Journal of South China University of Technology (Natural Science Edition) ›› 2007, Vol. 35 ›› Issue (12): 61-65.

• Mechanical Engineering • Previous Articles     Next Articles

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

Li Lin1  Wang 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

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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