Flow boiling heat transfer of R134a and R245fa in a 2.3 mm tube

Author(s)

Tibirica, Cristiano Bigonha ^[1] ; Ribatski, Gherhardt ^[1]

Affiliation

^[1] Univ Sao Paulo, EESC, Dept Mech Engn, BR-13566970 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER; v. 53, n. 11-12, p. 2459-2468, MAY 2010.
• Web of Science Citations: 77

Abstract

This paper presents new experimental flow boiling heat transfer results in micro-scale tubes. The experimental data were obtained in a horizontal 2.3 mm I.D stainless steel tube with heating length of 464 mm, R134a and R245fa as working fluids, mass velocities ranging from 50 to 700 kg m(-2) s(-1), heat flux from 5 to 55 kW m(-2), exit saturation temperatures of 22, 31 and 41 degrees C, and vapor qualities ranging from 0.05 to 0.99. Flow pattern characterization was also performed from images obtained by high-speed filming. Heat transfer coefficient results from 1 to 14 kW m(-2) K(-1) were measured. It was found that the heat transfer coefficient is a strong function of heat flux, mass velocity and vapor quality. The experimental data were compared against ten flow boiling predictive methods from the literature. Liu and Winterton {[}3], Zhang et al. {[}5] and Saitoh et al. {[}6] worked best for both fluids, capturing most of the experimental heat transfer trends. (C) 2010 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 07/53950-5 - A theoretical and experimental study on flow boiling heat transfer and critical heat flux in microchannels
• Grantee: Cristiano Bigonha Tibirica
• Support Opportunities: Scholarships in Brazil - Doctorate