Two vortex interaction patterns in a turbine rotor

The article analyses the unsteady interaction of vortex structures in a turbine rotor passage. In the form of sample cases, two high-pressure steam turbine stages are examined: a standard stage, used as the reference, which reveals regular performance characteristics and distributions of flow parameters, and a low-efficiency stage, in which a large separation zone is observed in the rear part of the rotor passage. In the latter case the combined interaction of all vortices has been found to take an extremely complex course and be a source of remarkable flow fluctuations. The methodology applied for extracting particular vortex structures from the general flow pattern bases on comparing entropy distributions with corresponding velocity vectors. The reported vortex interaction patterns are believed to be representative for a variety of turbine constructions of both land, and marine applications.