螺旋分选机流场及颗粒运动的数值模拟研究
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摘要
采用CFD-DEM单向耦合的数值模拟方法研究了螺旋分选机的流场和颗粒的运动特性,实验和模拟分析了1～1.5 mm粒级煤粒的分选过程.结果表明:水流在首圈回转过程中,水膜外缘不断增厚,内缘不断变薄.颗粒随水流进行回转运动,低密度颗粒悬浮在流膜上层,中高密度颗粒呈滚动或跳跃状态.密度、粒度和入料流量对颗粒的回转半径影响显著,当回转角度小于120°时,不同尺度颗粒的运动轨迹基本一致;回转角度大于120°后,密度和粒度越大的颗粒回转半径越小.入料量为3.0 m~3/h时,低密度颗粒和高密度颗粒回转半径差减小至14.07 mm.入料流量对螺旋分选机的分选密度影响明显,对不完善度影响较小.
Numerical simulation of unidirectional coupling CFD and DEM was adopted to study the flow field and particle motion characteristics of the spiral separator. Experiment and simulation analysis of the separation process of 1—1.5 mm coal particles was conducted. The results show that during the first rotation of the water flow, the thickness of the outer edge of the water film increases continuously, while the thickness of the inner edge decreases continuously. The particles move in a circular motion with the water flow. The low-density particles suspend in the upper layer of the flow film, while the medium-high-density particles are in a rolling or jumping state. Density, particle size and feed rate have significant effect on the rotating radius of the particles. When the rotation angle is less than 120°, the movement of particles with different particle sizes and density are basically the same. When the rotation angle is greater than 120°, the particles with larger density and particle size would have smaller rotating radius. When the feed rate is 3.0 m~3/h, the difference in rotating radius between the low-density particles and the high-density particles reduces to 14.07 mm. The feed rate has a significant effect on the separation density, but little effect on the imperfection.
Numerical simulation of unidirectional coupling CFD and DEM was adopted to study the flow field and particle motion characteristics of the spiral separator. Experiment and simulation analysis of the separation process of 1—1.5 mm coal particles was conducted. The results show that during the first rotation of the water flow, the thickness of the outer edge of the water film increases continuously, while the thickness of the inner edge decreases continuously. The particles move in a circular motion with the water flow. The low-density particles suspend in the upper layer of the flow film, while the medium-high-density particles are in a rolling or jumping state. Density, particle size and feed rate have significant effect on the rotating radius of the particles. When the rotation angle is less than 120°, the movement of particles with different particle sizes and density are basically the same. When the rotation angle is greater than 120°, the particles with larger density and particle size would have smaller rotating radius. When the feed rate is 3.0 m~3/h, the difference in rotating radius between the low-density particles and the high-density particles reduces to 14.07 mm. The feed rate has a significant effect on the separation density, but little effect on the imperfection.
引文
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[15] MISHRA B K,TRIPATHY A.A preliminary study of particle separation in spiral concentrators using DEM[J].International Journal of Mineral Processing,2010,94(3/4):192-195.
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[18] 韦鲁滨,李大虎,陈赞歌,等.颗粒在脉动气流场中受力和分选的数值模拟[J].中国矿业大学学报,2017,46(1):162-168.WEI Lubin,LI Dahu,CHEN Zange,et al.Numerical simulation of force and separation on particles in pulsing airflow[J].Journal of China University of Mining & Technology,2017,46(1):162-168.
[19] 杨宁,李静海.化学工程中的介尺度科学与虚拟过程工程:分析与展望[J].化工学报.2014,65(7):2403-2409.YANG Ning,LI Jinghai.Mesoscale science and virtual process engineering in chemical engineering:Analysis and prospect[J].Journal of Chemical Industry,2014,65(7):2403-2409.
[20] 叶贵川,马力强,黄根,等.螺旋分选机动力学分析及参数优化探讨[J].煤炭学报.2017,42(增2):479-485.YE Guichuan,MA Liqiang,HUANG Gen,et al.Dynamic analysis and parameter optimization of helical separator[J].Journal of China Coal Society,2017,42(Sup2):479-485.
[21] 黄尚安,唐玉白,黄枢.螺旋溜槽中的二次环流和矿粒运动轨迹的研究[J].中南矿冶学院学报,1987,18(2):130-136.HUANG Shang’an,TANG Yubai,HUANG Shu.Secondary circulation and particle trajectories in spiral chute[J].Journal of China Mining and Metallurgy University,1987,18(2):130-136.
[22] 卢继美.螺旋选矿机中水流的运动规律[J].有色金属(选矿部分),1980(4):34-43.LU Jimei.Movement law of water flow in spiral concentrator[J].Nonferrous Metals (Mineral Processing Section),1980(4):34-43.
[2] 杨小平.物理选矿[M].北京:冶金工业出版社,2014:171-173.YANG Xiaoping.Physical mineral processing[M].Beijing:Metallurgical Industry Press,2014:171-173.
[3] JAIN P K,RAYASAM V.An analytical approach to explain the generation of secondary circulation in spiral concentrators[J].Powder Technology,2017,308:165-177.
[4] KAPUR P C,MELOY T P.Industrial modeling of spirals for optimal configuration and design:Spiral geometry,fluid flow and forces on particles[J].Powder Technology,1999,102(3):244-252.
[5] HOLLAND-BATT A B,HOLTHAM P N.Particle and fluid motion on spiral separators[J].Minerals Engineering,1991,4(3/4):457-482.
[6] MATTHEWS B W,FLETCHER C A J,PARTRIDGE A C.Computational simulation of fluid and dilute particulate flows on spiral concentrator[J].Applied Mathematical Modelling,1998,22(12):965-979.
[7] 楚遵勇.螺旋分选机流场的数值模拟[D].北京:中国矿业大学(北京),2017:25-45.CHU Zunyong.Numerical simulation of flow field in spiral sorter[D].Beijing:China University of Mining and Technology (Beijing),2017:25-45.
[8] 高淑玲,魏德洲,崔宝玉,等.基于CFD的螺旋溜槽流场及颗粒运动行为数值模拟[J].金属矿山,2014(11):121-126.GAO Shuling,WEI Dezhou,CUI Baoyu,et al.Numerical simulation of flow field and particle motion behavior in helical chute based on CFD[J].Metal Mine,2014(11):121-126.
[9] KWON J,KIM H,LEE S,et al.Simulation of particle-laden flow in a humphrey spiral concentrator using dust-liquid smoothed particle hydrodynamics[J].Advanced Powder Technology,2017,28(10):2694-2705.
[10] 刘祚时,赵南琪,刘惠中,等.螺旋溜槽分选流场中矿粒运动轨迹研究[J].中国钨业,2016,31(5):66-71.LIU Zuoshi,ZHAO Nanqi,LIU Huizhong,et al.Study on orbital movement trajectory in spiral flow chamber choosing flow field[J].China Tungsten Industry,2016,31(5):66-71.
[11] 李华梁.CFD技术应用于螺旋选矿机结构优化的研究[D].南昌:江西理工大学,2016:23-31.LI Hualiang.Research on application of CFD technology in structural optimization of spiral concentrator[D].Nanchang:Jiangxi University of Science and Technology,2016:23-31.
[12] DOHEIM M A,ABDEL GAWAD A F,MAHRAN G M A,et al.Numerical simulation of particulate-flow in spiral separators:Part I.Low solids concentration (0.3% & 3% solids)[J].Applied Mathematical Modelling,2013,37(1/2):198-215.
[13] 卢洲,刘雪东,潘兵.基于CFD-DEM方法的柱状颗粒在弯管中输送过程的数值模拟[J].中国粉体技术.2011,17(5):65-69.LU Zhou,LIU Xuedong,PAN Bing.Numerical simulation of columnar particles transporting in elbows based on CFD-DEM method[J].China Powder Technology,2011,17(5):65-69.
[14] 杜俊.基于CFD-DEM方法的稀相气力输送数值模拟研究[D].武汉:武汉大学,2015:70-74.DU Jun.Numerical simulation of dilute phase pneumatic conveying based on CFD-DEM method[D].Wuhan:Wuhan University,2015:70-74.
[15] MISHRA B K,TRIPATHY A.A preliminary study of particle separation in spiral concentrators using DEM[J].International Journal of Mineral Processing,2010,94(3/4):192-195.
[16] 杨盼盼,肖鹏,丁燕,等.基于离散元法的沥青混合料细观特性分析[J].中国矿业大学学报,2017,47(4):900-906.YANG Panpan,XIAO Peng,DING Yan,et al.Microstructure characteristics analysis of asphalt mixture based on the discrete element method[J].Journal of China University of Mining & Technology,2017,47(4):900-906.
[17] 赵跃民,张曙光,焦红光,等.振动平面上粒群运动的离散元模拟[J].中国矿业大学学报,2006,35(5):586-590.ZHAO Yuemin,ZHANG Shuguang,JIAO Hongguang,et al.Simulation of discrete element of particles motion on the vibration plane[J].Journal of China University of Mining & Technology,2006,35(5):586-590.
[18] 韦鲁滨,李大虎,陈赞歌,等.颗粒在脉动气流场中受力和分选的数值模拟[J].中国矿业大学学报,2017,46(1):162-168.WEI Lubin,LI Dahu,CHEN Zange,et al.Numerical simulation of force and separation on particles in pulsing airflow[J].Journal of China University of Mining & Technology,2017,46(1):162-168.
[19] 杨宁,李静海.化学工程中的介尺度科学与虚拟过程工程:分析与展望[J].化工学报.2014,65(7):2403-2409.YANG Ning,LI Jinghai.Mesoscale science and virtual process engineering in chemical engineering:Analysis and prospect[J].Journal of Chemical Industry,2014,65(7):2403-2409.
[20] 叶贵川,马力强,黄根,等.螺旋分选机动力学分析及参数优化探讨[J].煤炭学报.2017,42(增2):479-485.YE Guichuan,MA Liqiang,HUANG Gen,et al.Dynamic analysis and parameter optimization of helical separator[J].Journal of China Coal Society,2017,42(Sup2):479-485.
[21] 黄尚安,唐玉白,黄枢.螺旋溜槽中的二次环流和矿粒运动轨迹的研究[J].中南矿冶学院学报,1987,18(2):130-136.HUANG Shang’an,TANG Yubai,HUANG Shu.Secondary circulation and particle trajectories in spiral chute[J].Journal of China Mining and Metallurgy University,1987,18(2):130-136.
[22] 卢继美.螺旋选矿机中水流的运动规律[J].有色金属(选矿部分),1980(4):34-43.LU Jimei.Movement law of water flow in spiral concentrator[J].Nonferrous Metals (Mineral Processing Section),1980(4):34-43.