This paper introduces a numerical model of an electromagnetic rotary stirrer based on the finite-element model. Such stirrers are used to improve the quality of continuously cast steel, particularly billets and blooms. The method determines the magnetic flux density profile and compares it to experimental measurements. In addition, it calculates the Lorentz force field as a function of the stirrer position, the current applied, and the frequency. The stirrer position at the end of the mold affects the profile symmetry of the force, creating a component of the force. With this model, it will be possible to simulate the fluid dynamics effects in the molten steel.

A fully couple flow of molten steel, heat transfer, and solidification in the mold region of a continuous casting round billet under mold electromagnetic stirring (M-EMS) are investigate with computational tools of fluid flow and electromagnetic simulations. A finite element model is employed to simulate the electromagnetic stirrer in the mold and calculate the Lorenz force distribution. The Lorenz forces are applied as a source term in the Navier-Stokes equations of the fluid flow model, which was solved through a finite volume model. The flow pattern produced by the stirrer is mainly rotational, with velocities of 0.37 m s À1 close to the solidifying shell for the higher current. The results indicate that a higher M-EMS current produces a reduction of the temperature in the strand center; a decrease of 42 8C is observed for a current of 350 A/4.25 Hz. The M-EMS also produces a thinner shell close to the stirrer center and a larger region of solid fraction in the billet center.

To investigate the inclusion removal in billets cast under electromagnetic stirring (EMS) influence, a numerical model has been developed to compute the magnetic field, the Lorentz force, the steel flow velocities, and the particle transport within the liquid pool. The electromagnetic field was described by the Maxwell equations and the finite element method was applied using a commercial package. The turbulent fluid flow was described by the Navier‐Stokes equation and by the Reynolds Stress model and the finite volume method was applied using another numerical package. The time average of the Lorentz force was calculated in each element center and this value was applied as a body force in the Navier‐Stokes equation. The magnetic flux density profile was compared with the data obtained in the stirrer of the steel plant. The particle transport model includes the drag force, the buoyancy force and the random walk model, to include the turbulence effects on the particle trajectory. The inclusion removal was calculated and analysed in function of casting speed and stirring current for one size section of mold. The inclusions considered in the calculations have a fixed density and four values of diameter. The numerical results of the electromagnetic model are in agreement with the experimental measurements. A good relationship between the electromagnetic model and the fluid flow model could be shown. An interesting effect is the break of the rotation motion due to the EMS by the jet from the nozzle. The fraction of inclusions removed by the top surface of the mold was improved due to the EMS.

This paper presents the MSDEF (Modelo Simulador da Dispersão de Efluentes de Foguetes, in Portuguese) model, which represents the solution for time-dependent advection-diffusion equation applying the Laplace transform considering the Atmospheric Boundary Layer as a multilayer system. This solution allows a time evolution description of the concentration field emitted from a source during a release lasting time t r , and it takes into account deposition velocity, first-order chemical reaction, gravitational settling, precipitation scavenging, and plume rise effect. This solution is suitable for describing critical events relative to accidental release of toxic, flammable, or explosive substances. A qualitative evaluation of the model to simulate rocket exhaust clouds is showed.

O uso de agitadores eletromagnéticos (EMS) durante o lingotamento contínuo tornou-se imprescindível para a obtenção de aços de melhor qualidade. Embora os efeitos da agitação durante o processo de solidificação sejam pouco conhecidos do ponto de vista teórico, pode-se estudar esses efeitos sobre o perfil de escoamento antes do aço solidificar. Esse trabalho tem como objetivo estudar os efeitos térmicos e fluido-dinâmicos produzidos por um agitador rotatório para tarugos. Um modelo resolvido pelo método de elementos finitos foi desenvolvido através do software Ansys para resolver o problema magneto-fluido-dinâmico acoplado. Para fins de comparação, foram testados dois valores de corrente no agitador e analisadas as principais diferenças quanto ao escoamento, perfil térmico e fluxo de calor.
The electromagnetic stirring during the continuous casting became indispensable to obtain steel with high quality. Despite the fact that the stirring effects during the solidifying process are not very well known from the theoretical point of view, these effects can be studied on the steel flow. The aim of this work is to study the magnetic and the fluid dynamic effects due to a rotatory stirrer for billets. A model solved by the finite element method was developed using the Ansys commercial package to solve the coupled magnetic-fluid dynamic problem. To make a comparison simulations with two current values were carried out and the main differences concerning the fluid flow and the thermal profile were analyzed