Electric arcs used in welding manufacturing often involve 3-dimensional configurations. However, ... more Electric arcs used in welding manufacturing often involve 3-dimensional configurations. However, a large fraction of the numerical simulations done to deeper understand high intensity arc in the frame of welding is based on axi-symmetric models. The electric potential formulation introduced by Hsu and Pfender is the most commonly used electromagnetic model for computing axi-symmetric high intensity arcs. This model was initially developed for long arc. But the high intensity arcs applied to welding manufacturing use to be short. And it turns out that when considering an axi-symmetric configuration, when accounting for the electrode geometry, or when studying a short arc, the 3-dimensional model used in the literature for calculating the electromagnetic fields and the electric potential formulation do not provide the same simulation results: they do not represent the same physics. Some care is thus needed for selecting the relevant electromagnetic model for axi-symmetric short arc, o...
We have considered four different approaches for modelling the electromagnetic fields of high-int... more We have considered four different approaches for modelling the electromagnetic fields of high-intensity electric arcs: (i) three-dimensional, (ii) two-dimensional axi-symmetric, (iii) the electric potential formulation and (iv) the magnetic field formulation. The underlying assumptions and the differences between these models are described in detail. Models (i) to (iii) reduce to the same limit for an axi-symmetric configuration with negligible radial current density, contrary to model (iv). Models (i) to (iii) were retained and implemented in the open source CFD software OpenFOAM. The simulation results were first validated against the analytic solution of an infinite electric rod. Perfect agreement was obtained for all the models tested. The electromagnetic models (i) to (iii) were then coupled with thermal fluid mechanics, and applied to axi-symmetric gas tungsten arc welding test cases with short arc (2, 3 and 5 mm) and truncated conical electrode tip. Models (i) and (ii) lead to the same simulation results, but not model (iii). Model (iii) is suited in the specific limit of long axi-symmetric arc with negligible electrode tip effect, i.e. negligible radial current density. For short axi-symmetric arc with significant electrode tip effect, the more general axi-symmetric formulation of model (ii) should instead be used.
Electric arcs used in welding manufacturing often involve 3-dimensional configurations. However, ... more Electric arcs used in welding manufacturing often involve 3-dimensional configurations. However, a large fraction of the numerical simulations done to deeper understand high intensity arc in the frame of welding is based on axi-symmetric models. The electric potential formulation introduced by Hsu and Pfender is the most commonly used electromagnetic model for computing axi-symmetric high intensity arcs. This model was initially developed for long arc. But the high intensity arcs applied to welding manufacturing use to be short. And it turns out that when considering an axi-symmetric configuration, when accounting for the electrode geometry, or when studying a short arc, the 3-dimensional model used in the literature for calculating the electromagnetic fields and the electric potential formulation do not provide the same simulation results: they do not represent the same physics. Some care is thus needed for selecting the relevant electromagnetic model for axi-symmetric short arc, o...
We have considered four different approaches for modelling the electromagnetic fields of high-int... more We have considered four different approaches for modelling the electromagnetic fields of high-intensity electric arcs: (i) three-dimensional, (ii) two-dimensional axi-symmetric, (iii) the electric potential formulation and (iv) the magnetic field formulation. The underlying assumptions and the differences between these models are described in detail. Models (i) to (iii) reduce to the same limit for an axi-symmetric configuration with negligible radial current density, contrary to model (iv). Models (i) to (iii) were retained and implemented in the open source CFD software OpenFOAM. The simulation results were first validated against the analytic solution of an infinite electric rod. Perfect agreement was obtained for all the models tested. The electromagnetic models (i) to (iii) were then coupled with thermal fluid mechanics, and applied to axi-symmetric gas tungsten arc welding test cases with short arc (2, 3 and 5 mm) and truncated conical electrode tip. Models (i) and (ii) lead to the same simulation results, but not model (iii). Model (iii) is suited in the specific limit of long axi-symmetric arc with negligible electrode tip effect, i.e. negligible radial current density. For short axi-symmetric arc with significant electrode tip effect, the more general axi-symmetric formulation of model (ii) should instead be used.
Uploads
Papers by H. Nilsson