Three-dimensional investigation of particle treatment in an RF thermal plasma with reaction chamber

Particle treatment in a commercial inductively coupled plasma torch with a non-axisymmetric reaction chamber has been studied using a three-dimensional numerical model, including particle turbulent dispersion. Computations have been performed for two different coil current frequencies (3 and 13.56 MHz), showing that for lower frequencies particle trajectories deviate from their initial axial direction as a consequence of non-axisymmetric thermo-fluid-dynamic fields: these effects arise when the first and last coil turns induce unbalanced Lorentz forces in the discharge that prevail over fluid-dynamic inertia. For higher frequencies, almost axial particle trajectories have been predicted. Moreover, computations for different mass flow rates of the precursor particles and for different axial positions of the injection probe are shown, these parameters having an important influence on the effectiveness of the powder treatment process.