Study on Mixing Characteristics of Differential Self⁃cleaning Mixer Based on Discrete Element Method

doi:10.19491/j.issn.1001-9278.2020.04.010

Abstract

Abstract:

The mixing process of calcium carbonate?filled PE?HD composite in the LIST horizontal differential biaxial mixing equipment was simulated by a discrete element method, and the effects of addition speed and mixing rate on the material filling degree, residence time distribution and mixing uniformity of compounds in the self?cleaning mixer were investigated. The results indicated that the axial conveying capacity of the self?cleaning mixer was mainly derived from the pushing effect of subsequent materials. The optimum mixing effect could be achieved at a shaft rotation speed of 40 r/min and a feeding rate of 10 kg/h.

Key words: self?cleaning mixer, discrete method, mixing characteristics

CLC Number:

TQ 051.7

Xiliang SHAN, Yulu MA, Linsheng XIE, Huihao ZHU, Dayou DING. Study on Mixing Characteristics of Differential Self⁃cleaning Mixer Based on Discrete Element Method[J]. China Plastics, 2020, 34(4): 54-59.

Figures/Tables 11

结构参数	数值
长×宽×高/mm	310×175×120
中心距/mm	58
机筒内径/mm	82
搅拌轴长/mm	280
搅拌轴外径/mm	80
搅拌轴外径/mm	30

Tab.1. Structural parameters of self?cleaning mixer

Fig.1. Self?cleaning mixer geometry model

颗粒材料	参数	参数值
PE?HD?PE?HD	拉开力/N	0
	表面能/ J·m^-2	3
	接触塑性变形比	0.8
	切向刚度系数	0.3
PE?HD?碳酸钙	拉开力/N	0
	表面能/ J·m^-2	2
	接触塑性变形比	0.5
	切向刚度系数	0.25
碳酸钙?碳酸钙	拉开力/N	0
	表面能/ J·m^-2	0.25
	接触塑性变形比	0.2
	切向刚度系数	0.8

Tab. 2. EEPA model’s parameter settings

Fig.2. Curve of equilibration time and material fullness at different feed rates

Fig.6. Mesh division of the mixer

Fig.7. Time?dependent variation curve of discrete coefficient λ in different regions of a mixing chamber

Fig.8. G05 regional dispersion coefficient λ curve at different feed rates under steady state of the mixer

Fig.9. Dispersion coefficient λ curve in G05 at different speeds of the mixer under steady state

References 9

1	李琳. 短纤维增强复合材料的制备及其力学性能研究[D].长春：吉林大学,2019.
2	陈登丰. 搅拌器和搅拌容器的发展[J]. 压力容器, 2008, 25(2):33⁃41.
	CHEN D F. Development of Agitator and Agitator Vessel [J]. Pressure Vessel, 2008, 25(2):33⁃41.
3	栗广奉. 羟基聚硅氧烷平衡聚合脱挥及反应器研究[D]. 杭州：浙江大学, 2004.
4	YUE D, LIU Y, SHEN Z, et al. Study on Preparation and Properties of Carbon nanotubes/Rubber Composites[J]. Journal of Materials Science, 2006, 41(8):2 541⁃2 544.
5	冯刚. 螺杆挤出机挤出过程数值模拟研究进展[J]. 工程塑料应用, 2012, 40(4):96⁃99.
	FENG G. Research Progress in Numerical Simulation of Extruder Extrusion process [J]. Engineering Plastics Applications, 2012, 40(4):96⁃99.
6	PANTALEEV S, YORDANOVA S, JANDA A, et al. An Experimentally Validated DEM Study of Powder Mixing in a Paddle Blade Mixer[J]. Powder Technology, 2017, 311(1):287⁃302.
7	HASSANPOUR A, TAN H, BAYLY A, et al. Analysis of Particle Motion in a Paddle Mixer Using Discrete Element Method (DEM)[J]. Powder Technology, 2011, 206(1):189⁃194.
8	EITZLMAYR A, KHINAST J. Co⁃Rotating Twin⁃Screw Extruders: Detailed Analysis of Conveying Elements Based on Smoothed Particle Hydrodynamics. Part 1: Hydrodynamics [J]. Chemical Engineering Science, 2015, 134(9):861⁃879.
9	EITZLMAYR A, KHINAST J. Analysis of Flow and Mixing in Screw Elements of Corotating Twin‐screw Extruders via SPH[J]. Aiche Journal, 2016, 63(6):2 451⁃2 463.

[1]	PANG Junjian HE Yadong XIN Chunling YU Dongquan LI Qingchun. Comparison of Mixing Performance of Three-screw Extruders with Twin-screw Extruders [J]. China Plastics, 2012, 26(06): 107-111 .
[2]	PANG Junjian HE Yadon XIN Chunling YU Dongqua LI Qingchun. Numerical Study on Mixing Characteristics of Screw Elements in Three-screw Extruders [J]. China Plastics, 2012, 26(01): 103-108 .