Measurement of the thermal diffusivities of insulating materials using boiling water

Abstract

We present a method and corresponding experimental setup for estimating thermal diffusivities of insulating materials. The setup consists of a boiling water container placed on a heating plate; the test plate is placed atop the boiling water container. Under this condition, both the steady and transient input-response temperature characteristics are measured. We find that the water in its boiling state causes a nearly stable temperature at one side of the test plate. However, this stable condition is reached only after an initial transient period. Rather than using either steady or transient behavior of the response temperature characteristics exclusively in the analysis, we show the potential of using both by combining the experimental observations with the subsequent theoretical and optimization analyses. The proposed method and experimental setup do not require any prior estimation of other parameters. All the necessary information, including the thermal diffusivity, can be estimated from the input-response temperature characteristics only, as we show here.