On Simple Prediction Method for Thermal Contact Resistance Between Wavy Surfaces With Thermal Interface Material Under Low Mean Nominal Contact Pressure (Fundamental Study Based on 1-D Model)

Abstract

The thermal contact resistance (TCR) is the crucial issue in the field of heat removal from systems like electronic equipment, satellite thermal control systems, and so on. To cope with the problem, a lot of studies have been done mainly for flat rough surfaces. However, as pointed out so far, there are still wide discrepancies among measured and predicted TCRs, even for similar materials. To investigate the key factors for the abovementioned discrepancies, a fundamental analysis was conducted in our previous study [1] using a simple contact surface model, which was composed of the unit cell model proposed by Tachibana [2] and Sanokawa [3]. Furthermore, by introducing a 2-D microscopic surface model, which consists of random numbers and Abbott’s bearing area curve, the effects of surface waviness and roughness on the temperature fields near the contact interface have been investigated microscopically [4]. In this study, based on a 1-D wavy surface model, a fundamental study has been conducted to predict TCR and the thermal contact conductance (TCC), which is a reciprocal of TCR, between wavy surfaces with the thermal interface material (TIM) under a relatively low mean nominal contact pressure of 0.1–1.0 MPa. From comparison between the calculated and measured results, it has been shown that, in spite of a simple 1-D analysis, the present model predicts the temperature drop at the contact interface, which is obtained as the product of TCR and the heat rate flowing through TIM, within some 10 to 60% error for a TIM with the thermal conductivity of 2.3 W/(m·K) and the initial thickness of 0.5, 1 and 2 mm.