Filtered sub-grid constitutive models for fluidized gas-particle flows constructed from 3-D simulations

Sarkar, Avik; Milioli, Fernando Eduardo; Ozarkar, Shailesh S.; Li, Tingwen; Sun, Xin; Sundaresan, Sankaran

doi:10.1016/j.ces.2016.06.023

Cited by 131 publications

(118 citation statements)

References 27 publications

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“…For example, constant correlation coefficients are used to close sub-filter variances, e.g., Eq. (16). Applying a dynamic adaption procedure may considerably improve the local predictions of the SA-TFM approach [32].…”

Section: Pilot-scale Fluidized Bedmentioning

confidence: 99%

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Verification and Validation of Spatially Averaged Models for Fluidized Gas‐Particle Suspensions

Schneiderbauer

2020

Chem Eng & Technol

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Two different methods for closure modeling of the unresolved terms appearing in the filtered two-fluid model are discussed and compared. The spatially averaged two-fluid model is based on generalizing the concepts of large eddy simulation to gas-particle flows. In the approximate deconvolution method-two-fluid model approach, the unresolved terms are modeled by an approximate deconvolution method, where an approximation of the unfiltered solution is obtained by repeated filtering. Finally, these models are applied to a lab-scale and a pilot-scale fluidized bed. Both approaches yield fairly good agreement with a highly resolved reference simulation as well as with experimental data. Additionally, both methods deliver reasonable grid-independent solutions up to a grid resolution of 2 cm in the case of Geldart type A particles.

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Section: Pilot-scale Fluidized Bedmentioning

confidence: 99%

“…Nevertheless, such a procedure inevitably neglects the small (unresolved) scales [13,14]. Consequently, many sub-grid drag modifications have been proposed to account for the effect of these small mesoscale structures on the resolved macroscales [2,12,[15][16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Verification and Validation of Spatially Averaged Models for Fluidized Gas‐Particle Suspensions

Schneiderbauer

2020

Chem Eng & Technol

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“…A lot of efforts have been made to develop and validate mesoscopic (e.g., filtered model) TFM and macroscopic (e.g., averaged model) TFM . Heterogeneous drag development and validation are one of the most critical parts of coarse‐grid simulation and it is the focus of many previous studies .…”

Section: Introductionmentioning

confidence: 99%

“…In many previous studies, reasonably good predictions of the gas–solid flow behavior were reported by employing the standard TFM with only drag correction; other subgrid corrections, such as mesoscale stress, were assumed to be negligible and were not considered. However, some studies reported that the mesoscale stress (subgrid phase stress modeled in the coarse‐grid TFM) is about one‐order magnitude larger than the microscale stress (phase stress appearing in the standard TFM) at least. The neglecting of mesoscale stress will bring large uncertainty and it is needed for coarse‐grid simulations.…”

Section: Introductionmentioning

confidence: 99%

“…The underlying mechanics for why the mesoscale solid stress could be neglected are still not clear. Recently, a mesoscale solid stress anisotropy model was developed in the work of Sarkar et al As we know, solid flow anisotropic behavior was observed in fluidized beds that component of solid granular temperature (or fluctuation velocity) is much larger in the main flow direction, and especially in the fast fluidization regime, where the main velocity component is much larger than that in other directions. However, a comprehensive evaluation of flow anisotropy effect in all gas–solid fluidization regimes is also not available in the literature.…”

Section: Introductionmentioning

confidence: 99%

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Assessment of mesoscale solid stress in coarse‐grid TFM simulation of Geldart A particles in all fluidization regimes

Gao

Rogers

2018

AIChE Journal

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This study focused on assessing the effect of mesoscale solid stress in the coarse grid two‐fluid model (TFM) simulation of gas–solid fluidized beds of Geldart Group A particles over a broad range of flow regimes, including bubbling, turbulent, fast, and pneumatic transport fluidization regimes. Particularly, the impact of mesoscale solid pressure, mesoscale solid viscosity, and mesoscale solid stress anisotropy were investigated by comparing six different coarse‐grid TFM settings. Compared with the available experimental data, it is found that both the kinetic theory‐based TFM with only drag correction and the filtered TFM can predict the flow behavior in all fluidization regimes. Mesoscale solid pressure and viscosity have the opposite impact on flow hydrodynamics; they compete and offset each other, which confirms the assumption employed in many previous studies that the mesoscale solid stress could be neglected in coarse‐grid TFM simulation. Published 2018. This article is a U.S. Government work and is in the public domain in the USA. AIChE J, 64: 3565–3581, 2018

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A spatially‐averaged two‐fluid model for dense large‐scale gas‐solid flows

2017

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We present a spatially‐averaged two‐fluid model (SA‐TFM), which is derived from ensemble averaging the kinetic‐theory based TFM equations. The residual correlation for the gas‐solid drag, which appears due to averaging, is derived by employing a series expansion to the microscopic drag coefficient, while the Reynolds‐stress‐like contributions are closed similar to the Boussinesq‐approximation. The subsequent averaging of the linearized drag force reveals that averaged interphase momentum exchange is a function of the turbulent kinetic energies of both, the gas and solid phase, and the variance of the solids volume fraction. Closure models for these quantities are derived from first principles. The results show that these new constitutive relations show fairly good agreement with the fine grid data obtained for a wide range of particle properties. Finally, the SA‐TFM model is applied to the coarse grid simulation of a bubbling fluidized bed revealing excellent agreement with the reference fine grid solution. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3544–3562, 2017

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Filtered sub-grid constitutive models for fluidized gas-particle flows constructed from 3-D simulations

Cited by 131 publications

References 27 publications

Verification and Validation of Spatially Averaged Models for Fluidized Gas‐Particle Suspensions

Verification and Validation of Spatially Averaged Models for Fluidized Gas‐Particle Suspensions

Assessment of mesoscale solid stress in coarse‐grid TFM simulation of Geldart A particles in all fluidization regimes

A spatially‐averaged two‐fluid model for dense large‐scale gas‐solid flows

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