부산대학교 도서관

The present study aimed to conduct an experimental examination of heat transfer increase using tubes with extended surface of twisted fins for the condensation of vapor R-406A in horizontal tubes. The experimental setup comprised a main counter flow double-tube condenser, with water as the cooling fluid. Further, test and secondary condensers were used to reach desired vapor qualities. The tests were conducted on a smooth tube and four different tubes with extended surface of twisted fins and collected for different mass flow rate of refrigerant and in each mass flow rate for six different vapor quality. The refrigerant mass flow, temperature of refrigerant inlet water and condenser outlet water, were measured in each test. Also, the heat transfer coefficients were obtained based on the former data for different states. The results show that for the tubes with extended surface of fins, heat transfer enhanced by decreasing the pitch. The use of tubes with extended surface of fins increased the mean heat transfer coefficient by about 47% compared to the smooth tube. Eventually, a new correlation is defined for examination of the condensation heat transfer coefficient of R-406A in circular tubes with extended surface of twisted fins. [ABSTRACT FROM AUTHOR]