A High-efficiency Virtual Submesh Cellular Automata Method for Solidification Simulation with Low Mesh Anisotropy

抄録

The cellular automata (CA) method has been widely used in microstructure simulation during solidification, but it is time-consuming when used for multiple orientations and large-scale computation. In this work, a novel high-efficiency virtual submesh cellular automata (VISCA) method is proposed to reduce the mesh-induced artificial anisotropy. This method conceptually divides the mesh into a series of submeshes by giving a unique index to each CA cell. The proposed VISCA method results in a good accuracy in all orientations using uniform mesh, while an aggressive time stepping can be used. Compared with the previous CA models, the VISCA method exhibits a significant reduction in computational cost and improvement in computational efficiency. The nucleation is simulated based on a continuous nucleation model, and the Kurz-Giovanola-Trivedi (KGT) model is used to simulate the growth of the grains nucleated in the bulk material. The proposed VISCA method is comprehensively validated using an analytical solution, a casting simulation, and a directional solidification experiment. A quantitative comparison with the experiment in the directional solidification example shows that the difference in position of Columnar-to-Equiaxed Transition (CET) between the simulation and the experiment is within 1 mm while the length of directional solidification is 60 mm.