Simulation of single‐ and two‐phase flows on sliding unstructured meshes using finite volume method

We present an efficient finite volume method for unstructured grids with rotating sliding parts composed of arbitrary polyhedral elements for both single- and two-phase flows. Mathematical model used in computations is based on the ensemble averaged conservation equations. These equations are solved for each phase and in case of single-phase flow reduce to the transient Reynolds-averaged Navier-Stokes (TRANS) equations. Transient flow induced by rotating impellers is thus resolved in time. The use of unstructured grids allows an easy and flexible meshing for the entire flow domain. Polyhedral cell volumes are created on the arbitrary mesh interface placed between rotating and static parts. Cells within the rotating parts move each time step and the new faces are created on the arbitrary interfaces only, while the rest of the domain remain 'topologically' unchanged. Implicit discretization scheme allows a wide range of time-step sizes, which further reduce the computational effort. Special attention is given to the interpolation practices used for the reconstruction of the face quantities