An experimentally verified three-dimensional non-stationary fluid model of unloaded atmospheric pressure inductively coupled plasmas

A three-dimensional non-stationary numerical model of spectrochemical and technological inductively coupled plasma (ICP) systems is presented in the paper. The model considers the ICP as a gaseous media (with temperature-dependent electric conductivity) interacting with electromagnetic field generated by inductive coil. The model is based on simultaneous solution of the Maxwell's and gas flow equations together with the energy equation coupled-together by corresponding source terms and material properties to take into account inductive current forming within the carrier gas and subsequent Joule heating, the Lorentz force and how does it affect the gas flow pattern. It allows calculation of temporal evolution of three-dimensional distributions of electromagnetic fields, pressure, gas velocity and temperature within a plasma torch and a condensation chamber used for powder processing. The model is applicable for simulation of atmospheric pressure electrodeless plasmas under local thermodynamic equilibrium that consist of pure gases and their mixtures. Such operating conditions are typical for ICPs that are used for elemental analysis and technological powder processing. Special attention is paid to experimental verification of the model. The simulation results are cross-verified for both types of ICPs (spectrochemical and technological one) using high-speed optical and schlieren visualization of gas flows. The discrepancy between calculations and experimental data does not exceed 10%.