Three-dimensional modelling of unsteady high-pressure arcs in argon

Abstract

Three-dimensional, unsteady behaviour of high-pressure electric arcs in argon is studied by means of numerical simulations. Attention is paid to argon arcs whose steady structure is fairly well understood. Results are reported for the case of a one centimetre long arc, burning in argon and driven by a total current of 200 A and 300 A. The influence of the boundary conditions for the electrical potential on the macroscopic structure of the arc is studied and it is found that the distribution of the current density near the cathode is one of the critical parameters which can significantly modify both the distribution of mean quantities and the stability of the arc. All mean quantities found from three-dimensional calculations are compared with two-dimensional axi-symmetric fields obtained by a previously used code for arc simulations. The results indicate good agreement between the results from three-dimensional calculations, two-dimensional axi-symmetric simulations and results from physical experiments documented in the literature.

Multiscale Finite Element Modeling of Arc Dynamics in a DC Plasma Torch

“…For an argon plasma with a velocity of 1,000 m/s and at a temperature of 10,000 K (conditions that are easily met inside a DC torch), the local sound speed is almost 2,000 m/s and hence the local Mach number is ∼ 0.5; therefore compressibility effects may not be negligible. The common practice stated above is likely to be due to the fact that most software used for simulating plasma flows is based on incompressible flow solvers modified to include the electromagnetic effects (exceptions are the works by Kaddani et al [24] and Klinger et al [11]). …”

“…This method has been extensively developed and validated and seems promising for the description of complex multiscale phenomena, such as thermal plasma flows. Furthermore, as most methods used for the simulation of thermal plasmas have relied on SIMPLE-like algorithms (except for the work of Klinger et al [11] and Kaddani et al [24] of a free-burning arc), the use of a different numerical method tests the suitability of former numerical models, as a true solution should be independent of the numerical method employed. Moreover, this is the first time that a variational multiscale finite element method is applied to thermal plasma simulation.…”

Three-Dimensional Unsteady MHD Modeling of a Low-Current High-Voltage Nontransferred DC Plasma Torch Operating With Air

“…The restrike mode is characterized by a highly unstable movement of the arc where the reattachment phenomenon plays a significant role. The first models were two-dimensional (2D) or 2D axisymmetric thus, the vortex inflow and the arc root attachment could not be perfectly reproduced [7], [19], [20]. With the improvement of computing power, many research teams moved towards threedimensional models which are closer to real configurations [4].…”

Formation of self-organized anode patterns in arc discharge simulations

“…It could arguably be expected that the use of a time-dependent model, together with robust and high accuracy numerical methods, may lead to the capturing of spontaneous anode attachment spot formation, in a similar manner as in the DBD simulations in [20], for the intermediate flow rates. 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).…”