In this paper, motivated by a need to develop heat spreaders with post-containing (or nested channeled) configurations, we develop analytical models for the Squeeze Flow behavior of particle-filled Thermal Interface Materials (TIMs) between parallel plates and those with posts. The fluids are modeled as either Newtonian, or as Bingham fluids. The pressure distribution is analytically described for axisymmetric and non-axisymmetric configurations of fluids squeezed between parallel plates as well as for non-planar configurations with a cylindrical post at the center of one of the two circular plates. The developed analytical solutions to Newtonian behavior of the fluids are validated using squeeze flow models created in a commercial finite element code (COMSOL). The analysis for non-planar geometries is verified that as the post height is reduced to zero, the developed solution reduces to that of the parallel plate configuration. The influence of the height of the post on the force is systematically analyzed from which it is observed that the force required to compress the fluid increases with the post height. With increased post height, the force solution deviates by a greater amount from the parallel plate solution. The Bond-Line Thickness (BLT) of Newtonian and Bingham fluids contained within circular plates is determined. It is shown that materials with greater yield strength produce higher BLTs. The effect of backpressure is also shown to increase the BLT. Lastly, it is shown that as particles are added into the fluid, the effective viscosity increases and as a result a greater force is required to squeeze the fluid material.

This content is only available via PDF.
You do not currently have access to this content.