Modelling of inhomogeneous mixing of plasma species in argon–steam arc discharge for broad range of operating conditions

Modeling of argon–steam thermal plasma flow for abatement of fluorinated compounds

“…The diffusion coefficients were determined using the method of combined diffusion coefficients [52,53]. The calculated radial temperature profiles near the exit nozzle very well fit the experimental values, and, the velocity profiles also agreed well with experiment [47,48,50,51], whereas the predicted existence of supersonic flow was confirmed experimentally at currents 500 and 600 A [48,51]. The flow and heat transport strongly depends on the species distribution in the plasma that affect e.g.…”

“…For the radiation model, both the net emission coefficient method and the partial characteristic method [37][38][39][40] were used, while deviations from laminar flow were studied using the large-eddy-simulation (LES) turbulent model [41][42][43]. The numerical model showed the following findings: the tangential motion of the plasma affects the overall arc power and physical quantities only to a negligible extent [44,45]; at currents higher than 400 A, the plasma flow transits into the supersonic regime in the region close to the nozzle orifice [46][47][48]; the plasma flow exhibits the quasi-laminar structure close the nozzle orifice [42,43,49]; and, finally, at currents ranging from 150 to 600 A, steam and argon species are mixed together inhomogeneously in the discharge area nearby the nozzle orifice [50,51]. The numerical model considered diffusion due to density, temperature, pressure and electric potential gradients.…”

“…In contrast to our previous research [50,51], the present work focuses on numerical modeling of a modified hybrid DC plasma torch that can operate at powers up to 75 kW. Compared to the original discharge chamber geometry [48,50,51] the baffles with central holes for water have different shape and dimension, and circulation of water in the chamber is designed differently.…”

“…In contrast to our previous research [50,51], the present work focuses on numerical modeling of a modified hybrid DC plasma torch that can operate at powers up to 75 kW. Compared to the original discharge chamber geometry [48,50,51] the baffles with central holes for water have different shape and dimension, and circulation of water in the chamber is designed differently. Unlike the above-mentioned research [50,51], the outlet region for the plasma jet is extended to 20 cm from the nozzle, the plasma jet flows to the surrounding atmosphericpressure steam atmosphere contained in a plasma-chemical reaction chamber, the nozzle diameter is smaller (5.3 mm), and the range of currents is lower, from 120 to 220 A (20-40 kW).…”

“…Compared to the original discharge chamber geometry [48,50,51] the baffles with central holes for water have different shape and dimension, and circulation of water in the chamber is designed differently. Unlike the above-mentioned research [50,51], the outlet region for the plasma jet is extended to 20 cm from the nozzle, the plasma jet flows to the surrounding atmosphericpressure steam atmosphere contained in a plasma-chemical reaction chamber, the nozzle diameter is smaller (5.3 mm), and the range of currents is lower, from 120 to 220 A (20-40 kW). The aim of the simulation was to calculate the physical properties as well as chemical species densities of the arc and the generated plasma jet.…”