Thermal contact resistance on cylindrical flux channel with high contact ratio

Abstract

This paper considers the resistance to the heat flow between two thick solids with a high contact ratio in a vacuum. Based on the least-action principle, we derive closed-form mathematical expressions for the temperature distribution and non-dimensional thermal contact resistance, both expressed as functions of the radii ratio. Furthermore, the thermal contact resistance is investigated as a function of contact pressure and microhardness. A comparison of the conventional and proposed methods reveals that the proposed method is more accurate for calculating the thermal contact resistance with a high contact ratio. In equipment with high contact pressure, such as electromagnetic launch, we compare armature melting models using different calculation methods for contact resistance. Small and all contact models were established based on the traditional and proposed methods, respectively. The melting morphology of the armature obtained from the all contact model is highly consistent with the experimental results. During the experiment, in areas where the armature did not melt, the small contact model incorrectly calculated the melting of the armature. The all contact model can describe the strong cooling effect of the rail on the armature, preventing the armature from melting. The all contact model obtained higher heat sources, contact thermal conductivity, and contact pressure in the melting region. Under the combined effect of the three factors, a deeper and more concentrated melting morphology was obtained. This morphology is more consistent with the experimental results.