Three-dimensional modeling and schlieren visualization of pure Ar plasma flow in inductively coupled plasma torches

A three-dimensional, non-stationary model has been developed for simulating the behavior of pure Ar inductively coupled plasma (ICP) torches. The model correctly accounts for all the geometrical features of the torch and for all the physical processes occurring in it. A standard Fassel-type ICP torch and all its feasible variations were considered in the modeling. Based on a series of numerical experiments, temporal evolutions of three dimensional distributions of the following key plasma parameters are obtained: fields of plasma flows, plasma temperature and pressure. Numerical experiments revealed a number of unusual effects: effect of reverse gas flow, formation of separated plasmoids, plasma pulsation and rotation. Evolution of spatial structures of both gas flow and temperature fields in plasma torch after cold gas, as well as plasma ignition and its release to steady state, were experimentally investigated using the developed optical schlieren system.