Solid-solid thermal contact problems: current understanding

The past 40 years of theoretical and experimental research on contact heat transfer are reviewed. Thermophysical and mechanical processes involved in heat propagation through various kinds of solid-solid junctions are considered. Analytical and semiempirical expressions are presented which simulate these processes both under vacuum conditions and in the presence of a heat conducting medium in gaps. Reasons for the experimentally observed heat flux rectification are explained. Studies on the thermal contact under non-stationary regime are covered, as is the possibility of applying classical heat conduction theory to the thermal contact. A thermodynamic interpretation of the thermal contact resistance is suggested and basic approaches to the study of contact phenomena are described. The heat conduction of nanosystems is briefly reviewed. Theoretical problems yet to be solved are pointed out and possible solution methods suggested.