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Article
Publication date: 7 January 2020

Valdis Bojarevics and Koulis Pericleous

The purpose of this paper is to investigate a new type of nozzle which is free from erosion and non-contaminating the outflow metal. Cold crucible melting technique with…

Abstract

Purpose

The purpose of this paper is to investigate a new type of nozzle which is free from erosion and non-contaminating the outflow metal. Cold crucible melting technique with electromagnetic induction is used to obtain reactive metal castings and produce high-quality metal powders for aerospace, automotive and medical applications. An important part of this technology is the nozzle used to pour the molten alloy through the bottom opening.

Design/methodology/approach

The paper uses mathematical modeling technique, previously validated on multiple similar cases, to investigate a new type of nonconsumable nozzle made of copper segments.

Findings

The design of the nozzle requires to satisfy the narrow balance between the thin solidified protective layer on the wall while avoiding the blockage of the outflow if the nozzle is frozen completely. The sensitivity of the outflow to the nozzle diameter is investigated. The AC electromagnetic force leads to high mixing rates, transitional flow structures and turbulence of the melt, contributing to the melt shape dynamics and the heat loss to walls.

Originality/value

The beneficial features of the cold crucible melting to purify the melt from particulate contamination are explained using the full melting and pouring cycle.

Details

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

Keywords

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Article
Publication date: 3 May 2013

Hong Wang, Georgi Djambazov and Koulis Pericleous

The purpose of this paper is to describe how a 3D/1D transient heat transfer model has been developed for getting accurate thermal boundary conditions when investigating…

Abstract

Purpose

The purpose of this paper is to describe how a 3D/1D transient heat transfer model has been developed for getting accurate thermal boundary conditions when investigating the heat transfer in the TiAl castings and also for reducing the computational cost and simplifying the mesh generation.

Design/methodology/approach

Heat transfer in the mould is assumed to take place only in a direction perpendicular to the mould wall, called 1D heat transfer. The coordinates of cell centre and the temperature in the mould wall can be calculated by the model instead of meshing mould. Heat transfer in the mould is computed via the FD solution of a 1D heat transfer equation.

Findings

For some types of geometry, the model works very well. However, for some, which contain the geometric feature called “dead corner”, the model can't cover. There is some impact on the accuracy of the model.

Practical implications

In the casting industry, the geometry of the casting is usually very complex and contains different features. This leads to difficult meshing when using numerical model to predict the casting process. Furthermore, an accurate calculation is very important on the thermal boundary during filling and solidification, to support practice, to improve the process and minimise the casting defects.

Originality/value

In this paper, a novel method is developed to calculate the heat transfer through the casting‐mould interface to the mould wall in a casting.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 23 no. 4
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 13 September 2011

Valdis Bojarevics, Alan Roy and Koulis Pericleous

The purpose of this paper is to create a numerical model of electrode induction melting process for the gas atomization (EIGA) and process and investigate the complex…

Abstract

Purpose

The purpose of this paper is to create a numerical model of electrode induction melting process for the gas atomization (EIGA) and process and investigate the complex interaction of the electromagnetic and thermal fields on the fluid flow with free surface.

Design/methodology/approach

The modelling approach is based on the free surface code SPHINX which includes time dependent electromagnetic, thermal and fluid flow with free surface modelling and the commercial software COMSOL for investigating 3D electromagnetic effects.

Findings

The melting dynamics, liquid film formation and the outflow free surface behavior are predicted by SPHINX using an optimized geometry. Quasi‐stationary AC electromagnetic solutions with COMSOL predict some 3D effects of the coil, including frequency dependent estimates of voltage, electric current and power.

Originality/value

The importance of magnetic forces controlling the free surface jet formation, partial semi‐levitation and the outflow superheat is uncovered by numerical modelling tools. An optimized geometry is presented for the EIGA process.

Details

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

Keywords

Content available
Article
Publication date: 1 August 2001

Abstract

Details

Aircraft Engineering and Aerospace Technology, vol. 73 no. 4
Type: Research Article
ISSN: 0002-2667

Keywords

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