Non equilibrium calculation of the inductively coupled plasma torch. Effect of the axial cold channel

The radial temperature and velocity profiled of a monoatomic gas (Ar) predi cted by the model at atmospheric pressure indicated deviation from local th ermodynamic equilibrium on the wall and on the axis of the plasmatorch. Sub stantial deviations have been noted when a cold carrier gas is introduced o n the axis since electron temperatrue is around 6000 K whereas temperature of heavy particules decreases down to 2000 K. In this paper we will compare these temperatures and identify where the gradient themperature is establi shed in the plasma torch. This model proposes a two-dimensional flow in the case of an argon axial gas injected axially at 8 l/mn simulateously of two others argon flow (plasma gas 20 l/mn and sheath gas 40 l/mn), in a torch of 41 mm diameter. The frequency of the generator is around 5Mhz and in the usual operating conditions the voltage measured on the inductor is 4,44 kV and the radio frequency current is 120 A. The power induced is around 20 k W (6,5 - 7 kV and a plate current of 3,2 - 3,4 A).