Analysis of Thermal Resistance of Orthotropic Materials Used for Heat Spreaders

摘要

The general solution to the thermal resistance through a rectangular orthotropic thermal spreader depends on several dimensionless geometric and thermal parameters. The solution is presented graphically for several values of the length-to-thickness thermal conductivity ratio, the Biot number, and the nondimensional width of the applied heat flux, which can be readily applied to engineering applications for electronic component design. The graphs are applicable to a wide range of spreader materials that include aluminum, K1100/epoxy, and K1100/C-C graphite composites. A methodology is presented to assist thermal engineers in designing thermal management systems for electronic components. The advantages of the use of high-conductivity composite materials over ordinary engineering materials in terms of weight savings are illustrated by three examples, in which a comparison is made between aluminum and composites for use as heat spreader materials in typical electronic packaging heat transfer applications.