Flow control and heat transfer enhancement inside a two-dimensional channel using porous blocks and applying bleeding condition between them

Abstract

There are different methods to enhance forced convective heat transfer. In the current study, porous blocks are used on the hot wall of a two-dimensional channel. Use of porous media can enhance the heat transfer by improving the flow mixing with subsequent increment in the effective thermal conductivity of the domain at the position of the used permeable media. However, a cavity-like flow appears between the blocks, which deteriorates heat transfer there. In this study, a bleeding condition by suction is applied to improve heat transfer there. Effects of some important parameters including porous media permeability, porous blocks relative height, flow Reynolds number, and the bleeding coefficient on the thermal performance and pressure loss are investigated. The outcomes reveal that the bleeding condition effect on heat transfer mainly depends on the bleeding coefficient. For example, the effect of bleeding condition on the total average Nusselt number is negligible for the bleeding coefficient (σ) less than 0.01, while it could improve the average Nusselt number by 36% at σ = 0.05. Furthermore, increasing the permeability of porous blocks, the effect of the bleeding condition becomes more highlighted from the performance number point of view.