Contact analysis of different flow regimes in gas fluidization

The particle contacts in different particle-fluid flow regimes, such as fixed, expanded and fluidized beds, in gas fluidization are investigated for group A and B powders by means of a combined approach of computational fluid dynamics anddiscrete element method. To establish the connection between macroscopic and microscopic descriptions of complex particle-fluid flows, focus is given to the correlation between coordination number (CN) and porosity (e). It is found that the CN-e relationship for group A powders has a transitional point between the expanded and fluidized bed flow regimes at a bulk scale, unlike group B powders. A new phase diagram is established in terms of CN-e relationship that has two branches representing expanded and fluidized (bed) states.