Spectral remote sensing of the dynamic temperature distribution in glass plates

Abstract

Dynamic temperature distributions in 3.71, 6.76, and 11.68 mm thick float glass test plates were experimentally determined using both the spectral remote sensing method and thermocouples fused in the plates. The measurements were made while the test plates cooled, from an initial temperature of approximately 550 °C, by radiation and natural convection in the laboratory ambient. Temperatures determined using the spectral remote sensing method are compared with those from the thermocouples fused in the glass and with theoretical predictions to demonstrate the accuracy and limitations of the spectral method. The agreement between this method, thermocouple measurements, and theoretical predictions show the spectral method can be used to measure the temperature to within approximately ± 0.5 % at the front surface, ± 1 % at the center plane, and ± 5 % at the rear surface of a 6.76 mm thick float glass plate. The accuracy of the reconstructed temperature distribution is a function of plate thickness and is limited by uncertainties in both the spectral absorption coefficient of the glass and by the accuracy with which the emerging spectral radiance can be measured.