Evaporation Performance of Microfin Tube with R-134a

摘要

Micro-fin tubes, having the following geometries 1) Herringbone, single groove tube, 2) Herringbone, cross groove tube and plain tube, were studied for the evaporation performance of R-134a in this paper. The test refrigerant was entered the tube side of test section at a known vapor quality. Then the refrigerant was evaporated at 70F in the test section by water flowing in the annulus side. The pressure drop data were taken with evaporation process, which includes the acceleration term. Both single and cross groove tubes have much better performance than does plain tube. The new SGT geometry shows better evaporation performance than the cross groove tube in this study. The data were taken at fixed mass flow rate and heat flux for incremental changes in inlet vapor quality. Those data yield graphs of h and dp/dz vs. vapor quality for the three flow rates. The average vapor quality in the test section will span 0.2 to 0.90.