Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


akron1302535388.pdf (1.12 MB)

ETD Abstract Container

Abstract Header

Finite Element Analysis of Drop Deformation in the Entrance Region of a Cylindrical Tube

Yingsheng, Xing
http://rave.ohiolink.edu/etdc/view?acc_num=akron1302535388

Abstract Details

2011, Doctor of Philosophy, University of Akron, Polymer Engineering.
The finite element method was employed to investigate the large deformation of a viscoelastic drop, which was suspended in a viscoelastic medium, moving along the central axis of a cylindrical tube in the entrance region. For the investigation, finite element equations were developed, with the aid of the penalty function method, based on the system equations consisting of the continuity and momentum equations for both the drop and suspending medium, and auto-remeshing technique was employed to describe the moving interface between the drop and suspending medium. The system equations were formulated using the integral-type KBKZ constitutive equation to deal with a moving boundary problem. The effects of (1) the ratio of the relaxation times of the drop and the suspending medium, (2) the viscosity ratio of the drop and suspending medium, (3) the initial drop size, and (4) an apparent shear rate on the extent of the drop deformation were investigated by considering five combinations of viscoelastic drop and viscoelastic suspending medium. The computed shapes of a viscoelastic drop, suspended in another viscoelastic medium, moving along the central axis of a cylindrical tube in the entrance region elongated continuously as it moved towards the tube entrance and recoiled slightly after it passed the tube inlet. Further, the extent of drop deformation became greater as the ratio of the relaxation times of the drop and the suspending medium decreased, as the initial drop radius was increased, and as the apparent shear rate was increased. For comparison, also computed were the shapes of a Newtonian drop, suspended in another Newtonian medium, moving along the central axis of a cylindrical tube in the entrance region. A maximum deformation of a Newtonian drop occurred at an axial position very close to the end of the converging section of the straight section of the cylindrical tube, while a maximum deformation of a viscoelastic drop occurred at an axial position slightly inside the straight section of the cylindrical tube. It has been found that a Newtonian drop deformed faster than a viscoelastic drop as the respective drops moved along the central axis of a conveying cylindrical tube. In order to explain the above observations, the extensional stress distributions along the centerline of the converging cylindrical tube were computed for both a Newtonian suspending medium and a viscoelastic suspending medium. The difference in the rate of drop deformation between Newtonian and viscoelastic drops, each moving along the central axis of a converging cylindrical tube, was attributable to the elasticity of a viscoelastic drop. This is because the large elastic modulus of a viscoelastic drop would tend to resist deformation, as compared to the deformation of a Newtonian drop. Interestingly enough, the rate of recoil of a viscoelastic drop was found to be much slower than that of a Newtonian drop, which was also attributable to the elasticity of a drop. It should be noted that the recoil of a viscoelastic drop is dictated predominantly by its relaxation modulus whereas the recoil of a Newtonian drop is determined strictly by its interfacial tension.
Chang Dae Han, Dr. (Advisor)
Gustavo Carri, Dr. (Committee Member)
Xiaosheng Gao, Dr. (Committee Member)
Hendrik Heinz, Dr. (Committee Chair)
Thein Kyu, Dr. (Committee Member)
178 p.
Materials Science; Mathematics; Molecular Physics; Plastics; Polymer Chemistry; Polymers
Finite Element Analysis; Drop deformation; Entrance Region; Rheology-Processing-Morphology Relationship; Elasticity; viscosity

Recommended Citations

Citations

  • Yingsheng, X. (2011). Finite Element Analysis of Drop Deformation in the Entrance Region of a Cylindrical Tube [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1302535388

    APA Style (7th edition)

  • Yingsheng, Xing. Finite Element Analysis of Drop Deformation in the Entrance Region of a Cylindrical Tube. 2011. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1302535388.

    MLA Style (8th edition)

  • Yingsheng, Xing. "Finite Element Analysis of Drop Deformation in the Entrance Region of a Cylindrical Tube." Doctoral dissertation, University of Akron, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1302535388

    Chicago Manual of Style (17th edition)

akron1302535388
633
© 2011, all rights reserved.
This open access ETD is published by University of Akron and OhioLINK.