Considerations for Practical Industrial CFD Simulations of Fluidized Systems

Computational Fluid Dynamics (CFD) is based upon both fundamentals and empirical models. The fundamental principles, such as conservation of mass, momentum and energy, are known. Empirical models, on the other hand, have more limited scopes of applicability, and thus are less fully understood.

CFD for fluidized systems, such as fluidized beds or circulating systems, has additional inherent complexity, compared with pure fluid flows. Results can be highly dependent upon empirical models related to fluid-particle, or particle-particle interaction terms, which take the form of drag, collisional, stress, granular temperature, or similar models. The development and validation of these models, which is often undertaken at small test scales, is a topic of significant, current research.

Many industrial systems utilizing fluidization, on the other hand, are constructed and operated at scales which may be orders of magnitude larger than the lab-scale or pilot-scale units upon which they are based. Industrial processes such as Fluidized Catalytic Cracking (FCC), polyolefins production, gasification, pyrolysis, or cement manufacture, to name a few, often involve characteristic length scales which can be up to ten meters or greater.

This presentation examines the relationship between empirical model development and practical CFD simulations of industrial systems. The role of test data, and the scale at which the data is obtained, is explored. Impacts of test data on model calibration for industrial-scale simulations are discussed. Multiple industrial case studies with practical outcomes are presented.