Numerical Investigation of Fluid Flow and Heat Transfer in Microchannel

Abstract

Microchannels are of current interest for use in compact heat exchangers, micro biochips, micro reactors, VLSI system where very high heat transfer performance is desired. These electronic equipments are virtually synonyms with modern life applications such as appliances, instruments and computers. The dissipation of heat is necessary for the proper functioning of these instruments Microchannels provide very high heat transfer coefficients because of their small hydraulic diameters. Here, an investigation of fluid flow and heat transfer in microchannels is conducted. Fluid flow and heat transfer experiments were conducted on a silicon microchannel heat exchanger (MHE) .A Three-dimensional Computational Fluid Dynamics (CFD) model was built using the commercial package, FLUENT, to investigate the conjugate fluid flow and heat transfer phenomena in a siliconbased rectangular microchannel heat sink. This work focused on laminar flow (Re < 200) within rectangular microchannel with hydraulic diameter 86μm for single-phase liquid flow. The influence of the thermophysical properties of the fluid on the flow and heat transfer, are investigated by evaluating thermophysical properties at a reference bulk temperature. The micro-heat sink model consists of a 10 mm long silicon substrate, with rectangular microchannels, 57μm wide and 180μm deep, fabricated along the entire length. water at 293K is taken as working fluid. The results indicate that thermophysical properties of the liquid can significantly Influence both the flow and heat transfer in the microchannel. Assumption of hydrodynamic, fully developed laminar flow is valid here on basis of Langhaar’s equation. The local heat transfer coefficient and averaged Nusselt number is calculated and plotted for pressure drop of 50kpa, 30kpa and 10kpa.also result is verify for heat flux 50W/cm2, 90W/cm2 and 150 W/cm2.