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Research Papers: Multiphase Flows

Numerical Simulations for Hydrodynamics of Air-Water External Loop Airlift Reactor Flows With Bubble Break-Up and Coalescence Effects

[+] Author and Article Information
Deify Law

Department of Mechanical Engineering,
Baylor University,
Waco, TX 76711
e-mail: deify.law@gmail.com

Francine Battaglia

Department of Mechanical Engineering,
Virginia Tech,
Blacksburg, VA 24061

1 Corresponding author.

Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received August 24, 2012; final manuscript received May 1, 2013; published online June 5, 2013. Assoc. Editor: Olivier Coutier-Delgosha.

J. Fluids Eng 135(8), 081302 (Jun 05, 2013) (9 pages) Paper No: FE-12-1406; doi: 10.1115/1.4024396 History: Received August 24, 2012; Revised May 01, 2013

The external loop airlift reactor (ELALR) is a modified bubble column reactor that is composed of two vertical columns interconnected with two horizontal tubes and is often preferred over traditional bubble column reactors because it can operate over a wider range of conditions. In the present work, the gas-liquid flow dynamics in an ELALR were simulated using an Eulerian–Eulerian ensemble-averaging method with bubble breakup and coalescence effects in a three-dimensional system. The population balance models (PBM) of Luo and Svendsen (1996, “Theoretical Model for Drop and Bubble Breakup in Turbulent Dispersions,” AIChE J., 42, pp. 1225–1233) and Prince and Blanch (1990, “Bubble Coalescence and Breakup in Air-Sparged Bubble Columns,” AIChE J., 36, pp. 1485–1499) were used to simulate the bubble breakup and coalescence effects, respectively. The bubble breakup and coalescence closure models were implemented into CFDLib, a multiphase flow source code developed by Los Alamos National Laboratory, and validated with experiments. The computational fluid dynamics (CFD) simulations were then compared to experimental measurements from a 10.2 cm diameter ELALR for superficial gas velocities ranging from 1 to 20 cm/s. From this work, the 3D PBM simulations of an external loop airlift reactor were generally comparable with the 3D single bubble size simulations. However, the 3D PBM simulations have closer agreement with experimental findings than the single bubble size simulations especially regarding the length of gas bubbles in the downcomer.

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References

Law, D., Jones, S. T., Battaglia, F., and Heindel, T. J., 2011, “A Combined Numerical and Experimental Study of Hydrodynamics for an Air-Water External Loop Airlift Reactor,” ASME J. Fluids Eng., 133(2), p. 021301. [CrossRef]
Bandara, U. C., and Yapa, P. D., 2011, “Bubble Sizes, Breakup, and Coalescence in Deepwater Gas/Oil Plumes,” J. Hydraul. Eng., 137(7), pp. 729–738. [CrossRef]
Hibiki, T., and Ishii, M., 2002, “Interfacial Area Concentration of Bubbly Flow Systems,” Chem. Eng. Sci., 57(18), pp. 3967–3977. [CrossRef]
Ishii, M., and Kim, S., 2004, “Development of One-Group and Two-Group Interfacial Area Transport Equation,” Nucl. Sci. Eng., 146(3), pp. 257–273.
Strasser, W., and Wonders, A., 2012, “Hydrokinetic Optimization of Commercial Scale Slurry Bubble Column Reactor,” AIChE J., 58(3), pp. 946–956. [CrossRef]
Luo, H., and Svendsen, H. F., 1996, “Theoretical Model for Drop and Bubble Breakup in Turbulent Dispersions,” AIChE J., 42, pp. 1225–1233. [CrossRef]
Prince, M. J., and Blanch, H. W., 1990, “Bubble Coalescence and Breakup in Air-Sparged Bubble Columns,” AIChE J., 36, pp. 1485–1499. [CrossRef]
Olmos, E., Gentric, C., Vial, C., Wild, G., and Midoux, N., 2001, “Numerical Simulation of Multiphase Flow in Bubble Column Reactors: Influence of Bubble Coalescence and Breakup,” Chem. Eng. Sci., 56, pp. 6359–6365. [CrossRef]
Wang, T. F., Wang, J. F., and Jin, Y., 2006, “A CFD-PBM Coupled Model for Gas-Liquid Flows,” AIChE J., 52, pp. 125–140. [CrossRef]
Degaleesan, S., Dudukovic, M., and Pan, Y., 2001, “Experimental Study of Gas-Induced Liquid Flow Structures in Bubble Columns,” AIChE J., 47(9), pp. 1913–1931. [CrossRef]
Buwa, V. V., and Ranade, V. V., 2002, “Dynamics of Gas-Liquid Flow in a Rectangular Bubble Column: Experiments and Single/Multi-Group CFD Simulations,” Chem. Eng. Sci., 57, pp. 4715–4736. [CrossRef]
Chen, P., Sanyal, J., and Dudukovic, M. P., 2005, “Numerical Simulation of Bubble Column Flows: Effect of Different Breakup and Coalescence Closures,” Chem. Eng. Sci., 60, pp. 1085–1101. [CrossRef]
Martinez-Bazan, C., Montanes, J. L., and Lasheras, J. C., 1999, “On the Break-Up of an Air Bubble Injected into a Fully Developed Turbulent Flow—Part 1. Breakup Frequency,” J. Fluid Mech., 401, pp. 157–182. [CrossRef]
Chen, P., Dudukovic, M. P., and Sanyal, J., 2005, “Three-Dimensional Simulation of Bubble Column Flows With Bubble Coalescence and Breakup,” AIChE J., 51(3), pp. 696–712. [CrossRef]
Liu, Y., and Li, W. Z., 2010, “Numerical Simulation of Droplet Size Distribution in Vertical Upward Annular Flow,” ASME J. Fluids Eng., 132, p. 121402. [CrossRef]
Saffman, P. G., and Turner, J. S., 1956, “On the Collision of Drops in Turbulent Clouds,” J. Fluid Mech., 1(1), pp. 16–30. [CrossRef]
Lehr, F., Millies, M., and Mewes, D., 2002, “Bubble-Size Distributions and Flow Fields in Bubble Columns,” AIChE J., 48(11), pp. 2426–2443. [CrossRef]
Jayaprakash, A., Singh, S., and Chahine, G., 2011, “Experimental and Numerical Investigation of Single Bubble Dynamics in a Two-Phase Bubbly Medium,” ASME J. Fluids Eng., 133(12), p. 121305. [CrossRef]
Das, A. K., Das, P. K., and Thome, J. R., 2009, “Transition of Bubbly Flow in Vertical Tubes: New Criteria Through CFD Simulation,” ASME J. Fluids Eng., 131, p. 091303. [CrossRef]
Das, A. K., Das, P. K., and Thome, J. R., 2009, “Transition of Bubbly Flow in Vertical Tubes: Effect of Bubble Size and Tube Diameter,” ASME J. Fluids Eng., 131, p. 091304. [CrossRef]
Oliveira, M. S. N., and Ni, X. W., 2004, “Effect of Hydrodynamics on Mass Transfer in a Gas-Liquid Oscillatory Baffled Column,” Chem. Eng. J., 99, pp. 59–68. [CrossRef]
Liao, Y. F., Liu, J. T., Wang, Y. T., and Cao, Y. J., 2011, “Prediction of Gas Holdup in Cyclonic-Static Micro-Bubble Flotation Column Based on BP Neural Networks,” J. China Univ. Min. Technol., 40(3), pp. 443–447.
Kashiwa, B. A., Padial, N. T., Rauenzahn, R. M., and VanderHeyden, W. B., 1993, “Cell-Centered Ice Method for Multiphase Flow Simulations,” Department of Energy, Washington, DC, Report No. LA-UR-93-3922.
Kashiwa, B. A., and Rauenzahn, R. M.1994, “Multimaterial Formalism,” Department of Energy, Washington, DC, Report No. LA-UR-94-771.
Kashiwa, B. A., 1998, “An Extended k-Epsilon Turbulence Model for Multiphase Flow,” Department of Energy, Washington, DC, Report No. LA-UR-98-2923.
Padial, N. T., VanderyHeyden, W. B., Rauenzahn, R. M., and Yarbro, S. L., 2000, “Three-Dimensional Simulation of a Three-Phase Draft-Tube Bubble Column,” Chem. Eng. Sci., 55(16), pp. 3261–3273. [CrossRef]
Law, D., Battaglia, F., and Heindel, T. J., 2008, “Model Validation for Low and High Superficial Gas Velocity Bubble Column Flows,” Chem. Eng. Sci., 63, pp. 4605–4616. [CrossRef]
Batchelor, G. K., 1988, “A New Theory of the Instability of a Uniform Fluidized Bed,” J. Fluid Mech., 193, pp. 75–110. [CrossRef]
Kumar, S., and Ramkrishna, D., 1996, “On the Solution of Population Balance Equations by Discretization—I. A Fixed Pivot Technique,” Chem. Eng. Sci., 51, pp. 1311–1332. [CrossRef]
Levich, V. G., 1962, Physicochemical Hydrodynamics, Prentice-Hall, Englewood Cliffs, NJ.
Kirkpatrick, R. D., and Lockett, M. J., 1974, “The Influence of Approach Velocity on Bubble Coalescence,” Chem. Eng. Sci., 29, pp. 2363–2373. [CrossRef]
Kim, W. K., and Lee, K. L., 1987, “Coalescence Behavior of Two Bubbles in Stagnant Liquids,” J. Chem. Eng. Jpn., 20, pp. 448–453. [CrossRef]
Miyahara, T., Matsuba, Y., and Takahashi, T., 1983, “The Size of Bubbles Generated From Perforated Plates,” Int. Chem. Eng., 23, pp. 517–523.
Addessio, F. L., Baumgardner, J. R., Dukowicz, J. K., Johnson, N. L., Kashiwa, B. A., Rauenzahn, R. M., and Zemach, C., 1990, “A Computer Code for Fluid Dynamics Problems With Large Distortion and Internal Slip,” Report No. LA-10613-MS-REV.
Hirt, C. W., Amsden, A. A., and CookJ. L., 1974, “An Arbitrary Lagrangian-Eulerian Computing Method for all Flow Speeds,” J. Comput. Phys., 14, pp. 227–253. [CrossRef]
Ekambara, K., Nandakumar, K., and Joshi, J. B., 2008, “CFD Simulation of Bubble Column Reactor Using Population Balance,” Ind. Eng. Chem. Res., 47, pp. 8505–8516. [CrossRef]
Joshi, J. B., 2001, “Computational Flow Modeling and Design of Bubble Column Reactors,” Chem. Eng. Sci., 56(21–22), pp. 5893–5933. [CrossRef]
Jones, S. T., 2007, “Gas-Liquid Mass Transfer in an External Airlift Loop Reactor for Syngas Fermentation,” Ph.D. thesis, Department of Mechanical Engineering, Iowa State University, Ames, IA.

Figures

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Fig. 1

Geometrical model of air-water external loop airlift reactor [1]

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Fig. 2

Schematic of the 14 cm diameter bubble column reactor of Degaleesan et al. [10]

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Fig. 3

Comparison of (a) 2D and (b) 3D average axial liquid velocity predictions over 20–110 cm heights of each bubble size group with experiments at 9.6 cm/s superficial gas velocity with 14 cm bubble column diameter

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Fig. 4

Comparison of (a) 2D and (b) 3D average gas holdup predictions over 20–110 cm heights of each bubble size group at 9.6 cm/s superficial gas velocity with 14 cm bubble column diameter

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Fig. 5

Comparison of 2D and 3D time-averaged bubble size fraction distributions predicted by each size group and Chen et al. [12] at 40 cm height of the bubble column

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Fig. 6

Gas holdup as a function of superficial gas velocity comparing monodispersed simulations with population balance simulations for the ELALR

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Fig. 7

Riser superficial liquid velocity as a function of superficial gas velocity comparing monodispersed and PBM simulations with experiments [38] for the ELALR

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Fig. 8

Comparison of 3D time-averaged bubble size distributions in the riser of the ELALR predicted for each inlet superficial gas velocity

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Fig. 9

Comparison of instantaneous gas holdup contours of the 3D monodispersed and PBM simulations at Ug = (a) 15 cm/s and (b) 20 cm/s

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Fig. 10

Comparison of 3D (a) mono and (b) PBM instantaneous gas holdup simulations with (c) experiment [38] at 20 cm/s superficial gas velocity near the upper connector, where the arrows indicate the approximate length of experimental bubble near the upper connector in the downcomer

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