Numerical analysis of three-dimensional magnetohydrodynamic effects in an inductively coupled plasma wind tunnel

This paper introduces a three-dimensional model for the 350 kW Plasmatron X inductively coupled plasma facility at the University of Illinois Urbana-Champaign, designed for testing high-temperature materials. Simulations of the facility have been performed using a three-dimensional, multiphysics computational framework, which reveals pronounced three-dimensional characteristics within the facility. The analysis of the plasma and electromagnetic field in the torch region reveals the influence of the helical coils, which cause a non-axisymmetric distribution of the plasma discharge. Additionally, simulations of the torch-chamber configuration at two operating pressures have been conducted to examine the impact of plasma asymmetry in the torch on jet characteristics in the chamber. The results indicate an unsteady, three-dimensional behavior of the plasma jet at high pressure. Spectral Proper Orthogonal Decomposition (SPOD) has been performed on the unsteady flow field to identify the dominant modes and their associated frequencies. At low pressure, a steady, supersonic, nearly axisymmetric plasma jet forms with consistent flow properties, such as temperature and velocity. However, strong non-equilibrium effects at low pressures lead to substantial deviations in species concentrations from axial symmetry despite having an almost axisymmetric distribution for quantities such as velocity and temperatures.