Three-dimensional effects in the modelling of ICPTs Part II: Induction coil and torch geometry

In this paper, a 3-D numerical study is performed to investigate the effects of the induction coil design and torch geometry on the characteristics of argon discharges in inductively coupled plasma torches working at atmospheric pressure. Simulations are performed by means of the commercial code FLUENT(C) suitably customized to solve the electromagnetic field equations in the frame of an extended grid model. Steady state continuity, momentum and energy equations are solved for optically thin plasmas under the assumption of LTE and laminar flow. Results are presented for different coil geometries including conventional helicoidal, double-stage and planar configurations. The physical behaviour of a torch with elliptical cross-section is also analyzed. Additionally, the effects on plasma temperature and velocity fields of reducing the post-coil length in a conventional torch are shown.