3D Numerical Simulation of the Hollow Square-Typed Polymer Based on Gas-Assisted Extrusion Method

Abstract:

According to the properties of hollow square-typed polymer extrudate, the three dimensional numerical simulation of hollow square-typed polymer extrudate based on gas-assisted extrusion technology was performed by using finite element method. Meanwhile, four different gas-assisted modes imposed on the outer and inner wall of hollow square-type extrudate were considered. The extrudate swell ratios and field distributions, such as pressure drop, velocities and normal stresses of four different gas-assisted modes were obtained and compared with each other. Research results show that the extrudate swell ratios and field distributions of different gas-assisted modes are completely different. For the mode of gas-assisted on the single wall, the extrudate swell or shrink phenomena are large due to the non-symmetric properties of field distributions. For the no gas-assisted mode, although the physical field values are large, the extrudate swell ratio is not large due to the interaction role of both walls. For the mode of gas-assisted on both walls, the physical field values, such as pressure drop, normal velocities and stresses are all diminished, and the extrudate swell phenomenon was completely eliminated.

• Periodical: Materials Science Forum (Volume 861)
• Pages: 189-194
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.861.189
• Online since: July 2016
• Authors: Zhong Ren*, Xing Yuan Huang
• Keywords: Extrudate Swell, Extrusion Forming, Gas-Assisted Extrusion, Hollow Polymer, Physical Field Distribution

References

[1] S. Middleman, J. Gavis, Expansion and contraction of capillary jets viscoelastic liquids, Phys. Fluids. 4 (1961) 963-969.

DOI: 10.1063/1.1706446

[2] R.I. Tanner, A theory of die-swell, J. Polym. Sci. Pol. Chem. 8 (1970) 2067-(2078).

[3] R.I. Tanner, A theory of die-swell revisited, J. Non-Newtonian Fluid Mech. 129 (2005) 85-87.

DOI: 10.1016/j.jnnfm.2005.05.010

[4] A. Tyler, M. Bagley, Singular behavior of the mass conductivity of liquid 4He in a superleak at the superfluid transition, J. Low Temp. Phys. 26 (1977) 573-582.

DOI: 10.1007/bf00655430

[5] W.W. Graessley, W.S. Park, R.L. Crawley, Experimental tests of constitutive relations for polymers undergoing uniaxial shear flows, Rheol. Acta. 16 (1977) 291-301.

DOI: 10.1007/bf01523739

[6] K.J. Ruschak, A method for incorporating free boundary with surface tension in finite-element fluid-flow simulators, Int. J. Numer. Methods Eng. 15 (1980) 639-448.

DOI: 10.1002/nme.1620150502

[7] D.G. Kiriakidis, E. Mitsoulis, Viscoelastic simulations of extrudate swell for an HDPE melt through slit and capillary dies, Adv. Polym. Tech. 12 (1993) 107-117.

DOI: 10.1002/adv.1993.060120201

[8] V. Ganvir, B.P. Gautham, H. Pol, M.S. Bhamla, L. Sclesi, R. Thaokar, A. Lele, M. Mackley, Extrudate swell of linear and branched polyethylenes: ALE simulations and comparison with experiments, J. Non-Newtonian Fluid Mech. 166 (2011) 12–24.

DOI: 10.1016/j.jnnfm.2010.10.001

[9] N. Intawong, A. Wiratket, P. Meechue, Flow visualization & extrudate swell behavior of natural rubber compound in annular die capillary rheometer, Polimeros. 24 (2014) 434-440.

DOI: 10.1590/0104-1428.1696

[10] W.A. Gifford, The effect of surface tension on extrudate swell from square and rectangular channels, Polym. Eng. Sci. 38 (1998) 1167-1173.

DOI: 10.1002/pen.10284

[11] C. Keawkanoksilp, W. Apimonsiri, S. Patcharaphun, N. Sombatsompop, Rheological properties and melt strength of LDPE during coextrusion process, J. Appl. Polym. Sci. 125 (2012) 2187-2195.

DOI: 10.1002/app.36427

[12] E. Behzadfar，M. Ansari，V. K. Konaganti, et al, Extrudate swell of HDPE melts: I. Experimental. J. Non-Newtonian Fluid Mech. 225 (2015) 86-93.

DOI: 10.1016/j.jnnfm.2015.07.008

[13] R. Brzoskowski, J.L. White, W. Szydlowski, F.C. Weissert, N. Nakajima, K. Min, Air-lubricated die for extrusion of rubber compounds, Rubber Chem. Technol. 60 (1987) 945-956.

DOI: 10.5254/1.3536166

[14] R.F. Liang, M.R. Mackley, The gas-assisted extrusion of molten polyethylene, J. Rheol. 45 (2001) 211-226.

DOI: 10.1122/1.1332786

[15] Z. Ren, X.Y. Huang, H.S. Liu, et al, Numerical and experimental studies for gas assisted extrusion forming of molten polypropylene, J. Appl. Polym. Sci. 132 (2015) 1-13.

DOI: 10.1002/app.42682

[16] N.P. Thien, R.I. Tanner, New constitutive equation derived from network theory, J. Non-Newtonian Fluid Mech. 2 (1997) 353-365.

DOI: 10.1016/0377-0257(77)80021-9