Step-heating method of measuring thermal diffusivity using parameter estimation

Abstract

A variant of the monotonic heating method has been developed for measuring the thermal diffusivity of different types of solid materials, by step-heating with small temperature increments. In analysing the experimental data, the parameter estimation procedure is used. As the estimation of each parameter is influenced by its sensitivity coefficient, the result of simultaneous estimation of a number of parameters is presented and discussed. The method has been applied to various materials without a protective atmosphere. The maximum range was from room temperature to 1100 K. Results obtained in measuring the thermal diffusivity of aluminosilicate brick, polytetrafluoroethylene, expanded polystyrene, and carbon felt are presented. Sources of measurement uncertainty are analysed and its total amount is estimated.