华南理工大学学报(自然科学版) ›› 2007, Vol. 35 ›› Issue (12): 61-65.

• 机械工程 • 上一篇    下一篇

延伸流场中的气熔两相流实验现象与分析

李琳1 王洪2 彭玉成3   

  1. 1.华南理工大学 机械工程学院,广东 广州 510640; 2. 华南理工大学 物理科学与技术学院,广东 广州 510640;3. 华南理工大学 工业装备与控制工程学院,广东 广州 510640
  • 收稿日期:2007-01-08 出版日期:2007-12-25 发布日期:2007-12-25
  • 通信作者: 李琳(1962-) ,女,博士,副教授,主要从事机械设计研究. E-mail:linli@scut. edu.cn
  • 作者简介:李琳(1962-) ,女,博士,副教授,主要从事机械设计研究.
  • 基金资助:

    国家自然科学基金资助项目(1 9632004 ) ;广东省自然科学基金资助项目(05300261 ) ;广东省科技攻关项目(2006B12401005) ;华南理工大学自然科学基金资助项目

Experimental Observation and Córresponding Analysis of Bubbles and Polymer Melt in Elongated Flow Field

Li LinWang Hong2  Peng Yu-cheng3   

  1. 1. School of Mechanical Engineering , South China Univ. of Tech. , Guangzhou , 510640 , Guangdong , China;2. School of Physics , South China Univ. of Tech. , Guangzhou 510640 , Guangdong , China;3. School of Industrial Equipment and Control Engineering , South China Univ. of Tech. , Guangzhou 510640 , Guangdong , China
  • Received:2007-01-08 Online:2007-12-25 Published:2007-12-25
  • Contact: 李琳(1962-) ,女,博士,副教授,主要从事机械设计研究. E-mail:linli@scut. edu.cn
  • About author:李琳(1962-) ,女,博士,副教授,主要从事机械设计研究.
  • Supported by:

    国家自然科学基金资助项目(1 9632004 ) ;广东省自然科学基金资助项目(05300261 ) ;广东省科技攻关项目(2006B12401005) ;华南理工大学自然科学基金资助项目

摘要: 为研究气泡在熔体中的动力学,自行设计了圆柱形可视化流道,直接将CO2 气体注入聚合物熔体中,观察CO2 气泡在小孔延伸流场中不同住直区域时,其形态、大小、运动、变形等动力学现象.并从经典两相流理论的角度出友,分析了流场结构参数、加工条件对气泡在聚合物熔体中形态、分布、运动变化等的影响.实验结果表明:气相在熔体中是以泡状存在的,单一的大气泡经过延伸后,将发生破裂,成为许多细碎的小气泡,且破裂的小气泡的大小、分布、密度等与加工温度、速度、进气压力等有关;气泡经过小孔延伸后破裂,使气熔两相趋于混合,有利于CO2 作为发泡剂在泡沫塑料制品生产中的应用.

关键词: 延伸流场, 气泡, 熔融聚合物, 两相流

Abstract:

In order to investigate the dynamics of the bubbles in polymer melt , a self-designed columniform visible flow channel was used , and CO2 gas was directly injected into the polymer melt to obsertre the dynamic characteristics such as shape , size , motion and deformation of the bubbles in different locations in a small-pore enlongated flow field. Moreover , the variations of shape , distribution and motion of the bubbles with the flow-field structural
parameters and the processing conditions were revealed based on the classic two-phase flow theory. Experimental results indicate that (1) the gas phase in the melt exists in the form of bubbles; (2) many small bubbles may form due to the breaking up of a large enlongated bubble , the size , distribution and density of the small bubbles being related to the precessing temperature , velocity and injectión pressure; and (3) the breaking up of bubbles after the enlongation may result in the mixing of the gas and the melt , which is helpful for the application of CO2 as an foaming agent to the production of foamed plastic products.

Key words: elongated flow field, bubble, polymer melt, two-phase flow