Thermal temperature measurements of plasma torch by alexandrite effect spectropyrometer

Abstract

An alexandrite effect spectropyrometer is used to directly measure the thermal temperature of an argon gas plasma jet from a 100kW DC plasma torch, and the directly measured thermal temperature of the plasma is 11178±382 K. By using the spectral correction function to delete the spectral lines and to correct its underlying spectrum of the relative spectral power distribution of the plasma jet, the remaining continuum spectral power distribution represents the thermal spectral emission of the plasma jet. The calculated thermal temperature of the corrected relative continuum spectral power distribution by the spectropyrometer is 10106K ±345K, which is the true thermal temperature of the plasma jet. The blackbody level (BL) of the thermal plasma jet is defined as the ratio of the true thermal temperature to the directly measured temperature, and the blackbody level is a measure of how well the thermal plasma jet approaches a blackbody. The accuracy of directly measured thermal temperature depends on the blackbody level, the higher the blackbody level, and the higher the thermal temperature measurement accuracy. Copyright © 2010 Peir-Jyh Wang et al.