Numerical study of thermal contact resistance considering spots and gap conduction effects

Abstract

Thermal contact resistance is a crucial parameter for the thermal management of electronic devices, as it directly impacts the heat dissipation efficiency across densely packed component interfaces. This paper proposes a finite element modeling approach to predict thermal contact resistance. The model is based on the optically measured surface topography of Al6061 alloy pairs using a white light interferometer. A mechanical-thermal sequential coupling approach is developed to simulate the contact area and temperature distribution of the contact model. Elastic-plastic deformable mechanics and interface heat transfer in terms of spots and gap conduction are incorporated into the approach. The research indicates that the pressure between longitudinal surfaces significantly influences heat transfer preceding the solid contact point. At an upper surface load pressure of 0.15 MPa, the thermal contact resistance is 329 mm²·K/W. With a gradual increase in load up to 0.6 MPa, the thermal resistance decreases to 244 mm²·K/W. Moreover, the transition of interstitial gas from free molecules to a continuous state results in decreased thermal conductivity. Specifically, at gas pressures of 5 Pa and 1 atm, the thermal contact resistance reduces from 557 mm²·K/W to 270 mm²·K/W. Furthermore, the numerical results, when compared to experimental data under different gas pressures, exhibit a discrepancy of less than 15%. This outcome effectively validates the accuracy of the proposed method.