Comparison between a two- and a three-dimensional arc plasma configuration

Abstract

A three-dimensional (3D) argon arc plasma at atmospheric pressure is presented. The model is developed using the commercial code Fluent. Two arc plasma configurations are studied: a free burning arc and a transferred arc. In the free burning arc configuration, the 3D results are compared with a two-dimensional (2D) configuration. The natural axis of symmetry of the system, given by the physical operating conditions and by the cathode tip geometry, leads to a good agreement between the 2D and 3D results. The model is validated by comparisons with experimental and theoretical temperature fields. The results show a small difference between the 2D and 3D models, as does the other literature. In the transferred arc configuration model the injection is given by three injectors. A rigorous modelling of the injection cannot be treated using a symmetric plane or a symmetric axis, so the results are presented in a real 3D configuration and compared with results obtained in a 2D configuration. Indeed, in a 2D configuration, due to the symmetrical condition on the axis, the main assumption consists of representation of the real injection geometry by an equivalent surface injection. The imposed mass flow rate is then distributed along a ring and differences can appear in the results.

Formation of self-organized anode patterns in arc discharge simulations

“…Additional insight into the role of timedependent and three-dimensional numerical models to describe an apparently stead-state axisymmetric flow is provided by the study conducted by Kaddani et al [27] of a free-burning arc using a LTE model. Their results indicate that instabilities inherently develop in a transient and three-dimensional model, which would otherwise be mitigated by the forced symmetry in twodimensional or steady-state models (e.g., the results reported in [74] using a 3D steady-state model did not report the occurrence of anode patterns).…”

Effect of the deviation of the current density profile center on the three-dimensional non-transferred arc plasma torch

“…At the cathode surface, the exponential current density profiles were commonly used in the previous literatures [5,23,24,33]. The results obtained by the exponential profiles are proved to be sufficient accurate, but the current density at the end of the profile is not strictly zero.…”

Magnetic field approaches in dc thermal plasma modelling

“…for the boundary conditions of equations (16) and (17) or a null value far from the arc [6][7][8][9][10].…”

“…Instead of using the B&S formulation, almost all authors use the potential vector (PV) approach ( [6][7][8][9][10][11] for example).…”

“…This point has been studied by some authors in RF plasmas configurations where people propose to calculate the magnetic field in an extended domain [12] [13] or by B&S equations [12]. In AC/DC, in order to overcome this problem, the authors very often consider a null flux as boundary condition for vector potential components at the modelled geometry edges [9][10] or a value equal to zero if the boundary is far from the arc [6][7][8]. Very few authors, as He-Ping Li [11], propose, only for three dimensional DC configurations the use of Biot & Savart equation as a boundary condition for potential vector.…”