MP-PIC simulation of particle clusters in fast fluidized bed risers

doi:10.11949/j.issn.0438-1157.20171666

Abstract

Abstract:

A three-dimensional Eulerian-Lagrangian model, based on MP-PIC method, was developed to simulate particle clusters in fast fluidized bed risers. In the model, gas phase was simulated by large eddy simulation (LES), real particles were displaced by numerical-particles and particles was described by Newton movement equations, drag between gas and particles was calculated by Gidaspow model, and normal stress of particles was calculated and interpolated into Eulerian grids to describe particle contraction. The model was used to simulate gas solid movement in a 3D fast fluidized bed riser with dimension of height H=3 m and diameter d=0.1 m and adjusted according to experimental data. Cluster characteristics of particles (ρ_p=2650 kg·m^-3 and d_p=250 mm) was studied at operational condition of U_g=5.28 m·s^-1gas velocity. The results indicate that the MP-PIC simulation can recognize different shapes of clusters, such as stripe-shaped, saddle-shaped and U-shaped, as well as disclose cluster development including formation, expansion, coalescence and breakup. Mean particle concentration distribution of clusters in the riser cross section shows a core-annular structure with low middle and high edge concentrations, which is opposite to mean cluster velocity distribution. The mean particle concentration of clusters decrease while the mean cluster velocity increase with increase of riser height, but the change of both concentration and velocity slows down above certain riser height.

Key words: Eulerian-Lagrangian, MP-PIC, numerical simulation, fast fluidized bed, particle clusters, multiphase flow, mesoscale

摘要：

为了研究快速流化床颗粒的团絮特征，建立了基于多相质点网格法的快速流化床气固多相流三维数理模型，气相场采用大涡湍流模型，通过求解牛顿运动方程得到颗粒相运动信息，气固间相互作用力采用Gidaspow曳力模型，固体间作用力通过计算颗粒应力梯度得到。基于该模型，对三维快速流化床上升管（H=3 m、d=0.1 m）气固流动开展了数值模拟，并与实验进行了校正，研究了在气速工况U_g=5.28 m·s^-1下的颗粒（ρ_p=2650 kg·m^-3、d_p=250 mm）团絮性质，实现了对上升管内颗粒团絮的基本类型（条形团絮、马鞍形团絮、U形团絮）的成功预测，并揭示了不同类型团絮在上升管内形成、发展、聚并直至破碎的演化规律。结果表明，上升管径向颗粒团絮的平均颗粒浓度分布呈现中间低两边高的环核结构，颗粒团絮速度的分布与其相反；随着轴向高度的增加，颗粒团絮的颗粒浓度逐渐降低而速度逐渐增加，但达到一定高度后变化减缓。

关键词: 欧拉-朗格朗日, 多相质点网格法, 数值模拟, 快速流化床, 颗粒团絮, 多相流, 介尺度

CLC Number:

TK229
TQ018

SUN Ziwen, CHEN Dailin, ZHONG Wenqi, YU Ai-Bing. MP-PIC simulation of particle clusters in fast fluidized bed risers[J]. CIESC Journal, 2018, 69(8): 3443-3451.

孙子文, 陈岱琳, 钟文琪, Aibing Yu. 快速流化床颗粒团絮特征的MP-PIC数值模拟[J]. 化工学报, 2018, 69(8): 3443-3451.

References 36

[1]	李佑楚. 流态化过程工程导论[M]. 北京:科学出版社, 2008:534-585. LI Y C. Introduction to Fluidization Process[M]. Beijing:Science Press, 2008:534-585.
[2]	李晓祥, 石炎福, 黄卫星, 等. 快速流化床提升管中气固流动行为的非线性分析[J]. 化工学报, 2004, 55(2):182-188. LI X X, SHI Y F, HUANG W X, et al. Nonlinear analysis of gas-solid flow behavior in fast fluidized bed riser[J]. Journal of Chemical Industry and Engineering(China), 2004, 55(2):182-188.
[3]	SHARMA A K, TUZLA K, MATSEN J, et al. Parametric effects of particle size and gas velocity on cluster characteristics in fast fluidized beds[J]. Powder Technology, 2000, 111:114-122.
[4]	CHALERMSINSUWAN B, PRAJONGKAN Y, PIUMSOMBOON P. Three-dimensional CFD simulation of the system inlet and outlet boundary condition effects inside a high solid particle flux circulating fluidized bed riser[J]. Powder Technology, 2013, 245:80-93.
[5]	YUAN P T, GIDASPOW D. Computation of flow patterns in circulating fluidized beds[J]. AIChE Journal, 1990, 36(6):885-896.
[6]	CHALERMSINSUWAN B, GIDASPOW D, PIUMSOMBOON P. Comparisons of particle cluster diameter and concentration in circulating fluidized bed riser and downer using computational fluid dynamics simulation[J]. Korean Journal of Chemical Engineering, 2013, 30(4):963-975.
[7]	TSUJI Y, TANAKA T, YONEMURA S. Cluster patterns in circulating fluidized beds predicted by numerical simulation (discrete particle model versus two-fluid model)[J]. Powder Technology, 1998, 95:254-264.
[8]	ZHAO Y, CHENG Y, WU C, et al. Eulerian-Lagrangian simulation of distinct clustering phenomena and RTDs in riser and downer[J]. Particuology, 2010, 8(1SI):44-50.
[9]	VARAS A E C, PETERS E A J F, KUIPERS J A M. CFD-DEM simulations and experimental validation of clustering phenomena and riser hydrodynamics[J]. Chem. Eng. Sci., 2017, 169(Suppl. C):246-258.
[10]	LU H L, SUN Q Q, HE Y R, et al. Numerical study of particle cluster flow in risers with cluster-based approach[J]. Chem. Eng. Sci., 2005, 60(23):6757-6767.
[11]	WANG S Y, SHEN Z H, LU H L, et al. Numerical predictions of flow behavior and cluster size of particles in riser with particle rotation model and cluster-based approach[J]. Chem. Eng. Sci., 2008, 63(16):4116-4125.
[12]	LU H L, WANG S Y, HE Y R, et al. Numerical simulation of flow behavior of particles and clusters in riser using two granular temperatures[J]. Powder Technology, 2008, 182(2):282-293.
[13]	ZHANG N, LU B N, WANG W, et al. Virtual experimentation through 3D full-loop simulation of a circulating fluidized bed[J]. Particuology, 2008, 6(6):529-539.
[14]	LU L Q, XU J, GE W, et al. EMMS-based discrete particle method (EMMS-DPM) for simulation of gas-solid flows[J]. Chem. Eng. Sci., 2014, 120:67-87.
[15]	DAI Q, CHEN C, QI H. A generalized drag law for heterogeneous gas-solid flows in fluidized beds[J]. Powder Technology, 2015, 283:120-127.
[16]	CHEN C, DAI Q, QI H. Improvement of EMMS drag model for heterogeneous gas-solid flows based on cluster modeling[J]. Chem. Eng. Sci., 2016, 141:8-16.
[17]	DAI Q, CHEN C, QI H. Influence of meso-scale structures on drag in gas-solid fluidized beds[J]. Powder Technology, 2016, 288:87-95.
[18]	AGRAWAL K, LOEZOS P N, SYAMLAL M, et al. The role of meso-scale structures in rapid gas-solid flows[J]. Journal of Fluid Mechanics, 2001, 445:151-185.
[19]	ZHOU Q, WANG J W, LI J H. Three-dimensional simulation of dense suspension upflow regime in high-density CFB risers with EMMS-based two-fluid model[J]. Chem. Eng. Sci., 2014, 107:206-217.
[20]	王帅, 刘国栋, 赵飞翔, 等. 循环流化床中颗粒团聚特性的模拟[J]. 化工学报, 2014, 65(6):2027-2033. WANG S, LIU G D, ZHAO F X, et al. Modeling of clusters characteristics in circulating fluidized beds[J]. CIESC Journal, 2014, 65(6):2027-2033.
[21]	RHODES M J, WANG X S, NGUYEN M, et al. Onset of cohesive behavior in gas fluidized beds:a numerical study using DEM simulation[J]. Chem. Eng. Sci., 2001, 56:4433-4438.
[22]	ZHU H P, ZHOU Z Y, YANG R Y, et al. Discrete particle simulation of particulate systems:a review of major applications and findings[J]. Chem. Eng. Sci., 2008, 63:5728-5770.
[23]	DEEN N G, ANNALAND M V S, HOEF M A V D, et al. Review of discrete particle modeling of fluidized beds[J]. Chem. Eng. Sci., 2007, 62:28-44.
[24]	SNIDER D M, CLARK S M, O'ROURKE P J. Eulerian-Lagrangian method for threedimensional thermal reacting flow with application to coal gasifiers[J]. Chem. Eng. Sci., 2011, 66:1285-1295.
[25]	LIU H P, LU H L. Numerical study on the cluster flow behavior in the riser of circulating fluidized beds[J]. Chem. Eng. J., 2009, 150(2):374-384.
[26]	SNIDER D M. Three fundamental granular flow experiments and MP-PIC predictions[J]. Powder Technology, 2007, 176:36-46.
[27]	SNIDER D M. An incompressible three-dimensional multiphase particles-in-cell method for dense particle flows[J]. Journal of Computational Physics, 2001, 170:523-549.
[28]	WANG Q G, YANG H R, WANG P N, et al. Application of MP-PIC method in the simulation of a circulating fluidized bed with a loop seal(Ⅰ):Determination of modeling parameters[J]. Powder Technology, 2014, 253:814-821.
[29]	KARIMIPOUR S, PUGSLEY T. Application of the particle in cell approach for the simulation of bubbling fluidized beds of Geldart A particles[J]. Powder Technology, 2012, 220:63-69.
[30]	ABBASI A, EGE P E, LASA H I. MP-PIC simulation of a fast fluidized bed steam coal gasifier feeding section[J]. Chem. Eng. J., 2011, 174(1):341-350.
[31]	GIDASPOW D. Multiphase Flow and Fluidization:Continuum and Kinetic Theory Description[M]. San Diego:Academic Press, 1994.
[32]	HARRIS S E, CRIGHTON D G. Solitons, solitary waves and voidage disturbances in gas-fluidized beds[J]. Journal of Fluid Mechanics, 1994, 266:243-276.
[33]	AUZERAIS F M, JACKSON R, RUSSEL W B. The resolution of shocks and the effects of compressible sediments in transient settling[J]. Journal of Fluid Mechanics, 1988, 195:437-462.
[34]	CHEN D L, LIU X J, SUN Z W, et al. Experiments on particle cluster behaviors in a fast fluidized bed[J]. Chin. J. Chem. Eng., 2017, 25:1153-1162.
[35]	SOONG C, TUZLA K, CHEN J. Identification of particle clusters in circulating fluidized bed[M]//Circulating Fluidized Bed Technology Ⅳ. AVIDAN A A. New York:AIChE, 1994:615-620.
[36]	HARRIS A T, DAVIDSON J F, THORPE R B. The prediction of particle cluster properties in the near wall region of a vertical riser (200157)[J]. Powder Technology, 2002, 127(2):128-143.