Simulations of the solid/liquid two-phase flow field in jet loop reactors

Angst, R.; Mier, Patrick; Kraume, Matthias

doi:10.1016/b978-008043944-0/50840-4

Cited by 3 publications

(3 citation statements)

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“…This term has been modeled according to the Kinetic Theory of Granular Flows 11. The contribution of the turbulent dispersion, F DF , is likely to be significant as previously reported numerical studies 12–15. They highlighted the importance of modeling of turbulent dispersion force while simulating solid suspension in stirred reactor.…”

Section: Computational Modelingsupporting

confidence: 53%

Hysteresis in cloud heights during solid suspension in stirred tank reactor: Experiments and CFD simulations

2010

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Solid suspension in stirred tank reactor is widely used in process industries for catalytic reactions, dissolution of solids, crystallization, and so on. Suspension quality is a key issue in design and operation of stirred reactor and its determination is not straight forward. Cloud height measurements of solid suspension provide a relatively simple way to quantify quality of suspension. In this work, experiments were carried out to quantify variation of cloud heights with impeller speed and particle characteristics. These measurements were carried out using visual observations, image analysis, and ultrasound velocity profiler techniques. The obtained data demonstrated the existence of hysteresis in cloud heights with respect to impeller speed. Apart from possible applications in reducing power required for achieving desired solid suspension quality, the existence of hysteresis also provides a new way to evaluate computational fluid dynamics (CFD) simulations of solid-liquid flows in stirred vessels. An attempt was made to capture observed hysteresis in cloud heights in CFD simulations. The simulated results were compared with the experimental data. The presented models and results (experimental and computational) will be useful for simulating complex solidliquid flows in stirred reactors.

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Section: Computational Modelingsupporting

confidence: 53%

Hysteresis in cloud heights during solid suspension in stirred tank reactor: Experiments and CFD simulations

2010

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“…Therefore, the contribution of the turbulent dispersion is likely to be significant. The previously reported numerical studies have also highlighted the importance of the modeling of the turbulent dispersion force while simulating solid suspension in a stirred reactor. ,, Considering these results, the turbulent dispersion of the dispersed phase was considered in the present study. In the present study, the default value of the dispersion Prandtl number, 0.75, was used.…”

Section: Mathematical Modelingmentioning

confidence: 97%

“…However, the simulations with the Euler−Lagrange approach can only handle slurries with a low solid volume fraction (≤5%) and hence cannot be used for concentrated slurries. There are few published studies which have reported the simulation of the solid suspension in a stirred reactor using a two-fluid model. − They have predicted the suspension quality with reasonable success, but all these studies were limited to a low volume fraction of solids (≤5%). However, stirred reactors with a solid volume fraction more than 10% are commonly encountered in some industrial applications.…”

Section: Introductionmentioning

confidence: 99%

Computational Fluid Dynamics Simulation of the Solid Suspension in a Stirred Slurry Reactor

Khopkar

Kasat

Pandit

et al. 2006

Ind. Eng. Chem. Res.

126

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A comprehensive computational fluid dynamics CFD model was developed in the present study to gain insight into the solid suspension in a stirred slurry reactor. The preliminary simulations highlighted the need for the correct modeling of the interphase drag force. A two-dimensional model problem was then developed using CFD to understand the influence of free stream turbulence on the particle drag coefficient. The proposed correlation was then incorporated in a two-fluid model (Euler-Euler) along with the standard k-turbulence model with mixture properties to simulate the turbulent solid-liquid flow in a stirred reactor. A multiple reference frame approach was used to simulate the impeller rotation in a fully baffled reactor. A computational model was mapped on to a commercial CFD solver FLUENT6.2 (of Fluent Inc., USA). The model predictions were compared with the published experimental data of Yamazaki et al. [Powder Technol. 1986, 48, 205] and Godfrey and Zhu [AIChE Symp. Ser. 1994, 299, 181]. The predicted results show reasonably good agreement with the experimental data. The computational model and results discussed in this work would be useful for extending the applications of CFD models for simulating large stirred slurry reactors.

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