Thermal Analysis of an Impinging Jet on a Plate With and Without a Porous Layer

Abstract

This work shows numerical results for a jet impinging against a flat plane covered with a layer of a porous material, which is maintained at a higher temperature than the incoming fluid. Parameters such as permeability and thickness of the porous layer and thermal conductivity ration are varied in order to analyze their effects on the local distribution of Nu. The macroscopic equations for mass, momentum, and energy are obtained based on a volumeaverage concept. The numerical technique employed for discretizing the governing equations was the control volume method with a boundary-fitted nonorthogonal coordinate system. The SIMPLE algorithm was used to handle the pressure-velocity coupling. Results indicate that inclusion of a porous layer decreases the peak in Nu avoiding excessive heating or cooling at the stagnation point. Also found was that the integral heat flux from the wall is enhanced for certain range of values of layer thickness, porosity, and thermal conductivity ratio.

A numerical investigation of heat transfer and entropy generation during jet impingement cooling of protruding heat sources without and with porous medium

“…The flow parameters are Re ¼ 750; H=W ¼ 2:0; Da ¼ 10 À3 ; k s =k f ¼ 10:0 and porous layer thickness to channel height ðh=HÞ is 0.5. The local Nusselt number distribution is found to be in good agreement with de Lemos and Fischer [26] as shown in Fig. 3.…”

“…In order to study the heat transfer characteristics of impinging jet with an attached porous layer, simulations are performed similar to de Lemos and Fischer [26] where Local Thermal Equilibrium (LTE) is assumed between saturated fluid and solid matrix of porous medium. The flow parameters are Re ¼ 750; H=W ¼ 2:0; Da ¼ 10 À3 ; k s =k f ¼ 10:0 and porous layer thickness to channel height ðh=HÞ is 0.5.…”

“…Jeng et al [22] experimentally studied heat transfer characteristics in a 180-deg turn around channel with discrete aluminum-foam blocks. Rong [25][26][27][28]. de Lemos and Fischer [26] performed analysis on jet impingement heat transfer on a flat plate with and without porous layer with Local Thermal Equilibrium (LTE) assumption.…”

“…Rong [25][26][27][28]. de Lemos and Fischer [26] performed analysis on jet impingement heat transfer on a flat plate with and without porous layer with Local Thermal Equilibrium (LTE) assumption. It was found that, porous layer on the plate eliminates the second peak in Nu and allows for controlling heat transfer from the wall.…”

Thermal analysis of a metal foam subject to jet impingement

“…The use of porous medium however not necessarily improves the heat transfer as compared to without porous medium [7]. De Lemos and Fishcher [7] considered a jet impingement cooling on a heated plate covered with and without a porous layer. They investigated the effect of porosity and thickness of the porous layer.…”