Fluidized bed simulation:structure-dependent multiscale CFD

doi:10.3969/j.issn.0438-1157.2013.01.012

Abstract

Abstract: Meso-scale structure is key to gas-solids fluidization modeling.Traditional two-fluid model is not suitable for describing multiscale behavior in fluidized beds.In contrast, the structure-dependent multi-fluid model (SFM), which is based on the energy-minimization multi-scale (EMMS) method, takes into account the heterogeneous structure within local space (or, sub-grid structure) and hence its prediction is only weakly dependent on grid resolution, reducing greatly computing load.Based on the structural characterization of SFM, we proposed an EMMS based mass transfer model to explain why literature data scatter up to several orders of magnitude.These models were integrated into a whole set of multiscale computational fluid dynamics (CFD) method, with which we predicted the typical S-shaped axial profile of volume fraction and further revealed the "choking" mechanism and the reason why scale-up of a fluidized bed was so difficult.Currently, 3D, whole-loop, transient, reactive simulation of an industrial circulating fluidized bed could be made possible.In prospect, to realize the shift of research mode from simulation to virtual process engineering, we still need breakthrough in understanding meso-scale structures.

Key words: meso-scale structure, EMMS, fluidization, multi-scale, CFD, SFM

摘要： 介尺度结构是研究气固流态化多尺度行为的关键。传统的基于平均化处理方式的双流体模拟不能准确描述流化床中的多尺度流动和传递行为。相较而言,基于能量最小多尺度(EMMS)方法的结构多流体模型(SFM)基于局部空间(网格)内的非均匀介尺度结构流动特征,其宏观预测结果与网格分辨率基本无关,因而可以大幅降低模拟计算量。基于SFM模拟得到的流动结构,EMMS多尺度传质模型进一步成功解释了传统传质文献中的数据差异。集成上述模型,形成了一整套模拟流化床流动-传递-反应耦合过程的多尺度计算流体力学(CFD)方法,并将其应用于预测循环流化床中典型的S型轴向分布、揭示噎塞转变的机理以及流化床放大困难的原因。多尺度CFD使工业规模循环床的三维、全系统、动态流动-反应耦合过程的准确模拟成为可能,并为实现从模拟向实时虚拟过程转变的目标打下基础。

关键词: 介尺度结构, EMMS, 流态化, 多尺度, CFD, 结构多流体模型

CLC Number:

TQ021.1

WANG Wei, HONG Kun, LU Bona, ZHANG Nan, LI Jinghai. Fluidized bed simulation:structure-dependent multiscale CFD[J]. CIESC Journal, 2013, 64(1): 95-106.

王维, 洪坤, 鲁波娜, 张楠, 李静海. 流态化模拟:基于介尺度结构的多尺度CFD[J]. 化工学报, 2013, 64(1): 95-106.

References 74

[1]	Davidson J F.Symposium on fluidization-discussion[J].Transactions of the Institute of Chemical Engineers, 1961,39:230-232
[2]	Kunii D, Levenspiel O.Fluidization Engineering[M].New York:John Wiley, 1969
[3]	Gidaspow D.Multiphase Flow and Fluidization:Continuum and Kinetic Theory Descriptions[M].Boston:Academic Press, 1994
[4]	Reh L.Fluidized bed processing[J].Chemical Engineering Progress, 1971,67(2):58-63
[5]	Yerushalmi J, Turner D H, Squires A M.Fast fluidized-bed[J].Industrial & Engineering Chemistry Process Design and Development, 1976,15(1):47-53
[6]	Squires A M, Kwauk M, Avidan A A.Fluid beds:at last, challenging two entrenched practices[J].Science, 1985,230(4732):1329-1337
[7]	Li Y, Kwauk M.The dynamics of fast fluidization//Grace J, Matsen J.Fluidization[C].New York:Plenum, 1980:537-544
[8]	Li J, Tung Y, Kwauk M.Method of energy minimization in multi-scale modeling of particle-fluid two-phase flow//Basu P, Large J.Circulating Fluidized Bed TechnologyⅡ[C].Oxford:Pergamon Press, 1988:89-103
[9]	Li J, Kwauk M.Particle-fluid Two-phase Flow:Energy-minimization Multi-scale Method[M].Beijing:Metallurgy Industry Press, 1994
[10]	Ge W, Li J.Physical mapping of fluidization regimes—the EMMS approach[J].Chemical Engineering Science, 2002,57(18):3993-4004
[11]	Shi Z, Wang W, Li J.A bubble-based EMMS model for gas-solid bubbling fluidization[J].Chemical Engineering Science, 2011,66(22):5541-5555
[12]	Lin Q, Wei F, Jin Y.Transient density signal analysis and two-phase micro-structure flow in gas-solids fluidization[J].Chemical Engineering Science, 2001,56(6):2179-2189
[13]	Li J, Zhang J, Ge W, Liu X.Multi-scale methodology for complex systems[J].Chemical Engineering Science, 2004,59(8/9):1687-1700
[14]	Zhang J, Ge W, Li J.Simulation of heterogeneous structures and analysis of energy consumption in particle-fluid systems with pseudo-particle modeling[J].Chemical Engineering Science, 2005,60(11):3091-3099
[15]	Ge W, Chen F, Gao J, Gao S, Huang J, Liu X, Ren Y, Sun Q, Wang L, Wang W, Yang N, Zhang J, Zhao H, Zhou G, Li J.Analytical multi-scale method for multi-phase complex systems in process engineering—Bridging reductionism and holism[J].Chemical Engineering Science, 2007,62(13):3346-3377
[16]	Ge W, Wang W, Yang N, Li J, Kwauk M, Chen F, Chen J, Fang X, Guo L, He X, Liu X, Liu Y, Lu B, Wang J, Wang J, Wang L, Wang X, Xiong Q, Xu M, Deng L, Han Y, Hou C, Hua L, Huang W, Li B, Li C, Li F, Ren Y, Xu J, Zhang N, Zhang Y, Zhou G, Zhou G.Meso-scale oriented simulation towards virtual process engineering(VPE)—the EMMS Paradigm[J].Chemical Engineering Science, 2011,66(19):4426-4458
[17]	Li J, Ge W, Kwauk M.Meso-scale phenomena from compromise:a common challenge not only for chemical engineering[J].arXiv, 2009:0912.5407v3
[18]	Wang J, Ge W, Li J.Eulerian simulation of heterogeneous gas-solid flows in CFB risers:EMMS-based sub-grid scale model with a revised cluster description[J].Chemical Engineering Science, 2008,63(6):1553-1571
[19]	Lu B, Zhang N, Wang W, Li J.Extending EMMS-based models to CFB boiler applications[J].Particuology, 2012:10:663-671
[20]	Hong K, Wang W, Zhou Q, Wang J, Li J.An EMMS-based multi-fluid model(EFM)for heterogeneous gas-solid riser flows(Ⅰ):Formulation of structure-dependent conservation equations[J].Chemical Engineering Science, 2012,75:376-389
[21]	Anderson T B, Jackson R.A fluid mechanical description of fluidized beds[J].Industrial & Engineering Chemistry Fundamentals, 1967,6(4):527-539
[22]	Soo S L.Fluid Dynamics of Multiphase Systems[M].Waltham:Blaisdell Publishing Co., 1967
[23]	Wallis G B.One Dimensional Two-phase Flow[M].New York:McGraw-Hill, 1969
[24]	Jackson R.Fluid mechanical theory//Davidson J, Harrison D.Fluidization[C].New York:Academic Press, 1971:65-119
[25]	Sinclair J L, Jackson R.Gas-particle flow in a vertical pipe with particle-particle interactions[J].AIChE Journal, 1989,35(9):1473-1486
[26]	Ergun S.Fluid flow through packed columns[J].Chemical Engineering Progress, 1952,48(2):89-94
[27]	Wen C Y, Yu Y H.Mechanics of fluidization[J].Chemical Engineering Symposium Series, 1966,62(62):100-111
[28]	Li J H, Kwauk M.Multiscale nature of complex fluid-particle systems[J].Industrial & Engineering Chemistry Research, 2001,40(20):4227-4237
[29]	Ding J, Gidaspow D.A bubbling fluidization model using kinetic theory of granular flow[J].AIChE Journal, 1990,36(4):523-538
[30]	Tsuo Y P, Gidaspow D.Computation of flow patterns in circulating fluidized-beds[J].AIChE Journal, 1990,36(6):885-896
[31]	Yang N, Wang W, Ge W, Li J.CFD simulation of concurrent-up gas-solid flow in circulating fluidized beds with structure-dependent drag coefficient[J].Chemical Engineering Journal, 2003,96(1/2/3):71-80
[32]	Jiradilok V, Gidaspow D, Damronglerd S, Koves W, Mostofi R.Kinetic theory based CFD simulation of turbulent fluidization of FCC particles in a riser[J].Chemical Engineering Science, 2006,61(17):5544-5559
[33]	Xiao Haitao(肖海涛), Qi Haiying(祁海鹰), You Changfu(由长福), Xu Xuchang(徐旭常).Theoretical model of drag between gas and solid phase[J].Journal of Chemical Industry and Engineering(China)(化工学报), 2003,54(3):311-315
[34]	Tsuji Y, Kawaguchi T, Tanaka T.Discrete particle simulation of two-dimensional fluidized bed[J].Powder Technology, 1993,77(1):79-87
[35]	Xu B H, Yu A B.Numerical simulation of the gas-solid flow in a fluidized bed by combining discrete particle method with computational fluid dynamics[J].Chemical Engineering Science, 1997,52(16):2785-2809
[36]	Hoomans B P B, Kuipers J A M, Briels W J, van Swaaij W P M.Discrete particle simulation of bubble and slug formation in a two-dimensional gas-fluidised bed:a hard-sphere approach[J].Chemical Engineering Science, 1996,51(1):99-118
[37]	Xu M, Ge W, Li J.A discrete particle model for particle-fluid flow with considerations of sub-grid structures[J].Chemical Engineering Science, 2007,62(8):2302-2308
[38]	Benyahia S, Sundaresan S.Do we need sub-grid scale corrections for both continuum and discrete gas-particle flow models?[J].Powder Technology, 2012,220:2-6
[39]	Pope S B.Turbulent Flows[M].Cambridge:Cambridge University Press, 2000
[40]	Ma J, Ge W, Xiong Q, Wang J, Li J.Direct numerical simulation of particle clustering in gas-solid flow with a macro-scale particle method[J].Chemical Engineering Science, 2009,64(1):43-51
[41]	Xiong Q, Li B, Zhou G, Fang X, Xu J, Wang J, He X, Wang X, Wang L, Ge W, Li J.Large-scale DNS of gas-solid flows on Mole-8.5[J].Chemical Engineering Science, 2012,71:422-430
[42]	Benyahia S.Fine-grid simulations of gas-solids flow in a circulating fluidized bed[J].AIChE Journal, 2012,58(11):3589-3592
[43]	Agrawal K, Loezos P N, Syamlal M, Sundaresan S.The role of meso-scale structures in rapid gas-solid flows[J].Journal of Fluid Mechanics, 2001,445:151-185
[44]	Igci Y, Andrews A T, Sundaresan S, Pannala S, O’Brien T.Filtered two-fluid models for fluidized gas-particle suspensions[J].AIChE Journal, 2008,54(6):1431-1448
[45]	Parmentier J-F, Simonin O, Delsart O.A functional subgrid drift velocity model for filtered drag prediction in dense fluidized bed[J].AIChE Journal, 2012,58(4):1084-1098
[46]	Syamlal M, Pannala S. Multiphase Continuum Formulation for Gas-solids Reacting Flows//Pannala S,Syamlal M,O’Brien T.Computational Gas-Solids Flows and Reacting Systems[M].New York:IGI Global, 2011:1-65
[47]	Reh L.Fluid dynamics of CFB combustors//Kwauk M, Li J.Circulating Fluidized Bed Technology V[C].Beijing:Science Press, 1996:1-15
[48]	Kriebitzsch S H L, van der Hoef M A, Kuipers J A M.Drag force in discrete particle models — continuum scale or single particle scale?[J].AIChE Journal, 2012:DOI:10. 1002/ aic.1380
[49]	Ullah A, Wang W, Li J.Evaluation of drag models for cocurrent and countercurrent gas-solid flows[J].Chemical Engineering Science, 2013:in revision
[50]	Wang W, Li J.Simulation of gas-solid two-phase flow by a multi-scale CFD approach—extension of the EMMS model to the sub-grid level[J].Chemical Engineering Science, 2007,62(1/2):208-231
[51]	Lu B, Wang W, Li J.Searching for a mesh-independent sub-grid model for CFD simulation of gas-solid riser flows[J].Chemical Engineering Science, 2009,64(15):3437-3447
[52]	Wang W, Lu B, Zhang N, Shi Z, Li J.A review of multiscale CFD for gas-solid CFB modeling[J].International Journal of Multiphase Flow, 2010,36(2):109-118
[53]	Wang W, Ge W, Yang N, Li J.Meso-scale Modeling—The Key to Multi-scale CFD Simulation//Marin G B. Advances in Chemical Engineering[M].Amsterdam:Elsevier Inc., 2011:1-58
[54]	Lu B, Wang W, Li J.Eulerian simulation of gas-solid flows with particles of Geldart groups A, B and D using EMMS-based meso-scale model[J].Chemical Engineering Science, 2011,66(20):4624-4635
[55]	Yang N, Wang W, Ge W, Wang L, Li J.Simulation of heterogeneous structure in a circulating fluidized-bed riser by combining the two-fluid model with the EMMS approach[J].Industrial & Engineering Chemistry Research, 2004,43(18):5548-5561
[56]	Wang W, Lu B, Dong W, Li J.Multi-scale CFD simulation of operating diagram for gas-solid risers[J].Canadian Journal of Chemical Engineering, 2008,86(3):448-457
[57]	Li J H, Wen L X, Ge W, Cui H P, Ren J Q.Dissipative structure in concurrent-up gas-solid flow[J].Chemical Engineering Science, 1998,53(19):3367-3379
[58]	Ullah A, Wang W, Li J.Generalized fluidization revisited[J].Industrial & Engineering Chemistry Research, 2013:to be submitted
[59]	Zhang N, Lu B, Wang W, Li J.Virtual experimentation through 3D full-loop simulation of a circulating fluidized bed[J].Particuology, 2008,6(6):529-539
[60]	Zhang N, Lu B, Wang W, Li J.3D CFD simulation of hydrodynamics of a 150 MWe circulating fluidized bed boiler[J].Chemical Engineering Journal, 2010,162(2):821-828
[61]	Lu B, Zhang N, Wang W, Li J, Chiu J H, Kang S G.3D full-loop simulation of an industrial-scale circulating fluidized bed boiler[J].AIChE Journal, 2012,DOI:10.1002/ aic.13917
[62]	Fox R O.Large-eddy-simulation tools for multiphase flows[J].Annual Review of Fluid Mechanics, 2012,44:47-76
[63]	Wang Linna(王琳娜).Multi-scale mass transfer model and experimental validation for heterogeneous gas-solid two-phase flow[D].Beijing:Chinese Academy of Sciences, 2002
[64]	Wang L N, Yang N, Li J H.Multi-scale mass transfer model for gas-solid two-phase flow[J].Chemical Engineering Communications, 2005,192(10/12):1636-1654
[65]	Dong W, Wang W, Li J.A multiscale mass transfer model for gas-solid riser flows(Ⅰ):Sub-grid model and simple tests[J].Chemical Engineering Science, 2008,63(10):2798-2810
[66]	Dong W, Wang W, Li J.A multiscale mass transfer model for gas-solid riser flows(Ⅱ):Sub-grid simulation of ozone decomposition[J].Chemical Engineering Science, 2008,63(10):2811-2823
[67]	Breault R W.A review of gas-solid dispersion and mass transfer coefficient correlations in circulating fluidized beds[J].Powder Technology, 2006,163(1/2):9-17
[68]	Kumar V, Reddy A S K.Why FCC riser is taller than model predictions?[J].AIChE Journal, 2011,57(10):2917-2920
[69]	Cheng Congli(程从礼).Energy-minimization multi-scale core-annulus(EMMS/CA)model for circulating fluidized beds[D].Beijing:Chinese Academy of Sciences, 2001
[70]	Lu B, Wang W, Li J, Wang X, Gao S, Lu W, Xu Y, Long J. Multi-scale CFD simulation of gas-solid flow in MIP reactors with a structure-dependent drag model[J].Chemical Engineering Science, 2007,62(18/19/20):5487-5494
[71]	Grace J R, Cui H, Elnashaie S S E H.Non-uniform distribution of two-phase flows through parallel identical paths[J].Canadian Journal of Chemical Engineering, 2007,85(5):662-668
[72]	Li Jinghai(李静海), Ouyang Jie(欧阳洁), Gao Shiqiu(高士秋), Ge Wei(葛蔚), Yang Ning(杨宁), Song Wenli(宋文立).Multi-scale Modeling of Complex Systems of Particle-fluid(颗粒流体复杂系统的多尺度模拟)[M].Beijing:Science Press, 2005
[73]	Liu X, Guo L, Xia Z, Lu B, Zhao M, Meng F, Li Z, Li J.Harnessing the power of virtual reality[J].Chemical Engineering Progress, 2012,108(7):28-33
[74]	Wang W, Ge W, Yang N, Li J.Meso:the next big thing in simulation?[J]. TCE, 2012(852):40-43