CFD-DEM numerical simulation of flow characteristics in stagnation zone of spouted bed based on dynamic dual grid

doi:10.11949/0438-1157.20210397

Abstract

Abstract:

A CFD-DEM model of gas-solid two-phase flow in spouted bed was established based on the dynamic double-grid method. At the same time, the radial mixing experiment and simulation study in spouted bed were carried out. The characteristics of stagnation zone in spouted bed within 0—2.0 s were compared and analyzed with the single-grid method, which verified the reliability of the calculation results using the dynamic double-grid method. Then, the spouted bed with different inlet gas velocities and different initial stacking heights is numerically simulated, focusing on tracking the particle flow process in the stagnation area. The results show that: the experimental results of radial mixing are in good agreement with the numerical simulation results. There is a certain stagnation area in the spouted bed, and the particle mobility in the stagnation area is poor. The initial stacking height is constant, and with the increase of inlet velocity, the height decline rate of stagnation zone and the extension speed to nozzle have no obvious change. The inlet velocity remains the same. With the increase of the initial accumulation height, the falling velocity of particles in the stagnation zone also increases, but the extension velocity toward the nozzle gradually slows down.

Key words: dynamic double grid, fluidized bed, two-phase flow, CFD-DEM, mix, experimental verification, particle flow, stagnation zone

摘要：

基于Fortran语言自行开发了基于动态双重网格方法下的喷动床内气固两相流动的CFD-DEM方法，同时开展了喷动床内径向混合实验与模拟研究，又结合单网格方法对喷动床内0~2.0 s内的滞止区特性进行对比分析，验证了动态双网格方法计算结果的准确性。然后利用动态双网格方法对不同进口气速下和不同初始堆积高度下的喷动床进行数值模拟研究，对滞止区颗粒流动过程进行追踪，结果表明：径向混合实验结果与数值模拟结果有很好一致性；在喷动床内存在一定的滞止区，滞止区内的颗粒流动性较差；初始堆积高度不变，随着进口速度的增加，滞止区高度下降速率和向喷口延伸速度无明显变化；进口速度不变，随着初始堆积高度的增加，滞止区颗粒下降速度随之增加，但其向喷口延伸速度逐渐变慢。

关键词: 动态双重网格, 流化床, 两相流, CFD-DEM, 混合, 实验验证, 颗粒流, 滞止区

CLC Number:

TQ 028.8

Hongyuan WANG, Lyu JI, Fanxu MENG, Bin LI, Jianmeng YANG, Haisheng CHEN. CFD-DEM numerical simulation of flow characteristics in stagnation zone of spouted bed based on dynamic dual grid[J]. CIESC Journal, 2021, 72(11): 5563-5572.

王洪远, 纪律, 孟繁旭, 李斌, 杨建蒙, 陈海生. 基于动态双重网格下喷动床滞止区流动特性CFD-DEM数值模拟[J]. 化工学报, 2021, 72(11): 5563-5572.

Figures/Tables 13

Fig.1 Schematic diagram of grid model division

Fig.2 Comparison between experiment and simulation of radial mixing process of particles

Fig.3 Vertical velocity nephogram of particle radial mixing process

Fig.4 Geometric model of spouted bed

Table 1 Calculation parameter in numerical simulation

参数	数值	参数	数值
颗粒形状	球形	气体密度/(kg/m³)	1.205
颗粒直径D/m	0.004	气体黏度/(Pa·s)	1.8×10^-5
颗粒弹性系数/(N/m)	200	空气进口速度/(m/s)	27
恢复系数	0.9	床体几何尺寸/m	0.15×0.004×0.9
颗粒数目	1904	喷口参数/m	0.01×0.004
颗粒密度/(kg/m³)	2700	初始床高/m	0.18
摩擦系数	0.1	时间步长/s	1×10^-5

Fig.5 Mixed sequence diagram within 2 s of single grid model

Fig.6 Mixed sequence diagram within 2 s of dynamic double grid model

Fig.7 Average height of tracer particles in stagnation zone under two grid methods

Fig.8 Average width of tracer particles under two grid methods

Fig.9 Average height of tracer particles in stagnation zone at different speeds

Fig.10 Average width of tracer particles at different speeds

Fig.11 Average height of tracer particles at different heights

Fig.12 Average width of tracer particles at different heights

References 30

1	付金良. 喷动流化床内气体混合的实验研究和气固两相流动的数值模拟[D]. 南京: 东南大学, 2006.
	Fu J L. Experimental research of gas mixing and numerical simulation for gas-solid two phases flow in a spouted-fluidization bed[D]. Nanjing: Southeast University, 2006.
2	袁竹林, 朱立平, 耿凡. 气固两相流动与数值模拟[M]. 南京: 东南大学出版社, 2013.
	Yuan Z L, Zhu L P, Geng F. Gas Solid Two Phase Flow and Numerical Simulation[M]. Nanjing: Southeast University Press, 2013.
3	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.
4	张科. 复杂稠密气固两相流动的CFD-DEM模拟研究[D]. 杭州: 浙江大学, 2012.
	Zhang K. CFD-DEM simulation of complex dense gas-solid flow[D]. Hangzhou: Zhejiang University, 2012.
5	Tsuji Y, Kawaguchi T, Tanaka T. Discrete particle simulation of two-dimensional fluidized bed[J]. Powder Technology, 1993, 77(1): 79-87.
6	王迎慧, 归柯庭, 刘利, 等. 磁流化床气固两相流动的数值模拟及实验验证[J]. 东南大学学报(自然科学版), 2002, 32(6): 936-940.
	Wang Y H, Gui K T, Liu L, et al. Numerical simulation of gas-solid flows in MFBs and experimental demonstration[J]. Journal of Southeast Univwrsity (Natural Science Edition), 2002, 32(6): 936-940.
7	张锴, Stefano Brandani. 流化床内颗粒流体两相流的CFD模拟[J]. 化工学报, 2010, 61(9): 2192-2207.
	Zhang K, Stefano B. CFD simulation of particle-fluid two-phase flow in fluidized beds[J]. CIESC Journal, 2010, 61(9): 2192-2207.
8	李斌, 滕昭钰, 张尚彬, 等. 不同进气方式的流化床内颗粒混合特性的数值模拟[J]. 动力工程学报, 2019, 39(2): 85-91.
	Li B, Teng Z Y, Zhang S B, et al. Numerical simulation on particle mixing characteristics in a fluidized bed under different intake modes[J]. Journal of Chinese Society of Power Engineering, 2019, 39(2): 85-91.
9	Kuang S B, Li K, Zou R P, et al. Application of periodic boundary conditions to CFD-DEM simulation of gas-solid flow in pneumatic conveying[J]. Chemical Engineering Science, 2013, 93: 214-228.
10	王敬哲. 气流-喷动床气固两相流动与干燥特性研究[D]. 大连: 大连理工大学, 2017.
	Wang J Z. Study on gas solid two phase flow and drying characteristics in spouted bed with gas stream[D]. Dalian: Dalian University of Technology, 2017.
11	彭丽, 吴迎亚, 李佳瑶, 等. 基于DEM模拟气固鼓泡床中颗粒碰撞参数对流场间歇性的影响[J]. 化工学报, 2015, 66(6): 2041-2048.
	Peng L, Wu Y Y, Li J Y, et al. Effect of granular collision parameters on DEM simulation of flow field intermittency in gas-solids bubbling fluidized bed[J]. CIESC Journal, 2015, 66(6): 2041-2048.
12	Olaofe O O, Patil A V, Deen N G, et al. Simulation of particle mixing and segregation in bidisperse gas fluidized beds[J]. Chemical Engineering Science, 2014, 108: 258-269.
13	Hilton J E, Mason L R, Cleary P W. Dynamics of gas-solid fluidised beds with non-spherical particle geometry[J]. Chemical Engineering Science, 2010, 65(5): 1584-1596.
14	杨建蒙, 李斌, 王洪远, 等. 基于MFIX开源程序下的气固两相流动特性的数值模拟[J]. 动力工程学报, 2020, 40(7): 564-570.
	Yang J M, Li B, Wang H Y, et al. Numerical simulation of gas-solid two-phase flow based on MFIX[J]. Journal of Chinese Society of Power Engineering, 2020, 40(7): 564-570.
15	钟文琪. 喷动流化床流体动力学特性及放大规律研究[D]. 南京: 东南大学, 2007.
	Zhong W Q. Study on hydrodynamic characteristics and amplification law of spouted fluidized bed[D]. Nanjing: Southeast University, 2007.
16	Apostolou K, Hrymak A N. Discrete element simulation of liquid-particle flows[J]. Computers & Chemical Engineering, 2008, 32(4/5): 841-856.
17	庞明军, 魏进家, 刘海燕, 等. 泡状流相分布及湍流结构的欧拉-拉格朗日双向耦合数值研究[J]. 西安交通大学学报, 2010, 44(7): 1-5.
	Pang M J, Wei J J, Liu H Y, et al. Numerical investigation on phase distribution and turbulence of liquid in bubbly flow using Euler-Lagrange two-way method[J]. Journal of Xi'an Jiaotong University, 2010, 44(7): 1-5.
18	Shrestha S, Kuang S B, Yu A B, et al. Particle shape effect on bubble dynamics in central air jet pseudo-2D fluidized beds: a CFD-DEM study[J]. Chemical Engineering Science, 2019, 201: 448-466.
19	田凤国, 章明川, 齐永锋, 等. 流化床轴径向混合特性的数值研究[J]. 中国电机工程学报, 2006, 26(21): 119-124.
	Tian F G, Zhang M C, Qi Y F, et al. A numerical investigation on axial/lateral mixing in fluidized beds[J]. Proceedings of the CSEE, 2006, 26(21): 119-124.
20	李斌, 纪律. 流化床炉内颗粒混合的离散单元法数值模拟[J]. 中国电机工程学报, 2012, 32(20): 42-48, 137.
	Li B, Ji L. Numerical simulation of particle mixing in circulating fluidized bed with discrete element method[J]. Proceedings of the CSEE, 2012, 32(20): 42-48, 137.
21	Ding J M, Gidaspow D. A bubbling fluidization model using kinetic theory of granular flow[J]. AIChE Journal, 1990, 36(4): 523-538.
22	Clarke D A, Sederman A J, Gladden L F, et al. Investigation of void fraction schemes for use with CFD-DEM simulations of fluidized beds[J]. Industrial & Engineering Chemistry Research, 2018, 57(8): 3002-3013.
23	Zhang H, Liu M, Li T, et al. Experimental investigation on gas-solid hydrodynamics of coarse particles in a two-dimensional spouted bed[J]. Powder Technology, 2017, 307: 175-183.
24	Volk A, Ghia U, Liu G R. Assessment of CFD-DEM solution error against computational cell size for flows through a fixed-bed of binary-sized particles[J]. Powder Technology, 2018, 325: 519-529.
25	Peng Z B, Doroodchi E, Luo C M, et al. Influence of void fraction calculation on fidelity of CFD-DEM simulation of gas-solid bubbling fluidized beds[J]. AIChE Journal, 2014, 60(6): 2000-2018.
26	Wu G R, Ouyang J, Yang B X, et al. Use of compromise-based local porosities for coarse grid DEM simulation of bubbling fluidized bed with large particles[J]. Advanced Powder Technology, 2013, 24(1): 68-78.
27	吴国荣, 欧阳洁. 鼓泡床床层高度的细网格DEM模拟[J]. 化工学报, 2014, 65(6): 2092-2097.
	Wu G R, Ouyang J. Fine grid DEM simulation of bed layer height in bubbling fluidized-bed[J]. CIESC Journal, 2014, 65(6): 2092-2097.
28	Boyce C M, Holland D J, Scott S A, et al. Limitations on fluid grid sizing for using volume-averaged fluid equations in discrete element models of fluidized beds[J]. Industrial & Engineering Chemistry Research, 2015, 54(43): 10684-10697.
29	张俊强. 基于双重网格的流化床内流动与传热特性的数值模拟[D]. 保定: 华北电力大学, 2017.
	Zhang J Q. Numerical simulation of the hydrodynamics and heat transfer characteristics of fluidized bed based on double-grid method[D]. Baoding: North China Electric Power University, 2017.
30	Alobaid F, Ströhle J, Epple B. Extended CFD/DEM model for the simulation of circulating fluidized bed[J]. Advanced Powder Technology, 2013, 24(1): 403-415.

[1]	Mingkun XIAO, Guang YANG, Yonghua HUANG, Jingyi WU. Numerical study on bubble dynamics of liquid oxygen at a submerged orifice [J]. CIESC Journal, 2023, 74(S1): 87-95.
[2]	Shaohua ZHOU, Feilong ZHAN, Guoliang DING, Hao ZHANG, Yanpo SHAO, Yantao LIU, Zheming GAO. Experimental study of flow noise in short tube throttle valve and noise reduction measures [J]. CIESC Journal, 2023, 74(S1): 113-121.
[3]	Aiqiang CHEN, Yanqi DAI, Yue LIU, Bin LIU, Hanming WU. Influence of substrate temperature on HFE7100 droplet evaporation process [J]. CIESC Journal, 2023, 74(S1): 191-197.
[4]	Yingying TAN, Xiaoqing LIU, Lin WANG, Lisheng HUANG, Xiuzhen LI, Zhanwei WANG. Experimental study on startup dynamic characteristics of R1150/R600a auto-cascade refrigeration cycle [J]. CIESC Journal, 2023, 74(S1): 213-222.
[5]	Kaijie WEN, Li GUO, Zhaojie XIA, Jianhua CHEN. A rapid simulation method of gas-solid flow by coupling CFD and deep learning [J]. CIESC Journal, 2023, 74(9): 3775-3785.
[6]	Yubing WANG, Jie LI, Hongbo ZHAN, Guangya ZHU, Dalin ZHANG. Experimental study on flow boiling heat transfer of R134a in mini channel with diamond pin fin array [J]. CIESC Journal, 2023, 74(9): 3797-3806.
[7]	Song HE, Qiaomai LIU, Guangshuo XIE, Simin WANG, Juan XIAO. Two-phase flow simulation and surrogate-assisted optimization of gas film drag reduction in high-concentration coal-water slurry pipeline [J]. CIESC Journal, 2023, 74(9): 3766-3774.
[8]	Xiaosong CHENG, Yonggao YIN, Chunwen CHE. Performance comparison of different working pairs on a liquid desiccant dehumidification system with vacuum regeneration [J]. CIESC Journal, 2023, 74(8): 3494-3501.
[9]	Erqi WANG, Shuzhou PENG, Zhen YANG, Yuanyuan DUAN. Evaluation of vapor-liquid equilibrium models for mixtures containing HFOs [J]. CIESC Journal, 2023, 74(8): 3216-3225.
[10]	Linqi YAN, Zhenlei WANG. Multi-step predictive soft sensor modeling based on STA-BiLSTM-LightGBM combined model [J]. CIESC Journal, 2023, 74(8): 3407-3418.
[11]	Kexin HUANG, Tong LI, Anqi LI, Mei LIN. Mode decomposition of flow field in T-junction with rotating impeller [J]. CIESC Journal, 2023, 74(7): 2848-2857.
[12]	Yuying GUO, Jiaqiang JING, Wanni HUANG, Ping ZHANG, Jie SUN, Yu ZHU, Junxuan FENG, Hongjiang LU. Water-lubricated drag reduction and pressure drop model modification for heavy oil pipeline [J]. CIESC Journal, 2023, 74(7): 2898-2907.
[13]	Xuanzhi HE, Yongqing HE, Guiye WEN, Feng JIAO. Ferrofluid droplet neck self-similar breakup behavior [J]. CIESC Journal, 2023, 74(7): 2889-2897.
[14]	Chao NIU, Shengqiang SHEN, Yan YANG, Bonian PAN, Yiqiao LI. Flow process calculation and performance analysis of methane BOG ejector [J]. CIESC Journal, 2023, 74(7): 2858-2868.
[15]	Zhenghao YANG, Zhen HE, Yulong CHANG, Ziheng JIN, Xia JIANG. Research progress in downer fluidized bed reactor for biomass fast pyrolysis [J]. CIESC Journal, 2023, 74(6): 2249-2263.