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Modeling of induction stirred ladles
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
2012 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Over the years numerous computational fluid dynamics models have been developed in order to study the fluid flow in gas and induction stirred ladles. These models are used to gain insight in the industrial processes used in ladle treatment of steel. A unified model of an induction stirred Ladle in two and three dimensions is presented. Induction stirring of molten steel is a coupled multi-physics phenomena involving electromagnetic and fluid flow. Models presented in this thesis gives a more accurate description of the real stirring conditions and flow pattern, by taking into account the multi-physics behavior of the induction stirring process in an induction stirred ladle. This thesis presents a formulation of coupled electromagnetic and fluid flow equations. The coupled electromagnetic and fluid flow equations are solved using the finite element method in two and three-dimensions. The simulation model is used to predict values of steel velocities and magnetic flux density. The simulation model is also used to predict the effect of increased current density on flow velocity. Magnetic flux density values obtained from the model are verified against experimental values.

 

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2012. , 34 p.
Keyword [en]
induction ladle, electromagnetic, Lorentz forces, magnetic stirrer, magnetic diffusion, Navier-Stokes, FEM
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:kth:diva-97895ISBN: 978-91-7501-324-4 (print)OAI: oai:DiVA.org:kth-97895DiVA: diva2:534130
Presentation
2012-06-15, Sal M127, KTH, Brinellvägen 23, Stockholm, 09:00 (English)
Opponent
Supervisors
Note
QC 20120615Available from: 2012-06-15 Created: 2012-06-15 Last updated: 2012-06-15Bibliographically approved
List of papers
1. A computational fluid dynamics model of a 20Kg induction stirred laboratory scaled ladle
Open this publication in new window or tab >>A computational fluid dynamics model of a 20Kg induction stirred laboratory scaled ladle
2005 (English)In: Proceedings of the COMSOL Multiphysics User´s Conference 2005 Stockholm, 2005Conference paper, Published paper (Refereed)
Abstract [en]

Over the years numerous Computational fluid dynamics models [1,2,3,4,5,6,7,8] have been developed, in order to study the fluid flow in gas and induction stirred ladles. These models were used to gain more insight in the industrial processes used in ladle treatment of steel. In this paper a computational fluid dynamics model of a 20 Kg laboratory scaled induction ladle (Situated at the Dept. of Material Science and Engineering - KTH) is presented. This particular laboratory furnace can be equipped with an electromagnetic stirrer, which can be used to agitate the steel melt. The CFD model so developed will make it feasible to have information about the fluid flow in this particular laboratory furnace. This information would promote the analysis of experimental results and the implementation of new strategies. The objective of this paper is to obtain an understanding and insight of the ladle refining process by solving the electromagnetic force field and predict the flow pattern produced by these force fields using a single straight induction stirrer, with the help of 20Kg laboratory scaled furnace. The size of this 20Kg laboratory scaled furnace is very small compared to the size of electromagnetic stirrer because of which the magnetic field inside the ladle will essentially be two dimensional. The magnetic field component in third dimension (Y-direction) is very small compared to other two (X and Z direction) hence a two dimensional model also provides a better understating of the model. The flow field produced by a straight induction stirrer is of complex nature due to the three dimensional electromagnetic force and the flow phenomenon. In order to provide more information about the stirring of molten steel within the ladle, which is essentially a three-dimensional phenomenon, a three-dimensional model is also presented incorporating equations governing the fluid flow as well as the electromagnetic forces in the system. Both the models two and three – dimensional are developed in two parts. First, the calculation of electromagnetic forces, which is done with the help of FEMLAB3.1 and second, using these electromagnetic forces (Lorenz forces) as the source term for solving incompressible Navier stokes equation to compute the velocity profile of the agitated melt, which is done by combining the Electromagnetic module with Chemical Engineering module of commercial software FEMLAB 3.1. The CFD model so developed is verified using experimental measurements of the magnetic flux in the laboratory furnace. This CFD model of the induction ladle is developed with the possible extension of the model in mind, i.e. it should be easy to expand the model to incorporate temperature as well as transport of chemical species and non – metallic inclusions.

Keyword
FEMLAB 3, 1, induction ladle, electromagnetic Lorenz forces, magnetic stirrer, mangetic diffusion equation, Navier-stokes equation
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-97892 (URN)
Note
QS 2012Available from: 2012-06-15 Created: 2012-06-15 Last updated: 2012-06-15Bibliographically approved
2. Numerical simulation of induction stirred ladle
Open this publication in new window or tab >>Numerical simulation of induction stirred ladle
2006 (English)In: Proceedings of the COMSOL User´s Conference 2006 Birmingham, 2006Conference paper, Published paper (Refereed)
Abstract [en]

Induction ladle plays an important role in a broad range of metal-processing operations. The treatment of steel in the ladle is as old as the use of ladles in steelmaking. The main purpose for ladle treatment of hot metal and liquid steel include desulphurization, deoxidation, alloying, and inclusion shape control. Over last few years efforts are made to develop simulation models of induction ladle [1]-[8], in order to study heat transfer and fluid flow in gas and induction stirred ladles. These models provide more information about the industrial processes used in ladle treatment of steel. In this paper a simulation model of a laboratory scaled induction ladle is presented. The simulation model so developed will make it feasible to have information about the fluid flow phenomenon and thermal heat transfer. In order to perform the numerical simulation of the furnace, physical processes involved are expressed as a coupled-nonlinear system of partial differential equations arising from a thermal-magneto-hydrodynamic problem. The simulation model is formulated in a twodimensional domain. The equations of electromagnetic model to describe magnetic diffusion inside the ladle through magnetic stirrer are expressed by well known system of Maxwell’s equations. Moreover, the heat equations governing the induction heating are provided. The hydrodynamic model for fluid flow in the molten metal is described by wellknown incompressible Navier-Stokes equation.Numerical simulation are performed by solving the coupled system of equations using the commercial software COMSOL Multiphysics® application mode by combining Electromagnetics, Fluid Dynamics and Heat transfer modules.

 

Keyword
induction ladle, induction heating, electromagnetic forces, Maxwell´s equations, Navier-Stokes equations
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-97893 (URN)
Note
QS 2012Available from: 2012-06-15 Created: 2012-06-15 Last updated: 2012-06-15Bibliographically approved
3. Multiphysics modeling of an induction-stirred ladle in two and three dimensions
Open this publication in new window or tab >>Multiphysics modeling of an induction-stirred ladle in two and three dimensions
2012 (English)In: International Journal for Numerical Methods in Fluids, ISSN 0271-2091, E-ISSN 1097-0363, Vol. 70, no 11, 1378-1392 p.Article in journal (Refereed) Published
Abstract [en]

A unified model of an induction-stirred ladle in two and three dimensions is presented. Induction stirring of molten steel is a coupled multiphysics phenomena involving electromagnetic and fluid flow. Models presented in this paper gives a more accurate description of the real stirring conditions and flow pattern by taking into account the multiphysics behavior of the induction-stirring process in an induction-stirred ladle. This paper presents formulation of coupled electromagnetic and fluid flow equations. The coupled electromagnetic and fluid flow equations are solved with the use of the finite element method in two and three dimensions. The model is used to predict values of steel velocities and magnetic flux density. The model is also used to predict the effect of increased current density on flow velocity. Magnetic flux density values obtained from the model are verified against the experimental values.

Keyword
induction ladle, electromagnetic, Lorents forces, magnetic stirrer, magnetic diffusion, Navier-Stokes, FEM
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-97894 (URN)10.1002/fld.2749 (DOI)000310478500003 ()2-s2.0-84868118366 (Scopus ID)
Note

QC 20121203

Available from: 2012-06-15 Created: 2012-06-15 Last updated: 2017-12-07Bibliographically approved

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