**5.2 Case 3**

52 Advanced Fluid Dynamics

‐0.5 0 0.5 1 1.5 2 2.5

Fig. 6. Comparison of solid phase velocity profile presented by Miller and Gidaspow (1992) with the CFD simulations (-▲-) and experimental data performed by Samuelsberg and B. H.

To get an impression regarding the flow behavior inside the column, the time averaged solid volume fraction is plotted at different column heights, 0.16 m, 0.32 m and 0.48 m (Figure 7).

Fig. 7. Axial profile of the solid phase volume fraction fields in the center (left) and radial profiles at 0.48 m, 0.32 m, 0.16 m (right up to down). Superficial velocity 0.36 m s-1

Here it can be observed the strong tendency of the solid particles to be near the wall.

Hjertager (1996) (●).

**S o l i d s V e l o c i t y , m / s**

**H= 0.32 m**

‐1 ‐0.8 ‐0.6 ‐0.4 ‐0.2 0 0.2 0.4 0.6 0.8 1

**r/R**

Pilot plant scale riser reactor (Bader, R., Findlay, J. and Knowlton, TM 1988). Riser height: 13 m, riser diameter 0.3 m. Entrance with angle 60°, gas superficial velocity 3.7 m and solids flux 98 kg/(s.m^2) as shown in Figure 8.

Fig. 8. Solids volumetric fraction in the center of the riser. Simulation time 15 sec. Left to right: LES Smagorinsky, LES WALE, LES Dynamic model, Detached Eddy Simulation (DES).

In the Figure 8 can be observed that the solid particles enter to the reactor uniformly distributed, after a short distance these particles start falling due to the gravity and they start flowing over the wall of the inclined pipe. After this, the solids fall into a turbulent zone where they get mixed. Some of the particles will continue falling over the vertical wall opposite to the entrance. The core-annular zone is formed at some height in the middle of the column.

Fluid Dynamics of Gas – Solid Fluidized Beds 55

Collin, A., K.-E. Wirth, and M. Stroeder. 2009. "Characterization of an annular fluidized

Collin, Anne, Karl‐Ernst Wirth, and Michael Ströder. 2008. "Experimental characterization

Cheng, Yi, Changning Wu, Jingxu Zhu, Fei Wei, and Yong Jin. 2008. "Downer reactor: From

Chow, Fotini Katopodes, and Parviz Moin. 2003. "A further study of numerical errors in

Demori, M., V. Ferrari, D. Strazza, and P. Poesio. 2010. "A capacitive sensor system for the

Du, Bing, W. Warsito, and Liang-Shih Fan. 2005. "ECT Studies of Gas−Solid Fluidized Beds

Fischer, C., M. Peglow, and E. Tsotsas. 2011. "Restoration of particle size distributions from

Fraguío, M.S., M.C. Cassanello, S. Degaleesan, and M. Dudukovic. 2009. "Flow regime

Franka, Nathan P., and Theodore J. Heindel. 2009. "Local time-averaged gas holdup in a

Fu, Y., T. Wang, J.-C. Chen, C.-G. Gu, and F. Xu. 2011. "Experimental investigation of jet

Geldart, D. 1973. "Types of gas fluidization." *Powder Technology* 7 (5) (May): 285-292.

Gidaspow, Dimitri. 1994. *Multiphase flow and fluidization: continuum and kinetic theory* 

Gonzalez,, S.G. 2008. Modeling and simulation of cocurrent downflow reactor (Downer).

Grace, John. 1997. *Circulating fluidized beds*. 1st ed. London;: Blackie Academic &

Gross Benjamin, and Ramage Michael P. 1981. FCC Reactor With A Downflow Reactor

Guo, Q., and J. Werther. 2008. "Influence of a gas maldistribution of distributor design on

the hydrodynamics of a CFB riser." *Chemical Engineering and Processing: Process* 

*Science* 66 (12) (June 15): 2842-2852. doi:16/j.ces.2011.03.054.

*Technology* 193 (1) (July 10): 69-78. doi:16/j.powtec.2009.02.008.

*Lixue/Journal of Experiments in Fluid Mechanics* 25 (1): 48-53+64. Geldart, D. 1986. *Gas fluidization technology*. Chichester, New York: Wiley.

Master's thesis, Campinas, Brazil: State University of Campinas.

*Engineering* 86 (3) (June 1): 536-542. doi:10.1002/cjce.20056.

Crowe, Clayton T. 2005. *Multiphase Flow Handbook*. 1st ed. CRC Press, September 19.

doi:16/j.ces.2011.02.055.

*Physical* 163 (1): 172-179.

*Research* 48 (3): 1072-1080.

doi:16/0032-5910(73)80037-3.

*Intensification* 47 (2): 237-244.

Professional.

Riser. April 14.

*descriptions*. Boston: Academic Press.

5020-5030. doi:10.1021/ie049025n.

bed." *Powder Technology* 190 (1-2): 31-35.

364-384. doi:16/j.powtec.2008.01.022.

380. doi:doi: 10.1016/S0021-9991(02)00020-7.

spout fluidized beds." *Chemical Engineering Science* 66 (11) (June 1): 2368-2376.

of the flow pattern in an annular fluidized bed." *The Canadian Journal of Chemical* 

fundamental study to industrial application." *Powder Technology* 183 (3) (April 21):

large-eddy simulations." *Journal of Computational Physics* 184 (2) (January 20): 366-

analysis of two-phase flows of oil and conductive water." *Sensors and Actuators, A:* 

of Different Diameters." *Industrial & Engineering Chemistry Research* 44 (14) (July 1):

fiber-optical in-line measurements in fluidized bed processes." *Chemical Engineering* 

diagnosis in bubble columns via pressure fluctuations and computer-assisted radioactive particle tracking measurements." *Industrial and Engineering Chemistry* 

fluidized bed with side air injection using X-ray computed tomography." *Powder* 

influence on gas-solid the two-phase crossflow in a confined domain." *Shiyan Liuti* 
