Effect of elongational viscosity on polymer melt distribution in extrusion dies

A method for incorporating the elongational viscosity effects in the Control Volume Method simulation of a polymer flow field has been proposed. Preliminary applications and testing of this method indicated that it helps improve the accuracy of the simulation. It has been found that the effect of the elongational viscosity seems to be important when the ratio of the gaps inside the die is higher than about 6:1. If the ratio is lower, the elongational viscosity can be neglected.