Computations for a Three-by-Three Array of Protrusions Cooled by Liquid Immersion: Effect of Substrate Thermal Conductivity

Abstract

A computational study of natural convection in an enclosure as applied to applications in cooling of electronic components is reported. The investigation is for a configuration consisting of a three by three array of heated protrusions placed on a vertical substrate. The vertical sidewalls are all insulated, and the top and bottom walls serve as isothermal heat sinks. A thin layer at the back of each protrusion is the heat source, where heat is generated uniformly and volumetrically. The coolant is the flourinert liquid FC75. The code was first validated with experimental results reported earlier on the same configuration. The effect of the substrate conductivity, κs on the heat transfer and fluid flow was then studied for power levels of 0.1 and 0.7 Watts per protrusion. The computations indicate that the effect of increasing κs is dramatic. The protrusion temperatures which were found to be nominally steady, were substantially reduced. The percentage of generated power that is directly conducted to the substrate increased with an increase in κs . The fluid velocity field, which was unsteady, was not significantly affected by changes in κs .