0
Research Papers: Multiphase Flows

Modeling of Axial-Symmetric Flow Structure in Gas–Solids Risers

[+] Author and Article Information
Pengfei He

Department of Mechanical
and Industrial Engineering,
New Jersey Institute of Technology,
Newark, NJ 07102
e-mail: ph36@njit.edu

Dawei Wang

Department of Mechanical
and Industrial Engineering,
New Jersey Institute of Technology,
Newark, NJ 07102
e-mail: dw56@njit.edu

Rajesh Patel

Department of Mechanical
and Industrial Engineering,
New Jersey Institute of Technology,
Newark, NJ 07102
e-mail: rsp25@njit.edu

Chao Zhu

Department of Mechanical
and Industrial Engineering,
New Jersey Institute of Technology,
Newark, NJ 07102
e-mail: chao.zhu@njit.edu

1Present address: Department of Chemical and Biomolecular Engineering, Ohio State University, Columbus, OH, 43210.

2Present address: Department of Mechanical Engineering, Pandit Deendayal Petroleum University, Raisan, Gujarat 382007, India.

3Corresponding author.

Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received December 15, 2014; final manuscript received August 18, 2015; published online December 8, 2015. Assoc. Editor: E. E. Michaelides.

J. Fluids Eng 138(4), 041302 (Dec 08, 2015) (8 pages) Paper No: FE-14-1753; doi: 10.1115/1.4031686 History: Received December 15, 2014; Revised August 18, 2015

Pneumatic transport of solids in a riser has a unique nonuniform flow structure, characterized by the core solids acceleration and the wall solids deceleration along the riser, which causes the down-flow of solids and hence back mixing. To predict this nonuniform flow structure, this paper presents a mechanistic model that includes two controlling mechanisms: the interparticle collision damping for axial transport of solids and the effects of collision-induced diffusion and turbulent convection for radial transport of solids. The model predictions are partially validated against available measurements, such as axial and radial distributions of concentration and velocity of solids.

FIGURES IN THIS ARTICLE
<>
Copyright © 2016 by ASME
Your Session has timed out. Please sign back in to continue.

References

Li, Y. , and Kwauk, M. , 1980, “ The Dynamics of Fast Fluidization,” Fluidization, Springer, New York, pp. 537–544.
Issangya, A. S. , Grace, J. R. , Bai, D. , and Zhu, J. , 2000, “ Further Measurements of Flow Dynamics in a High-Density Circulating Fluidized Bed Riser,” Powder Technol., 111(1), pp. 104–113. [CrossRef]
Pärssinen, J. H. , and Zhu, J.-X. , 2001, “ Particle Velocity and Flow Development in a Long and High-Flux Circulating Fluidized Bed Riser,” Chem. Eng. Sci., 56(18), pp. 5295–5303. [CrossRef]
Herb, B. , Dou, S. , Tuzla, K. , and Chen, J. C. , 1992, “ Solid Mass Fluxes in Circulating Fluidized Beds,” Powder Technol., 70(3), pp. 197–205. [CrossRef]
Du, B. , Warsito, W. , and Fan, L. , 2004, “ ECT Studies of the Choking Phenomenon in a Gas–Solid Circulating Fluidized Bed,” AIChE J., 50(7), pp. 1386–1406. [CrossRef]
Harris, B. J. , and Davidson, J. F. , 1994, “ Modeling Options for Circulating Fluidized Beds: A Core/Annulus Deposition Model for Circulating Fluidized Beds,” Circulating Fluidized Bed Technology IV, AIChE, New York, pp. 32–39.
Louge, M. , and Chang, H. , 1990, “ Pressure and Voidage Gradients in Vertical Gas-Solid Risers,” Powder Technol., 60(2), pp. 197–201. [CrossRef]
Louge, M. Y. , Mastorakos, E. , and Jenkins, J. T. , 1991, “ The Role of Particle Collisions in Pneumatic Transport,” J. Fluid Mech., 231(1), pp. 345–359. [CrossRef]
Büssing, W. , and Reh, L. , 2001, “ On Viscous Momentum Transfer by Solids in Gas–Solids Flow Through Risers,” Chem. Eng. Sci., 56(12), pp. 3803–3813. [CrossRef]
Zhu, C. , and You, J. , 2007, “ An Energy-Based Model of Gas–Solid Transport in a Riser,” Powder Technol., 175(1), pp. 33–42. [CrossRef]
Bolton, L. W. , and Davidson, J. F. , 1988, “ Recirculation of Particles in Fast Fluidized Risers,” Circulating Fluidized Bed Technology II, Pergamon Press, Oxford, UK, pp. 139–146.
Senior, R. C. , and Brereton, C. , 1992, “ Modeling of Circulating Fluidised-Bed Solids Flow and Distribution,” Chem. Eng. Sci., 47(2), pp. 281–296. [CrossRef]
Richardson, J. F. , and Zaki, W. N. , 1954, “ Sedimentation and Fluidisation: Part I,” Trans. Inst. Chem. Eng., 32, pp. 35–53.
You, J. , Patel, R. , Wang, D. , and Zhu, C. , 2010, “ Role of Inter-Particle Collision on Solids Acceleration in Riser,” Particuology, 8(1), pp. 13–18. [CrossRef]
Zhu, C. , Liang, S. C. , and Fan, L. S. , 1994, “ Particle Wake Effects on the Drag Force of an Interactive Particle,” Int. J. Multiphase Flow, 20(1), pp. 117–129. [CrossRef]
Wang, D. , You, J. , and Zhu, C. , 2010, “ Modeling of Core Flow in a Gas–Solids Riser,” Powder Technol., 199(1), pp. 13–22. [CrossRef]
Zhu, C. , Jun, Y. , Patel, R. , and Wang, D. , 2011, “ Interactions of Flow and Reaction in Fluid Catalytic Cracking Risers,” AIChE J., 57(11), pp. 3122–3131. [CrossRef]
He, P. , Zhu, C. , and Ho, T. C. , 2015, “ A Two-Zone Model for Fluid Catalytic Cracking Riser With Multiple Feed Injectors,” AIChE J., 61(2), pp. 610–619. [CrossRef]
Nieuwland, J. J. , Meijer, R. , Kuipers, J. A. M. , and Van Swaaij, W. P. M. , 1996, “ Measurements of Solids Concentration and Axial Solids Velocity in Gas-Solid Two-Phase Flows,” Powder Technol., 87(2), pp. 127–139. [CrossRef]
Wei, F. , Lin, H. , Cheng, Y. , Wang, Z. , and Jin, Y. , 1998, “ Profiles of Particle Velocity and Solids Fraction in a High-Density Riser,” Powder Technol., 100(2), pp. 183–189. [CrossRef]
Qi, X. , Huang, W. , and Zhu, J. , 2008, “ Comparative Study of Flow Structure in Circulating Fluidized Bed Risers With FCC and Sand Particles,” Chem. Eng. Technol., 31(4), pp. 542–553. [CrossRef]
Patel, R. , He, P. , Zhang, B. , and Zhu, C. , 2013, “ Transport of Interacting and Evaporating Liquid Sprays in a Gas–Solid Riser Reactor,” Chem. Eng. Sci., 100, pp. 433–444. [CrossRef]

Figures

Grahic Jump Location
Fig. 1

Schematic representation of riser flow structure with radial transport mechanism

Grahic Jump Location
Fig. 2

Parabolic fitting of radial profile of solid velocity data

Grahic Jump Location
Fig. 3

Parabolic fitting on radial profile of solid volume fraction data

Grahic Jump Location
Fig. 4

Axial profile of solid velocity against the data by Parssinen and Zhu [3]

Grahic Jump Location
Fig. 5

Radial profile of solid velocity against the data by Parssinen and Zhu [3]

Grahic Jump Location
Fig. 6

Cross-sectional averaged solid velocity verses solid volume fraction

Grahic Jump Location
Fig. 7

Axial profile of pressure and gas density

Grahic Jump Location
Fig. 8

Axial profile of solid volume fraction

Grahic Jump Location
Fig. 9

Radial profile of solid volume fraction

Grahic Jump Location
Fig. 10

Axial profile of gas velocity

Grahic Jump Location
Fig. 11

Radial profile of gas velocity

Grahic Jump Location
Fig. 12

Radial profile of solid velocity

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In