Study Of Aluminum Foam Bubble Growth Dynamics

The research purpose of this paper is to study effect laws of processing parameters of foaming by theoretical calculation on bubble radius are obtained, and theoretical gist is provided for optimization of processing parameters of foamed Aluminum.Island model is used to analyze the course of bubble growth. Continuity equation, motion equation, mass diffusion conservation equation and mass conservation equation of bubble surface are deduced. These four equations are combined with other laws including Sievert's law and ideal gas law together to form the bubble growth dynamics equations in the liquid. The expression of the bubble growth dynamics equation in the metal melt is gained after confirming viscosity, diffusion coefficient, surface tension of metal melt, changing into nondimensionalized equations and neglecting inertia.The effects of foaming time, foaming temperature, mass percent of second phase and pressure on bubble radius are attained by programming the bubble growth dynamics equation:1 Foaming time affect bubble radius greatly. Contrasting to experimental curse, the main reason of difference between two curses is that theoretical curse is build on analyses of one bubble growth, and the factors, such as coalescence, collapse and interaction among bubbles in the experiment, are not considered.2 Foaming temperature affect bubble radius greatly. Contrasting to experimental curse, there is much difference, and theoretical results are half of experimental results. The main reason of difference between two curses is that the factors, such as solubility and fluidity of metal melt, are neglected, thereby, effect of foaming temperature on bubble radius weaken.3 Effect of mass percent of second phase on bubble radius is gradually enhancive. When mass percent of second phase less than 2%, effect is very little, but effect gradually enhances by increasing of mass percent of second phase. This is very similar with experimental phenomenon.4 Effect of pressure on bubble radius is little and very smooth. Effect trend is right, but the change is less than the experimental data.At last, the personal perspectives of author are put forward about aspects of accurate answer of dynamics equations, physical model of bubble growth, et al.