, Gorenflo's and Jung et al.'s correlations showed 5.8 and 6.4 per cent deviations, respectively, in the entire nucleate boiling range up to the CHF.