APPROXIMATE SIMULATION METHOD ON THE 3-DIMENSIONAL POLYMER MELTS FLOWIN A DIE

Two kinds of practical approximate simulation methods for three-dimens ional viscoelastic flow in a die have been developed by which solution s at high shear rate can be obtained with low memory capacity and CPU time. The velocity and stress fields were calculated separately. The v elocity field was obtained using the pure-viscous non-Newtonian model and the stress field using the viscoelastic model by substituting this velocity field. In one case the White-Metzner model was applied as a viscoelastic model without a square term in stress. In the second case the stress field was calculated by the streamwise integration which c ould apply even to the viscoelastic model including the square of stre ss. In addition a modified pure-viscous non-Newtonian model has been d eveloped respresenting the strain-thickening elongational viscosity in order to extend these approximate methods to similar materials. The v elocity field which was calculated using a modified pure-viscous non-N ewtonian model was considerably closer to that for the viscoelastic mo del with the same flow characteristics as shown for the original pure- viscous non-Newtonian model.