Modelling of a transferred arc in presence of an external magnetic field

This paper reports the second part of the study of an electric arc and its interaction with the anode material. First, a three-dimensional model is presented and validated in a natural symmetric configuration for which many experimental results exist. In the three-dimensional model, two situations are considered for the anode surface: the classical zero heat flux condition and the use of the anode model. In the second case, the specific properties of the anode material are taken into account and play a role in the current conservation between the plasma and the anode, and therefore, affect the arc behaviour near the electrode. The results for the two approaches are similar in two dimensions, but differences exist in real three-dimensional cases when external forces such as cross flow or magnetic field tend to bend the arc. Second, we present a comparison between the two methods in the case where the arc is deviated by an external magnetic field. For this comparison, we adopt a configuration used at Odeillo during the 1970s and compare the results obtained by our code with the experimental ones. We find that it is essential to consider the complete anode model if the arc deflection is to be predicted correctly. Once our developments are validated, the computational code is applied in a free-burning arc configuration, where the plasma column is deflected by an external cross flow.

Section: 22mentioning

confidence: 93%

Section: 22mentioning

confidence: 99%

Section: 22mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Numerical modelling of an electric arc and its interaction with the anode: part II. The three-dimensional model—influence of external forces on the arc column

Gonzalez¹,

Lago²,

Freton³

et al. 2005

Three-dimensional numerical modelling of a magnetically deflected dc transferred arc in argon

Blais

Proulx

Boulos

2003

The aim of this work is to develop a numerical model for the deflection of dc transferred arcs using an external magnetic field as a first step into the modelling of industrial arc furnaces. The arc is deflected by the use of a conductor aligned parallel to the arc axis through which flows an electric current. The model is validated by comparing the results of axisymmetric calculations to modelling results from the scientific literature. The present model is found to be a good representation of the electric dc arc as differences with the literature are easily explained by model parameters such as the critical boundary conditions at the electrodes. Transferred arc cases exhibit the expected behaviour as the temperature T, the velocity v⃗ and the electrical potential drop Δϕ all increase with the arc current I and the argon flow rate Q. Three-dimensional geometry is implemented, enabling one to numerically deflect the arc. For the deflected arc cases, the deflection increases with the arc current I and conductor current Iconductor and decreases with the flow rate Q and x0, the arc–conductor distance. These deflection behaviours are explained using physical arguments.

A numerical modelling of an electric arc and its interaction with the anode: part III. Application to the interaction of a lightning strike and an aircraft in flight

Lago¹,

Gonzalez²,

Freton³

et al. 2006

A numerical model is proposed to describe the arc and its interaction with a composite material in an anodic configuration. After a validation step with experimental results in two dimensions (2D) from the literature, the model is used to quantify the degradation level of the material versus the pulse duration and the current intensity value. The flux components show the importance of the Joule effect in the composite. Then, in order to simulate the aircraft displacement, an external convective force is applied. A three-dimensional (3D) model is thus developed and used to evaluate the degradation of the composite material. This model shows the behaviour of the plasma column representing the lightning strike and quantifies the power transferred to the anode.