EUROPEAN STEEL TECHNOLOGY AND APPLICATION DAYS 2017 - ESTAD 2017

In the Electric Arc Furnace (EAF) chemical and electrical energy is used for melting and superheating of scrap and DRI/HBI. Although the fluid-dynamic and thermodynamic phenomena during the different furnace steps are qualitatively known, some of these effects may cause process problems. To serve as an example, a free-burning electric arc not covered by foamy slag overheats the furnace walls (hot spots). Another example is the erosion of refractory lining due to high velocity and temperature gradients close to the wall. However, it is a challenge to implement such phenomena in an overall numerical model. Nowadays, CFD (Computational Fluid Dynamics) is able to provide a detailed insight into the EAF process. SMS group has developed a holistic CFD EAF model (3d, multiphase, non-isothermal, transient) based on ANSYS FLUENT 17.0. The model covers different aspects such as: - Blowing of oxygen through several injectors (supersonic) and a door lance (subsonic). - Movement of melt, slag and furnace gas (CO, O2) during flat-bath operation. - Energy transfer of the electric arcs into the melt and onto the furnace walls (hot spot prediction). - Furnace wall load (stress, temperature) and CO post-combustion inside the furnace domain. The paper describes the CFD model and focuses on results for a 120 t AC EAF and a 140 t DC shaft-type furnace.