| Title |
An Experimental Study on Thin Film Evaporation of Water on Enhanced Tubes Used for Evaporators of Absorption Chillers |
| Authors |
Do-Hyun Park ; Ho-Seung Han ; Nae-Hyun Kim |
| DOI |
https://doi.org/10.6110/KJACR.2019.31.5.183 |
| Keywords |
전열촉진관 ; 증발기 ; 흡수식 냉동기 ; 유하 액막 증발 ; 열전달계수 Tube ; Evaporator ; Absorption chiller ; Thin film evaporation ; Heat transfer coefficient |
| Abstract |
Thin film evaporation of water using enhanced tubes is one of the most common mode of heat transfer in absorption chillers evaporators. Proper design of the evaporators require adequate knowledge of evaporation heat transfer coefficient. In this study, seven enhanced tubes with different enhancement geometries were tested at a saturation temperature of 12℃, 15℃ tube-side water inlet temperature and a film flow rate of . The results indicated that the evaporation heat transfer coefficient of the Floral tube was lower than that of the smooth tube, while the Corrugated tube yielded almost the same heat transfer coefficient as the smooth tube. Notched Floral tube yielded a heat transfer coefficient of 72%, which is higher than that of smooth tube. It was found that Notched geometry was better than the End-cross geometry. Moreover, addition of Floral and Corrugated geometry formations to tubes having three- dimensional protrusions, such as Notched or End-cross tubes further enhanced the evaporation heat transfer. As for the overall heat transfer coefficient, which accounts for both evaporation and tube-side heat transfer, End-cross Corrugated tube yielded the highest heat transfer coefficient at 57% as compared to smooth tube. |