15th European Conference on Turbomachinery Fluid dynamics & Thermodynamics
Authors
Abstract
Particle image velocimetry (PIV) is a powerful measurement technique for characterization of complex turbomachinery flows thanks to the capability of instantaneous whole-field acquisition with low-intrusiveness. This article presents measurement method and results performed in a high-speed short-duration turbine test facility of the von Karman Institute for Fluid Dynamics. The facility has a unique capability to test an engine-size fully annular turbine stage under engine relevant aero-thermal conditions (Mach number, Reynolds number, and gas to wall temperature ratio) for typical testing time of 0.2-0.4 seconds. For presented study case, a single stage high pressure turbine with a purge flow injection matching 1.74% of the stage mass flow was investigated. The test section adopted the rainbow-rotor configuration, the rotor blades were divided into six circumferential sectors combining different hub-contouring and tip-shape design while maintaining the same base blade profile. Sets of planar PIV measurements were conducted at the downstream of rotor, covering approximately 1.1 rotor pitch 0.15 rotor axial chord at 38% and 58% blade span positions. Phase-lock-averaging (PLA) method was applied in rotor-domain in order to retrieve deterministic flow fields associated with rotor blades while averaging out the flow gradients attributed to stationary components such as the upstream vanes. Moreover, sector-resolved PLA was performed to isolate the effect of different blade geometries in rainbow-rotor configuration. PIV results were compared with experimental data acquired by four-hole-probes (4HP) measurements and Reynolds Averaged Navier Stokes (RANS) simulation results. As confirmed by 4HP and RANS datasets, the PIV results show an enhanced influence of the different hub platform design on the rotor downstream flow fields.
ETC2023-256
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