Study on Apparent Viscosity of Foam and Droplet Movement Using a Cold Model

摘要

The apparent viscosities of foams generated by passing argon through silicone oil are measured. The foams are found to be non-Newtonian flows having apparent viscosities 4-5 times higher than the dynamic viscosity of the origin fluid. The movements of different particles and droplets and their residence times are studied. The measured average velocities of the particles/droplets are substantially lower than the values estimated based on the dynamic viscosities. For both mechanical and gas stirrings, the flows of the foam are very different from pure liquid. The movement of the bar and stirring gas bubbles only pushes a limited number of bubbles which are very close to them to move. No bulk flow as in pure liquid is generated by the stirring.