# Boundary-Conforming Finite Element Methods for Twin-Screw Extruders: Unsteady - Temperature-Dependent - Non-Newtonian Simulations

## TL;DR

This paper introduces a boundary-conforming space-time finite element method with a novel mesh update technique for efficient, accurate simulations of unsteady, temperature-dependent non-Newtonian flows in twin-screw extruders, validated by experiments.

## Contribution

The paper presents the SRMUM mesh update method enabling efficient, re-mesh-free simulations of complex twin-screw extruder flows with temperature dependence.

## Key findings

- Mesh convergence demonstrated in 2D and 3D cases.
- Agreement with experimental results confirmed.
- Method successfully applied to complex industrial scenarios.

## Abstract

We present a boundary-conforming space-time finite element method to compute the flow inside co-rotating, self-wiping twin-screw extruders. The mesh update is carried out using the newly developed Snapping Reference Mesh Update Method (SRMUM). It allows to compute time-dependent flow solutions inside twin-screw extruders equipped with conveying screw elements without any need for re-meshing and projections of solutions - making it a very efficient method. We provide cases for Newtonian and non-Newtonian fluids in 2D and 3D, that show mesh convergence of the solution as well as agreement to experimental results. Furthermore, a complex, unsteady and temperature-dependent 3D test case with multiple screw elements illustrates the potential of the method also for industrial applications.