Secondary flow and radial mixing modelling for CFD-based Through-Flow method: an axial turbine application

TitleSecondary flow and radial mixing modelling for CFD-based Through-Flow method: an axial turbine application
Publication TypeConference Proceedings
Year of Publication2018
AuthorsRicci M, Pacciani R, Marconcini M, Arnone A
Conference NameATI 2018 - 73rd Conference of the Italian Thermal Machines Engineering Association
VolumeEnergy Procedia 148
ISSN Number1876-6102
Accession NumberWOS:000480453000028
Other NumbersScopus 2-s2.0-85056601997
KeywordsAxisymmetric Euler equation, radial mixing, secondary flows, Through-Flow model, turbomachinery

The paper presents the theoretical bases and an application of a CFD-based Through-Flow model. The code solves the axisymmetric Euler equations and takes into account the effect of tangential blockage and body force. It inherits its numerical scheme from a state-of-the-art CFD solver (TRAF code). Blade body forces are calculated directly from the tangency condition to the meridional flow surface, which is iteratively adapted during the time-marching procedure. Dissipative forces are computed through a realistic distribution of entropy along streamlines. Both secondary flow and tip leakage effects on the meridional flow-field are included through the adoption of a concentrated vortex model, while the corresponding loss contributions are evaluated from correlations. Also, a radial mixing model considering both turbulent diffusion and spanwise convection is implemented. The accuracy of the method is assessed by comparison with CFD calculations and experimental data on the transonic CT3 turbine stage tested in the framework of the TATEF2 European project. A good agreement in terms of overall performance and radial distributions is achieved for both design and off-design operating conditions.

Refereed DesignationRefereed