3-DIMENSIONAL SIMULATION OF POLYMER MELT FLOW IN A COAT-HANGER DIE

The power-law fluid of polymer melts in a coat-hanger die is modeled t hree-dimensionally and simulated using finite element method, In order to get an optimum coat-hanger die, design equation devloped perviousl y based on one-dimensional flow model in manifold and slot is employed , From the calculated flow rate distributions, the optimum process con dition for maximum flow rate uniformity can be determind, The optimum conditions were mainly dependent on the manifold angle and power-law i ndex of polymer melt, The effects of disturbances of power-law index, die width, slot thickness, and manifold angle from the optimum values are investigated thoroughly, Results show that any departure of proces s conditions from optimum value decreases flow rate uniformity, The ef fect of land length is also analyzed, Manifold angle is a primary fact or governing uniformity of residence time distribution, Two-dimensiona l analysis is also conducted and its results are compared with those o f three-dimensional to show that application of two-dimensinal model u sing lubrication approximation in the region of manifold is subject to critical error.