| In this study, a hydrodynamic model for multiphase flows, based on the principles of mass conservation, momentum balance and energy conservation for each phase, is proposed and applied to model separation, dissemination and fluidization systems.; In the first part, continuous operation of a lamella electrosettler to separate fine particles in non-aqueous media is described. This device is tested with a model {dollar}alpha{dollar}-alumina-kerosene-aerosol OT system. The measurements of alumina concentration distribution inside the device made using X-ray densitometer showed the existence of concentration varying suspension layer. The proposed predictive hydrodynamic model computed concentration profiles, which qualitatively agree with the experimental measurements. A general expression for electroboundary layer, beneath downward facing wall, is obtained for both batch and continuous electrosettling.; A simulation study of hydrodynamics of the electrostatic coal-pyrites separation shows that to obtain good coal recoveries, high inlet air velocities must be used. To also obtain high pyrites removal, pyrites exit ports must be located where the pyrite particle trajectory hits the electrode. This study led to an optimized design of electrostatic separator.; This completely predictive hydrodynamic model is extended to study the dissemination of powders from a high pressure disseminator through an orifice into a controlled geometry enclosure (rectangular bag), which is used to conduct detonation experiments at various solids concentrations. The computed cloud jet length agreed reasonably well with the cloud movement observed in the high speed movie of the experiment of dissemination of powders, obtained from IITRI. The computations and the experiment both show that particle jet entering the bag breaks up in a snake-like fashion due to an asymmetrical inlet condition.; In last part of this study, the interphase friction coefficients and the apparent weights carried by fluid and particulate phases in momentum balance are modified. This modified hydrodynamic model along with a fluctuating kinetic energy equation is used to simulate the behavior of three-phase fluidization systems. The computations for dimethyl phthalate, 0.889 mm glass beads and 4 mm dispersed air bubble system showed a solids shear viscosity of 1 to 10 poises, which agree with measured apparent bed viscosities in the literature. |
