Characterization of atmospheric pressure H2O/O2 gliding arc plasma for the production of OH and O radicals

Atmospheric pressure H2O/O2 gliding arc plasma is generated by a 88 Hz, 6 kV AC power supply. The properties of the produced plasma are investigated by optical emission spectroscopy. The relative intensity, rotational, vibrational, excitation temperatures and electron density are studied as a function of applied voltage, electrode spacing, and oxygen flow rate. The rotational and vibrational temperatures are determined simulating the OH(A2Σ+(v″=0)→X2Π(v′=0)) bands with the aid of LIFBASE simulation software. The excitation temperature is obtained from the CuI transition taking non-thermal equilibrium condition into account employing intensity ratio method. The electron density is approximated from the Hα Stark broadening using the Voigt profile fitting method. It is observed that the rotational and vibrational temperatures decrease with increasing electrode spacing and O2 flow rate, but increase with the applied voltage. The excitation temperature is found to increase with increasing applied voltage and O2 flow rate, but decrease with electrode spacing. The electron density increases with increasing applied voltage while it seems to be in a downward trend with increasing electrode spacing and O2 flow rate.