Angular momentum Based-Analysis of Gas-Solid fluidized beds in vortex chambers

Gas-solid vortex chambers are a promising alternative for reactive and non-reactive processes requiring enhanced heat and mass transfer rates and order-of-milliseconds contact time. The conservation of angular momentum is instrumental in understanding how the interactions between gas, particulate solids, and chamber walls influence the formation of a rotating solids bed. Therefore, this work applies the conservation of angular momentum to derive a model that gives the average angular velocity of solids in terms of gas injection velocity, wall-solids bed drag coefficient, gas and particle properties, and chamber geometry. Three datasets from pub-lished studies, comprising 1 g-Geldart B-and D-type particles in different vortex chambers, validate the model results. Using a sensitivity analysis, we assessed the effect of input variables on the average angular velocity of solids, average void fraction, and average bed height. Results indicate that the top and bottom end-wall boundaries exert the most significant braking effect on the rotating solids bed compared with the cylindrical outer wall and gas injection boundaries. The wall-solids bed drag coefficient appears independent of the gas injection velocity for a wide range of operating conditions. The proposed model is a valuable tool for analyzing and comparing gas-solid vortex typologies, unraveling improvement opportunities, and scale-up.

Automated summary

Gas-solid vortex chambers are a promising alternative for processes requiring enhanced heat and mass transfer rates. This study derives a model based on the conservation of angular momentum to understand the formation of a rotating solids bed. The model is validated using experimental data and can be used for analyzing and comparing gas-solid vortex typologies.