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An anchor-shaped geometrical design for a Submerged Entry Nozzle for the slab continuous casting of steel is presented in this work. To evaluate its performance, transient 3D multiphase numerical simulations were carried out using the Computational Fluid Dynamics technique. The performance of the proposed nozzle is numerically compared with that of a conventional cylindrical nozzle. Computer results show that the chance of formation of Karman’s vortexes and powder entrapment becomes small for the anchor-shaped SEN.

Nowadays, around 95% of the world raw steel is cast by means of the continuous casting process [

Formation of Karman’s vortexes on the meniscus of the mold is promoted by improper designs of the SEN. These vortexes cause powder entrapment and macro inclusions in the steel products [

An anchor-shaped design for a SEN for the slab continuous casting of steel is presented here. Its performance is evaluated by means of mathematical modeling. Transient 3D numerical simulations are carried out using the Computational Fluid Dynamics (CFD) technique. The performance of the proposed SEN is compared with that of a conventional cylindrical SEN.

The geometry of the considered two-port anchor-shaped SEN is shown in

0.01 m, pool height = 0.05 m, discharge angle = 12 degrees to the horizontal.

The flow of an isothermal incompressible Newtonian fluid and the mass conservation are represented by the Navier-Stokes equations and the continuity equation [

where ρ is the fluid density; u_{i} is the i^{th} component of the fluid velocity u; t is time; x_{j} is j spatial coordinate; p is pressure; and μ_{eff} is the effective fluid viscosity. To maintain the mass balance in the system, the continuity equation

The effective viscosity μ_{eff} of Equation (1) is determined from the expression

_{0} is the laminar viscosity and μ_{t} is the turbulent viscosity. On the other hand, μ_{t} is obtained from the expression_{K}, σ_{ε}, C_{1}, C_{2} and C_{μ} are 1.0, 1.3, 1.44, 1.92 and 0.09, respectively [_{in} and D_{n} are the inlet nominal velocity and the nozzle diameter, respectively. The Pressure-Implicit with Splitting of Operators (PISO) algorithm was employed for the pressure-velocity coupling.

The Volume of Fluid (VOF) model is employed to issue the multiphase flow. VOF is based on the assumption that two or more phases are not interpenetrating [_{q} is introduced as a variable. In each control volume the volume fractions of all phases sum to unity. The tracking of the interface between the phases is accomplished by solving the continuity equation for each phase [

To analyze the performance of the conventional and anchor-shaped SEN, transient 3-D two-phase (air, molten steel) isothermal computer simulations were carried out using a time step of 0.001 s. This time step value was determined from numerical experiments, and corresponds to the maximum value which still provides numerical stability. Computer runs of 90 s of integration time were considered to obtain a well developed molten steel flow in the mold. The mold dimensions were as follows: height, 2 m; width, 0.6 m; thickness, 0.2 m. The initial level of molten steel was 1.82 m, the remaining volume of the mold was air. The physical properties of molten steel were as follows: density, 7100 kg/m^{3}; viscosity, 0.0067 kg/(m.s). Boundary conditions were as follows: velocity inlet 2.83 m/s, which corresponds to a casting speed of 1.5 m/min; turbulent kinetic energy 0.08 m^{2}/s^{2}, turbulent dissipation rate 0.755 m^{2}/s^{3}. The computational mesh employed in the computer simulations is shown in

of the velocity vectors around the anchor-shaped SEN is significantly smaller than the case of the cylindrical SEN. This phenomenon is due to the presence of the solid arms of the anchor-shaped SEN which act as physical barriers to the flow of molten steel.

Finally,

velocity magnitude than the cylindrical SEN. This means that the anchor-shaped SEN causes less turbulence in the mold.

An anchor-shaped Submerged Entry Nozzle design for the continuous casting of steel was proposed in this work. The performance of this nozzle was numerically compared with the performance of a conventional cylindrical nozzle. From the computer results, the following conclusions arise:

1) The cylindrical SEN exhibits the deepest depression of the free surface and the largest velocity vectors in the upper section of the mold.

2) The velocity vectors near the free surface in the vicinity of the SEN are greater for the cylindrical SEN than that corresponding to the anchor-shaped SEN.

3) The chance for the formation of Karman’s vortexes and powder entrapment becomes small for the anchor-shaped SEN.

Hernandez, C.A., Barron, M.A. and Miranda, R. (2016) Anchor-Shaped Design of a Submerged Entry Nozzle for the Continuous Casting of Steel. Open Journal of Applied Sciences, 6, 593- 600. http://dx.doi.org/10.4236/ojapps.2016.69058