We present preliminary results from numerical simulations of
blood flow in a prototype of a centrifugal pump. The simulations
involve incompressible Navier-Stokes governing equations, stabilized 
space-time finite element formulations, and
parallel implementation on distributed memory architectures.
The examples illustrate our approach of custom hybrid 
structured-unstructured tetrahedral meshes, which accommodate the
rotation of the pump impeller with respect to the stationary housing,
without assuming axisymmetry of either part.