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

Abstract

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.

A Multiphysics Simulation Approach for Efficient Modeling of Lightning Strike Tests on Aircraft Structures

“…Herein the lightning strike electric arc model is based on the preceding Gas Tungsten Arc (GTA) models available in the literature [19][20][21][22][23][24][25][26][27][28][29]. In general the preceding plasma modelling has assumed the thermal plasma to be in local thermodynamic equilibrium.…”

“…These models take into account the discontinuity phenomena between the anode and the arc-plasma interface. The Lago and Gonzalez et al models [22,23] did not include the cathode region in their simulations, but developed a model to simulate the effect of metal vapour in the plasma column combined to a moving welding torch. The plasma models of Tanaka and Lowke summarized in [25,26] are the most complete, based on the Sansonnens et al model [27], they also include the cathode and anode regions with weld pool formation, and the boundary conditions are directly applied at the external borders with no assumption on the cathode surface temperature.…”

A multiscale technique for the validation of a numerical code for predicting the pressure field induced by a high-power spark

“…In our case we consider a pre-heating of 1000K in the arc region. As it is pointed out in [44] the initial condition has only a minor impact on the rest of the simulation. Some results for the pressure field are depicted in Figure 9.…”

“…In spite of this, many solutions have been obtained in axis-symmetric geometries, see for instance [37,30,38,39,2,40], or in three dimensional geometries, see [41,42,43,44,45,46]. Most of the algorithms are based on the SIMPLEC approach described in [47] and then used in [37,30].…”

“…Moreover in almost all the three-dimensional cases the maximum number of degrees of freedom (dof) used is under 100000: in [42] 60025 dof are used, in [45] 56000 dof are used and finally in [41] 48216 dof are used. In [44] 162729 dof are used, which is higher than the 100000 threshold. We stress that the conditioning number depends on many factors: in (5) the constant depends on the discretization methods.…”