Vpliv izgub v labirintnih tesnilih na izkoristek visokotlačne Francisove turbine (Effect of Losses in Labyrinth Seals on Efficiency of a High Head Francis Turbine)

The paper presents numerical simulations of flow in a model of a high head Francis turbine and comparison of results to the measurements. Numerical simulations were done by two CFD (Computational Fluid Dynamics) codes, ANSYS CFX and OpenFOAM. Steady-state simulations were performed by standard k-ɛ and SST models, while for transient simulations the SAS SST model in combination with ZLES in the draft tube was used. With proper grid refinement in distributor and runner and taking into account losses in labyrinth seals quite accurate prediction of torque on the shaft, head and efficiency was obtained.