Binary alloy dendrite growth in presence of shrinkage induced convection

Abstract

In this paper, the effect of shrinkage induced flow on binary alloy dendrite growth is investigated. The standard enthalpy model for dendritic solidification is modified to incorporate unequal phase densities and coupled with a flow solver to simulate shrinkage driven flow. Simulations show that shrinkage induced convection towards the solidification interface leads to increased solute accumulation at the interface resulting in reduced solidification rate. Thus even if the change in volume due to density difference is considered, the predicted growth rate will not be accurate unless shrinkage driven convection is incorporated in the model. The effect of Lewis number on shrinkage is also investigated and it is found that the relative decrease in dendrite growth rate due to shrinkage induced flow is not affected significantly by change in Lewis number.