Fractal model of thermal contact conductance considering thermal stress and asperity interactions

The thermal contact conductance (TCC) of rough surfaces is a fundamental issue in heat transfer. Thermal stress and asperity interactions have important impacts on the TCC. A new fractal model for predicting the TCC that considers thermal stress and asperity interactions is developed. First, an improved normal contact mechanics model is constructed that considers the asperity deformation, thermal stress, and interactions of a single asperity from a microscopic viewpoint. Then, a new TCC prediction model is proposed according to the improved contact mechanics model and classical heat conduction theory. Furthermore, the predicted values of the TCC are compared with published experimental results and reported models. Finally, the influences of surface topography, temperature differences, and material properties on the TCC are further revealed. This study can provide deep insight into the thermal design of sophisticated equipment.