Hydrodynamic simulations of gas-solid flow in a riser

Conservation of mass and momentum equations for gas and solid phases were used to compute the hydrodynamics of flow in risers for two core-annular flow regimes. The principal input into the model was a semiempirical viscosity for fluidized catalytic cracking particles. The computed time-averaged radial fluxes and particle concentrations agree with experimental data obtained in a riser by Miller (Ph.D. Thesis, Illinois Institute of Technology, Chicago, IL, 1991) and Knowlton et al. (PSRI Challenge Problem Presented at the Eighth International Fluidization Conference, Tour, France, 1995). The model also computed the dynamics of flow, the dominant frequency of instantaneous particle concentrations, the granular temperature, and the granular pressure in reasonable agreement with measurements.