Development of a numerical model for hydrogen bubble generation, dynamics and trapping during solidification of aluminium alloys through Eulerian-Lagrangian framework

Abstract

ABSTRACTIn the present study, the authors developed a new numerical model to predict the bulk fluid flow, heat transfer, hydrogen species transfer with the hydrogen bubble generation, dynamics and trapping during solidification of aluminium through the continuum theory with Lagrangian bubble dynamics. The generated bubble size is assumed to be dependent on the microstructure. The bubble drag force is newly proposed in the Euler-Lagrange framework. In a model casting system, almost all generated hydrogen bubbles are trapped into a solidified aluminium. However, the hydrogen bubbles are capable of generating in the melt phase and detaching from the mushy zone when the initial hydrogen concentration is high. In this case, the hydrogen bubbles move upward due to buoyancy and this movement is slightly affected by the surrounding melt flow.