A 3D discrete-element model for simulating liquid feeding during dendritic solidification of steel. (May 2019)

• Record Type: Journal Article
• Authors: Feng, Yi; Založnik, Miha; Thomas, Brian; Phillion, André
• Is Part Of: IOP conference series. Volume 529(2019)
• Publication Date: 2019-05
• Subjects: Materials science -- Periodicals; 620.1105
• DOI: 10.1088/1757-899X/529/1/012031
• Languages: English
• ISSNs: 1757-8981

Abstract

Abstract: A 3D meso-scale discrete-element model has been developed to simulate fluid flow during dendritic solidification of steel. The model domain is a representative volume element consisting of a set of equiaxed dendritic grain envelopes along with extra-dendritic liquid channels, where the final grain shape is given by a Voronoi tessellation. Solidification of each grain is simulated via a volume average approach. The output of the solidification simulation at a given solid fraction is used as the input mesh for the fluid flow simulation. A single domain Darcy-Brinkman model is used to calculate the pressure field within the liquid channels, with Poiseuille flow assumed to occur in the extra-dendritic region, and Darcy flow assumed to occur within the dendrite envelope. Mass conservation over each element is then used to derive a flow equation that is solved via the finite element method. The results of this new model are first compared with a previously-developed granular model [1] where fluid flow only occurs between the grains, and then compared with different forms of the Carman-Kozeny equation. It is shown that the intra-dendritic liquid fluid flow plays a major role in the semi-solid pressure field, and thus needs to be included when investigating hot tearing susceptibility in engineering alloys undergoing dendritic solidification.