Simulation of interdendritic liquid permeability for low and high solid fractions during the solidification of mushy alloys

A numerical model has been developed for the determination of liquid flow permeability through columnar dendrite during growth and segregation in the Al–Si alloys. Therefore, in the present work two separate computational models of the grain growth and interdendritic liquid flow are coupled for modelling of the permeability in partly solid alloy. The grain growth is simulated using a cellular automation finite difference (CAFD) for a 2D dendrite, and fluid flow by using a computational fluid dynamic (CFD) model for determining permeability. A new model has been presented for calculation and modification of the dendrites permeability in the high solid fractions. Simulation results show which Si concentration variations in each time step could transform of dendrite shape. Also dendrites morphology could alter the interdendritic permeability factor.