The impact of molecular radiation processes in water plasma on performance of water-vortex and hybridstabilized electric arcs

Abstract

Numerical investigation of radiation properties in the worldwide unique type of thermal plasma generator with water vortex stabilization (Gerdien arc) and combined stabilization of arc by argon (Ar) flow and water vortex (the so called hybrid arc) has been carried out. A twodimensional axisymmetric numerical model describes the region between the inlet and outlet nozzles in the arc discharge chamber. It is assumed that plasma flow is steady, laminar, compressible and in the state of local thermodynamic equilibrium. The governing equations are solved numerically by the Finite Volume Method. Here we study the contribution of water molecular species and of ∼ 3 500 newly-included Ar lines on radiation transport within the discharge region of water and hybrid arcs. Radiation loss from the arc is calculated by the partial characteristics method for atmospheric pressure water and argon-water discharges. In contrast to our previously published results, band spectra of H2, O2, OH molecules and re-calculated Ar line spectrum have been included in the partial characteristics. Results carried out for 150–600 A and for Ar mass flow rates of 7.5–27.5 slm proved that reabsorption in water plasma increases of about 3.5% for all currents but decreases remarkably in the hybrid plasma. For a given current and increasing mass flow rate of Ar reabsorption decreases. Comparison between present calculation and available experiments shows good agreement.