(380an) An Investigation of Gas Fluidized Bed of Flexible Fibers Using the Coupled DEM/CFD Method

Gas fluidized bed of flexible fibers is investigated using the coupled approach of discrete element method (DEM) and computational fluid dynamics (CFD). In the numerical simulation, a flexible fiber is formed by connecting a number of spheres using elastic bonds. The fiber can deform as the bonds undergo stretching/compressive, bending, and twisting deformations. The resultant drag on a fiber by a gas is a collection of drag forces on each sphere component. The fibers of the same volume but various aspect ratios are examined for the effect of fiber elongation. It is observed that the minimum fluidization velocity increases with increasing fiber aspect ratio (AR) for AR ≥2, due to the increase in porosity. However, the minimum fluidization velocity for the spheres (AR = 1) with the same volume as the elongated fibers is between those of AR = 3 and AR =4 fibers, because the sizes of the voids are larger for the spheres compared to the AR=2 and 3 fibers and also the effect of gas drag on the fiber motion is reduced as the sphere component size increases. At last, the effects of fiber flexibility and cohesive liquid bridge force on the fluidization behavior are reported.