CALCULATION OF TEMPERATURE AND FLOW IN RF PLASMATORCH - INFLUENCE OF COLD CHANNEL PRODUCED BY AXIAL GAS INJECTION

Due to a high increasing of number of industrial application attention has been devoted to the mathematical modeling of RF plasma torches. In the particular case of the thermal treatment of solid particles it's necessary to consider the properties of the gas flow and temperature and then analyze plasma-particles heat and mass transfer. Injection of particles axially in the plasma is obtained by means of a carrier gas who gives kinetic energy to the particles but lead to a modification of plasma properties. In this paper we compare the flow and the temperature fields of the double and triple gas flow of an RF plasma torch (U = 4,44 kV, I = 120 A, diameter of the torch 41 mm). In the case of double gas flow we use Argon as plasma gas (20 l/mn) and as sheath gas (40 l/mn). The argon carrier gas introduces axially (8 l/mn) leads to large modification compared to the results obtained in the previous case.