NUMERICAL SIMULATION OF THE GAS-SOLID FLOW IN AN INTERNALLY CIRCULATING FLUIDIZED BED WITH A DEM- CFD MODEL

摘要

The solids motion was investigated via discrete element method (DEM)combined with computational fluid dynamics (CFD) in an internally circulating gas-solid fluidized bed (ICFB). The motion of individual particles in a uniform particle system was monitored by the solution of the Newton's second law of motion. The force acting on each particle consists of the contact force between particles and the force exerted by the surrounding fluid. The flow field of gas was predicted by the Navier-Stokes equation. Numerical simulation indicates that there is a large scale lateral particle circulation from the high-velocity region to the low-velocity region in internally circulating fluidized beds with uneven air distribution. Such manner of the bed materials is supposed to enhance heat and mass diffusion, confirming that ICFB is an preferable alternative for municipal solid waste (MSW) incineration.