Simple evaluation method for temperature drop at contact interface between rough surfaces under low contact pressure conditions

Abstract

For heat removal from systems such as electronic equipment, satellite thermal control systems, and nuclear reactors, reduction of thermal contact resistance (TCR) is the most crucial issue to be addressed. Several studies have attempted to propose evaluation equations for predicting TCR for flat rough surfaces. However, as is well known, there are still wide discrepancies among measured results, even for similar materials. In this study, based on the conventional unit cell model for flat surfaces with roughness and the newly proposed contact surface model for wavy surfaces with roughness, thermal contact resistance under a low contact pressure of 0.I-I.0 MPa is investigated theoretically and experimentally. Comparison of the measured and calculated results shows that the measured temperature drop at the interface (that is, the thermal contact resistance) between flat surfaces with roughness lies between the values evaluated by the unit cell model for the cases with and without the heat flow constriction. Furthermore, when the rough surface has waviness, the introduction of macroscopic constriction resistance is shown to be important for evaluating the temperature drop at the interface.