A Two-Temperature Chemical Non-Equilibrium Model of an Oxygen Cutting Torch Including the Region above the Work-Piece

Summary form only given. There is increasing evidences of deviations from thermal and chemical equilibrium in highly constricted arcs. Although, equilibrium models of such arcs inside cutting torches have been studied, non-equilibrium models including the region above the work-piece are rare. In this paper, we present a two-temperature chemical non-equilibrium model of an oxygen cutting-torch to find the distribution of velocity, temperature, current, potential and pressure over a work-piece. We consider the plasma to consist of two sub-gases: one made of electrons and the other made of all other heavy particles including ions, atoms and molecules. While all the electrons have a temperature Te, all other heavy particles follow a different temperature Th for the same location. Together with mass continuity and momentum equations, separate energy conservation equations are solved for electrons and heavy particles. Apart from electromagnetic body force terms in the momentum equations and joule heating terms in the energy equation, additional energy exchange terms are introduced in the energy equations to account for transfer of energy from one sub-gas to the other. A dedicated property routine that includes chemical as well as temperature non-equilibrium is used to supply properties required for fluid dynamic simulations. Results are presented for different arc currents and geometries. Boundary conditions, appropriate for the model, are discussed.