Spectral remote sensing of the dynamic temperature distribution in glass
Abstract
Determining the temperature distribution within a semitransparent medium using remotely sensed spectral emission data is called the spectral remote sensing (SRS) method. The SRS method requires the formulation of a model describing the internal radiative energy transfer and the measurement of the spectral radiance emerging from the medium. Using measured spectral radiance data and the model for the radiative transfer of the emerging spectral radiance allows the temperature distribution within the medium to be determined using an inversion procedure. The dynamic temperature distribution in 3.71, 6.76, and 11.68 mm thick float glass test plates were experimentally determined using both the SRS method and thermocouples fused into the plates. Measurements were made for each test plate cooling from an initial temperature of approximately 520$\sp\circ$C under three different conditions. These three conditions were: (1) radiation and natural convection heat exchange to the laboratory ambient, (2) radiation exchange between the rear test plate surface and a heater, and (3) with the rear surface of the test plate made opaque and highly reflecting by the application of a thin coating of gold. To validate the accuracy and limitations of the SRS method, the temperatures in the glass test plates determined using the SRS method are compared with temperatures from thermocouples fused in the glass and with theoretical predictions. The agreement between dynamic temperatures determined using the SRS method, thermocouple measurements, and theoretical predictions demonstrate that the SRS method can be used to measure the temperature response to within approximately $\pm$0.5% for the front surface, $\pm$1% for the center plane and $\pm$5% for the rear surface of float glass plates 6.76 mm thick. The experimental results from the SRS method indicate that in general for a plate thickness greater than 6.76 mm the accuracy of the internal temperature determination improves, and for a plate thinner than 6.76 mm the accuracy decreases.
Degree
Ph.D.
Advisors
Viskanta, Purdue University.
Subject Area
Mechanical engineering
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.