The Use of Porous Fins for Heat Transfer Augmentation in Parallel-Plate Channels

Abstract

In this study, a steady, fully developed laminar forced convection heat augmentation via porous fins in isothermal parallel-plate duct is numerically investigated. High-thermal conductivity porous fins are attached to the inner walls of two parallel-plate channels to enhance the heat transfer characteristics of the flow under consideration. The DarcyBrinkman-Forchheimer model is used to model the flow inside the porous fins. This study reports the effect of several operating parameters on the flow hydrodynamics and thermal characteristics. This study demonstrates, mainly, the effects of porous fin thickness, Darcy number, thermal conductivity ratio, Reynolds number, and microscopic inertial coefficient on the thermal performance of the present flow. It is found that the highest Nusselt number is achieved at fully filled porous duct which requires the highest pumping pressure. The results show that using porous fins requires less pumping pressure with comparable high heat augmentation weight against fully filled porous duct. It is found that higher Nusselt numbers are achieved by increasing the microscopic inertial coefficient (A), the Reynolds number (Re), and the thermal conductivity of the porous substrate k 2 . The results show that heat transfer can be enhanced (1) with the use of high thermal conductivity fins, (2) by decreasing the Darcy number, and (3) by increasing microscopic inertial coefficient.

An empirical correlation for isothermal parallel plate channel completely filled with porous media

“…The following empirical Nusselt number correlation with maximum 3.1% deviation for 100 < Re < 2000 is suggested: (8) The deviation in the correlation was calculated with respect to the CFD results and were calculated for friction factor as Deviation= |f Correlation -f CFD |/f CFD and for Nusselt number as Deviation = |Nu Correlation -Nu CFD |/Nu CFD .The Nusselt number correlation approaches clear isothermal clear parallel plate channel Nusselt number value of 7.54 for Da ® 4, A® 0, and k ® 1. The following empirical Nusselt number correlation with maximum 3.1% deviation for 100 < Re < 2000 is suggested: (8) The deviation in the correlation was calculated with respect to the CFD results and were calculated for friction factor as Deviation= |f Correlation -f CFD |/f CFD and for Nusselt number as Deviation = |Nu Correlation -Nu CFD |/Nu CFD .The Nusselt number correlation approaches clear isothermal clear parallel plate channel Nusselt number value of 7.54 for Da ® 4, A® 0, and k ® 1.…”

Analytical investigation of porous pin fins with variable section in fully-wet conditions

“…Kiwan and Al-Nimr introduced the concept of using fins made up of porous materials by introducing the Darcy model for first time [1,2]. Hamdan and Al-Nimr [3] studied the increase in heat transfer between two parallel porous channels by using porous fins. Kundu and his colleagues presented an analytical study to determine the performance of convective porous fins with various geometries [4].…”

Experimental Pressure Drop and Heat Transfer in a Rectangular Channel With a Sinusoidal Porous Screen

“…Numerical models by Kiwan and Al-Nimr [6], and Hamdan and Al-Nimr [7] employ 1-dimensional porous fins periodically between parallel plates to perturb laminar flow. The objectives of the studies are to replace the solid fins with the porous fins that provide similar thermal performance as the solid fins but with the advantage of significant weight reduction for the compact heat exchanger design.…”

“…The objectives of the studies are to replace the solid fins with the porous fins that provide similar thermal performance as the solid fins but with the advantage of significant weight reduction for the compact heat exchanger design. The investigations [6,7] show the augmentation of heat transfer and friction factor in a porous finned channel relative to a smooth channel with varying effects from the fin geometry, porosity, and thermal conductivity. Numerical and experimental investigations by Zhang and Chen [8] report the mean f and Nu across periodic triangular ducts where the walls are solid non-porous.…”