Flat rectangular plate heat sinks are often used to cool large electronic components by the combined effects of natural convection and thermal radiation. There is, however, a paucity of rational design techniques for these devices. Thus, a systematic program to investigate the use of flat, rectangular plate heat sinks with surface coatings to enhance the net radiative exchange with the surroundings has been undertaken. The preliminary results of this program are presented in this work. A two-dimensional numerical model of a single electronic component mounted on a vertically oriented, flat rectangular plate heat sink that is located immediately above an upward-facing, horizontal component board was developed for this investigation. This model, which is solved using a control volume method based on the SIMPLER algorithm, accounts for the fully-coupled natural convection, conduction and radiative heat transfer processes that occur in the two-dimensional heat sink configuration described above. The results of a parametric study performed with the numerical model confirm the necessity of employing a heat sink, since for the ranges of values investigated, from 64 to 88 percent of the energy dissipated in the component is transferred to the surroundings from the heat sink. The parametric study examines the effects of component power, heat sink size (height), the thickness and emissivity of the heat sink, the vertical location of the component on the heat sink, and the temperature of the horizontal component board on the temperature of the component mounted on the heat sink.
