Experimental Investigation of Thermal Contact Resistance at Flat/Curved Surface Interfaces under various temperature, pressure and surface roughness levels

Abstract Thermal Contact Resistance (TCR) is a critical factor in heat transfer processes across diverse engineering applications. Existing theoretical models and empirical correlations for TCR prediction remain insufficient for diverse operating conditions, experimental investigation is required for specific geometries and environments. This study systematically investigates TCR for two typical contact configurations, i.e. flat and hinge-type curved surface contact, under varying temperatures, pressures, and surface roughness levels. A high-precision steady-state heat flux experimental system was designed, integrating heating, cooling, and pressure-loading subsystems to ensure controlled operation conditions. Experimental results revealed that TCR decreases with rising contact temperature and pressure, while increases significantly with surface roughness. And the surface roughness exerting the most dominant influence. The effect of pressure on TCR is relatively minor at smaller surface roughness, whereas the pressure dependence becomes more significant at larger roughness. Empirical correlations for TCR as functions of contact pressure, roughness, and temperature were formulated for both flat and curved surface contacts based on the experimental data. The maximum fitting errors of the correlations are 6% for flat surface contact and 9.2% for curved surface contact, which demonstrates the reliability of the fitting results. These relationships enable the theoretical calculation of TCR for both flat and curved surface contacts under varying operating conditions.