Abstract: In this paper, the finite element method of Picard iterative format was applied for analyzing three-dimensional extrudate swell of viscoelastic fluid flows using Wager integral constitutive equations. During each iteration, the updated streamline of boundaries was generated according to boundary condition of velocity. The streamline of Gauss point was acquired according to the velocity field of previous iteration. The stress was treated as pseudo-body and the format of iteration was given. Extrudate swell of different width and length of the rectangular die were analyzed. Results of swell ratios influenced by width and length of die were shown. It showed that the swell ratio increased with increasing ratio of width to thickness, and decreased with increasing length of runner. The results were very accurate and were compared with two dimension solutions and experiment. It proved that this method was efficient and reliable.

Key words: extrudate swell, polymer, extrudate swell, numerical simulation, melt