Influences of Groove Depth on the Coupling of Small Tip Clearance and Circumferential Grooves

Coupling of small tip clearance and circumferential grooves of axial-flow compressors significantly improves the stability margin, as well as pressure ratio and efficiency. Different groove depth under coupling of small tip clearance and circumferential grooves has been designed for the isolate subsonic NPU-rotor based. Moreover, influences and mechanism of groove depth on the coupling of small tip clearance and circumferential grooves have been further studied by utilizing a numerical simulation calculation method. The results showed that the role of casing treatment reduced driving force of generating leakage action, postponed negative effects intersecting incoming flow with tip clearance flow and improved flow field of tip passages by sucking leakage flow into the groove.