  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.
