Natural convection to air from an array of vertical parallel plates with discrete and protruding heat sources

Numerical and experimental studies are carried out on natural convection heat transfer to air from an array of vertical parallel plates with protruding and discrete heat sources, such as IC packages. Two-dimensional (2-D) Navier-Stokes and energy equations including heat conduction through the plates and heat sources are numerically solved under the conditions of modified Grashof number Gr*=2.3 X 10(3) similar to 8.8 X 10(5) and plate height to spacing ratio L=I/h=8 similar to 30. The numerical solutions agree well with the experimental values except for the large aspect ratio L=30, where the three-dimensional (3-D) effects become significant. A correlation expression for the local Nusselt number is proposed; it can predict the protrusion surface temperature within +/-20% error. A method for estimating the maximum inner temperature of the heat source is proposed, and the thermally optimum spacing of the parallel plates is discussed.