Reduction of Thermographic Phosphors Data to Heat Rates

Abstract

Thermographic phosphors have emerged as a new technique for measuring heat fluxes, which relies on the temperature de- INTRODUCTIONIn search of an accurate and stable heat flux determination technique, researchers have begun to investigate temperaturederivative measurement approaches. Heat flux determination is usually accomplished in one of two ways. 1) Heat flux can be measured directly with devices that are calibrated to return a voltage proportional to the heat heat flux. These devices are difficult to calibrate, expensive and tend to integrate high-frequency components in the data. 2) Heat fluxes can also be determined by measuring temperature and using a data reduction technique to discover the heat flux. Although temperature measurements are much more reliable and cheaper to obtain than heat fluxes, the data reduction of heat fluxes from temperatures is an ill-posed problem, and any uncertainty in the measurement becomes amplified during the data reduction.Mathematically, the difficulty of determining heat fluxes from temperature measurements arises from the differentiation of data [Kress, 1989]. Frankel and Keyhani [1997] suggested the use of temperature derivatives to stabilize the inverse heat conduction solution. Since then, numerous conference proceed-