基于无根多体系统构建每一个颗粒,采用拉格朗日方法追踪颗粒与其颗粒段,考虑颗粒段之间的铰约束与碰撞效应,分析不同流化风速、颗粒长度等对颗粒流化状态的影响。研究发现：颗粒运动形态多样,呈现伸展、绕曲等多种形式,与流化实验过程中捕捉到的叶丝颗粒的状态近似。短颗粒易被流化带出,随着流化的进行,提升管内较短的颗粒（<0.03 m）数量百分比逐渐下降,甚至低于6%。流出颗粒的数量百分比随其长度的增加而下降;颗粒取向角呈现中间高、两头高的分布趋势;近壁区域颗粒多呈竖直/近竖直状态（±80°~±90°）。次中心区域水平状态（约0°）颗粒的数量百分比随流化的进行增长较为明显;随风速的增大,近壁区域中竖直/近竖直分布的颗粒量增加。
Abstract
Based on the rootless multi-body system, each particle is constructed. The Lagrange method is used to trace the particles and their segments. Considering the hinge constraints and collision effects between particle segments, the effects of different fluidization velocities and particle lengths on the fluidization state of particles are analyzed. The results indicate that the transient morphology of particles is diverse, during the fluidization, including stretching, winding and other forms, which is similar to the state of cut tobacco particles captured during the fluidization experiments. Short particles can be easily discharged by the air flow. As fluidization progresses, the percentage of the number of shorter particles （<0.03 m） in the riser gradually decreases, even less than 6%. The number percentage of the discharged particles decreases with the increase of their length, and the particle orientation angle shows a distribution trend of high in the middle and high at both ends. Most of the particles in the near-wall region are vertical or nearly vertical （plus or minus 80°-90°）. The number percentage of particles with the horizontal state of the subcenter region （about 0°） increases significantly with the progress of fluidization. As the air velocity increases, the amount of vertical or nearly vertical particles increases in the near-wall region.
关键词
生物质 /
流态化 /
颗粒运动 /
多体系统 /
分布特征 /
流化状态
Key words
biomass /
fluidization /
filamentous biomass particles /
multi-body system /
distribution characteristics /
fluidization state
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参考文献
[1] 陆海峰, 卞耀, 郭晓镭, 等. 生物质气流床气化可行性分析与减碳效应[J]. 华东理工大学学报(自然科学版), 2024, 50(3): 328-334.
LU H F, BIAN Y, GUO X L, et al.Feasibility analysis and carbon reduction effect of biomass entrained flow gasification[J]. Journal of East China University of Science and Technology, 2024, 50(3): 328-334.
[2] 德雪红, 杨洋, 金敏, 等. 生物质成型机成型模孔内表面摩擦力分形预测[J]. 太阳能学报, 2022, 43(9): 369-375.
DE X H, YANG Y, JIN M, et al.Fractal prediction of frictional force against interior surface of forming channel in biomass ring die pellet machine[J]. Acta energiae solaris sinica, 2022, 43(9): 369-375.
[3] 闫文刚, 付九如, 李震, 等. 沙柳颗粒压缩成型过程宏细观模拟研究[J]. 太阳能学报, 2023, 44(9): 449-454.
YAN W G, FU J R, LI Z, et al.Research on macro and meso simulation in compression process of salix Psammophila granules[J]. Acta energiae solaris sinica, 2023, 44(9): 449-454.
[4] 汪靖良, 方庆艳, Yin Chungen, 等. 燃煤机组耦合生物质直燃发电研究进展: 非球形生物质大颗粒气固两相动力学模型[J]. 洁净煤技术, 2023, 29(9): 14-23, 5.
WANG J L, FANG Q Y, YIN C G, et al.Research progress on direct-fired biomass power generation in coal-fired units: gas-solid two-phase dynamic model for large non-spherical biomass particles[J]. Clean coal technology, 2023, 29(9): 14-23, 5.
[5] 周长江, 陈钇杰, 陈海康, 等. 基于CFD-DEM的柔性生物质颗粒取向特性研究[J]. 湖南大学学报(自然科学版), 2023, 50(10): 212-222.
ZHOU C J, CHEN Y J, CHEN H K, et al.Investigation on flexible biomass particle orientation characteristics based on CFD-DEM[J]. Journal of Hunan University (natural sciences), 2023, 50(10): 212-222.
[6] 赵海超, 许冰洋, 张军, 等. 丝状生物质颗粒在矩形提升管内的分布特性[J]. 太阳能学报, 2023, 44(9): 455-461.
ZHAO H C, XU B Y, ZHANG J, et al.Study on distribution characteristics of filamentous biomass particles in rectangular fluidized riser[J]. Acta energiae solaris sinica, 2023, 44(9): 455-461.
[7] GUO F H, HE Y, HASSANPOUR A, et al.Thermogravimetric analysis on the co-combustion of biomass pellets with lignite and bituminous coal[J]. Energy, 2020, 197: 117147.
[8] WANG J, ZHANG S Y, GUO X, et al.Thermal behaviors and kinetics of pingshuo coal/biomass blends during copyrolysis and cocombustion[J]. Energy & fuels, 2012, 26(12): 7120-7126.
[9] LIU L, MEMON M Z, XIE Y B, et al.Recent advances of research in coal and biomass co-firing for electricity and heat generation[J]. Circular economy, 2023, 2(4): 100063.
[10] GENG F, TENG H X, GUI C G, et al.Investigation on distribution characteristics of flexible biomass particles in a fluidized bed riser[J]. Fuel, 2020, 271: 117528.
[11] WU K, LI B, GAO L Y, et al.Study on the distribution characteristics of flexible filamentous particle clusters in a fluidized bed dryer[J]. Powder technology, 2018, 331: 7-19.
[12] WU K, ZHANG E Q, XU J, et al.Three-dimensional simulation of gas-solid flow in a fluidised bed with flexible ribbon particles[J]. International journal of multiphase flow, 2020, 124: 103181.
[13] 洪嘉振. 计算多体系统动力学[M]. 北京: 高等教育出版社, 1999.
HONG J Z.Computational dynamics of multibody systems[M]. Beijing: Higher Education Press, 1999.
[14] 姚文莉, 陈滨, 刘才山, 等. 含摩擦的多刚体系统碰撞问题的滑动状态步进法[J]. 应用数学和力学, 2007, 28(12): 1448-1454.
YAO W L, CHEN B, LIU C S, et al.Sliding state stepping algorithm solving impact problems of multi-rigid-body system with joint friction[J]. Applied mathematics and mechanics, 2007, 28(12): 1448-1454.
[15] GENG F, CHAI H L, MA L, et al.Simulation of dynamic transport of flexible ribbon particles in a rotary dryer[J]. Powder technology, 2016, 297: 115-125.
[16] 耿凡, 袁竹林, 王宏生, 等. 流化床中细长柔性颗粒分布特性的数值研究[J]. 中国电机工程学报, 2009, 29(35): 102-108.
GENG F, YUAN Z L, WANG H S, et al.Numerical simulation on the distribution characteristics of flexible slender particles in a circulating fluidized bed[J]. Proceedings of the CSEE, 2009, 29(35): 102-108.
[17] GENG F, LUO G, LI Y M, et al.Numerical simulation on distribution characteristics of flexible filamentous particles in a fluidized bed dryer[J]. Powder technology, 2014, 267: 322-332.
[18] 蔡杰, 赵孝保, 耿凡. 气/固双向耦合的细长颗粒流化运动特征的数值研究[J]. 太阳能学报, 2018, 39(11): 3169-3177.
CAI J, ZHAO X B, GENG F.Numerical study on fluidized behaviors of slender particles based on gas-solid two-way coupling[J]. Acta energiae solaris sinica, 2018, 39(11): 3169-3177.
[19] 蔡杰, 赵孝保, 袁竹林, 等. 循环流化床内细长颗粒取向分布的多向耦合数值模拟[J]. 燃烧科学与技术, 2018, 24(2): 158-164.
CAI J, ZHAO X B, YUAN Z L, et al.Numerical simulation on orientation distribution of slender particles in a CFB based on gas-solid multi-way coupling[J]. Journal of combustion science and technology, 2018, 24(2): 158-164.
基金
徐州市基础研究计划（KC23050）; 国家自然科学基金青年项目（51506215）
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