CFD-DEM simulation of fluidization of rod-like particles in a fluidized bed

Abstract

In chemical and energy industries, fluidization concerning rod-like particles is often encountered, but little effort has been made in this respect. Understanding fluidization of rod-like particles is crucial for the guidance of relevant industrial process. To investigate the fluidization of the rod-like particles with different aspect ratios, CFD-DEM coupling algorithm is employed in this article to simulate a bubbling fluidized bed, in which the rod-like particles are modeled by super-ellipsoids. The simulations results show that, in the case of same particle volume, the rod-like particles with smaller aspect ratio obtain larger force from the gas and the particles can absorb more energy from fluid flow, and the fluidization phenomenon, like slugging and bubbles, is easier to form. The local voidage fraction and particle's projected face area perpendicular to fluid flow direction are directly related to particle orientations, which have great influence on drag force and fluidization. Due to the significance of particle orientation, a further investigation is made for the factors that influence the distribution of particle orientation. The results show that particle orientation is greatly affected by fluidization time, fluidization velocity, and the structure of the fluidized bed.