Based on the cylinder fluidized bed built by Shedid and Hassanto, a three-dimensional Euler–Euler simulation of the effect on the convective heat transfer characteristics between the fluidized particles and the inner heated surface was carried out under different operation conditions including particles sphericity, superficial gas velocity and initial solid packing height in the vertical fluidized bed. Moreover, the experimental average temperature had been chosen to test the validity of numerical average temperature. Contour plots of transient distribution of solid volume fraction and solid temperature have been obtained in fluidized bed on horizontal cross-section in order to understand the effects of hydrodynamic and flow patterns on heat transfer characteristics. The results showed that the solid phase concentration distributed from the initial centrally symmetric annular stratification to the final severely turbulent fluidization by observing contour plots of the solid-phase volume fraction on horizontal cross-section. Solid temperature decreased from center to periphery in the radial direction at initial state since the gas–solid heat exchange rate affected the particle temperature in the entire bed. The temperature distribution of particles was non-uniform on the annular region due to the bed without being fluidized. With the process of fluidization underway, the particles temperature distribution tended to be uniform in horizontal cross-section because the bed material heat transferred from the center's cylindrical heater wall to the bed. The effective thermal conductivity was used to calculate the individual gas and solid phase convective heat transfer coefficient from heater surface to fluidized beds. Not only the average temperature of both heating wall and fluid but the difference of the average temperature between wall and fluid were decreasing with increasing superficial gas velocity. It enhanced turbulence intensity and led to increase the heat transfer coefficient between heater surface and fluid with the same time. The solid average convective heat transfer coefficient growed up with the initial height increasing of the bed material due to the contact area enlargement of particles and the heated surface in the fluidized bed.
[1] Liu R, Jin B, Zhong Z et al. Reduction of bed agglomeration in CFB combustion biomass with aluminum-contain bed material [J]. Process Saf.Environ. Prot, 2007, 85 (B5): 441–445.
[2] Kalita P, Saha U K, Mahanta P. Parametric study on the hydrodynamics and heat transfer along the riser of a pressurized circulating fluidized bed unit [J]. Experimental Thermal and Fluid Science, 2013, 44: 620–630.
[3]Mohammad A Dehnavi, Shahrokh Shahhosseini, S Hassan Hashemabadi et al. CFD simulation of hydrodynamics and heat transfer in gas phase ethylene polymerization reactors. International Communications in Heat and Mass Transfer. 2010, 37: 437–442.
[4] Lim K S, Gururajan V S, Agarwal P K. Mixing of Homogeneous Solids in Bubbling Fluidized Beds: Theoretical Modelling and Experimental Investigation using Digital Image Analysis [J]. Chemical Engineering Science, 1993, 48(12): 2251-2265.
[5] Gao J S, Lan X Y, Fan Y P, et al. Hydrodynamics of Gas-solid Fluidized Bed of Disparately Sized Binary Particles [J]. Chemical Engineering Science, 2009, 64(20): 4302-4316.
[6] Yusuf R, Halvorsen B, M Christian Melaaen. Eulerian–Eulerian simulation of heat transfer between a gas–solid fluidized bed and an immersed tube-bank with horizontal tubes [J]. Chem. Eng. Sci. 2011, 66, 1550–1564.
[7] Shuyan W, L Guodong, W Yanbo et al. Numerical investigation of gas-to-particle cluster convective heat transfer in circulating fluidized beds [J]. Int. J. Heat Mass Transfer, 2010, 53, 3102–3110.
[8] Abdelmotalib H M, Ko D G, Ik-Tae Im. A study on wall-to-bed heat transfer in a conical fluidized bed combustor [J]. Appl. Therm. Eng. 2016, 99, 928-937.
[9] Armstrong L M, Gu S, Luo K H. Study of wall-to-bed heat transfer in a bubbling fluidised bed using the kinetic theory of granular flow [J]. Int. J. Heat Mass Transfer, 2010, 53, 4949-4959.
[10] Lu Y, Zhang T, Dong X. Bed to wall heat transfer in supercritical water fluidized bed: comparison with the gas-solid fluidized bed [J]. App;. Therm.Eng. 2015, 88, 297-305.
[11] Mostafazadeh M, Rahimzadeh M, Hamzei M. Numerical analysis of the mixing process in a gas–solid fluidized bed reactor [J]. Powder Technol, 2013, 239, 422-433.
[12] Gidaspow D. Hydrodynamics of Fluidization and Heat Transfer: Supercomputer Modeling [J]. Appl.Mech.Rev, 1986, 39, (1),1-23.
[13] Dong N H, Armstrong L M, Gu S et al. Effect of tube shape on the hydrodynamics and tube-to-bed heat transfer in fluidized beds [J]. Appl. Therm. Eng. 2013, 60, 472-479.
[14] Behjat Y, Shahhosseini S, Hashemabadi S H. CFD modeling of hydrodynamic and heat transfer in fluidized bed reactors [J]. Int. Commun. Heat Mass Transfer, 2008, 35, 357-368.
[15] Schmidt A, Renz U. Eulerian computation of heat transfer in fluidized beds [J]. Chemical Engineering Science, 1999, 54, 5515-5522.
[16] Armstrong L M, Gu S, Luo K H, The influence of multiple tubes on the tube-to-bed heat transfer in a fluidized bed [J]. International Journal of Multiphase Flow, 2010, 36, 916-929.
[17] Mohamed H Shedid, M A M Hassan. Heat transfer characteristics of the ?uidized bed through the annulus [J]. Heat Mass Transfer, 2016, 52, 1943–1952.
[18] Natale F D, Amedeo. Lancia, Roberto Nigro. Surface-to-bed heat transfer in fluidised beds: Effect of surface shape [J]. Powder Technology, 2007, 174, 75–81.
[19] Gidaspow D, He Y, Lu H. Hydrodynamic modeling of binary mixture in a gas bubbling fluidized bed using the kinetic theory of granular flow [J]. Chemical Engineering Science, 2003, 58, 1197-1205.
[20] Ergun S. Fluid Flow Through Packed Columns [J]. Journal of Materials Science & Chemical Engineering, 1952, 48(2), 89-94.
[21] Wen C Y, Yu Y H. Mechanics of Fluidization [J]. Chemical Engineering Progress Symposium Series, 1966, 62, 100-111.
[22+] Leina Hua, Hu Zhao, Jun Li et al. Eulerian-Eulerian simulation of irregular particles in dense gas-solid fluidized beds. Powder Technology, 2015, 284, 299-311.
[23] Samy M El-Behery, El-Askary W A, Mofreh H Hamed et al. Hydrodynamic and thermal fields analysis in gas-solid two-phase flow [J]. International Journal of Heat and Fluid Flow, 2011, 32, 740–754.
[24] J A M Kuipers, W Prints, W P M van Swaaij. Calculation of wall-to-bed heat transfer coefficients in gas-fluidized beds [J]. AIChE Journal, 1992, 38, 1079-1091.
[25] Patil D J, Smit J, M van Sint Annaland et al. Wall-to-bed heat transfer in gas-solid bubbling fluidized bed [J]. AIChE Journal, 2006, 52, 58-74.
[26]Olsson S E, Almstedt A E. Local instantaneous and time-averaged heat transfer in a pressurized fluidized bed with horizontal tubes: influence of pressure, fluidization velocity and tube-bank geometry [J]. Chem. Eng. Sci. 1995, 50, 3231–3245.
