Hydrodynamic Behavior of Particles in a Jet Flow of a Gas Fluidized Bed

Document Type : Research Article


1 Chemical Engineering Department, Iran University of Science and Technology, Tehran, I. R. IRAN

2 Institute of Particle Science & Engineering, University of Leeds, Leeds LS2 9JT, UK


Numerous investigations have been devoted towards understanding the hydrodynamics of gas jets in fluidized beds. However, most of them address the problem from  macroscopic point of view, which does not reveal the true behavior in the jet region at the single particle level. The present work aims to understand the jet behavior from a more fundamental level, i.e. the individual particle level. A thin rectangular gas fluidized bed, constructed from acrylic glass, with a vertical jet nozzle located at the centre of the distributor was used in the work. A high speed camera with a speed up to 10,000 frames per second was used to observe the jet behavior. Analysis of large quantity of images allowed determination of solids flux, solids Velocity and solids concentration in the jet region. The model present in this work has shown better agreement with the experimental data in compare with the previous models presented in the literature.


Main Subjects

[1] Basov,  V. A., Markhevka, V. I., Melik-Akhnazarov, T. Kh. and Orochko, D. I., Investigationof the structure of a non-uniform fluidised bed, Inter-national Chemical Engineering, 9,263 (1969).
[2] Wu, C. S. and Whiting, W. B., Interacting  jets  in a fluidised bed, Chemical Engineering and Commu-nications, 73, 1 (1988).
[3] Blake, T.B., Webb, H., Sunderland, P.B., The non-dimensionalisation of equations describing flui-disation with application to the correlation of jet penetration height,Chemical Engineering Science, 45, 365 (1990).
[4] Mathur, K. B. and Gishler, D. E., A technique  for contacting gases with coarse solid particles, Journal of American Institute of Chemical Engineers, 1, 157 (1955).
[5] Merry, J. M. D., Penetration of vertical  jets  into fluidized beds, Journal of American Institute of Chemical Engineers, 21, 507 (1975).
[6] Yang, W. C. and Keairns, D.,  Estimating  the jet penetration depth of multiple vertical grid jets, IndustrialEngineeringChemistryand Fundamentals, 18, 317 (1980).
[7] Richner, D.W, Minoura, T., Princhet, J.W. and Blae, T.R., Computer simulation of isothermal fluidization in large scale laboratory rigs, Journal of American Institute of Chemical Engineers, 36, 361 (1990).
[8] Hong, R.H., Li, H.Z.,  Li,  H. B. and Wang, Y., Studies on the inclined jet penetration length in a gas-solid fluidized bed, Powder Technology, 92, 205 (1997).
[9] Hong, R.Y., Guo, Q.J., Luo, G.H.,Zhang, J.Y. and Ding, J., On the jet penetration height in fluidized  beds with two vertical jets, Powder Technology, 133, 216 (2003).
[10] Massimilla, L. “Gas jets in fluidised beds”, in: Davidson, J.F., Clift, R., and Harrison, D., (Eds.), Fluidisation II, Academic Press, London, p.133 (1985).
[11] Lefroy, G.A. and Davidson, J.F., The mechanics of spouted beds, Transactions of Institution of Chemical Engineers, 47, T120 (1969).
[12] Massimilla, L. and Westwater, Journal of Institute of Chemical Engineers, 9,132 (1959).
[13] Suciu, G.C. and Patrascu, M., Particle circulating in a spouted bed, Powder Technology, 19, 109 (1978).
[14] Chiba, T., Terashima, K. and Kobayashi, K., Lateral distribution of bubble sizes in two dimensional gas-fluidised beds, Journal of Chemical Engineering of Japan, 6, 167 (1975).
[15] Saxena, S.C., Marthur, A. and Sharma, G.K., Bubble dynamic and elutriation studies in gas fluidized beds, Chemical Engineering and Communications, 20, 35 (1984).
[16]Van Velzen, D. V., Flamm, H.J., Langenkamp, H., Casile, A., Motion of solids in spouted bed, Can. J. Chemical Eng., 52 156 (1974).
[17] Roy, D., Larachi, F., Legros, R. and Chauoki, J., A study of solids behaviour in a spouted bed using 3-D tracking, CanadianJournalofChemical Engineering, 52, 561 (1994).
[18] Stein, M., Ding, Y. L. and  Seville, J. P. K., Experimental verification of the scaling relationships for bubbling gas fluidised beds using the PEPT technique, Chemical Engineering Science, 57, 3649 (2002).
[19] Bolous, M. I. and Waldie, B.,  High  Resolution Measurement of Particle Velocities in a Spouted Bed Using Laser-Doppler Anemometry, Canadian Journal of Chemical Engineering, 64, 939 (1986).
[20] He, Y.L., Lim, C.J., Grace, J.R., Zhu, J.X. and Qin, S.Z., Particle velocity profile and solid flow pattern in spouted beds, Canadian Journal of Chemical Engineering, 72, 229 (1994).
[21] Makkawi, Y. T. and Wright, P. C., The voidage function and effective drag force for fluidized beds, Chemical Engineering Science, 58, 2035 (2003).
[22] Lim, K. S., Agarwal, P. K. and O’Neill, B. K., Measurement and modelling of bubble parameters in a two-dimensional gas fluidized bed using image analysis, PowderTechnology, 60, 159 (1990).
[23] Lim, K. S., Agarwal, P. K., Bubble velocity in fluidized beds: the effect of non vertical bubble rise on its measurement using submersible probes and it’s relationship with bubble size, Powder technol., 69, p. 239(1992).
[24] Agarwal, P. K., Hull, A. S. and Kim, K. S., Digital image analysis techniques for the study of bubbling fluidized beds, in Chapter 12 of “Non-invasive monitoring of multiphase flows”,Chaouki, J., Larachi, F. and Dudukovic, M.P., (Eds), p. 407 (1996).
[25] Saadevandi, A.  and Turton, R., The application of computer-based imaging to the measurements of particle velocity and voidage profiles in a fluidized bed, Powder Technology, 98, 183 (1998).
[26] Goldschmidt, M.J.V., Link J. M., van Swaaij, W. P. M., “Fluidization X” Hydrodynamic modeling of dense gas-fluidized beds: validation of a multi-fluid continuum model with non-intrusive digital image analysis measurements, Kwauk, M., Li, J. and Yang W.C., (Eds.), p.405 (2000).
[27] Goldschmidt, M.J.V., Hydrodynamic modelling of fluidized bed spray granulation, PhD thesis, (2001). Hong, R.H., Li, H.Z., Cheng, M.Y., and Zhang,  J.Y., Numerical simulation and verification of a gas-solid jet fluidised bed, Powder Technology, 87, 73 (1996).
[28] Stein, M., Ding, Y.L., Seville, J.P.K. and Parker, D.J., Solids motion in gas bubbling fluidised beds, Chemical Engineering Science, 55, 5291 (2000).
[29] Abramovich, G. N.,  The theory of turbulent jets, M.I.T. Press,Cambridge, Massachusetts(1963).
[30] Michele, G.  De., Elia, A. and Massimilla, L., The intraction between jets and fluidized beds,Ing. Chim. Ital., 12 (11-12) (155-162) (1976).
[31] Schlichting, H.,  Grrenzschicht-theorie,  Vol.  5, Verlag G.Braun, Karlsruhe, Auflage (1965).
[32] Donsi, G., Massimilla, L. and Colantuoni, L., The dispersion of axi-symetric gas jets in fluidized beds, in grace and matsen(eds), “fluidization”, Plenum, New York, 1(980).
[33] Aisa, L.,  Garcia, J. A., Cerecedo, L. M.,  Garcia Palacin, I., Calvo, E., Particle concentration and local mass flux measurements in two-phase flows with PDA. Application to a study on the dispersion of spherical particles in a turbulent air jet, International Journal of Multiphase flow,28 p. 301 (2002).