基于DEM方法的旋转流化床纳米颗粒流动特性研究

doi:10.11949/0438-1157.20230312

摘要/Abstract

摘要：

基于DEM方法利用MFIX软件分别模拟了两种不同粒径纳米颗粒在旋转流化床内的流动。模拟结果与以往实验结果进行比较发现结果吻合较好，验证了旋转流化床模型的准确性和可靠性。对纳米颗粒在旋转流化床中的运动过程进行数值模拟，加入范德华力，得到了纳米颗粒分布、纳米颗粒速度矢量分布以及纳米颗粒床层压降在不同离心加速度下随气速的变化。结果表明，少部分纳米颗粒在旋转流化床上部游离，其余颗粒随旋转流化床运动，当纳米颗粒上升到60°旋转角附近时，颗粒出现回落，然后进行反复运动，由于纳米颗粒的运动受到颗粒堆积的影响，最终纳米颗粒在旋转流化床底部往复循环。纳米颗粒在旋转流化床内的压降均随离心加速度和气速的增加而增加，相同条件下TiO₂颗粒的床层压降大于Al₂O₃颗粒的床层压降，而且与TiO₂相比Al₂O₃ 颗粒先达到稳定状态。

关键词: DEM方法, 纳米颗粒, 旋转流化床, 数值模拟

Abstract:

In this paper, based on the DEM method, the flow of two kinds of nanoparticles with different particle sizes in the rotating fluidized bed was simulated by using MFIX software.Comparing the simulation results with previous experimental results, it is found that the results are in good agreement, which verifies the accuracy and reliability of the rotating fluidized bed model. The movement process of nanoparticles in a rotating fluidized bed is numerically simulated. Adding the van der Waals force, the distribution of nanoparticles, the velocity vector distribution of nanoparticles and the pressure drop of the nanoparticle bed layer changing with gas velocity under different centrifugal accelerations were simulated. The results indicate that a small fraction of nanoparticles become entrained in the upper region of the rotating fluidized bed, while the majority of particles follow the movement of the bed. When the nanoparticles reach an angle of approximately 60°, they experience a downward motion followed by repeated cycles due to particle accumulation. The bed pressure drop in the rotating fluidized bed increases with increasing centrifugal acceleration and gas velocity. Under the same conditions, the bed pressure drop for TiO₂ particles is higher than that of Al₂O₃ particles, and Al₂O₃ particles reach a steady state earlier compared to TiO₂ particles.

Key words: DEM method, nanoparticles, rotating fluidized bed, numerical simulation

中图分类号:

TK 229

陈巨辉, 张谦, 舒崚峰, 李丹, 徐鑫, 刘晓刚, 赵晨希, 曹希峰. 基于DEM方法的旋转流化床纳米颗粒流动特性研究[J]. 化工学报, 2023, 74(6): 2374-2381.

Juhui CHEN, Qian ZHANG, Lingfeng SHU, Dan LI, Xin XU, Xiaogang LIU, Chenxi ZHAO, Xifeng CAO. Study on flow characteristics of nanoparticles in a rotating fluidized bed based on DEM method[J]. CIESC Journal, 2023, 74(6): 2374-2381.

图/表 8

图1 旋转流化床结构示意图

Fig.1 Schematic diagram of rotating fluidized bed structure

图2 旋转流化床计算简化模型

Fig.2 Simplified calculation model of rotating fluidized bed

表1 数值模拟参数

Table1 Parameters applied in numerical simulation

参数	数值
TiO₂ 颗粒粒径/nm	21
Al₂O₃ 颗粒粒径/nm	13
TiO₂ 颗粒密度/(kg/m³)	3800
Al₂O₃ 颗粒密度/(kg/m³)	2900
颗粒数	23000
气体密度/(kg/m³)	1.205
气体黏度/(Pa/s)	1.8×10^-5
弹簧刚度/(N/m)	800
恢复系数	0.9
颗粒-颗粒摩擦因数	0.32
颗粒-壁面摩擦因数	0.34
离心加速度10g/(rad/s)	40.41
离心加速度20g/(rad/s)	57.16
离心加速度30g/(rad/s)	70
离心加速度40g/(rad/s)	80.83
CFD时间步长/s	5.0×10^-6
DEM时间步长/s	2.5×10^-4
网格划分	100×100×5

图3 计算结果验证

Fig.3 Verification of calculation results

图4 纳米颗粒分布

Fig.4 Distribution of nanoparticle

图5 颗粒速度矢量图

Fig.5 Velocity vector of particle

图6 颗粒TiO2在不同气速下床层压降

Fig.6 Bed pressure drop of granular TiO2 at different gas velocities

图7 颗粒Al2O3在不同气速下床层压降

Fig.7 Bed pressure drop of particulate Al2O3 at different gas velocities

参考文献 31

1	侯旺君, 闫翎鹏, 曹哲勇, 等. 煤基零维纳米碳材料的合成、性能及其在能源转换和存储应用中的研究进展[J]. 化工学报, 2022, 73(11): 4791-4813.
	Hou W J, Yan L P, Cao Z Y, et al. Research progress of synthesis and properties of coal-based zero-dimensional nanocarbon materials and their applications in energy conversion and storage[J]. CIESC Journal, 2022, 73(11): 4791-4813.
2	赵之端, 赵蒙, 刘道银, 等. 振动和搅拌对SiO₂纳米颗粒聚团流化的影响对比研究[J]. 工程热物理学报, 2021, 42(1): 136-142.
	Zhao Z D, Zhao M, Liu D Y, et al. Comparative study on the effect of vibration and stirring on the fluidization of SiO₂ nanoparticle agglomerates[J]. Journal of Engineering Thermophysics, 2021, 42(1): 136-142.
3	郭婷, 何川, 李海念, 等. 声场对导向管喷流床环隙区流化质量的影响[J]. 化学反应工程与工艺, 2019, 35(6): 501-508.
	Guo T, He C, Li H N, et al. Effect of an acoustic field on fluidization quality in the annulus of a spout-fluidized bed with a draft tube[J]. Chemical Reaction Engineering and Technology, 2019, 35(6): 501-508.
4	王荘, 吕潇, 邵媛媛, 等. 流态化的往昔寻觅及未来启示[J]. 化工学报, 2021, 72(12): 5904-5927.
	Wang Z, Lyu X, Shao Y Y, et al. Early exploration of fluidization theory and its inspiration to the future[J]. CIESC Journal, 2021, 72(12): 5904-5927.
5	Liu Z H, Ma H Q, Zhao Y Z. CFD-DEM simulation of fluidization of polyhedral particles in a fluidized bed[J]. Energies, 2021, 14(16): 4939.
6	谭新杰. 流化床内气固两相流动数值模拟研究[J]. 价值工程, 2022, 41(28): 142-144.
	Tan X J. Numerical simulation of gas-solid two-phase flow in fluidized bed[J]. Value Engineering, 2022, 41(28): 142-144.
7	Song Y F, Hao W W, Chen H W, et al. Study on hydrodynamic characteristics of the liquid-solid circulating fluidized bed with a central pulsating nozzle by numerical approach[J]. Advanced Powder Technology, 2022, 33(11): 103805.
8	刘金平, 曹长青. 侧壁辅助进气微小流化床内纳米颗粒流化特性的数值模拟[J]. 广东化工, 2013, 40(24): 15-16, 14.
	Liu J P, Cao C Q. Numerical simulation of fluidization characteristics of nanoparticles in micro-scale fluidized beds with auxiliary side intakes[J]. Guangdong Chemical Industry, 2013, 40(24): 15-16, 14.
9	Hamidifard S, Bahramian A, Rasteh M. Mesh sensitivity analysis on hydrodynamics behavior of a fluidized bed containing silver oxide nanoparticle agglomerates: transition from bubbling to slugging and turbulent flow regimes[J]. Powder Technology, 2018, 331: 28-40.
10	Nakamura H, Watano S. Fundamental particle fluidization behavior and handling of nano-particles in a rotating fluidized bed[J]. Powder Technology, 2008, 183(3): 324-332.
11	Quevedo J, Pfeffer R, Shen Y Y, et al. Fluidization of nanoagglomerates in a rotating fluidized bed[J]. AIChE Journal, 2006, 52(7): 2401-2412.
12	王靖瑞, 李庆民, 刘衡, 等. 纳米复合涂层对微米级金属粉尘吸附行为的抑制作用[J]. 电工技术学报, 2022, 37(12): 3172-3182.
	Wang J R, Li Q M, Liu H, et al. Suppression effect of nanocomposite coating on the adsorption behavior of micron-scale metal dust[J]. Transactions of China Electrotechnical Society, 2022, 37(12): 3172-3182.
13	杨涛, 赵鹏程, 赵亚楠, 等. 铅铋基石墨烯纳米流体热物性研究[J]. 核技术, 2021, 44(12): 87-98.
	Yang T, Zhao P C, Zhao Y N, et al. Thermophysical properties of lead-bismuth-based graphene nanofluids[J]. Nuclear Techniques, 2021, 44(12): 87-98.
14	冯宇轩, 罗坤, 樊建人. 静电除尘器中纳米颗粒运动与荷电特性[J]. 中国科学院大学学报, 2021, 38(3): 297-305.
	Feng Y X, Luo K, Fan J R. Particle transport and charging mechanism of the nano particle within an electrostatic precipitator[J]. Journal of University of Chinese Academy of Sciences, 2021, 38(3): 297-305.
15	王远保, 刘道银, 王铮, 等. 纳米颗粒的流化特征及滞后现象研究[J]. 动力工程学报, 2018, 38(2): 145-150.
	Wang Y B, Liu D Y, Wang Z, et al. Study on fluidization characteristics and hysteresis phenomena of nanoparticles[J]. Journal of Chinese Society of Power Engineering, 2018, 38(2): 145-150.
16	孔令菲, 陈延佩, 王维. 气固流态化中颗粒介尺度结构的动力学研究[J]. 化工学报, 2022, 73(6): 2486-2495.
	Kong L F, Chen Y P, Wang W. Dynamic study of mesoscale structures of particles in gas-solid fluidization[J]. CIESC Journal, 2022, 73(6): 2486-2495.
17	李强, 侯健, 廖长林, 等. 颗粒间作用力和eDLVO理论在水煤浆中的应用[J]. 中南大学学报(自然科学版), 2021, 52(10): 3728-3740.
	Li Q, Hou J, Liao C L, et al. Application of interparticle potential and eDLVO theory in coal water slurry[J]. Journal of Central South University (Science and Technology), 2021, 52(10): 3728-3740.
18	邢耀文, 刘敏, 桂夏辉, 等. 基于原子力显微镜的颗粒间表面力研究[J]. 中国矿业大学学报, 2019, 48(6): 1352-1357, 1374.
	Xing Y W, Liu M, Gui X H, et al. Surface force between particles studied using atomic force microscopy[J]. Journal of China University of Mining & Technology, 2019, 48(6): 1352-1357, 1374.
19	Singh P, Mahanta P, Kalita P. Numerical study on the gas-solid hydrodynamics and heat transfer in a rotating fluidized bed with static geometry dryer[J]. International Journal of Heat and Mass Transfer, 2020, 153: 119666.
20	任盼锋, 海润泽, 李奇, 等. 流化床液固两相传质过程的模拟研究进展[J]. 化工学报, 2022, 73(1): 1-17.
	Ren P F, Hai R Z, Li Q, et al. Review of numerical study on liquid-solids two-phase mass transfer process in fluidized bed[J]. CIESC Journal, 2022, 73(1): 1-17.
21	马永丽, 刘明言, 胡宗定. 气液固流化床流动介尺度模型研究进展[J]. 化工学报, 2022, 73(6): 2438-2451.
	Ma Y L, Liu M Y, Hu Z D. Development of flow mesoscale modeling of the gas-liquid-solid fluidized beds[J]. CIESC Journal, 2022, 73(6): 2438-2451.
22	李铁男, 赵碧丹, 赵鹏, 等. 气固流化床启动阶段挡板内构件受力特性的CFD-DEM模拟[J]. 化工学报, 2022, 73(6): 2649-2661.
	Li T N, Zhao B D, Zhao P, et al. CFD-DEM simulation of the force acting on immersed baffles during the start-up stage of a gas-solid fluidized bed[J]. CIESC Journal, 2022, 73(6): 2649-2661.
23	蒋鸣, 周强. 气固流化床介尺度结构形成机制及过滤曳力模型研究进展[J]. 化工学报, 2022, 73(6): 2468-2485.
	Jiang M, Zhou Q. Progress on mechanisms of mesoscale structures and mesoscale drag model in gas-solid fluidized beds[J]. CIESC Journal, 2022, 73(6): 2468-2485.
24	黄正梁, 洪颖, 田思航, 等. 聚乙烯颗粒间范德华力的原子力显微镜测量[J]. 化学反应工程与工艺, 2020, 36(4): 319-324, 355.
	Huang Z L, Hong Y, Tian S H, et al. Measurement of van der Waals force between polyethylene particles based on atomic force microscope[J]. Chemical Reaction Engineering and Technology, 2020, 36(4): 319-324, 355.
25	彭恺然, 刘红帅, 平新雨, 等. CFD-DEM耦合模拟中拖曳力模型精度[J]. 吉林大学学报(地球科学版), 2021, 51(5): 1400-1407.
	Peng K R, Liu H S, Ping X Y, et al. Accuracy of drag force models in the CFD-DEM method[J]. Journal of Jilin University (Earth Science Edition), 2021, 51(5): 1400-1407.
26	金志恒, 堵祖荫. 固定床反应器床层压降的计算[J]. 化工与医药工程, 2017, 38(2): 7-11.
	Jin Z H, Du Z Y. Calculation of pressure drop in layers in fixed bed reactor[J]. Chemical and Pharmaceutical Engineering, 2017, 38(2): 7-11.
27	杨晨, 徐祥, 阳绍军, 等. 加压下颗粒移动床空隙率实验研究[J]. 中国粉体技术, 2017, 23(4): 22-26.
	Yang C, Xu X, Yang S J, et al. Experimental research of voidage in granular moving bed[J]. China Powder Science and Technology, 2017, 23(4): 22-26.
28	冯静安, 唐小琦, 王卫兵, 等. 基于网格无关性与时间独立性的数值模拟可靠性的验证方法[J]. 石河子大学学报(自然科学版), 2017, 35(1): 52-56.
	Feng J A, Tang X Q, Wang W B, et al. Reliability verification method of numerical simulation based on grid independence and time independence[J]. Journal of Shihezi University (Natural Science), 2017, 35(1): 52-56.
29	黄山, 徐伟, 张喻捷, 等. 基于Ansys Workbench的往复吊厢吊杆网格无关性分析[J]. 起重运输机械, 2022(1): 62-66.
	Huang S, Xu W, Zhang Y J, et al. Grid independence analysis of derrick of reciprocating car based on Ansys Workbench[J]. Hoisting and Conveying Machinery, 2022(1): 62-66.
30	谢宇, 任金波, 黄煌辉, 等. 基于卡方检验的计算流体动力学网格无关性分析[J]. 科学技术与工程, 2020, 20(1): 123-127.
	Xie Y, Ren J B, Huang H H, et al. Grid independence analysis of computational fluid dynamics based on Chi-square test[J]. Science Technology and Engineering, 2020, 20(1): 123-127.
31	史亚琪, 李彦君, 杜玉朋, 等. 气-固微型流化床压降特性及最小流化速度的实验研究[J]. 过程工程学报, 2021, 21(4): 420-430.
	Shi Y Q, Li Y J, Du Y P, et al. Experimental study on pressure drop characteristics and minimum fluidization velocity of gas-solid micro-fluidized bed[J]. The Chinese Journal of Process Engineering, 2021, 21(4): 420-430.

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