Study of thermal contact resistance of rough surfaces based on the practical topography

An approach is proposed to predict the thermal contact resistance (TCR) of rough surfaces. The practical rough topography of surfaces is measured by a contour profiler and is reconstructed to numerically analyze the mechanical and thermal contact performance. The studied material pairs are Ti-6Al-4V-Ti-6Al-4V and C/C-SiC-high temperature ceramic (HTC). The TCR with air gap and vacuum gap conditions are calculated. The approach is validated by the comparison with experimental results of surfaces with the same topography at the same temperatures and loading pressures. The influence of thermal contact conductance between real contact asperities on the TCR of rough surfaces is studied. The approach can be used to predict TCR of different materials with different gap medium under different temperatures and loading pressures. The results show that the real contact area increases approximate linearly, while TCR decreases with the increasing pressure.