Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10391807 | Experimental Thermal and Fluid Science | 2011 | 11 Pages |
Abstract
The flow boiling heat transfer characteristics of R134a in the multiport minichannel heat exchangers are presented. The heat exchanger was designed as the counter flow tube-in-tube heat exchanger with refrigerant flowing in the inner tube and hot water in the gap between the outer and inner tubes. Two inner tubes were made from extruded multiport aluminium with the internal hydraulic diameter of 1.1Â mm for 14 numbers of channels and 1.2Â mm for eight numbers of channels. The outer surface areas of two inner test sections are 5979Â mm2 and 6171Â m2, while the inner surface areas are 13,545Â mm2 and 8856Â mm2 for 14 and eight numbers of channels, respectively. The outer tube of heat exchanger was made from circular acrylic tube with an internal hydraulic diameter of 25.4Â mm. The experiments were performed at the heat fluxes between 15 and 65Â kW/m2, mass flux of refrigerant between 300 and 800Â kg/m2Â s and saturation pressure ranging from 4 to 6Â bar. For instance the boiling curve, average heat transfer coefficients are discussed. The comparison results of two test sections with different the number of channels are investigated. The results are also compared with nine existing correlations. The new correlation for predicting the heat transfer coefficient was also proposed.
Keywords
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Fluid Flow and Transfer Processes
Authors
Jatuporn Kaew-On, Kittipong Sakamatapan, Somchai Wongwises,