Numerical Simulation of Inductively Coupled Plasma Flows under Chemical Nonequilibrium

This paper presents a detailed review of the numerical modeling of inductively coupled plasma flows under local thermodynamic equilibrium and under chemical non-equilibrium. First, the physico-chemical models are described, i.e. the thermodynamics, transport phenomena and chemical kinetics models. Particular attention is given to the correct modelling of ambipolar diffusion in multi-component chemical non-equilibrium plasmas. Then, the numerical aspects are discussed, i.e. the space discretization and iterative solution strategies. Finally, computed results are presented for the flow, temperature and chemical concentration fields in an air inductively coupled plasma torch. Calculations are performed assuming local thermodynamic equilibrium and under chemical non-equilibrium, where two different finite-rate chemistry models are used. Besides important non-equilibrium effects, we observe significant demixing of oxygen and nitrogen nuclei, which occurs due to diffusion regardless of the degree of non-equilibrium in the plasma.