Numerical Analysis of Convective Heat Transfer From an Elliptic Pin Fin Heat Sink With and Without Metal Foam Insert

TLDR

The pin fin heat sink model comprises six elliptical pin rows with 3 mm major diameter, 2 mm minor diameter, and 20 mm height. The study investigates how air flow Reynolds number, metal foam porosity, and permeability affect the overall Nusselt number, pressure drop, and heat sink efficiency. A three‑dimensional conjugate heat transfer model using Darcy–Brinkman–Forchheimer and Navier–Stokes equations, solved with a finite volume code employing point implicit Gauss–Seidel and algebraic multigrid, was validated against experimental data and used to analyze flow and heat transfer in the heat sink with various metal foams of differing porosities and permeabilities. The results indicate that structural properties of the metal foam insert can significantly influence both flow and heat transfer in a pin fin heat sink, with the Nusselt number increasing more than 400 % when porosity decreases and Reynolds number increases, while pressure drop rises with decreasing permeability and increasing Reynolds number.

Abstract

A numerical analysis of forced convective heat transfer from an elliptical pin fin heat sink with and without metal foam inserts is conducted using three-dimensional conjugate heat transfer model. The pin fin heat sink model consists of six elliptical pin rows with 3 mm major diameter, 2 mm minor diameter, and 20 mm height. The Darcy–Brinkman–Forchheimer and classical Navier–Stokes equations, together with corresponding energy equations are used in the numerical analysis of flow field and heat transfer in the heat sink with and without metal foam inserts, respectively. A finite volume code with point implicit Gauss–Seidel solver in conjunction with algebraic multigrid method is used to solve the governing equations. The code is validated by comparing the numerical results with available experimental results for a pin fin heat sink without porous metal foam insert. Different metallic foams with various porosities and permeabilities are used in the numerical analysis. The effects of air flow Reynolds number and metal foam porosity and permeability on the overall Nusselt number, pressure drop, and the efficiency of heat sink are investigated. The results indicate that structural properties of metal foam insert can significantly influence on both flow and heat transfer in a pin fin heat sink. The Nusselt number is shown to increase more than 400% in some cases with a decrease in porosity and an increase in Reynolds number. However, the pressure drop increases with decreasing permeability and increasing Reynolds number.