COMPUTATIONAL MODELING OF GAS PARTICLE FLOW IN A RISER/

Axial solid velocity, solid volume fraction, and solid shear viscosity were computed in the riser of a circulating fluidized-bed reactor usi ng a two-phase 2-D computational fluid dynamic model. The time-average d model predictions agree well with the experimental data of Miller an d Gidaspow (1992). The model predicts a core-annulus flow in the riser , similar to that found experimentally. The maximum velocity in the co re agrees well with the measurements, but the downflow in the annulus is somewhat overpredicted. The solid volume fractions profiles agree w ell in both core and annulus, with discrepancy in the core at the leve l close to the inlet. The radial profile of solid shear viscosity comp uted by the turbulent kinetic energy model is ten times lower in the c ore than that found experimentally but with a linear function of solid volume fraction in the measurement, the computed profile agrees well with experiments.