Published online by Cambridge University Press: 25 February 2011
Numerical models describing the plasma physics in the column and plume of a nontransferred, dc arc torch were used in conjunction with two experiments to quantify the extent of turbulence in the free plume. Numerical predictions were made by solving the governing conservation equations with suitable boundary conditions. The solutions indicate a high temperature, high velocity region starting at the anode which decays rapidly as the plume interacts with the atmosphere. The turbulent viscosity is predicted to be up to 140 times higher than the molecular viscosity at specific locations. Modeling results for the plume compare favorably with spectroscopic temperature measurements, and with the cone angles measured with holographic interferometry, which quantifies the amount of turbulence in the plume.