Investigation of Vortex Flow Features in Compressor Flows Based on Vortex Identification Methods

Three-dimensional multiscale vortex flow in compressors is highly complex due to adverse pressure gradients. A deeper understanding of the vortex flow in compressors is significant for improving the aerodynamic design. Nonetheless, accurate identification and effective distinction of complex vortices are highly demanded in analyzing compressor flow mechanisms. The Liutex method and its corresponding decomposition method for vortex flow motions have advantages in extracting clear vortex structures. The local trace criterion (LT_cri) and the LT_cri-based elliptical region (LTER) indication can distinguish the tangled vortices in compressor flow by indicating the compressibility, local spiraling pattern and compactness. In the current study, vortex identifications based on Liutex and LT_cri are employed to investigate the features and evolution of complex vortices in typical compressor flows, including the corner separation flow in a highly loaded compressor cascade, and the tip leakage flow in a low-speed and a transonic compressor rotor. Results show that the compressibility, spiraling pattern and compactness of vortices have close correlations with the vortex structures and flow features in both spatial and temporal perspectives, which provide some new interpretations of vortex evolution regimes in compressors.