Flow Variations in Transonic Compressors Tip Flow — An Experimental Perspective Utilizing High Speed PIV

In modern compressor, the demand for highly loaded stages, coupled with lightweight design, necessitates a growing need for high manufacturing accuracy. However, it is challenging to eliminate the underlying sources of uncertainty. Investigating potential factors influencing compressor behaviour has been a crucial area of research. Understanding these influences is essential to enhance design capabilities and drive further advancements in the field. This study explores flow variations in the tip flow of transonic compressors from an experimental perspective, utilizing high-speed Particle Image Velocimetry synchronized with blade passing frequency. This innovative approach, conducted in a high-speed compressor test rig, allows us to experimentally delve into the full annulus flow field and transient flow behaviour in a unique depth. This paper addresses the challenges encountered in the application of this measurement technique and examines the complete annulus information, focusing specifically on the variation in tip flow from passage to passage. Through the integration of blade tip timing data and 3D white light scan data of the BLISK, this study correlates aerodynamic variations with operational geometric discrepancies arising from manufacturing uncertainties. The investigations were conducted at a transonic compressor test facility, utilizing a representative high-pressure compressor front stage configuration operated at engine relevant conditions. The experimental findings shed light on the intricate relationship between geometric uncertainties and compressor tip aerodynamics, furthering our understanding and contributing to the advancement of axial compressor technology.