Hydrogen concentration profiles and velocity distributions in a reducing argon‐hydrogen plasma

Abstract The purpose of this study is to establish a spectroscopic diagnostic of an argon‐hydrogen reducing plasma, the hydrogen being injected into the initially formed argon plasma. From calculations using the spectral line intensities measured for H(α), H(β) as well as argon lines 4,259Å and 6,965Å, information is obtained on thermal equilibrium attainment after hydrogen injection. Also, hydrogen concentration profiles are calculated, from which hydrogen counterdiffusion zones are defined allowing the use of simplified diffusion equations, so that velocity profile distributions are obtained. The hydrogen concentration profiles clearly show the mixing pattern taking place around the injection ports, while the temperature profiles for hydrogen and argon evolve toward common limiting values attained when thermal equilibrium between both gas species is accomplished. Calculations show that the error should be of the order of 20% on velocities and 15% for the concentration measurements. The method used here may conceivably be extended to high temperature chemical raections (gas‐solid reaction or pyrolysis, for instance).