Influence of Wall Boundary Condition on the CFD Simulation of Nanoparticle Velocity Profiles in a Conical Fluidized Bed

فاقد چكيده فارسي

The hydrodynamic characteristics of TiO2 nanoparticle fluidization were studied experimentally in a conical fluidized bed and the results compared with numerical simulations. Local axial solid velocities in the bed have been measured by means of an optical fiber technique under different operating conditions of particle loading and air velocity. Interparticle adhesion forces between TiO2 nanoparticles give rise to the formation of agglomerates with a wide size distribution. The radial profiles of axial solid velocities have been simulated to assess the sensitivity of model to wall boundary conditions (BCs). The Eulerian-Eulerian two-phase model and Gidaspow drag function and three BCs consisting of no-slip, partial-slip, and free-slip BCs with frictional stress models have been used in the numerical simulations. A mean particle size of 125 μm was chosen for the numerical simulations. The numerical predictions using Gidaspow drag model and partial-slip BC agreed reasonably well with the axial solid velocity measurements in a conical fluidized bed with smooth wall