Numerical study of mixed convection on jet impingement cooling in a horizontal porous layer-using Brinkman-extended Darcy model

Abstract

In the present study, numerical investigation of jet impingement cooling of a heated surface immersed in a confined porous channel is performed under mixed convection conditions with Brinkman-extended Darcy model, which the Darcian and non-Darcian effects are evaluated. The results are presented in the mixed convection regime with wide ranges of Rayleigh number ( Ra), Péclet number ( Pe), jet width and Darcy number ( Da) in Darcy regime and non-Darcy regime. It is found that, the average Nusselt number ( Nu ¯ ) decreases with the increase in Da for the non-Darcy regime when Pe is low. When Pe is high, Nu ¯ increases with the increase in Da for the non-Darcy regime. Variation of Da in Darcy regime has negligible effect on the heat transfer performance. It is shown that mixed convection mode can cause minimum Nu ¯ unfavorably due to counteraction of jet flow against buoyancy driven flow. Minimum Nu ¯ occurs more obviously at higher values of Ra. Therefore, mixed convection conditions should be carefully considered when designing a system of jet impingement cooling through porous medium.