Experimental Study of HCFC-123 Film Condensation on Enhanced Tubes

摘要

Experimental studies of film condensation of HCFC-123 on single horizontal smooth tube and three doubly-enhanced tubes have been conducted. The objective is to enrich the basis data for film condensation of HCFC-123 on enhanced tubes and to obtain deeper understanding of the effect of surface geometries on condensation heat transfer performance. A modified Wilson plot technique was used to obtain the vapor side heat transfer coefficients. The results indicate that the predicted condensation heat transfer coefficients of smooth tube from Nusselt theory agree within +-5 percent with the experimental data. The inner heat transfer coefficients of tube No.1, tube No.2, tube No.3 are 2.16,1.95 and 2.48 times as that of smooth tube. At a saturation temperature of 38℃ outside enhanced ratios of the three enhanced tubes (No.1, No.2 and No.3) relative to the smooth tube are within 4.7～6.1, 3.4～4.5, 2.8～3.5, and at a saturation temperature of 40℃, the ratios are within 6.0～9.1, 4.2～6.6, 3.1～3.3, respectively. Thermal resistance analysis indicates that the percentage of outer thermal resistance of overall thermal resistance increases with the Reynolds number, and the outer thermal resistance is larger than that of the inner one for all the studied tubes at test conditions.