Flow Structure of Hub-Corner Separation in a Stator Cascade of a Multi-Stage Transonic Axial Compressor

Abstract

In this study, a multi-stage transonic axial compressor has been investigated using large-scale detached eddy simulation (DES). The complicated flow field of stator hub in the compressor was analyzed using data mining techniques, extracting important flow phenomena. The data mining techniques applied in the present study include vortex identification based on the critical point theory and topology data analysis of the limiting streamline pattern visualized by the line integral convolution (LIC) method. In the stator cascade, the incoming flow in the vicinity of the hub is subject to influences of the leakage flow and the secondary flow on the hub, and eventually accumulates near the filled clearance section on the blade suction side. As a result, a focal-type boundary layer separation is caused there, and separation vortex generates huge loss. In the aft-part of the passage, the separation vortex interacts with the leakage flow, generating further complicated flow field.