Theory for Thermal Contact
The Thermal Contact feature has correlations to evaluate the joint conductance at two contacting surfaces.
The heat fluxes at the upside and downside boundaries depend on the temperature difference according to the relations:
At a microscopic level, contact is made at a finite number of spots as in Figure 4-13.
Figure 4-13: Contacting surfaces at the microscopic level.
The joint conductance, h, has three contributions: the constriction conductance, hc, from the contact spots, the gap conductance, hg, due to the fluid at the interstitial space, and the radiative conductance, hr: