Compact Models for Transient Thermal Spreading Resistance in Half-space, Flux Tube, and Flux Channel Regions

Transient thermal spreading resistance is of great importance in thermal management of electronic components and devices. A small number of solutions exist for heat sources on a half-space for isoflux or isothermal boundary conditions. In addition, a finite number of solutions exist for semi-infinite flux tubes and flux channels. In this paper we review the available solutions and propose simple compact models for each class of problems using asymptotic correlations. These models offer several advantages. First, they provide an efficient and easy prediction tool. Second, by taking advantage of an appropriate length scale, the models can be applied for heat sources of more complex shape for which no solutions exist. Finally, in the case of flux tubes and channels, these models provide a simpler alternative to the exact series solutions which often require many terms for convergence. Models are developed for both types of heat sources: isothermal and isoflux.