Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Polish Maritime Research

2 Świrydczuk J.

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: secondary vortices

Sortuj według:

Ogranicz wyniki do:

Wake-blade interaction in steam turbine stages

Świrydczuk J.

Polish Maritime Research

2013

nr 2

30--40

The article discusses the phenomenon of stator Wake/Rotor cascade (W/R) interaction in a steam turbine stage, and the ability to capture it in turbine stage design calculations making use of standard numerical codes. Firstly, the W/R interaction is analysed by comparing its real, experimentally recorded course with the numerical results obtained using vortex theory models and methods. This part of the analysis ends with formulating a conclusion about stochastic nature of the W/R interaction and indicating its reason, which is the vortex structure of the stator wake. Next, a question is discussed whether and how this stochastic nature of the examined phenomenon can be taken into account in calculations of Reynolds Averaged Navier-Stokes (RANS) equations. Differences are indicated between the uniform pattern of the stator wake obtained using a RANS code and the vortex structure of the real wake. It is concluded, however, that despite these differences the RANS results correctly reflect the time-averaged course of the real W/R interaction, and the process of averaging the flow parameters on the sliding plane between stator and rotor calculation areas can be treated as sort of “numerical averaging” of different realisations of the W/R interaction.

Two vortex interaction patterns in a turbine rotor

Świrydczuk J.

Polish Maritime Research

2009

nr 2

45-53

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.