Hydrodynamic Characteristics of Dense Conical Fluidized Bed: CFD Simulation and Experimental Verification

Document Type: Full article


Department of Chemical Engineering, Hamedan University of Technology, Hamedan, Iran


> The hydrodynamic characteristics of dense conical fluidized bed were investigated experimentally and numerically. Experimental studies have been carried out in a bed containing TiO2 particles belonging to A/C boundary of Geldart's classification with a wide particle size distribution. Pressure measurements and an optical fiber technique allowed determining the effect ofhigh bed particles loading on the minimum fluidization velocity, local solid volume fraction and solid velocity. Two-fluid model approach with three different drag models and boundary conditions (BCs) consisting ofno-slip, partialslip and free-slip BC is presented for the numerical predictions. In this paper, we show the Gidaspow drag function with k-Â turbulent model by applying the partial-slip BC can improve the numerical results at high particle loading.



[1]    Olazar, M., San Jose, M. J., Zabala, G. and Bilbao, J., “A new reactor in jet spouted bed regime for catalytic polymerizations”, Chem. Eng. Sci., 49 (24), 4579 (1994).

[2]    Hematian, S. and Faramarz Hormozi, F., “Drying kinetics of coated sodium percarbonate particles in a conical fluidized bed dryer”, Powder Technol., 269 (1), 30 (2015).

[3]    Kmiec, A., “Hydrodynamics of flow and heat transfer in spouted beds”, Chem. Eng. J., 19 (3), 189 (1980).

[4]    Olazar, M., Aguado, R., Bilbao, J. and Barona, A., “Pyrolysis of sawdust in a conical spouted bed contactor with a HZSM-5 catalyst”, AIChE. J., 46 (5), 1025 (2000).

[5]    Zhou, T. and Li, H., “Estimation of agglomerate size for cohesive particles during fluidization”, Powder. Technol., 101 (1), 57 (1999).

[6]    Molerus, O., “Interpretation of Geldart's type A, B, C and D powders by taking into account interparticle cohesion forces”, Powder Technol., 33 (1), 81 (1982).

[7]    Wang, X. S., Rahman F. and Rhodes M. J., “Nanoparticle fluidization and Geldart’s classification”, Chem. Eng. Sci., 62 (1), 3455 (2007).

[8]    Liu, J., Grace, J. R., and Bi, X., “Novel multifunctional optical-fiber probe: I. development and validation”, AIChE. J., 49 (6), 1405 (2003).

[9]    Pugsley, T., Chaplin, G. and Khanna, P., “Application of measurement techniques to conical Lab-scale fluidized bed dryers containing pharmaceutical”, Trans. IChem. E, 85 (3), 273 (2007).

[10]  Pantzali, M. N., De Ceuster, B. Marin, G. B. and Heynderickx, G. J., “Three-component particle velocity measurements in the bottom section of a riser”, Int. J. Multiphase Flow, 72 (1), 145 (2015).

[11]  Li, J. and Kuipers, J. A. M., “Effect of pressure on gas-solid flow behavior in dense gas-fluidized beds; a discrete particle simulation study”, Powder Technol., 127 (2), 173 (2002).

[12]  Gidaspow, D., “Hydrodynamics of fluidization using kinetic theory: an emerging paradigm?”, Recent Res. Devel. Chem. Eng. Sci., 5 (2-3), 53 (2003).

[13]  Mostafa, A. A. and Mongia, H. C., “Investigation of Some Effective Parameters on the Fluidized Bed Grain Dryers”, Iranica J. Energy & Environm., 4 (4), 391 (2013).

[14]  Bahramian, A. and Olazar, M., “Profiling solid volume fraction in a conical bed of dry micrometric particles: Measurements and numerical implementations”, Powder. Technol., 212 (1), 181 (2011).

[15]  Van Wachem, B. G. M., Schouten, J. C., van den Bleek, C. M. and Sinclair, J. L., “Comparative analysis of CFD models of dense gas-solid systems”, AIChE. J., 47 (5), 1035 (2001).

[16]  Almuttahar, A. and Taghipour, F., “Computational fluid dynamics of high density circulating fluidized bed riser: study of modeling parameters”, Powder Technol., 185 (1), 11 (2008).

[17]  Benyahia, S., Syamlal, M. and O’Brien, T.J., “Evaluation of boundary conditions used to model dilute, turbulent gas/solids flows in a pipe”, Powder Technol., 156 (2-3), 62 (2005).

[18]  Johnson, P. C. and Jackson, R., “Frictional-collisional constitutive relations for granular materials, with application to plane shearing”, J. Fluid Mech., 176 (1), 67 (1987).

[19]  Hosseini, S. H., Ahmadi, G., Rahimi, R., Zivdar, M. and Nasr Esfahany, M., “CFD studies of solids hold-up distribution and circulation patterns in gas-solid fluidized beds”, Powder Technol., 200 (3), 202 (2010).

[20]  Bahramian, A., Olazar, M. and Ahmadi, G., “Effect of slip boundary conditions on the simulation of microparticle velocity fields in a conical fluidized bed”, AIChE. J., 59 (12), 4502 (2013).

[21]  Gidaspow, D., “Multiphase flow and fluidization”, First ed., Academic press, London., (1994).

[22]  Syamlal, M. and O’Brien, T. J., “Computer simulation of bubbles in a fluidized bed”, AIChE. Symp. Ser., 85, 22 (1989).

[23]  Arastoopour, H., Pakdel, P. and Adewumi, M., “Hydrodynamics analysis of dilute gas- solid flow in a vertical pipe”, Powder Technol., 62 (2), 163 (1990).

[24]  Geldart, D., “Types of gas fluidization,” Powder Technol., 7 (5), 285 (1973).

[25]  Schaeffer, D. G., “Instability in the evolution equations describing incompressible granular flow”, J. Diff. Eq., 66 (1), 19 (1987).

[26]  He, Y. L., Lim, C. J., Grace, J. J. R. and Qin, S. “Spout diameters in full and half spouted beds”, Can. J. Chem. Eng., 76 (4), 702 (1998).

[27]  Hagemeier, T., Börner, M., Bück, A. and Evangelos Tsotsas, E., “A comparative study on optical techniques for the estimation of granular flow velocities”, Chem. Eng. Sci., 131 (1), 63 (2015).