A CFD analysis of the performance of pin-fin laminar flow micro/meso scale heat exchangers

Abstract

A full three dimensional computational study was carried out using a finite-volume based solver for analyzing the performance of pin-fin based micro/meso scale heat exchangers with air as the working fluid. A staggered arrangement of cylindrical pin fins in rectangular channel geometry was used. Various configurations were considered consistent with a parallel experimental study being conducted based on a micro-wind tunnel setup. The pin/channel height used was 0.4 mm, and the pin diameters varied from 0.17-0.50 mm to give hydraulic diameters in the range of 0.13-0.78 mm. This gave volumetric area densities for the heat exchangers in the range of 5-15 mm2/mm3. Various heat exchanger configurations were simulated to determine performance characteristics such as the Nusselt number, friction factor, specific fluid friction power and Mach number in the Reynolds number regime for laminar flows. In addition a detailed numerical diagnosis was carried out to determine local behavior on the pin surfaces, end walls, etc to identify specific characteristics such as regions of high and low heat transfer, locations for possible shock formation, etc. The range of results obtained would be useful for future design of micro heat exchangers for use in small footprint, high heat flux dissipation applications like turbine blade and microelectronic systems.