Session: 33-03 Low Pressure Turbines 1

Paper Number: 102156

102156 - Piv Measurements in a High-Speed Low-Reynolds Low-Pressure Turbine Cascade 

The geared turbofan engine allows the low-pressure turbine (LPT) module to operate at different rotational speed than the fan. In such architecture, LPTs operate at transonic exit Mach numbers and low Reynolds numbers, providing a possibility to improve the efficiency and to reduce the engine weight. At these operating conditions, compressibility effects influence the blade aerodynamics and the loss mechanisms.    
The presented paper focuses on the characterization of the aerodynamics of a high-speed LPT cascade by means of particle image velocimetry (PIV). The measurements were carried out in the continuously running closed-circuit facility S-1/C at the von Karman Institute for Fluid Dynamics under engine-relevant conditions. The outlet Mach and Reynolds number were varied from 0.7 to 0.95 and from 65k to 120k, respectively. The test section was equipped with multiple transparent acrylic windows to allow optical measurements. 2D2C PIV measurements were performed in the blade passage on the blade-to-blade planes and Stereo time-average PIV were applied downstream of the cascade on pitch-span planes. The instantaneous flow field images obtained by the PIV measurement provided extensive data that support the understanding of various flow phenomena such as the onset of separation of the laminar boundary layer on the blade suction surface and the development of the secondary flows and its interaction with the main flow. 
The PIV results were combined with pneumatic and fast-response probe measurements, as well as with CFD results, to validate the reliability of the optical measurements and to provide comprehensive analysis of the high-speed LPT aerodynamics. 
 

Presenting Author: Mizuki Okada von Karman Institute for Fluid Dynamics

Presenting Author Biography: Mizuki Okada is a PhD student at the turbomachinery and propulsion department of von Karman Institute for Fluid Dynamics. Before starting his PhD program, he finished his masters in aerospace engineering at Kyushu University in Japan. Currently at VKI, he is implementing PIV in turbine test rigs to investigate the aerodynamics of high-speed turbines.

Authors:

Mizuki Okada von Karman Institute for Fluid Dynamics
Loris Simonassi von Karman Institute for Fluid Dynamics
Gustavo Lopes von Karman Institute for Fluid Dynamics
Sergio Lavagnoli von Karman Institute for Fluid Dynamics