Air-Side Heat Transfer in Finned Tube Heat Exchangers

Abstract

Because of the low heat transfer coefficient of gases, it is necessary to use extended surfaces on the gas side when exchanging heat with liquids or two-phase fluids. Such finned tube exchangers are a very important basic class of heat exchangers. Although finned tube exchangers have been in existence for 50 yr, there have been numerous developments in the technology. This paper attempts to survey the recent developments related to the air-side aspects of heat exchanger design. Nearly all of the recent developments have been empirical because of the complicated gas-side flow structure. Among the developments discussed are the use of special surface geometries for enhanced heat transfer, row effects, local heat transfer coefficient distribution, and correlations for heat transfer coefficient and pressure drop. Two important design configurations—circular finned tubes and plate fin designs—are considered separately.