Mbark El Morsli

Two-temperature chemically non-equilibrium modelling of an air supersonic ICP

In this work, a non-equilibrium mathematical model for an air inductively coupled plasma torch with a supersonic nozzle is developed without making thermal and chemical equilibrium assumptions. Reaction rate equations are written, and two coupled energy equations are used, one for the calculation of the translational?rotational temperature Thr and one for the calculation of the electro-vibrational temperature Tev. The viscous dissipation is taken into account in the translational?rotational energy equation.The electro-vibrational energy equation also includes the pressure work of the electrons, the Ohmic heating power and the exchange due to elastic collision.Higher order approximations of the Chapman?Enskog method are used to obtain better accuracy for transport properties, taking advantage of the most recent sets of collisions integrals available in the literature. The results obtained are compared with those obtained using a chemical equilibrium model and a one-temperature chemical non-equilibrium model. The influence of the power and the pressure chamber on the chemical and thermal non-equilibrium is investigated.

A chemical non-equilibrium model of an air supersonic ICP

A numerical model for an air inductively coupled plasma (ICP) torch with a supersonic nozzle is developed using reaction rates under chemical non-equilibrium. The reaction model takes into account 11 species (neutral species: N2, O2, NO, O, N and charged species: , , NO+, O+, N+, e−) in air ICP. The species distribution in the air inductively coupled thermal plasma with a supersonic nozzle is obtained by solving the mass conservation equations taking into account diffusion, convection and chemical reactions. The thermal conductivity, electrical conductivity, viscosity and diffusion coefficient are calculated at every step of the computational process using the method of Chapman and Enskog. The most recent sets of collisions integrals available in the literature are used, taking into account higher-order formulae to compute the electron transport properties.In this work, the deviation from chemical equilibrium (CE) is determined by comparing with the CE calculation result and is found to be very important. The influence of different order formulae to calculate the electron transport properties (electrical conductivity) on electromagnetic fields is also investigated and recommendations can be made according to the range of temperatures, powers and flow rates expected in the plasma torches.

Chemical non-equilibrium modelling of an argon–oxygen supersonic ICP

In this paper, a non-equilibrium mathematical model for an argon?oxygen inductively coupled plasma (ICP) torch with a supersonic nozzle is developed without making chemical equilibrium assumptions. Reaction rates of dissociation and recombination of diatomic gas and ionization are taken into account. Higher-order approximations of the Chapman?Enskog method are used to obtain better accuracy for transport properties, taking advantage of the most recent sets of collision integrals available in the literature.In order to validate the developed model, results are compared qualitatively and quantitatively with existing experimental data. The calculated results for the axial temperature profile for pure argon less than 10?mm above the substrate are in good agreement with spectroscopic measurements.

Mathematical Modelling of Advanced Thermal Plasma Reactors and Application to Nanoparticle Production

When using plasma torches or reactors, the high thermal energy available for melting and evaporation of refractory materials is a significant advantage over conventional flame or furnace heating because of the higher temperatures in part but also because of the flexibility to use oxidizing, neutral or reducing environment at will. It is therefore possible to use plasmas produce nonoxide materials, carbides, nitrides as well as pure metal nanoparticles. The rapid chemistry and active species characteristics of plasmas offers chemical routes that differ largely from more conventional chemical processing. It also offers the possibility of creating materials that are far from thermodynamic equilibrium through the use of rapid quenching. With the high temperatures obtained in thermal plasmas, combined to the possibility to control the reactivity of the plasma gas, processing of complex nanopowders can be obtained within a single processing unit. In the present study, it is found by mathematical modelling that ...