Entropy generation and heat transfers via laminar forced-convection channel flows over transverse fins in entrance regions

This study is concerned with the prediction of the generation of entropy as well as heat transfer characteristics of the two-dimensional laminar forced-convective flows within channels, onto whose walls one or two pairs of transverse fins are attached symmetrically. These fins, placed in the entrance regions of the channels, interrupt the development of the boundary layers, and result in changes of thermal performance and viscous friction. Consequently, local irreversibilities increase significantly due to the existence of the fins. Solutions of the elliptic momentum and energy equations are carried out through the stream function-vorticity analysis. Distribution of the entropy generation can be further obtained from the velocity and temperature solutions by solving the entropy generation equation. A co-ordinate transformation technique1,2 has also been employed in the present computation for the treatment of boundary conditions far downstream. Both walls of the channel are maintained at a constant temperature. Two limiting situations for fin properties, namely perfectly conductive and adiabatic, are considered. Results for various geometric arrangements under different Reynolds numbers are presented. A comparison of results for the finned and unfinned channels has also been carried out.