Measurement and Uncertainty Assessment of the Thermal Conductivity and Diffusivity of Silica Glass using Step-Wise Transient Method

Abstract

This paper investigates the accuracy of the step-wise transient (SWT) method and proposes a modified model that embodies the real-world experimental setup. The presented model incorporates all the imperfections of the thermocouple and heater, such as the thermal capacity and thermal contact resistance with the specimen. The viability of the proposed hypothesis was confirmed via the experiment simulation for soda-lime-silica glass material. The total uncertainty of the thermal conductivity and diffusivity measurement was assessed by combining all the associated errors: model, random, and measurement errors in input parameters. The scope of this work concentrates on one particular material, which can be potentially used as a reference material for calibrating other characterization methods. The results of thermal conductivity and diffusivity were λ = 1.017 W·m⁻¹·K⁻¹ and a = 0.507 mm²·s⁻¹ with total standard uncertainties 0.6 % and 0.4 %, respectively.