Boiling heat transfer correlations for refrigerant mixtures flowing inside micro-fin tubes

2008 ◽  
Vol 2 (4) ◽  
pp. 489-493
Author(s):  
Xiaoyan Zhang ◽  
Xingqun Zhang ◽  
Yunguang Chen ◽  
Xiuling Yuan
Author(s):  
Liang-Han Chien ◽  
H.-L. Huang

This study investigates a new enhanced boiling surface, which is made by wrapping wire mesh on finned tubes. Pool boiling performance of the new enhanced tubes has been tested in Refrigerant-134a at 5, 10, 20, and 26.67°C saturation temperatures. Brass or copper mesh of 80, 100, or 120 meshes per inch was wrapped on finned tubes of 42 or 60 FPI (fins per inch). The fin heights were either 0.2 mm or 0.4 mm. The test results show that the mesh covered fin tubes significantly enhanced the boiling performance by forming many pores of proper sizes on the surface and sustaining vapor in the tunnels formed by the mesh and fins. The preferred mesh size decreases with decreasing heat flux. The mesh covered on 60FPI fin tube having 0.4 mm fin height and 100 mesh per inch yields the best boiling performance. It enhances the boiling heat transfer coefficient by 7∼8 folds at 5°C as compared with the smooth tube.


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