Investigation of Heat Transfer Enhancement Through Permeable Fins

Heat transfer through rectangular permeable fins is modeled and analyzed theoretically in this work. The free stream fluid flow is considered to be normal to the upper surface of the permeable fin. The flow across the permeable fin is permitted in this work. The continuity, momentum, and energy equations are solved for the fluid flow using a similarity transformation and an iterative tridiagonal finite difference method. As such, a correlation for the Nusselt number is generated as functions of the Prandtl number (Pr) and dimensionless suction velocity $(fo)$ for $0.7<Pr≤10$ and $0<fo≤5$⁠, respectively. The energy equation for the permeable fin is generated and solved analytically using the developed correlation. It was found that permeable fins may have superiority in transferring heat over ordinary solid fins, especially at large $fo$ values and moderate holes-to-fin surface area ratios. In addition, the critical holes-to-fin surface area ratios, below which the permeable fins transfer more heat than solid fins, is found to increase as Pr and $fo$ increase. Finally, this work paves a way for a new passive method for enhancing heat transfer.