Influence of Non-uniform Contact Condition on Thermal Contact Resistance of the Joint

Previously, a quantitative measurement and an evaluation of the thermal contact resistance of the joint have been examined based on real contact area. These studies have performed under the condition that a real contact area distribution is uniform. However, in many cases, the joints are under non-uniform contact conditions due to the geometric errors of the joint interface.Then, in this research, the influence of non-uniform contact conditions on the thermal contact resistance is experimentally and analytically examined. As the result, the followings are clarified.1) Concave-convex model with contact length L and non-contact length (pitch p - L) can express contact ratio of the joint for the thermal contact resistance analysis.2) The thermal contact resistance is affected by not only the average contact ratio, but also distribution of the real contact area.3) Even if the joint has the same average contact ratio, the thermal contact resistance becomes the smallest in uniform contact distribution, and the lager the local non-uniformity becomes, the lager the resistance becomes.4) The mechanism that non-uniform contact conditions affect the thermal contact resistance of the joint can be explained by the electrical circuit with resistances corresponding to thermal contact resistance and thermal conductivity.