Issue
Korean Journal of Chemical Engineering,
Vol.27, No.2, 409-415, 2010
Effect of aspect ratio and fluid elasticity on chain orientation in isothermal film casting process
The characteristics of extensional flow and the chain orientations of the isothermal film casting process utilizing a two-dimensional (2-D) viscoelastic model with finite element methods (FEM) were studied. Steady state and transient solutions were obtained for a relatively large aspect ratio regime by employing successive iterative schemes. In this work, higher aspect ratios of the equipment caused highly oriented molecular structures because the aspect ratio increases as the flow changes from planar to uniaxial extensional flow. Fluid viscoelasticity always alleviated the neckin phenomenon and led to the planar extension regime even if dichotomous behavior was observed for draw resonance in extensional thickening and thinning fluids. Consequently, the change in the characteristic of extensional deformation from uniaxial deformation to the planar extension deteriorated the molecular orientation.
[References]
  1. Kanai T, Campbell GA, Film processing, Hanser Publishers, Cincinnati, 1999
  2. Dobroth T, Erwin L, Polym. Eng. Sci., 26, 462, 1986
  3. Jung HW, Hyun JC, Fiber spinning and film blowing instabilities in polymer processing instabilities: Control and understanding, Hatzikiriakos SG, Migler KB, Eds., Marcel Dekker, New York, 2005
  4. Co A, Draw resonance in film casting in polymer processing instabilities: Control and understanding, Hatzikiriakos SG, Migler KB, Eds., Marcel Dekker, New York, 2005
  5. Hyun JC, AIChE J., 24, 418, 1978
  6. Kim BM, Hyun JC, Oh JS, Lee SJ, AIChE J., 42(11), 3164, 1996
  7. Jung HW, Song HS, Hyun JC, AIChE J., 46(10), 2106, 2000
  8. Lee JS, Jung HW, Hyun JC, Scriven LE, AIChE J., 51(10), 2869, 2005
  9. Ito H, Doi M, Isaki T, Takeo M, J. Soc. Rheol. Jpn., 31, 157, 2003
  10. Yeow YL, J. Fluids Mech., 66, 613, 1974
  11. Anturkar NR, Co A, J. Non-Newtonian Fluid Mech., 28, 287, 1998
  12. Iyengar VR, Co A, Chem. Eng. Sci., 51(9), 1417, 1996
  13. Silagy D, Demay Y, Agassant JF, Polym. Eng. Sci., 36(21), 2614, 1996
  14. Silagy D, Demay Y, Agassant JF, J. Non-Newton. Fluid Mech., 79(2-3), 563, 1998
  15. Kim JM, Lee JS, Shin DM, Jung HW, Hyun JC, J. Non-Newton. Fluid Mech., 132(1-3), 53, 2005
  16. Shin DM, Lee JS, Kim JM, Jung HW, Hyun JC, J. Rheol., 51(3), 393, 2007
  17. Brooks AN, Hughes TJR, Comput. Methods Appl. Mech. Eng., 32, 199, 1982
  18. Sunwoo KB, Park SJ, Lee SJ, Ahn KH, Lee SJ, J. Non-Newton. Fluid Mech., 99(2-3), 125, 2001
  19. Rajagopalan D, J. Rheol., 43(1), 73, 1999
  20. Sollogoub C, Demay Y, Agassant JF, J. Non-Newton. Fluid Mech., 138(2-3), 76, 2006
  21. Gedde UW, Polymer Physics, Kluwer, 1995
  22. Choi SW, Shin DM, Lee JS, Kim JM, Jung HW, Hyun JC, Korean J. Chem. Eng., 26(1), 26, 2009