摘要
Heat transfer using air jet impingement technique is one of the conspicuous tasks in the looming world of electronic packaging system.Here,the material selection of heat sink becomes one of the prior and important assignments to construct a heat sink with desired characteristic cooling rate.In order to study the material effect of heat sink over the cooling characteristic,the present work takes an initiative in plotting the Nusselt magnitude over the radial distance for different material of heat sink.This is done by computing the flow regime and heat transfer characteristic of a 2D axis symmetric geometry in commercial simulating software,ANSYS CFX.The computation of cooling characteristic in form of Nusselt profile is done using SST+Gamma–theta turbulence model.Since the prediction of heat interaction due to the intermediacy and transition in the flow regime is a unique issue of this problem.The results for Nusselt curve signifies a tangible elevation in local Nusselt value(nonuniformity)with decrease in thermal diffusivity of target surface.Also the nonuniformity is observed to vanish above a critical range(66.76mm2/s)of thermal diffusivity.This happens due to presences of abnormal turbulence of heat flow which occurs inside the target surface.Since the variation in thermal diffusivity causes some imbalance competition between the heat storage and dissipation capabilities.Above all the target surface carrying thermal diffusivity less than 66.76mm2/s possesses a dominating heat storage capability,on behalf of which some heat transfer occurring in near jet and far jet regions are being restricted.These are transferred towards stagnation region in radial direction.
