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Article
Publication date: 1 March 2003

E. Baake, B. Nacke, A. Umbrashko and A. Jakovics

Experimental investigations of the turbulent flow velocities measured in the melt of experimental induction furnaces show, that beside the intensive local turbulence pulsations…

548

Abstract

Experimental investigations of the turbulent flow velocities measured in the melt of experimental induction furnaces show, that beside the intensive local turbulence pulsations, macroscopic low‐frequency oscillations of the recirculated toroidal main flow eddies play an important role in the heat and mass exchange processes. Traditional numerical calculations of the flow and transfer processes, based on wide spread commercial codes using various modifications of the k‐ε turbulence model show that these models do not take into account the low‐frequency oscillations of the melt flow and the calculated temperature and concentration distributions in the melt essentially differs from experimental results. Therefore, the melt flow dynamics in an induction crucible furnace was numerically simulated with help of transient three‐dimensional calculations using the large eddy simulation turbulence model. This leads to a good agreement between calculated and measured periods of low‐frequency oscillations and heat and mass transfer between the toroidal flow eddies.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 22 no. 1
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 7 March 2008

M. Kirpo, A. Jakovičs, B. Nacke and E. Baake

Aims to present recent activities in numerical modeling of turbulent transport processes in induction crucible furnace.

251

Abstract

Purpose

Aims to present recent activities in numerical modeling of turbulent transport processes in induction crucible furnace.

Design/methodology/approach

3D large eddy simulation (LES) method was applied for fluid flow modeling in a cylindrical container and transport of 30,000 particles was investigated with Lagrangian approach.

Findings

Particle accumulation near the side crucible boundary is determined mainly by the ρp/ρ ratio and according to the presented results. Particle settling velocity is of the same order as characteristic melt flow velocity. Particle concentration homogenization time depends on the internal flow regime. Separate particle tracks introduce very intensive mass exchange between the different parts of the melt in the whole volume of the crucible.

Originality/value

Transient simulation of particle transport together with LES fluid flow simulation gives the opportunity of accurate prediction of admixture concentartion distribution in the melt.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 27 no. 2
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 March 2005

A. Umbrashko, E. Baake, B. Nacke and A. Jakovics

Aims to present recent activities in experimental investigations and numerical modelling of the induction cold crucible installation.

495

Abstract

Purpose

Aims to present recent activities in experimental investigations and numerical modelling of the induction cold crucible installation.

Design/methodology/approach

Temperature and velocity measurements using thermocouples and electromagnetic velocity probes were performed in aluminium melt which was used as a model melt. Measured temperature field and flow pattern were compared with transient 3D calculations based on large eddy simulation (LES) turbulence modelling scheme. Numerical results are in good coincidence with the experimental data.

Findings

The modelling results show that only 3D transient LES is able to model correctly these heat and mass transfer processes.

Originality/value

It is revealed that transient 3D modelling provides a universal tool for simulating convective heat and mass transfer processes in the entire melt influenced by large scale instabilities in the recirculating flows, which contain several main vortexes of the mean flow.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 24 no. 1
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 13 September 2011

E. Baake, A. Jakovics, S. Pavlovs and M. Kirpo

The purpose of this paper is to present in‐depth numerical modelling of heat and mass exchange in industrial induction channel furnace (ICF).

258

Abstract

Purpose

The purpose of this paper is to present in‐depth numerical modelling of heat and mass exchange in industrial induction channel furnace (ICF).

Design/methodology/approach

The turbulent heat and mass exchange in the melt is calculated using a three‐dimensional (3D) electromagnetic model and a 3D transient large eddy simulation method. The simulation model has been verified by flow velocity and temperature measurements, which were carried out using an industrial sized channel inductor operating with Wood's metal as a low temperature model melt.

Findings

The ICF is well‐established for melting, holding and casting in the metallurgical industry. But there are still open questions regarding the heat and mass exchange in the inductor channel itself and between the channel and the melt bath. Different new designed channel geometries have been investigated numerically in order to find an optimized shape of the channel, which leads to an improved heat and mass transfer.

Originality/value

Long‐term computations for the industrial ICF have been performed. Low frequency oscillations of the temperature maximum and its position in the ICF channel are considered.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 30 no. 5
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 7 March 2008

A. Umbrasko, E. Baake, B. Nacke and A. Jakovics

Aims to present recent activities in numerical modeling of cold crucible melting process.

673

Abstract

Purpose

Aims to present recent activities in numerical modeling of cold crucible melting process.

Design/methodology/approach

3D numerical analysis was used for electromagnetic problem and 3D large eddy simulation (LES) method was applied for fluid flow modeling.

Findings

The comparative modeling shows, that higher H/D ratio of the melt is more efficient when total power consumption is considered, but this advantage is held back by higher heat losses through the crucible walls. Also, calculations reveal that lower frequencies, which are energetically less effective, provide better mixing of the melt.

Originality/value

3D electromagnetic model, which allows to take into account non‐symmetrical distribution of Joule heat sources, together with transient LES fluid flow simulation gives the opportunity of accurate prediction of temperature distribution in the melt.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 27 no. 2
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 March 2003

E. Baake, B. Nacke, F. Bernier, M. Vogt, A. Mühlbauer and M. Blum

Comprehensive knowledge of the complicated physical behavior of the induction furnace with cold crucible (IFCC) is required to utilize the advantages of this melting aggregate in…

712

Abstract

Comprehensive knowledge of the complicated physical behavior of the induction furnace with cold crucible (IFCC) is required to utilize the advantages of this melting aggregate in melting and casting chemically high‐reactive materials, like titanium‐aluminides (TiAl). Practical experiences show that the overheating temperature of the melt is decisive for the quality of the cast products. Therefore, a systematic analysis of the electromagnetic and in particular, the hydrodynamic and thermal behavior of the IFCC is carried out. The examinations of the influence of the construction elements as well as the process parameters on the temperature field and finally the overheating temperature in the IFCC are performed using specifically developed numerical models. The evaluation of the numerical results is done by experimental investigations, where aluminum serves as a model melt for the experimental determination of the thermal and hydrodynamic field of the melt. The analysis of the influence of construction‐elements on the overheating temperature is focused on the design of the crucible wall and the crucible bottom, on the height‐diameter ratio of the crucible and on the axial inductor position. The inductor current, the operation frequency and the crucible filling level are found to be very important for reaching a high overheating temperature.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 22 no. 1
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 6 March 2017

Wladimir Ebel, Alexander Nikanorov and Egbert Baake

The purpose of this paper is to research a multi-zone rubber vulcanization process heated by induction.

122

Abstract

Purpose

The purpose of this paper is to research a multi-zone rubber vulcanization process heated by induction.

Design/methodology/approach

The design is an abstract setup model with two zones, where the homogene rubber compound is heated with different regimes. Simulation is completely done in ANSYS Mechanical by the finite element method solution. The research is made mostly simulative.

Findings

The results show that it is possible to obtain a factor-three vulcanization level difference in a core of a 20-mm rubber plate in a distance of less than 60 mm, while the heating is done from the side of the surface.

Originality/value

The originality is the combination of rubber vulcanization with a dynamic heat source in a form of electromagnetic induction applied on the mold form. This allows a high level of control of the vulcanization process of the rubber compound.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 36 no. 2
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 13 September 2011

P. Turewicz, E. Baake and A. Umbrashko

The purpose of this paper is to describe how electromagnetic stirring during continuous casting of ferrous and non‐ferrous metals is applied in order to increase the homogeneity…

472

Abstract

Purpose

The purpose of this paper is to describe how electromagnetic stirring during continuous casting of ferrous and non‐ferrous metals is applied in order to increase the homogeneity and the material properties by improving the grain refinement in the solidification process. The fluid flow and thermal modeling was performed for studying the metal wire pulling process, where melt is being stirred at the solidification front (SF) by electromagnetic forces. Transient simulation has been carried out in order to investigate the periodical character of the process.

Design/methodology/approach

The numerical analysis was performed in 2D utilizing the rotational symmetry of the problem. First the electromagnetic fields were estimated using FEM and were subsequently exported as source terms in a coupled thermal and flow simulation with FVM.

Findings

The presented numerical model estimated the most suitable position between the stirring coil and the SF to achieve high flow velocities which improve the grain refinement process.

Originality/value

This work enables estimation of the melt solidification in an electromagnetic stirred continuous casting process with oscillating pull velocities.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 30 no. 5
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 7 January 2020

Martin Schulze and Egbert Baake

This paper aims to deal with different induction and conduction heating approaches to realize a tailored heating of round billets for hot forming processes. In particular, this…

123

Abstract

Purpose

This paper aims to deal with different induction and conduction heating approaches to realize a tailored heating of round billets for hot forming processes. In particular, this work examines the limits in which tailor-made temperature profiles can be achieved in the billet. In this way, a flow stress distribution based on the temperature field in the material can be set in a targeted manner, which is decisive for forming processes.

Design/methodology/approach

For the heating of round billets by induction, the rotationally symmetric arrangement is used and a parameterized 2D finite element method model is created. The harmonic electromagnetic solution is coupled with the transient thermal solution. For heating by means of conduction, the same procedure is used only with the use of a 3D model.

Findings

First results have shown that both methods can achieve very good results for billets with small diameters (d < 30 mm). For larger diameters, an adapted control of the heating process is necessary to ensure through heating of the material. Further investigations are carried out.

Practical implications

Using tailored heating for forging billets, several forming steps can be achieved in one step. Among other things, higher energy efficiency and throughput rates can be achieved.

Originality/value

The peculiarity of the tailored heating approach is that, in contrast to inhomogeneous heating, where only partial areas are heated, the entire component is heated to the target.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 39 no. 1
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 7 March 2008

J.D. Lavers

To provide a selective bibliography for researchers and graduate students who have an interest in induction processes applied to the electromagnetic processing of materials.

1424

Abstract

Purpose

To provide a selective bibliography for researchers and graduate students who have an interest in induction processes applied to the electromagnetic processing of materials.

Design/methodology/approach

The objective is to provide references that identify seminal, early work, and references that represent the current state of the art. References are listed in categories that cover the broad range of induction modeling and application issues.

Findings

A brief overview of the key areas in induction processing of materials is provided, but greater emphasis and space is devoted to the references provided.

Research limitations/implications

The middle years of each topic area are not covered.

Practical implications

A very comprehensive coverage of material is provided to those with an interest in induction processing of materials.

Originality/value

This paper fulfils an identified information/resources need.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 27 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

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