Investigation of influence of the outlet channel length of extruder die hydrodynamics of extrusion process

Influence of the outlet channel length of an extruder on a steady creeping outflow of viscoelastic fluid is investigated. Fluid motion is described by equations of conservation of mass and momentum supplemented by Giesekus's determinative rheological constitutive equation of the medium. On the basis of finite element method a numerical algorithm for solving the problem was developed. Distribution pattern of fluid velocity in an outflowing jet, pressure and stresses is analyzed; results of dependency of swelling degree of polymer fluid on die geometry and parameters of a rheological model are investigated. (paper)