Abstract: The constitutive behavior of lowdensity polyethylene (PE-LD)were described by the DCPP and S-MDCPP models in this study. The modified finite increment calculus (FIC) procedure was introduced into the iterative fractional step algorithm, and the discrete elastic viscous stress split (DEVSS) and streamlineupwind (SU) techniques were employed to cope with the convectiondominated problem of the viscoelastic flow analysis in order to enhance the computational stability. It showed that the velocity, isochromatic fringe pattern of principle stress difference and backbone stretch distributions predicted by the DCPP and S-MDCPP models agreed very well.Moreover, the predicted velocity, pressure and backbone stretch distributions using the S-MDCPP model at different Weissenberg numbers (Wi) were discussed and it exhibited the velocity and pressure were enlarged with the increase of Wi.

Key words: rheology, viscoelastic flow, polymer melt, constitutive model, numerical simulation