This paper examines the roles that granular flow theory might play in the modeling the solid-phase stresses in fluidized beds. It begins with a discussion of the historical limiting cases of the quasistatic and rapid-flow regimes. It then reviews the elastic granular theories that unify those two regimes. Finally it shows that measurements of solid-phase pressures cannot be explained by commonl...

Hydrogen-based direct reduction of iron oxide powder in gas-fluidized beds has become an emerging technology. Agglomeration fine at elevated temperatures is however one key issue hindering the technological development. To obtain better knowledge high-temperature agglomeration mechanism, (de-)fluidization behavior micron-sized combusted particles experimentally studied this Part I. Effects vari...

Introduction Over the last fifty years gas-solids fluidized beds have played a very important role in many areas in the process industry, especially in chemical and petroleum industries. The existence of different flow regimes in fluidized beds at different operating conditions has been known for a long time and numerous studies have been carried out to define the flow regimes [1-6]. It is well...

Particles distributions along a conical fluidized bed were predicted by an alternative arrangement of the minimum fluidization velocity equation. The proposed approach introduces two new equations which present the particle diameter in the bed as function of: height in the bed (Z), angle of inclination of the fluidized bed wall (θ), input flow rate (Qo), and gas distributor diameter (Do, 2ro). ...

This work presents a computational study of flow behaviour in a bubbling fluidized bed polymerization reactor. The model is developed by using the commercial CFD code Fluent 6.3. The model is based on an Eulerian description of the gas and the particle phase. The effect of distributor shape on fluidization is analyzed using the inbuilt Gidaspow and Syamlal-O’brien Drag Model. The computational ...

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Introduction Understanding the jetting phenomena near the gas distributor plate in a fluidized bed is important to gassolids mixing, heat and mass transfer, and erosion on any bed internals, which can all affect the performance of the bed. Moreover, acoustic vibration in a fluidized bed can be used to enhance the fluidization quality of particulate matter. Visualizing the jetting structure usin...

Fluidized beds can be used to gasify biomass in the production of producer gas, a flammable gas that can replace natural gas in process heating. Modeling these reactors with computational fluid dynamics (CFD) simulations is advantageous when performing parametric studies for design and scale-up. From a computational resource point of view, two-dimensional simulations are easier to perform than ...

We use a dynamic finite-difference model to simulate martian landslides in the Valles Marineris canyon system and Olympus Mons aureole using three different modal rheologies: frictional, Bingham, and power law. The frictional and Bingham modes are applied individually. Fluidized rheology is treated as a combination of frictional and power-law modes; general fluidization can include pore pressur...