Gravitational modulation of thermosolutal convection during directional solidification


Murray, B. T., Coriell, S. R., McFadden, G. B., Wheeler, A. A. and Saunders, B. V. (1993) Gravitational modulation of thermosolutal convection during directional solidification. Journal of Crystal Growth, 129, (1-2), 70-80. (doi:10.1016/0022-0248(93)90435-Y).

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Description/Abstract

During directional solidification of a binary alloy at constant velocity, thermosolutal convection may occur due to the temperature and solute gradients associated with the solidification process. For vertical growth in an ideal furnace (lacking horizontal gradients) a quiescent state is possible. The effect of a time-periodic vertical gravitational acceleration (or equivalently vibration) on the onset of thermosolutal convection is calculated based on linear stability using Floquet theory. Numerical calculations for the onset of instability have been carried out for a semiconductor alloy with Schmidt number of 10 and Prandtl number of 0.1 with primary emphasis on large modulation frequencies in a microgravity environment for which the background gravitational acceleration is negligible. The numerical results demonstrate that there is a significant difference in stability depending on whether a heavier or lighter solute is rejected. For large modulation frequencies, the stability behavior can be described by either the method of averaging or an asymptotic resonant mode analysis.

Item Type: Article
Related URLs:
Subjects: Q Science > QA Mathematics
Divisions: University Structure - Pre August 2011 > School of Mathematics > Applied Mathematics
ePrint ID: 808
Date Deposited: 25 Mar 2004
Last Modified: 27 Mar 2014 17:59
URI: http://eprints.soton.ac.uk/id/eprint/808

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