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ISSN Online: 2377-424X

ISBN CD: 1-56700-226-9

ISBN Online: 1-56700-225-0

International Heat Transfer Conference 13
August, 13-18, 2006, Sydney, Australia

NUMERICAL STUDY OF PHASE CHANGE WITH MARANGONI EFFECTS USING A VOF MULTIPHASE APPROACH

Get access (open in a dialog) DOI: 10.1615/IHTC13.p12.390
15 pages

Abstract

Numerical simulations of the solid-liquid phase change of bismuth with a free surface are carried out under different gravity conditions for both two and three-dimensional geometries. A multiphase approach using the Volume of Fluid (VOF) method over a fixed grid is used to solve the thermocapillary induced flow of the melt and gas phases. The dynamics of the gas phase affects heat transfer from the free surface and consequently the position and shape of the growth front. Higher temperature gradients lead to stronger melt thermocapillary flow and more deformed crystal interfaces, resulting in poorer quality crystals forming. Under normal gravity, buoyancy and thermocapillarity combine to add to the concavity of the interfaces, further deteriorating the resulting crystal. The three-dimensional models exhibit a smaller degree of crystal interface distortion in the principal flow direction compared to the corresponding two-dimensional cases. This is due to the sidewall retarding effects and cross-flow temperature gradients that create a highly three-dimensional flow field.