Terminal Settling Velocity of Particle in Suspension

In the steel making process, most slags and fluxes often contain solids phase such as CaO. It is well known that the suspension in which solid phase are suspended has higher viscosity than that of pure matrix liquid. Therefore, it is expected that the viscosity of slag containing solid phase will increase. In this study, terminal settling velocity of particle in suspension has been measured. The suspensions consist of silicone oil matrix and polyethylene beads, and the settling particles are bearing balls made of stainless steel. As a result of the higher viscosity of suspension, the terminal settling velocity of bearing ball becomes slower than that in pure silicone oil. It was clarified that the retardation of the terminal velocity and the increasing of drag coefficient depend only on the volume fraction of solid phase (the polyethylene beads) of the suspension, and it is independent of the size of the suspended beads and the viscosity of the matrix liquid. A correlation equation for predicting the drag coefficient of particles in suspension was proposed.