# Thermoelectric MHD in dendritic solidification

Kao, A., Djambazov, G., Pericleous, K. and Voller, V. (2009) *Thermoelectric MHD in dendritic solidification.* Magnetohydrodynamics, 45 (3). pp. 305-316. ISSN 0024-998X

## Abstract

The effects of a constant uniform magnetic field on dendritic solidification were investigated using an enthalpy based numerical model. The interaction between thermoelectric currents on a growing crystal and the magnetic field generates a Lorentz force that creates flow. The need for very high resolution at the liquid-solid boundary where the thermoelectric source originates plus the need to accommodate multiple grains for a realistic simulation, make this a very demanding computational problem. For practical simulations, a quasi 3-dimensional approximation is proposed which nevertheless retains essential elements of transport in the third dimension. A magnetic field normal to the plane of growth leads to general flow circulation around an equiaxed dendrite, with secondary recirculations between the arms. The heat/solute advection by the flow is shown to cause a change in the morphology of the dendrite; secondary growth is promoted preferentially on one side of the dendrite arm and the tip velocity of the primary arm is increased. The degree of approximation introduced is quantified by extending the model into 3-dimensions, where the full Navier-Stokes equation is solved, and compared against the 2-dimensional solution.

Item Type: | Article |
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Additional Information: | [1] This paper is published in Magnetohydrodynamics 45, 3 (2009), Special issue: Selected papers of the 7th pamir International Conference Fundamental and Applied MHD Giens, France, September 8-12, 2008. It is a (slightly) revised and retitled version of the paper, 'Effects of magnetic fields on crystal growth', which also formed part of the Proceedings of the 7th International PAMIR Conference: Fundamental and Applied MHD and COST P17 Annual Workshop 2008, held at Presqu'Île de Giens, France, 8-12 September 2008. |

Uncontrolled Keywords: | magnetic field, crystal growth, enthalpy, numerical model |

Subjects: | Q Science > QA Mathematics Q Science > QD Chemistry |

School / Department / Research Groups: | School of Computing & Mathematical Sciences School of Computing & Mathematical Sciences > Centre for Numerical Modelling & Process Analysis School of Computing & Mathematical Sciences > Centre for Numerical Modelling & Process Analysis > Computational Science & Engineering Group School of Computing & Mathematical Sciences > Department of Computer Systems Technology School of Computing & Mathematical Sciences > Department of Mathematical Sciences |

Related URLs: | |

Last Modified: | 03 Oct 2013 16:24 |

URI: | http://gala.gre.ac.uk/id/eprint/1882 |

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