1. Coarse-grid simulations of full-loop gas-solid flows using a hybrid drag model: Investigations on turbulence models.
- Author
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Li, Jun-Sen, Zhu, Li-Tao, Yan, Wei-Cheng, Rashid, Taha Abbas Bin, Xu, Qun-Jie, and Luo, Zheng-Hong
- Subjects
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TURBULENCE , *FLUIDIZATION , *HYDRODYNAMICS , *HYBRID computer simulation , *MULTIPHASE flow , *RISER pipe , *GAS flow - Abstract
The effect of fluid turbulence models on the coarse-grid simulation for the mesoscale gas-solid flow system is not as clear as that for gas-liquid/single flows. In this study, the effect of different turbulence models on predictions of riser-only, turbulent and bubbling flow hydrodynamics is quantified. Then the selected turbulence models are examined by coarse-grid simulations in a full-loop circulating fluidized bed (CFB) with a proposed hybrid drag model which integrates two SGMs and Hulin-Gidaspow model. Results show that the standard k -epsilon and k -omega models fail to capture a correct fluidization pattern in riser. Meanwhile, the RNG and realizable k -epsilon models and SST k -omega model enable satisfactory predictions which are highly comparable to discrete model predictions and experiments over different flow regimes. However, the realizable k -epsilon model produces more pronounced flow fluctuations causing computational instability. Using superior turbulence closures, full-loop simulations with the proposed hybrid model can predict desirable hydrodynamics. Unlabelled Image • A hybrid drag model is proposed for feasible coarse-grid full-loop CFB simulations. • Applicability of different turbulence models over various fluidization regimes. • Validated against the discrete particle model and experiments. • The RNG k -epsilon and SST k -omega are optimal for gas-solid flows. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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