Influence of Flatness and Waviness of Rough Surfaces on Surface Contact Conductance

Abstract

The effect of surface roughness, waviness and flatness deviations on thermal contact conductance is predicted. Threshold values of the surface parameters which do not adversely influence thermal contact conductance are determined. Flatness deviations less than ten times the average roughness and waviness less than about four times the average roughness do not significantly affect the contact conductance. A correlation is developed for contact conductance in terms of the surface parameters, the material properties and the contact pressure at the joint. Experiments are conducted in vacuum with rough, non-flat and wavy surfaces and the experimental results are demonstrated to agree well with the predictions.