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

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.

Keywords

nucleate pool boiling heat transfer coefficients refrigerants critical heat flux electronic cooling

Get full access to this article

View all access options for this article.

References

Hsu

Y. Y.

Graham

R. W.

, Transport processes in boiling and two-phase system (Washington, DC: Hemisphere Publishing Company 1976).

Van Stralen

S. J. D.

, ‘The growth rate of vapor bubbles in superheated pure liquids and binary mixtures’ Int. J. Heat Mass Transf. 11 (1968): 1467–1512.

Stephan

Abdelsalam

, ‘Heat transfer correlations for natural convection boiling’ Int. J. Heat Mass Transf. 23 (1980): 73–87.

Cooper

M. G.

, ‘Correlations for nucleate boiling formulation using reduced properties’ Physicochem. Hydrodyn. 3 (1982): 89–111.

Gorenflo

, ‘Pool boiling’ VDI heat atlas (Dusseldorf: VDI-Verlag 1984) ch. Ha.

Gorenflo

Chandra

Kottoff

Luke

, ‘Influence of thermophysical properties on pool boiling heat transfer of refrigerants’ Int. J. Refrig. 27 (2004): 492–502.

Jung

Kim

Song

, ‘Nucleate boiling heat transfer coefficients of pure halogenated refrigerants’ Int. J. Refrig. 26 (2003): 240–248.

Jung

Lee

Bae

Oho

, ‘Nucleate boiling heat transfer coefficients of flammable refrigerants’ Int. J. Refrig. 27 (2004): 409–414.

Thome

J. R.

, ‘Boiling of new refrigerants: A state-of-the-art review’ Int. J. Refrig. 19 (1996): 435–457.

10.

Gorenflo

, ‘State of the art pool boiling heat transfer of new refrigerants’ Int. J. Refrig. 24 (2001): 6–14.

11.

Molina

M. J.

Rowland

F. S.

, ‘Stratospheric sink for chlorofluoromethanes: Chlorine atom catalyzed destruction of ozones’ Nature 249 (1974): 810–812.

12.

Webb

R. L.

, Principles of enhanced heat transfer (New York: John Wiley & Sons. Inc. 1994).

13.

Zuber

, Hydrodynamic aspects of boiling heat transfer. AEC report no. AECU-4439, Physics and Mathematics, 1959.

14.

Kline

S. J.

McClintock

F. A.

, ‘Describing uncertainties in single-sample experiments’ Mech. Eng. 75 (1953): 3–8.

15.

Lemmon

E. W.

Huber

M. L.

McLinden

M. O.

, NIST reference fluid thermodynamics and transport properties. REFPROP version 8.0 (Gaithersburg, Maryland, USA: National Institute of Standards and Technology 2007).