Measuring the thermal resistance of vertical interfaces separating two different media using infrared thermography

Abstract

Abstract We propose a method to measure the thermal contact resistance at the vertical interface between two materials using lock-in infrared thermography with laser spot heating. We found an analytical expression for the surface temperature of the two media when one of them is illuminated by a modulated and focused laser spot. We analyzed how the thermal conductivities of the two-media affect the sensitivity to the interface thermal resistance. We concluded that the key factor is the product of both thermal conductivities: the higher this product, the lower the thermal resistance that can be detected. The surface temperature of two media with calibrated interface thickness is measured using an infrared camera. The thermal resistance of the interface is obtained by fitting the surface temperature to its analytical expression. The good agreement between the nominal and retrieved width of the interface confirm the validity of the model.