Heat and Mass Transfer of Flue Gas Flowing through Fin-tube Heat Exchangers with Steam Condensation

摘要

This paper covers experimental investigations on heat and mass transfer for fin-tube heat exchangers used in natural gas water heaters. The results show that the Renold's number of flue gas and the dimensionless group J(corrected Ja's number) of flue gas are the important factors which affect the total heat transfer coefficient of flue gas. Experiments and analyses indicate that Nusselt's number of flue gas doesn't always increase with the increase of Renold's number, but when Re is fixed, Nu always increases with increasing J. Based on the experiments and analyses, the improvement way for the condensing heat exchangers of the gas water heater/boiler is discussed.