Grain structure and segregation modeling using coupled FV and DP model

Abstract

A 3D solidification model was developed to predict the solidification grain structure at the mesoscopic level and the induced chemical segregation at the casting scale. The model introduces an innovative new coupling scheme between two numerical modeling approaches: a Finite Volume (FV), to solve the flow, heat and mass transfer, and a Discrete Particle, (DP), to mimic grain structure development. The coupled FV-DP model was built using the OpenFoam open source solver library. A series of validation benchmarks were used to demonstrate the model capability to predict the grain structure and to deal with mass exchange induced by the grain envelopes growth. The model has been applied to predict the temperature, grain structure and final segregation map of an Inconel 718 casting. The developed coupling scheme is shown to be a more accurate tool for quantitative prediction of the segregation in a superalloy casting when compared to single FV modeling approach.