Influence of reflected atmospheric plasma spraying torch radiations on long wavelength IR radiometry temperature measurement

APS torch radiant energy was measured in the 7.5-13 μm spectral band as a function of hydrogen flow rate. Hydrogen flow rates from 0 up to 10 Nl/min were experienced and prediction of the effects of reflected APS torch radiations on measured temperature was performed. Extraneous radiant energy from the APS torch was found to have dramatic effect on temperature measurement under some conditions. Correction of the measured temperature for reflected APS radiant energy is necessary in case of low target temperature or low target emissivity.