机筒槽深和机筒与螺棱间隙对力化学反应器的影响

从对力化学反应器挤出成型和剪切效果有重要影响的机筒螺槽深度(简称槽深)和机筒与螺棱间隙着手,分别通过改变机筒槽深和机筒与螺棱间隙,采用Polyfl ow软件对聚乙烯熔体在等温状态下的挤出过程进行数值模拟。对表征力化学反应器剪切效果的参数指标,如最大剪切速率、最大剪切应力和最大混合指数作相应的比较分析。研究结果表明,机筒未开槽(槽深0 mm)或槽深过大(2 mm)均降低了力化学反应器对物料的剪切和混合作用,而槽深为1 mm时,获得的最大剪切速率、最大剪切应力值和最大混合指数最大;随着机筒与螺棱间隙从0.5 mm依次增加到1 mm和2 mm,力化学反应器对物料的剪切及混合能力依次减弱,当机筒槽深为1 mm,且机筒和螺棱的间隙尺寸为0.5 mm时力化学反应器对物料的剪切和混合效果最好。

Inlfuence of Cylinder Groove Depth and Gaps between Cylinder and Screw on Force Chemical Reactor

From the following aspects that the cylinder groove depth and the gaps between cylinder and screw arris have great effects on the extruding performance and shearing action of force chemical reactor,by changing the cylinder groove depth and the gaps between cylinder and screw arris respectively,the extruding process of polyethylene melt in isothermal flow fields was simulat-ed with Ployflow software. To represent the shear effect of the force chemical reactor,contrastive analysis for some parameters,such as maximum shear rate,maximum shear stress and maximum mixing index,were carried out.The results show that,the shearing and mixing actions for material of the force chemical reactor are reduced when cylinder is machined with groove depth of 0 mm and 2 mm,respectively. When groove depth is 1 mm,the maximum shear rate,maximum shear stress and maximum mixing index are the largest. With the increase of the gaps between cylinder and screw arris (increasing from 0.5 mm to 1 mm and 2 mm in turn),the shear and mixing ability are gradually weaken for the force chemical reactor. When cylinder is machined with groove depth of 1 mm and the gaps between cylinder and screw arris is 0.5 mm,the shear and mixing effect of particles in flow channel is the best.