In order to deal with high temperatures faced by the components downstream
of the combustion chamber, some relatively cold air is bled at the compressor.
This air feeds the cavities under the turbine main annulus and cool down the rotor
disks ensuring a proper and safe operation of the turbine. This thesis manuscript
introduces a numerical study of the effect of the cavity flow close to the turbine
hub on its aerodynamic performance. The interaction phenomena between the cavity
and main annulus flow are not currently fully understood. The study of these
phenomena is performed based on different numerical approaches (RANS, LES and
LES-LBM) applied to two configurations for which experimental results are available.
A linear cascade configuration with an upstream cavity and various rim seal
geometries (interface between rotor and stator platform) and cavity flow rate available.
A rotating configuration that is a two stage turbine including cavities close
to realistic industrial configurations. Additional losses incurred by the cavity flow
are measured and studied using a method based on exergy (energy balance in the
purpose to generate work)
