Developing an empirical correlation for the thermal spreading resistance of a heat sink

Thermal spreading resistance is a key element in the thermal analysis of a heat sink which is larger in surface area than the component that it being used to cool. Current analytical solutions are far too mathematically cumbersome for practical use by practicing engineers. The current research presents a simple correlation that accurately calculates the thermal spreading within a heat sink, as a function of heat sink geometric and thermal characteristics. A CFD program is used to conduct numerous parametric studies that vary multiple geometric and thermal parameters of the heat sink. Extensive curve fitting analysis is used to develop an empirical equation that can be used to calculate the thermal spreading resistance within a heat sink as function multiple geometric and thermal parameters. The developed equation agrees with a previously derived analytical closed form solutions in most cases within +/−5%.