Experimental Analysis of Laminar Flow and Heat Transfer in a Multi-Port Finned Minichannel

Abstract

Due to their high heat transfer rate, small scale channels have been a popular area of study for the past three decades, especially for heat exchangers. In this study, fluid flow and heat transfer in a multi-port finned minichannel with a rectangular cross section was investigated experimentally under the constant heat flux boundary condition. The minichannel, which has a length of 638 mm, consists of 16 ports, 14 of which are identical finned rectangular channels with a width of 2.10 mm and a height of 5.85 mm while the remaining two ports at the outer edges of the channel were considered to be identical with the other ports. Deionized water was used as the working fluid with Reynolds number ranging between 75 and 190 in a single port. In order to correctly evaluate local heat transfer and friction coefficient values, thermal entrance effects and varying thermo-physical properties of the working fluid were taken into consideration throughout the study. Local Nusselt number varying with dimensionless axial thermal length, friction factor and average Nusselt number values varying with Reynolds number, and temperature distribution along the wall were evaluated to study fluid flow and heat transfer of the finned minichannel. The results were compared to theoretical values and presented graphically. Local Nusselt number values indicated fairly good agreement with theory while friction factor was overestimated. This was considered to be due to the effect of fins. In addition, three correlations were suggested in order to evaluate friction factor, local Nusselt number and average Nusselt number for the minichannel in given ranges of parameters.