Abstract
This paper presents an investigation of forces acting on particles used CFD-DEM simulation method in a rolling Circulating Fluidized Bed. In the simulation, the discrete particle phase is solved by the DEM approach and each individual particle motion is described by Newton's equations of motion; the continuum fluid phase is solved by the Navier-Stokes equations at a computational cell scale. Conclusions obtained from the simulation results are shown as follows. The behavior of particle movement in the radial direction is mainly dominated by unsteady forces including pressure gradient force F_<PG,Y> and virtual mass force F_<VM,Y> in a static CFB and by the component of gravity force F_<g,x> in a rolling CFB. The rolling motion of CFB has a large influence on the axial velocity of air phase, which is caused by the instantaneous change of the relative pressure and the distribution of discrete particles. By comparing forces acting on particles, as the magnitude order of electrostatic force F_E is extremely lower than that of any other forces, F_E is not taken into consideration. Furthermore, Van der waals force F_<VDW> as a adhesive force is also disregarded on account of the little particle number and low particle concentration at the present work.
