Modeling three-dimensional magneto-hydrodynamic phenomena in inductively coupled plasma discharges

The purpose of the present work is to investigate the plasma characteristics (e.g., threedimensionality, stability, turbulence) of the Plasmatron X facility using a state-of-the-art multi-physics computational framework developed at The Center for Hypersonics and Entry Systems Studies (CHESS) at the University of Illinois at Urbana-Champaign. The plasma is modeled under the Local Thermodynamic Equilibrium assumption. The flow governing equations (i.e., Navier-Stokes) are discretized in space based on a cell-centered finite volume method. Electromagnetic equations are solved in a mixed finite-element solver. The plasma and the electromagnetic solvers are coupled via the Joule heating and Lorentz forces in the energy and momentum equations and the electrical conductivity in the Maxwell equation. The steadystate simulation of the Plasmatron X torch shows that the plasma flowfield is non-axisymmetric as a result of the three-dimensional nature of the electromagnetic field induced by the helical coil. Further, a time-resolved simulation of the facility (torch along with the chamber region) reveals a significant unsteadiness in the plasma jet due to the shear layer instabilities between the hot plasma core and the cold ambient gas. These instabilities quickly break into smaller eddies and lead to a 3-dimensional flowfield in the jet region which may significantly impact the response of the material being tested in the facility.