Investigation of the Effect of Blade Passing on Two-Phase Flow Within Discrete Compressor Casing Recirculation Channel Using Particle Image Velocimetry

Abstract

Abstract Recirculation channels (RC) can improve the aerodynamic operational stability of axial compressors. The performance of compressors using RC is still unascertained during in-service operations, which might be subject to particle ingestion. Due to its inherent unsteadiness, little is known about the two-phase flow structure inside such discrete casing treatments. The present study provides the first insight into the two-phase flow within an RC via Particle Image Velocimetry, characterizing air and particle motions. The ensemble correlation method is used to obtain averaged flow field data corresponding to different blade positions with respect to the RC, providing the periodic dynamic characteristics of the flow. Measurements show that the blade passing frequency and operation condition impact the amount of recirculated air, the creation of stagnation and separation points, particle trajectories, and slip velocity inside the RC. As a result, this study shows that a robust RC design should consider the particle-wall interactions that can lead to significant erosion or fouling and possibility of blockage near the inlet.