C2 Swan spectrum used as a molecular pyrometer in transferred arc and the influence noise to signal ratio on the temperature values

Abstract

The C2 Swan system molecular emission spectrum is frequently observed in arc plasmas containing hydrocarbons. The spectra emitted from 5 kw in the transferred arc reactor at atmospheric pressure by CH4/CO 2/Ar mixture are recorded with the help of an optical system consisting of a linear CCD array coupled with 2m spectrometer. The rotational temperature of 4300±300K is found from the experimental Abel inverted spectra in the arc center after a point-to-point comparison of the spectrum with a computer simulated one. The influence of the noise to signal ratio has been studied, if the noise to signal ratio is about 10% we found an error of 7% at temperature 3000K and 10% at 6000K.