(87f) Discrete Particle Model for Non-Spherical Large Objects in Dense Gas-Solid Flows

In a number of applications of fluidized bed such as combustors, gasifiers and incinerators, large solid objects are included in the beds in addition to small medium particles for fluidization. The large solid objects are usually far from spherical and the prediction of non-spherical object motions in the beds is important for robust and efficient operations and bed designs. Depending on its orientation, large objects with various shapes experience different fluid and contact forces respectively from surrounding gas and particles and its motions become quite complex.

In the present study, to enable reliable numerical prediction of large non-spherical solid objects in dense gas-solid flows such as fluidized beds, Super-ellipsoid (SE) model that is a model to represent non-sphericity of particles in DEM framework was combined with Fictitious particle (FP) model that is a model to represent large solids in DEM-CFD framework. After a number of fundamental studies to check its accuracy and validity, the proposed model was compared against experiments in that positions, orientations and dynamic forces working on single non-spherical objects in a three-dimensional fluidized bed were measured non-invasively using a magnetometer and an acceleration sensor installed inside of the objects. Both the calculations and experiments showed characteristic orientation changes of the objects during fluidization and the efficacy of the proposed model was well demonstrated.