摘要
自主研制了可切换螺杆转速比的机筒全程透明的同向双螺杆挤出仪器,可分别进行等速及差速双螺杆挤出可视化实验研究。制备了羧甲基纤维素钠溶液作为加工流体,观察不同计量加料情况下,螺杆构型及双螺杆转速对流体输送行为的影响,提出了全新的包括正位移和拖曳流的部分充满流体输送模型。实验表明,在非充满情况下,流体输送的拓扑路线不同,与等速双螺杆相比,物料在差速双螺杆左右螺槽内充满度存在非对称现象,上下啮合区存在较大的堆积现象。2种螺杆构型输送机理相似,均存在拖曳流、正位移输送及螺杆机筒间隙漏流。在非充满情况下,初步建立了差速同向自洁双螺杆的流体输送解析理论,得到了不同情况下充满度计算公式。当产量一定时,随着螺杆转速的增加,螺槽充满度下降,漏流增大,拖曳流量减少,而正位移量增加。
A novel co-rotating extrusion device was self-developed,where the whole barrel was transparent and the speed ratio output of one screw to another screw could be adjusted to 1∶1 or 2∶1.The visualization experiments were conducted to study the extrusion processes using the speed ratios of screw pairs of 1∶1 and2∶1.A kind of colored sodium carboxymethyl cellulose was prepared as a test fluid,and its rheological properties were characterized.Effect of the screw configurations and screw speed on the conveying behavior was observed when the different feed rate was used.A new conveying model considering the positive displacement and drag flow was proposed.The experimental results show that the topologies of fluid conveying are quite different when the screw channel is partially filled.Compared with the twin screw configuration,the configuration with the speed difference in screw pair finds the asymmetry effect of fill degrees in the left and right channels,and the larger pile-up of fluid appears in the top and lower intermeshing regions.The both configurations share the similar conveying mechanism,including drag flow,positive displacement transport and the leakage between the barrel and the screw tip.Under the condition of partial fill,the analytical equations are derived for the first time regarding fluid conveying in co-rotating non-twin screw channels,and then the fill degrees under different operations can be obtained.When the output remains unchanged,with the increase of screw speed,the fill degree decreases along with the increase of leakage and the positive displacement transport in contrast to the decrease of drag flow.
作者
喻慧文
吴宏武
徐百平
周延辉
蓝叶青
王玫瑰
Huiwen Yu;Hongwu Wu;Baiping Xu;Yanhui Zhou;Yeqing Lan;Meigui Wang(National Engineering Research Center of Novel Equipment for Polymer Processing,South China University of Technology,Guangzhou 529020,China;Advanced Research Center for Polymer Processing Engineering of Guangdong Province,Technology Development Center for Polymer Processing Engineering of Guangdong Colleges and Universities,Guangdong Industry Polytechnic,Guangzhou 510300,China)
出处
《高分子材料科学与工程》
EI
CAS
CSCD
北大核心
2018年第8期88-95,共8页
Polymer Materials Science & Engineering
基金
国家自然科学基金资助项目(11272093)
关键词
差速双螺杆
粘弹流体
非充满
可视化
输送模型
co-rotating non-twin screw
viscoelastic fluid
partial fill
visualizatiort
conveying model
