Time-dependent two-temperature chemically non-equilibrium modelling of high-power Ar–N2 pulse-modulated inductively coupled plasmas at atmospheric pressure

Abstract

A time-dependent, two-dimensional, two-temperature and chemical non-equilibrium model was developed for high-power Ar–N2 pulse-modulated inductively coupled plasmas (PMICPs) at atmospheric pressure. The high-power PMICP is a new technique for sustaining high-power induction plasmas. It can control the plasma temperature and radical densities in the time domain. The PMICP promotes non-equilibrium effects by a sudden application of electric field, even in the high-power density plasmas. The developed model accounts separately for the time-dependent energy conservation equations of electrons and heavy particles. This model also considers reaction heat effects and energy transfer between electrons and heavy particles as well as enthalpy flow resulting from diffusion caused by the particle density gradient. Chemical non-equilibrium effects are also taken into account by solving time-dependent mass conservation equations for each particle, considering diffusion, convection and net production terms resulting from 30 chemical reactions. Transport and thermodynamic properties of Ar–N2 plasmas are calculated self-consistently using the first order approximation of the Chapman–Enskog method at each position and iteration using the local particle composition, heavy particle temperature and electron temperature. This model is useful to discuss time evolution in temperature, gas flow fields and distribution of chemical species.