Modelling Thermal Diffusivity of Heterogeneous Materials Based on Thermal Diffusivities of Components with Implications for Thermal Diffusivity and Thermal Conductivity Measurement

Abstract Effective thermal diffusivity models are useful for predicting diffusivities of heterogeneous materials. The literature contains that may be broadly categorised into four different types: (1) effective highly specific applications (e.g. empirical curve fitting measured data); (2) as a weighted averages the components’ and volume fractions; (3) calculated from conductivity, density heat capacity known ‘lumped parameter’ approach (which is most commonly employed method); (4) comparison times fixed quantity to transferred composite material with transfer time an diffusivity. latter three modelling methods were tested on theoretical materials, none performed consistently better than others, suggesting there scope further work in this area. Of methods, least accurate average was lumped parameter method. Given relationship often used derive conductivity data (or vice versa), it possible significant error introduced derived property addition any measurement error, which not acknowledged.