PIV Application to Transonic Axial and Radial Compressors

Abstract

This paper summarizes latest DLR activities in turbomachinery research, involving the laser-based planar particle image velocimetry technique (PIV, see Raffel et al., 2007). In the first part of this contribution the experimental investigation of a single-stage transonic axial compressor equipped with casing treatment (CT) will be described. The measurements focused on the investigation of the blade tip interaction with the CT and flow phenomena occurring at the compressor's surge line. A new approach regarding light sheet introduction via periscope probe as well as a smoke-based type of seeding particles have been approved. The results obtained were subsequently used for comparison and validation of numerical calculations of the same compressor geometry performed in parallel to the experiments. The second part of this paper gives an overview on PIV measurements performed in the diffuser passage of a transonic high pressure ratio centrifugal compressor. PIV was used to analyze and further improve the understanding of the complex flow phenomena inside the vaned diffuser given the capability of capturing spatial structures.