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

Abstract

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.

Study on Apparent Viscosity and Structure of Foaming Slag

“…[10] As discussed in the previous work, [10] the energy needed to deform an interface between liquid and gas is higher than the energy needed to deform the bulk liquid. This finding is in fact in good agreement with the literature.…”

“…Very interesting behaviors have recently been noticed in the foam generated by passing argon gas through silicone oil. [10] The foamed silicone oil shows shear-thinning non-Newtonian behavior; and the apparent viscosities measured show values of 2 to 5 times higher than the dynamic viscosity of the silicone oil. As a continuation, the present work studies the behavior of slag foams at elevated temperature.…”

“…Similar behavior has also been reported in literature [12] and in a previous work. [10] Non-Newtonian fluid is difficult to model, and its viscosity is hard to predict since the viscosity varies with different shear rates. It should be mentioned that the results may vary with the experimental setup and conditions, depending on the wall effects, type, and dimensions of the spindle and temperatures.…”

“…[15] A semiquantitative calculation is made in the previous work. [10] Assuming no volume change, when a sphere with radius of 1 mm is compressed into a spheroid with height c = 0.7 mm, the deformation leads to an increase of 6.4 pct in surface energy. The silicone oil used has a surface tension of 2.1 9 10 À2 J m À2 .…”

Study on Slopping Prevention in the BOF Steelmaking Process

“…A good slag foaming is very important for the metal refining, since it affects the refining efficiency in production. Therefore, it has been received a lot of studies both by high temperature experiments and by physical simulation experiments …”