Near-Wall Flow in the Blade Cascades Representing Last Rotor Root Sections of Large Output Steam Turbines

0533089 - ÚT 2022 RIV CN eng J - Journal Article
Šimurda, David - Fürst, J. - Hála, Jindřich - Luxa, Martin - Bobčík, M. - Novák, O. - Synáč, J.
Near-Wall Flow in the Blade Cascades Representing Last Rotor Root Sections of Large Output Steam Turbines.
Journal of Thermal Science. Roč. 30, č. 1 (2021), s. 220-230. ISSN 1003-2169. E-ISSN 1993-033X
R&D Projects: GA TA ČR(CZ) TH02020057
Institutional support: RVO:61388998
Keywords : turbine blade cascade * secondary flow * near wall flow * supersonic flow * CFD * experiment
OECD category: Applied mechanics
Impact factor: 2.013, year: 2021
Method of publishing: Limited access
https://link.springer.com/article/10.1007/s11630-020-1246-x

This paper investigates the flow past two variants of root section profile cascades for a last stage rotor considering three-dimensional flow structures in the near-wall region. Analyses were drawn based on RANS numerical simulations of both variants and on the experimental data obtained by the 3D traversing in the exit flow field of one of the variants. Extent of 3D structures at two different regimes and its influence on aerodynamic characteristics of the blade cascades was assessed. The distributions of Mach number along the profiles were compared with 2D optical measurements and its distortion due to the presence of the sidewall was explored. The interaction between main vortical structures was described and its influence on the loading of the blades, mechanical energy losses and exit flow angle was discussed. The results showed that for a front loaded blade the vortical structures appeared earlier and at a larger extent than for an aft loaded variant. However, due to different Mach number distribution, contribution of end wall flow to the energy losses was lower in the case of the aft loaded variant. The influence of the near wall flow on the loading was found to be rather weak while the deviation of the exit flow angle appeared to be comparable for both of the variants.
Permanent Link: http://hdl.handle.net/11104/0314022