Fluent－循环流化床数值模拟.ppt

Company Confidential Copyright 2001 Fluent Inc. All rights reserved. New Initiatives at Fluent Inc. Introduction Fluidized solids are captured and recirculated to the reactor; carrier gas is purged. Used in FCC units, reforming of petrochemicals, thermal cracking of hydrocarbons etc. Either the catalyst deactivates rapidly and needs regeneration, or large amounts of heat need to be brought into or removed from the system. The case Model cold flow in a combustion chamber. Eulerian granular multiphase model in Fluent 6 used. 7% volume fraction of 85 micron solids in air Unsteady, laminar flow Gidaspow’s drag law Mesh of 80 K mixed cells. Solver settings Double precision solver used. Time step of 0.01 s; default values for all solver settings. 18 % volume fraction of solids patched in the lower part of riser and downcomer Simulations carried out for 13 s of real time. Results: Streak lines Solids fraction contours Results Solids fractions Solids velocity Conclusions Solids fractions and velocity profiles predicted by the Eulerian-Granular model in Fluent 6 is physically reasonable. Experimentally observed features of flow in circulating fluidized bed are captured. * UGM 2001 Recirculating Fluidized Beds Sergio Vasquez and Srinivasa Mohan UGM 2001 Z = 6.5m Z = 2 Z = 5 Z = 7 Downcomer Riser Axial velocity profiles at Z = 6.5 * *