High temperature material processes

Local thermodynamic equilibrium (LTE), frequently used as fir t approximation in modeling of thermal plasma processes, is s ometimes unable to explain experimental results. It is particularly true near a wall and a surface impacted by the plasma jet. In this work, a 2-D custom model usin g the CFD commercial code Fluent was developed for argon-oxygen indu ctively coupled plasma (ICP) at atmospheric pressure. The assumption of the rmal equilibrium was made but not that of chemical equilibrium. The transport roperties were calculated using higher-order approximation of Chapman-E nskog theory. Reaction kinetics rates of dissociation and ionization were als o considered. The model was applied to a process torch used for carving experiments o n graphite, and the distribution of reactive species brought to the surface was analyzed in terms of reaction rate distribution: the experimental effect of diffe rent injection geometries on the distribution of the reaction rate is qualitatively re produced by the model.