科研之友
微信
新浪微博
Facebook
分享链接
摘要
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 and 2:1. 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.
- 出版日期2018-8-1
- 单位华南理工大学
