Comparison of turbulence models for bubble column reactors

Khan, Zoheb; Bhusare, Vishal; Joshi, Jyeshtharaj B.

doi:10.1016/j.ces.2017.01.023

Cited by 39 publications

(27 citation statements)

References 91 publications

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“…Besides the numerical aspects, proper turbulence modeling is important for the accuracy of the simulations; multi-phase turbulence models are derived from their single-phase equivalents and terms modeling inter-phase interactions are added to the transport equations of the turbulence model (see refs. [413,431]). In this respect, the multi-phase equivalent of the standard k-ε model is widely used [413][414][415]428,[432][433][434][435].…”

Section: The Eulerian Multi-fluid Approachmentioning

confidence: 99%

Two-Phase Bubble Columns: A Comprehensive Review

2018

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We present a comprehensive literature review on the two-phase bubble column; in this review we deeply analyze the flow regimes, the flow regime transitions, the local and global fluid dynamics parameters, and the mass transfer phenomena. First, we discuss the flow regimes, the flow regime transitions, the local and global fluid dynamics parameters, and the mass transfer. We also discuss how the operating parameters (i.e., pressure, temperature, and gas and liquid flow rates), the operating modes (i.e., the co-current, the counter-current and the batch modes), the liquid and gas phase properties, and the design parameters (i.e., gas sparger design, column diameter and aspect ratio) influence the flow regime transitions and the fluid dynamics parameters. Secondly, we present the experimental techniques for studying the global and local fluid dynamic properties. Finally, we present the modeling approaches to study the global and local bubble column fluid dynamics, and we outline the major issues to be solved in future studies.

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Section: The Eulerian Multi-fluid Approachmentioning

confidence: 99%

Two-Phase Bubble Columns: A Comprehensive Review

2018

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“…It must be noted that in the k – ϵ model, velocity fluctuations are not resolved but instead contained in the turbulent kinetic energy, whereas in the LES model the velocity fluctuations are resolved and calculated stepwise during the calculation. However, it must be noted that the computational demands of a LES model are far in excess of current computational resources needed for a k – ϵ model . Therefore, the mixture turbulence model is used in the subsequent flow simulations.…”

Section: Resultsmentioning

confidence: 99%

“…Based on previous studies (see Table ), it has been found that 1D and 2D simulations overpredict the value of flow variables (liquid velocity, gas hold‐up) by 20–100% and 50–200%, respectively . However, 3D computational fluid dynamics simulations have been proven to be useful as they help to understand the complex two‐phase fluid dynamics in a bubble column through details of mean flows (such as velocities and gas hold‐up), interphase momentum transfer and turbulence parameters …”

Section: Introductionmentioning

confidence: 99%

“…Several experimental and numerical investigations have been carried out to derive an appropriate drag closure (such as Tomiyama, Ishii Zuber, Schiller Naumann) for moving bubbles in liquids in specific flow conditions. Similarly, there has been substantial development in terms of using an appropriate turbulence closure (such as k–ϵ , Reynolds Stress Model and Large Eddy Simulation) in CFD analysis of bubble column but it can be seen from Table that no specific recommendation is available in the literature for these closure models. Indeed, the appropriate modeling of turbulence is still one of the main open questions in gas–liquid bubbly flows, and this flow property may significantly affect both the stresses and the bubble dispersion.…”

Section: Introductionmentioning

confidence: 99%

“…35 However, 3D computational fluid dynamics simulations have been proven to be useful as they help to understand the complex two-phase fluid dynamics in a bubble column through details of mean flows (such as velocities and gas hold-up), interphase momentum transfer and turbulence parameters. 10,11 Most of the simulations mentioned in Table 1 are restricted to low superficial gas velocity values (≤20 cm s −1 ). At higher gas velocities, no clear guidelines for the formulation of interphase forces (mainly drag force and lift force) are available because the turbulent model becomes too unpredictable and the model is unable to capture the turbulence associated with higher gas velocities, although some progress has been made in recent years.…”

Section: Introductionmentioning

confidence: 99%

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Effect of drag correlation and bubble‐induced turbulence closure on the gas hold‐up in a bubble column reactor

Kannan

Naren

Buwa

et al. 2019

J of Chemical Tech & Biotech

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BACKGROUND Gas–liquid hydrodynamics play an important role in processes across a wide range of applications in chemical technology and biotechnology. In most of these applications, gas is bubbled in the bottom of the reactor to conduct physical mixing or mixing‐induced chemical reaction. In either case, the gas bubble hydrodynamics play a critical role on the overall performance of these processes. In the present study, the gas–liquid multiphase system is simulated using a Eulerian–Eulerian two‐fluid Computational Fluid Dynamics (CFD) model. RESULTS The physical model is a cylindrical bubble column contactor wherein gas is sparged into liquid through a perforated sparger with a superficial gas velocity of ≈3–40 cm s−1. The CFD model for the contactor is built using the free and open source tool OpenFOAM v.4.0 to simulate the gas–liquid system. The time‐averaged volume fraction distribution was studied at different heights in the column. The effect of drag force and bubble‐induced turbulence are studied to arrive at appropriate closures for the CFD model. The results obtained from the numerical simulations were validated against available experimental results found in literature. CONCLUSION The recommended models, based on the present CFD study of the bubble column reactor, are the Ishii–Zuber drag closure with the modification that the parameter p is set to 2 for superficial gas velocities ≤20 cm s−1 and is set to 4 for 40 cm s−1 superficial gas velocity) and the mixed k–ϵ model to account for drag correlation and bubble‐induced turbulence closure, respectively. © 2019 Society of Chemical Industry

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Hydrodynamics in a jet bubbling reactor: Experimental research and mathematical modeling

et al. 2017

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The radial distribution of liquid velocity in the axial direction of a jet bubbling reactor has been measured by experimentation. Three different typical flow structures controlled by liquid jet, gas bubbling, and liquid jet coupled with bubbling are observed. A tank in series model is established on this basis. Calculated values in each region are in good agreement with measured values in jet, bubbling, and wall effect controlled areas. Axial flow rate, radial exchange rate, and jet controlled volume g are analyzed from energy input aspect under different u g and u j. Simulation results indicate that under the synergetic action of the liquid jet and gas bubbling effect, jet controlled area exhibits a "spindle" structure, and its size decreases with the increase of u g. When gas input power occupies about 67% of total energy consumption, the best synergy of liquid jet and gas bubbling is obtained. V

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Comparison of turbulence models for bubble column reactors

Cited by 39 publications

References 91 publications

Two-Phase Bubble Columns: A Comprehensive Review

Two-Phase Bubble Columns: A Comprehensive Review

Effect of drag correlation and bubble‐induced turbulence closure on the gas hold‐up in a bubble column reactor

Hydrodynamics in a jet bubbling reactor: Experimental research and mathematical modeling

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