LAUSR

Abstract The present study experimentally investigated the heat transfer characteristics of flow condensation in a mini channel with serrated fins. The hydraulic diameter of the aluminum channel was 1.28 mm with 11 offset rectangular channels. The vapor of refrigerant R134a was cooled by cold water with jet impingement. After the calibration of jet impingement cooling, the influences of different parameters on condensation heat transfer were identified with the experimental conditions of vapor quality from 0 to 1, heat flux from 5 kW/m 2 to 52 kW/m 2 , mass flux from 72 kg/(m 2 ·s) to 145 kg/(m 2 ·s) and saturation pressure from 0.38 MPa to 0.50 MPa. Flow patterns during condensation were also observed through the visualization design of test section. The experimental results reveal that the vapor quality and mass flux have insignificant influence on the local heat transfer coefficient. The heat transfer coefficient increases with the heat flux and decreases with the saturation pressure. Annular flow is dominant during the whole condensation process. As the existing empirical correlations fail to give reasonable prediction of the present experimental results, a new one is developed with the mean relative deviation and mean absolute relative deviation of 2.3% and 12.0%, respectively. The present work can provide valuable guidance for the design of mini channel condenser for engineering application.