Advanced Modelling of RF and DC Thermal Plasma Torches for Industrial Applications

Modeling results are presented for different industrial thermal plasma sources using a customized version of the FLUENT© code for 2D and 3D transient simulation with advanced CFD models that take into account turbulence effects using different approaches (Reynolds Stress Model and Large Eddy Simulation), species transport and radia-tion (Discrete Ordinate Model with interaction between radiation and solid surfaces). This modeling tool is very useful for the design and characterization of a wide range of atmospheric pressure thermal plasmas devices and ap-plications. Results will be presented for: 1) Turbulent 3-D modeling of ICPTs showing trajectory and heating history of powders injected in the torch through a carrier gas for spheroidization purposes, together with their effect on the plasma discharge for various geometric, electric and op-erating conditions; the helicoidal coil and the gas injection section of industrial plasma torches are taken into account without geometry simplifications; 2) Time-dependent effects arising in the fluid flow and temperature distribu-tion of a plasma generated in arc discharge twin-torch systems (for example, for hazardous waste incineration) with turbulence effects taken into account using a RANS approach; the effect on the discharge characteristics of using different types of plasma gas (air and Ar/H2 mix-tures), for various geometric and operating conditions is taken into account; 3) 3-D time dependent simulation of the behaviour of DC non-transferred arc torch for plasma spraying without any external assumption on the anode restriking and attachment and insight also on the down-stream expansion of the plasma jet using a LES turbulence model.