Thermal Contact Resistance and Heat Transfer Enhancement Mechanisms at Non-Smooth Contact Interfaces

As an important and effective indicator of contact heat transfer, thermal contact resistance is a widespread phenomenon in engineering. It can directly affect product reliability, full-load performance, power consumption and even life cycle in energy, aerospace, electronic packaging, cryogenic refrigeration, etc. Therefore, enhancing the interface heat transfer and suppressing thermal contact resistance have become increasingly important. Against this background, this paper seeks to elaborate on conceptions of thermal contact resistance and the ways to reduce it. After reviewing the existing methods of measuring thermal contact resistance and characterizing the interface morphology, we highlight the theoretical underpinnings of thermal contact resistance, including the two-dimensional mathematic characteristics of the contact interface and the theoretical and empirical models for quantifying it. Three categories of influencing factors, i.e., thermal, geometrical and mechanical states, are then presented. Based on the macroscopic formation mechanism, the paper summarizes the existing methods for suppressing thermal contact resistance, with close attention paid to polymer composite thermal interfacial materials and metal interfacial materials filled with high thermal conductivity filler. In light of the findings, this review provides five promising directions for future research on thermal contact resistance. It suggests that the failure modes and service life of interface materials are essential to apply such technologies to suppress thermal contact resistance in practice. This review will be a guide for future research in thermal contact resistance and for the widespread use of composite interface materials.