3D modelling of the cathodic arc root movement in a hollow ca hode of a thermal plasma torch

摘要

This paper deals on a 3D unsteady model of an arc in a hollow cathode.In this kind ofconfiguration the gas is injected in vortex,and an external magnetic field is used to produce an arcroot movement to diminish the cathode erosion.A 3D model is developed based on the @Fluentsoftware and a physical approach proposed to describe the arc root positions in time following theplasma characteristics.The mathematical developments take in account all the hydrodynamicplasma description and the electromagnetic effects due to the auto induced magnetic field and tothe external one.Results are presented in case of an air plasma and a current intensity equal to260A with an injected mass flow rate of 20g/s.After the presentation of the plasma characteristicsin term of temperature,velocity,magnetic field,the obtained mean arc root position is compared toexperimental one,and the arc root velocity to literature values deduced from empirical law.