加料机单、双头螺旋对颗粒群接触力的影响

Effect of single/double screw feeder on contact force of particles

为研究螺旋加料机不连续加料过程中颗粒群的运动特性及变化规律,研究了单、双头螺旋对颗粒群接触力的影响.以1. 5 mm直径小米颗粒为研究对象,基于Hertz-Mindlin颗粒无滑动接触模型,对颗粒之间接触力以及颗粒群与螺旋加料料管内壁接触力进行分析,建立了具有分料装置的螺旋加料模型;采用EDEM离散元软件,以间歇转动60°的方式对小米颗粒不连续加料过程进行数值仿真,得到了颗粒间接触力和颗粒群对螺旋加料料管内壁正向和切向压力的分布,比较了240 r·min^(-1)转速下单、双头螺旋输送中颗粒群接触力分布特点.结果表明:单头螺旋输送物料时,颗粒之间比较紧实,但颗粒在内壁接触处易翻滚;双头螺旋输送物料时,颗粒在内壁接触处不易翻滚,更易随轴作轴向运动,颗粒群的一致性更稳定.

To study the movement characteristics and variation law of particles in the discontinuous feeding process of screw feeder,the effect of single/double screw feeder on the contact force of particles was studied.The millet with 1.5 mm diameter was taken as research object,and the contact force among particles and the contact force between particles and trough were analyzed based on Hertz-Mindlin particle non-sliding contact model.The screw feeding model with feeding device was established.EDEM discrete element software was adopted to simulate the discontinuous feeding process of millet particles by intermittent rotation 60°.The normal and tangential pressure distributions between particles and particle groups on the inner wall of screw feeding tube were calculated.The contact force distribution characteristics of particle groups in single/double screw feeding at 240 r·min^-1 speed were compared.The results show that the particles are compact but easy to roll in the single-flight screw feeder.The stability of screw discontinuous quantitative feeding is better in the double-flight feeder.The particles are not easy to roll at the inner wall,and the axial movement of particles occurs easily with the shaft.