新型偏心三螺杆挤出机流体混合特性分析  

Study on mixing characteristics in conveying section of new eccentric tri⁃screw extruder

作　　者：刘杨 朱向哲[1] LIU Yang;ZHU Xiangzhe(School of Mechanical Engineering,Liaoning Shihua University,Fushun 113001,China)

机构地区：[1]辽宁石油化工大学机械工程学院,辽宁抚顺113001

出　　处：《中国塑料》2022年第7期150-156,共7页China Plastics

基　　金：国家自然科学基金项目(5197031333)。

摘　　要：在传统的三螺杆挤出机的基础上,设计了一种新型偏心三螺杆挤出机。该三螺杆挤出机中具有螺杆几何结构偏心、螺槽构型呈梯度变化特殊以及较高的面积利用系数等特征。利用有限元法对聚丙烯(PP)熔体在新型偏心三螺杆挤出机中流动和混合规律进行三维数值模拟,给出偏心三螺杆挤出机中压力和速度分布规律,计算了3种偏心螺杆挤出流场的停留时间分布、分布指数、分离尺度、最大剪切应力等混合表征参数。结果表明,螺杆偏心距不仅决定了螺杆端面形状,也改变了螺槽梯度的变化程度。随着螺槽梯度的逐渐减小,挤出机内粒子团聚效应逐渐降低、物料剪切作用逐渐增强。在3种新型偏心三螺杆挤出机中,偏心距e=3 mm的新型偏心螺杆挤出机的混合性能相对较好。A new eccentric three‑screw extruder was designed on the basis of the traditional tri‑screw extruder.The tri‑screw extruder had the characteristics of eccentric screw geometry,special gradient change of screw groove configura‑tion,and high area utilization coefficient.The three‑dimensional numerical simulation of the flow and mixing law of poly‑propylene(PP)melt in the new eccentric three‑screw extruder was carried out using the finite element method.The dis‑tribution law of pressure and velocity in the eccentric tri‑screw extruder were presented.The mixing characterization pa‑rameters such as the residence time distribution,distribution index,separation scale,and maximum shear stress of the tri‑eccentric screw extrusion flow fields were calculated.The results indicated that the screw eccentricity not only deter‑mined the shape of the screw end face but also changed the variation degree of the screw groove gradient.The particle ag‑glomeration effect in the extruder decreased but the material shear effect increased with a gradual decrease in the spiral groove gradient.Among the three new eccentric tri‑screw extruders,the new eccentric screw extruder with an eccentrici‑ty of 3 mm had relatively good mixing performance.

关 键 词：新型偏心三螺杆挤出机 偏心距 螺杆端面 螺槽梯度 

分 类 号：TQ320.64[化学工程—合成树脂塑料工业]