Heat Transfer Enhancement in Miniature Channels with Micro-fin Having Varying Fin Height Along the Axis of Flow

The demand for high heat flux removal techniques is increasing rapidly. Different techniques have been proposed to enhance the heat transfer in microchannel heat exchanger (MCHX) devices. The current work numerically investigates the enhancement of heat transfer and fluid flow through miniature channels with microfins. The effect of microfins with variable fin height along the flow axis is analyzed. Three designs of cylindrical finned rectangular miniature channels are proposed and they are as follows: uniform fin height (Case-1), fin height increasing (Case-2), and decreasing (Case-3) along flow direction. The pitch of the microfins in all three cases is kept constant. A constant heat flux is applied at the bottom wall of the channel. The thermal performance of all three cases of the finned miniature channels is analyzed and compared with the unmodified channel. The channel with designed microfins shows better thermal performance than the plain miniature channel, and heat transfer is enhanced significantly but with the expense of a considerable pressure drop. Case-1 with uniform fins shows better thermal performance than the other two cases and has a comparatively higher pressure drop. These findings will be helpful in design optimization of miniature channels used in heat transfer applications.