Measurement of thermal radiative and conductive properties of semitransparent materials using a photothermal crenel method

Abstract

This paper deals with a theoretical and an experimental study allowing the measurement of the radiative and the conductive properties of semitransparent materials. The method consists of applying a crenel heat flux on the front face of a semitransparent sample and recording the temperature at the rear face using an open thermocouple junction. Parameter identification is performed by the minimization of the ordinary least-squares function comparing the measured and the calculated temperatures. This later is obtained from the thermal model describing the heat transfer by conduction and radiation in the medium. This model is built by the thermal quadrupole formalism. Measurements are reported on commercial glasses and plexiglass samples, and the used iterative algorithm is based on the Gauss–Newton method.