DETERMINATION OF OPTIMAL PARAMETERS FOR COOLING AN ELECTRONIC COMPONENT BY NATURAL AND MIXED CONVECTION IN A CUBIC CAVITY

Abstract

This work aims to numerically study the controlled cooling by natural or mixed convective exchange of an electronic component of square section placed in the middle of the straight wall in a cubic cavity and subjected to a constant thermal flux density. A flow of air maintained at a cold ambient temperature and entering through an inlet of rectangular section located at the bottom of the left wall cools the component in the case of low temperatures. For strong temperature gradients, a two velocities extraction system placed at the top of the right wall works to remove the dissipated heat. The other walls of the cavity are considered adiabatic. The Rayleigh number (103 ≤ Ra ≤ 106) and the Reynolds number (0 ≤ Re ≤ 800) are the parameters governing the problem. The optimal Reynolds number, corresponding to the second speed of the extractor, is determined for Ra = 103, Re2o = 800. The two Rayleigh numbers allowing the operation with the two speeds are determined, Ra1=4×104 and Ra2=1.5×103. Streamlines and isotherms were also presented in the cubical enclosure to visualize the details of the temperature and the flow distribution. The maximum temperature in the component is around the center in the coordinate area (X=1, 0.1956≤ Y ≤0.6, Z=0.5).