Transient Thermal Diffusivity Measurement via the Flying Spot and Parabola Method

In a previous work, we developed methods based on the Pulsed Flying Spot (PFS) to estimate the thermal diffusivity on the plane of (an)isotropic materials. This thermal property is dependent on temperature or water content. In this work, we propose the device be used in transient temperature conditions to estimate the thermal diffusivity of 304L stainless steel. The first measurement in transient conditions makes it possible to simply and rapidly characterize many materials for temperature conditions other than the ambient. In the second step, we carry out transient thermal diffusivity measurements as a function of water content. We show, for a particularly heterogeneous material (a stoneware tile), that the thermal diffusivity is clearly dependent on the water content. Imbibition, for stoneware, leads to an increase in thermal diffusivity while drying leads to a decrease in the same value. This preliminary work can lead to contactless measurement of water content for different types of materials (food matrix, building materials, etc.).