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

摘要

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), Peclet 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.