Effect of bubble-induced Marangoni convection on dendritic solidification

A phase field (PF)-lattice Boltzmann (LB) model was developed to capture the bubble-dendrite interactions during solidification of binary alloys under microgravity conditions. The model can handle high density and viscosity ratios in problems such as bubble-dendrite interaction. In this work, the LB method was employed to solve both fluid flow and transport equations, while the finite difference method was used for the heat transfer equation. The solid/liquid interface was tracked by a cellular automaton (CA) model. After validating the model for several benchmark solutions, the Marangoni convection effects on dendrite growth and bubble dynamics were simulated in microgravity conditions. The results suggest that Marangoni convection for larger bubbles can alter the morphology of dendrites, but the effects are negligible for smaller bubbles. In addition, the results of the simulations were compared quantitatively and qualitatively with data from NASA's Pore Formation and Mobility Investigation (PFMI) experiment. (C) 2019 Elsevier Ltd. All rights reserved.