Sub-grid drag models for horizontal cylinder arrays immersed in gas-particle multiphase flows

Sarkar, Avik; Sun, Xin; Sundaresan, Sankaran

doi:10.1016/j.ces.2013.08.050

Cited by 25 publications

(24 citation statements)

References 25 publications

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“…Many subgrid drag modifications have, therefore, been put forth by academic researchers to account for the effect of small unresolved scales on the resolved meso‐scales in this case . Recently, the comparative study of Schneiderbauer et al revealed that although these drag modifications cited above show considerably different dependencies, they are able to predict main features of the gas and particle flow in bubbling fluidized beds adequately.…”

Section: Introductionmentioning

confidence: 99%

Filtered and heterogeneity‐based subgrid modifications for gas–solid drag and solid stresses in bubbling fluidized beds

2013

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Two different approaches to constitutive relations for filtered two-fluid models (TFM) of gas-solid flows are deduced. The first model (Model A) is derived using systematically filtered results obtained from a highly resolved simulation of a bubbling fluidized bed. The second model (Model B) stems from the assumption of the formation of subgrid heterogeneities inside the suspension phase of fluidized beds. These approaches for the unresolved terms appearing in the filtered TFM are, then, substantiated by the corresponding filtered data. Furthermore, the presented models are verified in the case of the bubbling fluidized bed used to generate the fine grid data. The numerical results obtained on coarse grids demonstrate that the computed bed hydrodynamics is in fairly good agreement with the highly resolved simulation. The results further show that the contribution from the unresolved frictional stresses is required to correctly predict the bubble rise velocity using coarse grids.

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Section: Introductionmentioning

confidence: 99%

Filtered and heterogeneity‐based subgrid modifications for gas–solid drag and solid stresses in bubbling fluidized beds

2013

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“…Additionally we define two characteristic values used to non-dimensionalize quantities: a length and a velocity. These characteristic values are based on the solids terminal velocity v t , which has been shown to describe the hydrodynamics of the suspension well in previous gas-particle filtering studies, such as Igci et al (gas-particle hydrodynamics) [3], Sarkar et al (gas-particle hydrodynamics with immersed cylinders) [7], Holloway and Sundaresan (reacting gas-particle flows) [10], and Agrawal et al (gas-particle scalar transport) [9]. The characteristic values are also defined in Table 2.…”

Section: Simulation Setupmentioning

confidence: 79%

“…More recently, such sub-grid methods have been extended to simulate gas-particle flows; filtered models have been developed for interphase drag [3][4][5][6], cylinder-suspension drag [7,8], interphase heat transfer [9], and reactive flows [10]. While these filtered-model simulations reduce the ability to predict fine-scale behavior, they can predict bulk flow behavior of large-scale devices with reasonable accuracy and significant computational savings.…”

Section: Introductionmentioning

confidence: 99%

Sub-grid models for heat transfer in gas-particle flows with immersed horizontal cylinders

Lane

Sarkar

Sundaresan

et al. 2016

Chemical Engineering Science

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Simulating full-scale heated fluidized bed reactors can provide invaluable insight to the design process. Such simulations are typically computationally intractable due to their complex multi-physics and various lengthscales. While it may be possible to simulate some large-scale systems, they require significant computing resources and do not lend themselves well to design optimization methods. To overcome these problems coarse-grid simulations can be used with supplementary constitutive sub-grid models to approximate the unresolved physics. This study details the development, implementation, and verification of a sub-grid model for heat transfer in gas-particle flows with immersed horizontal cylinders. Using the two-fluid model for multiphase flow, small periodic unit-cell domains were simulated over a wide range of flow and geometry conditions. The results were filtered and fit using nonlinear regression to build a Nusselt correlation based on the solids fraction, solids velocity, cylinder geometry (diameter and spacing), and the Peclet number. The proposed model is highly nonlinear and includes power-law contributions from each parameter. The model was verified using a nearly orthogonal experiment design where the input parameters were varied randomly to generate combinations not previously considered. The predicted filtered Nusselt numbers agreed well with the observed (simulated) values. Work is ongoing to further expand the capabilities of the model, including 3D simulations, vertical cylinders, and uncertainty quantification.

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“…29,30 Submodels that capture kinetic and thermodynamic data can also be incorporated for subsequent optimization of processes, as carried out by the CCSI Toolset. 16 More detailed simulations, such as those that use filtered constitutive relationships in coarse-grid computational fluid dynamics (CFD) simulations which may better capture the multi-scale nature inside processes such as fluidized beds, [31][32][33] can be used to refine the process design, a challenging task that has not been attained at this point. 16 Furthermore, at the process level, several studies simulated and optimized the pressure-swing adsorption (PSA) process for CO 2 sequestration 34 and used superstructure based methods to design PSA cycle configurations.…”

Section: Co 2 Capture Utilization and Storagementioning

confidence: 99%

Multi‐scale systems engineering for energy and the environment: Challenges and opportunities

et al. 2016

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Sub-grid drag models for horizontal cylinder arrays immersed in gas-particle multiphase flows

Cited by 25 publications

References 25 publications

Filtered and heterogeneity‐based subgrid modifications for gas–solid drag and solid stresses in bubbling fluidized beds

Filtered and heterogeneity‐based subgrid modifications for gas–solid drag and solid stresses in bubbling fluidized beds

Sub-grid models for heat transfer in gas-particle flows with immersed horizontal cylinders

Multi‐scale systems engineering for energy and the environment: Challenges and opportunities

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