Modeling polymer extrusion with varying die gap using Arbitrary Lagrangian Eulerian (ALE) method

A transient arbitrary Lagrangian Eulerian based finite element method is used to simulate the effects of varying the die gap during the extrusion of Newtonian fluids. The transient change of the extrudate shape, velocity, and pressure due to the die gap variation is described and studied. Moreover, varying the die gap creates oscillations on the simulated free surface of the extrudate at higher Reynolds number values thus requiring a finer mesh. A new method for defining the free surface is introduced to avoid free surface oscillations. The new method enables the use of a coarse mesh which makes it possible to run simulations with shorter computational time at higher Reynolds numbers. Published by AIP Publishing.