Stabilization of closed-cell aluminum foams by horizontal steady magnetic field: numerical simulation on drainage for node-Plateau borders system

Abstract

In order to improve the stabilization of closed-cell aluminum foams during preparation process, a horizontal steady uniform magnetic field was imposed. The three-dimensional microscopic drainage model of closed-cell aluminum foam has been developed, in which the surface viscosity was incorporated into the boundary conditions to quantify the mobility of the gas–liquid interface. The predicted results by the model agree well with the experimental data from literatures. The numerical results show that the uniform magnetic field has particularly suppression effect on the drainage flow in aluminum foam. And this effect increases with the increasing magnetic induction intensity. The suppression effect of magnetic field on drainage at the bottom of aluminum foam is higher than that at the top and middle of aluminum foam. For different stages of the drainage process, applying the magnetic field in the early stage is more effective than in the later stage. For different preparation methods, the application of magnetic field to powder metallurgy method has the best effect, followed by blowing foaming method and melting foaming method. Different combinations of particle concentration and magnetic induction intensity can achieve the same suppression effect. In the preparation of aluminum foam, it is suggested to combine magnetic field with the particles to improve the suppression efficiency of drainage behavior. The critical magnetic induction intensity is proposed. Under this critical condition, the magnetic field can completely replace the particles. Furthermore, the critical magnetic induction intensity shows linear relationship with the logarithm of Boussinesq number.

Keywords

• Numerical simulation
• Closed-cell
• Aluminum foam
• Magnetic field
• Drainage