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Granular grinding is one of the most important unit operations used in a wide variety of industries. Examples can be found in the food industry, for instance, rice processing, etc.. The performance of grinding can be characterized by the particle flow process. Thus in order to study the stable flow process of particles during grinding, we must establish a discrete element model (DEM) of granular axial flow in the grinding area between the grinding roller and the screen drum. DEM is a numerical method used for modelling the mechanical behaviour of granular materials. When DEM is used in grinding, the particle motion is controlled by contact models that are governed by physical laws. Using EDEM software, the process of grinding can be simulated and analyzed. The simulation system chooses continuous feeding; after a period of time, it reaches a steady flow. Research results show that the uneven distribution of particle flow density (PFD) is caused by the axial movement difference of particles in the grinding area. The form, flow rate and distribution of granular axial flow are influenced by static friction coefficient difference between particles and screen drum. Axial mean square deviation of single particles in the grinding area is positively correlated with the square of time, which follows a “super” diffusive behavior defined by some studies. By an overall consideration of the grinding area, we find that the axial average velocities increase, however, the average velocities that are synthesized by three-axis velocities gradually decrease along the axial direction. This is because in a different axial position with different PFI, the PFI plays the key role in energy transfer. More energy will be transferred between high PFI particles that may cause high particle velocity. We also find that the fluctuation velocity square of particles presents the trend of first increasing then decreasing and finally increasing along the axial direction. The difference between PFIs is also elucidated by the total energy dissipation in each collisional energy level for a single particle. Results show that the single particle can endure intenser collision, more energy loss in anterior half segment than those in the second half of the grinding area. As mentioned above, the particle flow was analyzed in terms of particle flow intensity, particle velocity, collision energy, collision number, and so on. Some experimental results confirm the validity of the simulation. The simulation reflects the stable flow characteristics of particles in the grinding area and provides bases and references for further studying the product quality control and grinding equipment parameters optimization.
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Keywords:
- particle flow /
- grinding area /
- discrete element /
- simulation
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[2] Zhao Y Z, Jiang M Q, Zheng J Y 2009 Acta Phys. Sin. 58 1812 (in Chinese) [赵永志, 江茂强, 郑津洋 2009 58 1812]
[3] Tahvildarian P, Mozaffari F E, Upreti S 2013 Particuology 11 619
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[6] Pasha M, Hassanpour A, Ahmadian H, Tan H S, Bayly A, Ghadiri M 2015 Powder Technol. 270 569
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[12] Lu G, Third J R, Muller C R 2014 Particuology 12 44
[13] Parker D J, Djkstra A E, Martin T W, Seville J P K 1997 Chem. Eng. Sci. 52 2011
[14] Third J R, Scott D M, Scott S A 2010 Powder Technol. 203 510
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[18] Han Y L, Jia F G, Tang Y R, Liu Y, Zhang Q 2014 Acta Phys. Sin. 63 174501 (in Chinese) [韩燕龙, 贾富国, 唐玉荣, 刘扬, 张强 2014 63 174501]
[19] Zhou X Q 2011 Rice Processing Technology and Equipment(Beijing:China Light Industry Press) p163 (in Chinese) [周显青 2011 稻谷加工工艺与设备(北京: 中国轻工业出版社)第163页]
[20] Khanal M, Jayasundara C T 2014 Particuology 16 54
[21] Jayasundara C T, Yang R Y, Yu A B, Curry D 2008 Chem. Eng. J. 135 103
[22] Yang R Y, Yu A B, Mcelroy L, Bao J 2008 Powder Technol. 188 170
[23] Yang R Y, Jayasundara C T, Yu A B, Curry D 2006 Miner. Eng. 19 984
[24] Meng F J, Liu K 2014 Acta Phys. Sin. 63 134502 (in Chinese) [孟凡净, 刘焜 2014 63 134502]
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[1] Sun Q C, Wang G Q 2008 Adv. Mech. 38 87 (in Chinese) [孙其诚, 王光谦 2008 力学进展 38 87]
[2] Zhao Y Z, Jiang M Q, Zheng J Y 2009 Acta Phys. Sin. 58 1812 (in Chinese) [赵永志, 江茂强, 郑津洋 2009 58 1812]
[3] Tahvildarian P, Mozaffari F E, Upreti S 2013 Particuology 11 619
[4] Sinnott M D, Cleary P W 2015 Miner. Eng. 74 163
[5] Wang M H, Yang R Y, Yu A B 2012 Powder Technol. 223 83
[6] Pasha M, Hassanpour A, Ahmadian H, Tan H S, Bayly A, Ghadiri M 2015 Powder Technol. 270 569
[7] Ma Z, Li Y M, Xu L Z 2013 Trans. CSAM. 44 22 (in Chinese) [马征, 李耀明, 徐立章 2013 农业机械学报 44 22]
[8] Jayasundara C T, Yang R Y, Yu A B, Rubenstein J 2010 Int. J. Miner. Process. 96 27
[9] Cleary P W 2006 Appl. Math. Model. 30 1343
[10] Cunha E R D, Carvalho R M D, Tavares L M 2013 Miner. Eng. 43 85
[11] Morrison R D, Cleary P W, sinnott M D 2009 Miner. Eng. 22 665
[12] Lu G, Third J R, Muller C R 2014 Particuology 12 44
[13] Parker D J, Djkstra A E, Martin T W, Seville J P K 1997 Chem. Eng. Sci. 52 2011
[14] Third J R, Scott D M, Scott S A 2010 Powder Technol. 203 510
[15] Zhu Y Y 1999 Rice Processing and Comprehensive Utilization(Beijing:China Light Industry Press) p149 (in Chinese) [朱永义 1999 稻谷加工与综合利用(北京: 中国轻工业出版社)第149页]
[16] Hu J P, Guo K, Zhou C J, Hou C 2014 Trans. CSAM. 45 61 (in Chinese) [胡建平, 郭坤, 周春健, 侯冲 2014 农业机械学报 45 61]
[17] Chen J, Zhou H, Zhao Z, Li Y M, Gong Z Q 2011 Trans. CSAM. 42 79 (in Chinese) [陈进, 周韩, 赵湛, 李耀明, 龚智强 2011 农业机械学报 42 79]
[18] Han Y L, Jia F G, Tang Y R, Liu Y, Zhang Q 2014 Acta Phys. Sin. 63 174501 (in Chinese) [韩燕龙, 贾富国, 唐玉荣, 刘扬, 张强 2014 63 174501]
[19] Zhou X Q 2011 Rice Processing Technology and Equipment(Beijing:China Light Industry Press) p163 (in Chinese) [周显青 2011 稻谷加工工艺与设备(北京: 中国轻工业出版社)第163页]
[20] Khanal M, Jayasundara C T 2014 Particuology 16 54
[21] Jayasundara C T, Yang R Y, Yu A B, Curry D 2008 Chem. Eng. J. 135 103
[22] Yang R Y, Yu A B, Mcelroy L, Bao J 2008 Powder Technol. 188 170
[23] Yang R Y, Jayasundara C T, Yu A B, Curry D 2006 Miner. Eng. 19 984
[24] Meng F J, Liu K 2014 Acta Phys. Sin. 63 134502 (in Chinese) [孟凡净, 刘焜 2014 63 134502]
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