Eulerian simulation of a circulating fluidized bed with a new flow structure-based drag model

Abstract

The heterogeneous flow in a circulating fluidized bed (CFB) deteriorates momentum, combined with its heat and mass transfer between gas and solid, have been confirmed by several experiments. Due to no consideration of this heterogeneous flow in Euler–Eluer two phase flow model, there are the significant deviation of average voidage between the simulating results and experimental data. Therefore, we developed a new model to evaluate the local heterogeneous flow parameters, based on which gas–solid drag force coefficient in calculating mesh was calculated. This drag coefficient based on these local heterogeneous flow structure parameters improves the Euler–Eluer two phase flow model greatly, which further is confirmed by better description of average voidage in experiments. With this drag force coefficient model, the nature of axial S-shape and radial core-annular distribution of solid concentration in CFB can be captured.