5. Conclusion

Thermal plasmas produced by arcs or radio-frequency discharges at near atmospheric pressure have a wide range of industrial applications, including cutting, welding, spraying, metal purification, extractive metallurgy, heating, powder spheroidization, ultra-fine powder synthesis, chemistry, waste destruction and the manufacture of shaped parts... Power ratings range from a few hundred W to several hundred MW. For many applications not involving chemical reactions, thermal plasmas can be considered to be at thermodynamic equilibrium (i.e. characterized by a single temperature). Plasma reactors must be adapted to each application. Their operation, given the gradients in temperature, velocity, composition, etc., encountered in these media, depends predominantly on transport properties (electrical and thermal conductivities, viscosity, diffusion coefficient). These are very different from those...