Numerical simulation and experimental analysis of gas/solid flow systems: 1999 Fluor-Daniel Plenary lecture

Gas/solid flow systems, including fluidized beds, are an essential part of many chemical processes. The optimum design and scale-up of these systems requires a through understanding of gas/solid flow patterns. Achievement of this understanding involves the development of experimental flow measurement techniques, and experimentally verified multiphase flow equations and numerical simulation tools. This paper provides a brief review of current techniques in solid flow measurement and recent contributions of the multiphase flow approach to gas/solid flow systems and fluidization. It features a review of the Eulerian approach, as well as different governing and constitutive equations, including the kinetic theory approach for cohesive and non-cohesive particles. The effects of inlet, outlet and boundary conditions are also discussed. Two- and three-dimensional transient numerical simulations of gas/solid flow patterns in circulating and bubbling fluidized beds are presented, along with a comparison of the predicted flow parameters with large-scale experimental data. In addition, recent improvements in the computational code to simulate a real process with complex geometries, developed in partnership with Fluent and AEA Technology, are highlighted. The paper is concluded with a discussion of the limitations and opportunities for research and development in this area.