Thermal Contact Resistance: Experiments and Simulation

Abstract

The engine bay and exhaust system of modern day vehicles consists of components, made out of different materials with different thermal conductivities. The heat transfer across the interface between two components in contact with each other is significant to determine their surface temperatures. This phenomenon becomes more critical for components which are made from materials with a lower thermal conductivity. The effect of thermal contact resistance on the surface temperatures of these components is analysed. Different parameters that affect the value are studied and their values are determined from literature. Component level analysis is carried out using physical tests and simulations. The complete vehicle simulation was then carried out by coupling thermal simulations with a CFD code. The criticial components which were affected by thermal contact resistance were identified in the engine bay and exhaust system. A method to estimate the value of contact resistance was developed based on material properties. A simulation was run with the estimated values of contact resistance and the results were found to correlate better to wind tunnel tests.