Dresden 2006 – scientific programme

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MM: Metall- und Materialphysik

MM 34: Symposium Materials Modelling III

MM 34.2: Talk

Thursday, March 30, 2006, 17:15–17:30, IFW A

A parallel 3D simulator for solidification microstructures with fluid flow — •Britta Nestler, Michael Selzer, and Frank Wendler — University of Applied Sciences Karlsruhe, Moltkestr. 30, 76133 Karlsruhe

The effect of fluid flow on three-dimensional crystal growth structures is studied by numerical simulations. It is a phenomenon with particular effects in three dimensions where solute is transported in the spatial domain and around the growing crystals. From experiments, it is well known that fluid flow dramatically alters the solidification structure during a casting process. The presence of flow admits the possibility of instabilities due to the flow itself, in addition to the well known morphological instabilities found in crystal growth. Hence, flow has an important influence on the process conditions and on the resulting material properties during the solidification from a melt. We first present a new model for an arbitrary number of phases with fluid flow, which is thermodynamically consistent. Then we introduce our parallel 3D simulator optimized for solving the coupled set of the phase-field model equations and the Navier-Stokes equations for fluid flow. The phase-field equations contain partial differential equations describing the transport of mass and heat and the corresponding temporal evolution of the phase states (order parameters) in the system. Examples of applying the simulator to the solidification of alloy microstructures under the influence of forced and convective flow are considered, and the interaction between diffusion and convection is discussed. In particular, we show simulation results of growing grains and of eutectic microstructures in a flow field.