Effects of drag and subgrid-scale turbulence modeling on gas–solid hydrodynamics of a pilot-scale circulating fluidized bed. (2nd February 2022)

• Record Type: Journal Article
• Authors: Gupta, Saurabh; De, Santanu; Loha, Chanchal; Karmakar, Malay
• Is Part Of: Chemical engineering science. Volume 248:Part A(2022)
• Publication Date: 2022-02-02
• Subjects: Riser -- Circulating fluidized bed -- Hydrodynamics -- Drag model -- Large eddy simulation -- OpenFOAM -- Simulation; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2021.117093
• Languages: English
• ISSNs: 0009-2509

Abstract

Highlights: 3-D, full loop, LES of a circulating fluidized bed are conducted using EE approach. Effects of drag and sgs turbulence models are investigated. Results are validated against measurements from an in-house pilot-scale model. The influence of change in the riser diameter is more pronounced for EMMS models. The hybrid EMMS drag model and sgs -TKE model made the most accurate predictions. Abstract: Large eddy simulation is performed on a circulating fluidized bed (CFB) based on an Eulerian-Eulerian approach. The riser of the CFB has two axial sections of different diameters joined by a diffuser. The effects of drag and subgrid-scale models are examined on hydrodynamic parameters, such as solids volume fraction ( ε s ), solids circulation rate ( G s ), and full loop pressure profiles. A hybrid energy minimization multi-scale (EMMS) drag model is applied that combines EMMS drag models for the bubbling and the fast fluidized bed regimes. Experiments are conducted on a pilot-scale CFB model, and numerical results are validated against the experimental measurements of pressure and G s . The change in the riser diameter has a significant influence on axial- and radial profiles of ε s, particularly in the upper riser section. The hybrid EMMS drag model and the sgs -TKE turbulence model give the best agreement to the experimental data.