涡流空气分级流场中颗粒运动及分布规律研究

doi:10.11949/0438-1157.20230732

摘要/Abstract

摘要：

为探究粗细颗粒在分级机内分离过程，基于颗粒-涡相互作用模型和离散元软球模型研究了涡流空气分级流场中湍流脉动对颗粒运动及切割粒径d₅₀的影响，探索了分级过程中颗粒的分布规律。湍流脉动主要影响小颗粒的运动轨迹，对大颗粒运动轨迹影响不大，对切割粒径d₅₀无明显影响；在风速12 m·s^-1，转笼转速1200 r·min^-1工况下，从径向分布来看，小于20 μm的细颗粒主要分布在转笼区，接近切割粒径d₅₀的颗粒在环形区内做旋流运动，大于25 μm的粗颗粒会在靠近导叶的区域聚集，由于颗粒间的相互作用导致一些较细的颗粒会掺混在这些粗颗粒中，从而产生“鱼钩效应”；从轴向分布来看，小于20 μm的细颗粒主要分布在分级机内靠近顶部区域，粗颗粒会逐渐向下沉降，粒径越大沉降越快。

关键词: 涡流空气分级机, 湍流, 颗粒分布, 软球模型, 计算流体力学, 数值模拟

Abstract:

To probe into the separation process of coarse and fine particles in the classifiers, based on the particle-eddy interaction model and the discrete element soft sphere model, the influence of turbulent fluctuation in the turbo air classification flow field on particle motion and cut size d₅₀ are investigated. The distribution laws of particles in the classification process are also explored. Turbulent fluctuation mainly influences the trajectory of small particles. It has little effect on the trajectory of large particles, and has no significant effect on cut size d₅₀. At an inlet air velocity of 12 m·s^-1 and a rotor cage rotating speed of 1200 r·min^-1, for the radial distribution, the fine particles less than 20 μm are mainly distributed in the rotor cage area, particles with size near d₅₀ move with swirling flow in the annular region, and the coarse particles larger than 25 μm gather in the area near the guide blade. Due to the interaction between particles, some fine particles may be mixed with the coarse particles,resulting in a “fish-hook effect”. For the axial distribution, the fine particles less than 20 μm are mainly distributed in the classifier near the top area, the coarse particles gradually settle downward and the larger the particle size the faster the settlement.

Key words: turbo air classifier, turbulent flow, particle distribution, soft sphere model, computational fluid dynamics, numerical simulation

中图分类号:

TQ 028.8

于源, 刘克润, 李兴帅, 刘家祥, 焦志伟. 涡流空气分级流场中颗粒运动及分布规律研究[J]. 化工学报, 2023, 74(10): 4074-4086.

Yuan YU, Kerun LIU, Xingshuai LI, Jiaxiang LIU, Zhiwei JIAO. Study of particle motion and distribution laws in the turbo air classification flow field[J]. CIESC Journal, 2023, 74(10): 4074-4086.

图/表 21

图1 颗粒-涡相互作用模型

Fig.1 Particle-eddy interaction model

图2 涡流空气分级机结构示意图1—进风口；2—蜗壳；3—导风叶片；4—转笼；5—撒料盘；6—细粉出口

Fig.2 Structural diagram of a turbo air classifier

表1 蜗壳型线离散点极坐标数据

Table 1 Polar coordinate data of discrete points on the volute profile

$θ$ /rad	r_m/mm
$π$ /6	162
$π$ /3	167
$π$ /2	177
2 $π$ /3	187
5 $π$ /6	200
$π$	216

表1 蜗壳型线离散点极坐标数据

Table 1 Polar coordinate data of discrete points on the volute profile

$θ$ /rad	r_m/mm
$π$ /6	162
$π$ /3	167
$π$ /2	177
2 $π$ /3	187
5 $π$ /6	200
$π$	216

图3 反距离权重插值

Fig.3 Inverse distance weight interpolation

表2 碳酸钙原料粒度颗粒数微分分布

Table 2 Particle size differential distribution of calcium carbonate raw material

颗粒粒径/μm	微分分布/%
<2	2.78
2~6	8.37
6~17	15.30
17~25	22.23
25~39	25.19
39~54	17.72
54~74	7.98
>74	0.43

表3 数值模拟参数设置

Table 3 Parameter settings in numerical simulation

参数	数值
μ/(Pa·s)	1.83×10^-5
$ρ$ /(kg·m^-3)	1.205
$φ$	0.6
$ρ p$ /(kg·m^-3)	2700
E/GPa	2
$μ q$	0.2
δt/s	10^-5
A/J	5×10^-19[33]

表3 数值模拟参数设置

Table 3 Parameter settings in numerical simulation

参数	数值
μ/(Pa·s)	1.83×10^-5
$ρ$ /(kg·m^-3)	1.205
$φ$	0.6
$ρ p$ /(kg·m^-3)	2700
E/GPa	2
$μ q$	0.2
δt/s	10^-5
A/J	5×10^-19[33]

图4 不同初始位置的颗粒轨迹

Fig.4 Particle trajectories at different initial positions

图5 10 μm颗粒对释放初始状态示意图

Fig.5 Schematic diagram of the initial release state of a pair of 10 μm particles

图6 10 μm颗粒对碰撞过程相互作用力动态变化

Fig.6 Dynamic changes of the interaction force of a pair of 10 μm particles during collision

图7 碰撞过程中颗粒团聚机理的定性分析[34]

Fig.7 Qualitative analysis of particle agglomeration mechanism during collision[34]

表4 计算d50与实验d50对比数据

Table4 Comparison of calculated d50 and experimental d50

工况	d₅₀/μm			d₅₀误差/%
工况	DPM	软球模型	物料实验	DPM与实验	软球模型与实验
12-1000	23.0	24.8	28.6	19.5	13.2
12-1200	20.9	23.7	26.0	19.6	8.8

图8 有无湍流脉动颗粒轨迹对比

Fig.8 Comparison of particles’ trajectories with and without turbulent fluctuation

图9 径向区域示意图

Fig.9 Schematic diagram of radial regions

图10 不同径向区域的颗粒数和颗粒分布

Fig.10 Particle number and particle distribution in different radial regions

图11 颗粒分布稳定（0.30 s）时粒径的径向分布

Fig.11 Radial distribution of particle when particle distribution is stable (0.30 s)

图12 19 μm颗粒的径向位置变化

Fig.12 The radial position changes of the 19 μm particle

图13 粒度为19和18 μm的颗粒对碰撞过程

Fig.13 The collision process of a pair of 19 and 18 μm particles

图14 轴向区域示意图

Fig.14 Schematic diagram of axial regions

图15 不同轴向区域的颗粒数和颗粒分布

Fig.15 Particle number and particle distribution in different axial regions

图16 颗粒分布稳定（0.30 s）时粒径的轴向分布

Fig.16 Axial distribution of particle when particle distribution is stable (0.30 s)

图17 颗粒轴向速度变化

Fig.17 The changes of particle axial velocity

参考文献 38

1	Sun Z P, Liang L L, Liu C Y, et al. CFD simulation and performance optimization of a new horizontal turbo air classifier[J]. Advanced Powder Technology, 2021, 32(4): 977-986.
2	Sun Z P, Sun G G, Liu J X, et al. CFD simulation and optimization of the flow field in horizontal turbo air classifiers[J]. Advanced Powder Technology, 2017, 28(6): 1474-1485.
3	Zeng Y, Zhang S, Zhou Y, et al. Numerical simulation of a flow field in a turbo air classifier and optimization of the process parameters[J]. Processes, 2020, 8(2): 237.
4	Eswaraiah C, Angadi S I, Mishra B K. Mechanism of particle separation and analysis of fish-hook phenomenon in a circulating air classifier[J]. Powder Technology, 2012, 218: 57-63.
5	卢道铭, 范怡平, 卢春喜. 颗粒空气分级技术研究进展[J]. 中国粉体技术, 2020, 26(6): 11-24.
	Lu D M, Fan Y P, Lu C X. Research progress of particle air classification technology[J]. China Powder Science and Technology, 2020, 26(6): 11-24.
6	于源, 陈薇薇, 付俊杰, 等. 几何相似涡流空气分级机环形区流场变化规律研究及预测[J]. 化工学报, 2023, 74(6): 2363-2373.
	Yu Y, Chen W W, Fu J J, et al. Study and prediction of flow field in the annular region of geometrically similar turbo air classifier[J]. CIESC Journal, 2023, 74(6): 2363-2373.
7	苏军伟, 顾兆林. 气固颗粒系统模拟的研究进展[J]. 化学反应工程与工艺, 2016, 32(3): 261-276.
	Su J W, Gu Z L. Advances in numerical simulation of gas-solid particle system[J]. Chemical Reaction Engineering and Technology, 2016, 32(3): 261-276.
8	李静海, 欧阳洁, 高士秋, 等. 颗粒流体复杂系统的多尺度模拟[M]. 北京: 科学出版社, 2005: 200-249.
	Li J H, Ouyang J, Gao S Q, et al. Multi Scale Simulation of Complex Particle Fluid Systems[M]. Beijing: Science Press, 2005: 200-249.
9	Wei Y K, Zhu L L, Zhang W, et al. Numerical and experimental investigations on the flow and noise characteristics in a centrifugal fan with step tongue volutes[J]. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 2020, 234(15): 2979-2993.
10	Lun Y X, Lin L M, He H J, et al. Effects of vortex structure on performance characteristics of a multiblade fan with inclined tongue[J]. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2019, 233(8): 1007-1021.
11	Qian J Y, Hou C W, Wu J Y, et al. Aerodynamics analysis of superheated steam flow through multi-stage perforated plates[J]. International Journal of Heat and Mass Transfer, 2019, 141: 48-57.
12	Wang Y F, Zhang F, Yuan S Q, et al. Effect of URANS and hybrid RANS-large eddy simulation turbulence models on unsteady turbulent flows inside a side channel pump[J]. Journal of Fluids Engineering, 2020, 142(6): 061503.
13	Li X J, Li B W, Yu B X, et al. Calculation of cavitation evolution and associated turbulent kinetic energy transport around a NACA66 hydrofoil[J]. Journal of Mechanical Science and Technology, 2019, 33(3): 1231-1241.
14	Olazar M, San José M J, Izquierdo M A, et al. Effect of operating conditions on solid velocity in the spout, annulus and fountain of spouted beds[J]. Chemical Engineering Science, 2001, 56(11): 3585-3594.
15	任文静. 涡流空气分级机流场分析及结构优化[D]. 北京: 北京化工大学, 2016.
	Ren W J. Flow field analysis and structure optimization of vortex air classifier[D]. Beijing: Beijing University of Chemical Technology, 2016.
16	Guizani R, Mhiri H, Bournot P. Effects of the geometry of fine powder outlet on pressure drop and separation performances for dynamic separators[J]. Powder Technology, 2017, 314: 599-607.
17	Yu Y, Ren W J, Liu J X. A new volute design method for the turbo air classifier[J]. Powder Technology, 2019, 348: 65-69.
18	Wu S B, Liu J X, Yu Y. Design of a new double layer spreading plate for a turbo air classifier[J]. Powder Technology, 2017, 312: 277-286.
19	白振霄. 湍流通道内柴油机排气微粒运动特性的研究[D]. 北京: 北京交通大学, 2011.
	Bai Z X. Study on the motion characteristics of diesel engine exhaust particles in turbulent channel[D]. Beijing: Beijing Jiaotong University, 2011.
20	Siqueira F C S, Farias I S, Moraes D Jr, et al. CFD simulation of annular oil flow wrapped with water[J]. The Canadian Journal of Chemical Engineering, 2019, 97(2): 444-451.
21	Jarrin N, Benhamadouche S, Laurence D, et al. A synthetic-eddy-method for generating inflow conditions for large-eddy simulations[J]. International Journal of Heat and Fluid Flow, 2006, 27(4): 585-593.
22	Hutchinson P, Hewitt G F, Dukler A E. Deposition of liquid or solid dispersions from turbulent gas streams: a stochastic model[J]. Chemical Engineering Science, 1971, 26(3): 419-439.
23	Lai A C K, Chen F Z. Modeling particle deposition and distribution in a chamber with a two-equation Reynolds-averaged Navier-Stokes model[J]. Journal of Aerosol Science, 2006, 37(12): 1770-1780.
24	Dehbi A. A CFD model for particle dispersion in turbulent boundary layer flows[J]. Nuclear Engineering and Design, 2008, 238(3): 707-715.
25	Mihajlovic M, Roghair I, van Sint Annaland M. On the numerical implementation of the van der Waals force in soft-sphere discrete element models for gas-solid fluidization[J]. Chemical Engineering Science, 2020, 226: 115794.
26	Chien S F. Settling velocity of irregularly shaped particles[J]. SPE Drilling & Completion, 1994, 9(4): 281-289.
27	Tsuji Y, Tanaka T, Ishida T. Lagrangian numerical simulation of plug flow of cohesionless particles in a horizontal pipe[J]. Powder Technology, 1992, 71(3): 239-250.
28	Israelachvili J N. Intermolecular and Surface Forces[M]. 3rd ed. USA: Academic Press, 2011.
29	Dollimore D, Pearce J. Changes in surface free energy for the adsorption of nitrogen on porous powders of alumina and silica coated with manganese oxides[J]. Surface Technology, 1980, 10(2): 123-131.
30	任成. 涡流空气分级机流场分布规律及结构对比研究[D]. 北京: 北京化工大学, 2019.
	Ren C. Comparative study on flow field distribution and structure of vortex air classifier[D]. Beijing: Beijing University of Chemical Technology, 2019.
31	Yu Y, Chen W, Kong X, et al. Design of the new guide vane for the turbo air classifier[J]. Materialwissenschaft Und Werkstofftechnik, 2023, 54(2): 196-206.
32	刘蓉蓉. 涡流空气分级机操作参数匹配和蜗壳结构改进的研究[D]. 北京: 北京化工大学, 2015.
	Liu R R. Study on operation parameter matching and volute structure improvement of vortex air classifier[D]. Beijing: Beijing University of Chemical Technology, 2015.
33	Mirzaei M, Jensen P A, Nakhaei M, et al. A hybrid multiphase model accounting for particle agglomeration for coarse-grid simulation of dense solid flow inside large-scale cyclones[J]. Powder Technology, 2022, 399: 117186.
34	张文斌, 祁海鹰, 由长福, 等. 碰撞诱发颗粒团聚及破碎的力学分析[J]. 清华大学学报(自然科学版), 2002, 42(12): 1639-1643.
	Zhang W B, Qi H Y, You C F, et al. Mechanical analysis of agglomeration and fragmentation of particles during collisions[J]. Journal of Tsinghua University (Science and Technology), 2002, 42(12): 1639-1643.
35	刘家祥, 何廷树, 夏靖波. 涡流分级机流场特性分析及分级过程[J]. 硅酸盐学报, 2003, 31(5): 485-489.
	Liu J X, He T S, Xia J B. Air flow field characteristics analyzing and classificationprocess of the turbo classifier[J]. Journal of the Chinese Ceramic Society, 2003, 31(5): 485-489.
36	Teng S L, Wang P, Zhang Q, et al. Analysis of fluid energy mill by gas-solid two-phase flow simulation[J]. Powder Technology, 2011, 208(3): 684-693.
37	Dueck J G, Min’kov L L, Pikushchak E V. Modeling of the “fish-hook” effect in a classifier[J]. Journal of Engineering Physics and Thermophysics, 2007, 80(1): 64-73.
38	Neesse T, Dueck J, Minkov L. Separation of finest particles in hydrocyclones[J]. Minerals Engineering, 2004, 17(5): 689-696.

[1]	叶展羽, 山訸, 徐震原. 用于太阳能蒸发的折纸式蒸发器性能仿真[J]. 化工学报, 2023, 74(S1): 132-140.
[2]	张义飞, 刘舫辰, 张双星, 杜文静. 超临界二氧化碳用印刷电路板式换热器性能分析[J]. 化工学报, 2023, 74(S1): 183-190.
[3]	王志国, 薛孟, 董芋双, 张田震, 秦晓凯, 韩强. 基于裂隙粗糙性表征方法的地热岩体热流耦合数值模拟与分析[J]. 化工学报, 2023, 74(S1): 223-234.
[4]	宋嘉豪, 王文. 斯特林发动机与高温热管耦合运行特性研究[J]. 化工学报, 2023, 74(S1): 287-294.
[5]	张思雨, 殷勇高, 贾鹏琦, 叶威. 双U型地埋管群跨季节蓄热特性研究[J]. 化工学报, 2023, 74(S1): 295-301.
[6]	肖明堃, 杨光, 黄永华, 吴静怡. 浸没孔液氧气泡动力学数值研究[J]. 化工学报, 2023, 74(S1): 87-95.
[7]	温凯杰, 郭力, 夏诏杰, 陈建华. 一种耦合CFD与深度学习的气固快速模拟方法[J]. 化工学报, 2023, 74(9): 3775-3785.
[8]	何松, 刘乔迈, 谢广烁, 王斯民, 肖娟. 高浓度水煤浆管道气膜减阻两相流模拟及代理辅助优化[J]. 化工学报, 2023, 74(9): 3766-3774.
[9]	邢雷, 苗春雨, 蒋明虎, 赵立新, 李新亚. 井下微型气液旋流分离器优化设计与性能分析[J]. 化工学报, 2023, 74(8): 3394-3406.
[10]	程小松, 殷勇高, 车春文. 不同工质在溶液除湿真空再生系统中的性能对比[J]. 化工学报, 2023, 74(8): 3494-3501.
[11]	刘文竹, 云和明, 王宝雪, 胡明哲, 仲崇龙. 基于场协同和耗散的微通道拓扑优化研究[J]. 化工学报, 2023, 74(8): 3329-3341.
[12]	洪瑞, 袁宝强, 杜文静. 垂直上升管内超临界二氧化碳传热恶化机理分析[J]. 化工学报, 2023, 74(8): 3309-3319.
[13]	岳林静, 廖艺涵, 薛源, 李雪洁, 李玉星, 刘翠伟. 凹坑缺陷对厚孔板喉部空化流动特性影响研究[J]. 化工学报, 2023, 74(8): 3292-3308.
[14]	汪林正, 陆俞冰, 张睿智, 罗永浩. 基于分子动力学模拟的VOCs热氧化特性分析[J]. 化工学报, 2023, 74(8): 3242-3255.
[15]	韩晨, 司徒友珉, 朱斌, 许建良, 郭晓镭, 刘海峰. 协同处理废液的多喷嘴粉煤气化炉内反应流动研究[J]. 化工学报, 2023, 74(8): 3266-3278.