MODELLING THE THERMO-SOLUTAL CONVECTION, SHRINKAGE FLOW AND GRAIN MOVEMENT DURING GLOBULAR EQUIAXED SOLIDIFICATION IN A MULTI-PHASE SYSTEM I.THREE-PHASE MODEL
Tongmin Wang
大连理工大学
Cite this article:
Tongmin Wang. MODELLING THE THERMO-SOLUTAL CONVECTION, SHRINKAGE FLOW AND GRAIN MOVEMENT DURING GLOBULAR EQUIAXED SOLIDIFICATION IN A MULTI-PHASE SYSTEM I.THREE-PHASE MODEL. Acta Metall Sin, 2006, 42(6): 584-590 .
Abstract A three-phase flow model has been developed to simulate globular equiaxed solidification based on the volume averaging and Eulerian- Eulerian methods. The three phases are liquid, solid and air respectively sharing a single pressure. The basic conservation equations of mass, momentum and enthalpy, and a user defined conservation equation of grain density have been solved for each phase. The thermal and mechanical (drag force) interactions among the phases have been considered. Grain nucleation, growth rate (mass exchange), solute partitioning at the liquid/solid interface and solute transport have also been accounted for. Due to the low density, the air phase floats always at the top region, forming a definable air/liquid melt interface, i.e. free surface. By tracking this free surface, the shrinkage cavity in an open casting system can be modeled. As the temperature and concentration dependent density and solidification shrinkage are explicitly included, the thermosolutal convection, together with feeding flow and grain movement can be taken into account. This paper focuses on the model description and the application examples will be introduced in the part II of this paper.
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