Natural Convection Air cooling of Electronic Components in Partially top vented Enclosures

Abstract

The study of natural convection from aheat source located at the bottom ofpartially top vented enclosure is presented.Air cooling for electronic componentssituated at the bottom of a top ventedenclosure is studied theoretically. The flowwas assumed to be laminar, steady and ofconstant physical properties. The processwas described by the continuity, momentumand energy partial differential equations,which were expressed in Cartesiancoordinates system. Due to the nature of thestudied problem and with propertransformation, at the dependent andindependent variables, these governingequations were expressed by a set ofdimensionless partial differential equations.This set of differential equations istransformed to set of difference equationsby the implantation of a finite differencetechnique. Accordingly, the solutions forthis problem were obtained by theapplication of the well-known Gauss Siedeliteration method. A computer program, byusing FORTRAN-90 language, wasdeveloped to solve the present proposedmathematical model. According to thissolution; the values of Nusselt number, fordifferent values of Rayleigh number areobtained.Comparisons between the presentobtained results and those results obtainedin previous theoretical results wereperformed for parametric variations of thevent opening size and shape. Also acorrelation for Nusselt number as a functionof Rayleigh number and equivalentdiameter of the vent is proposed.