Experimental investigation on the active flow control of axial flow compressor variable stator vane cascades with different penny settings

In modern aircraft engines, precise control of the clearance between blades and the casing or hub is essential to preventing contact during high-speed rotation. The penny structure of compressor variable stator vanes (VSV) inevitably generates local radial clearance between the casing and the blade, which deteriorates the flow field and adversely affects the aerodynamic performance of the VSV. Moreover, different penny settings significantly influence this aerodynamic performance. This study experimentally investigates the flow field of high-pressure compressor VSV, employing steady-state hole-type bleed to explore the control mechanisms of tip leakage vortices (TLV) and passage vortices (PV). The assessment focuses on optimizing the blade tip flow field and identifies key parameters affecting control effectiveness, including penny diameter and suction position/flow rate. Results indicate that optimal performance improvement occurs when the suction holes are positioned downstream of the blade's leading edge at 62.5% chord length, adjacent to the radial gap. This specific positioning significantly reduces the areas of high-loss regions and decreases loss intensity, effectively weakening TLV intensity and its interaction with PV. While suction holes located in the front part of the blade passage provide better control over PV, their effectiveness diminishes as the suction position shifts rearward, whereas TLV control effectiveness increases. Regarding suction flow rate, the findings reveal that increasing the suction flow rate, particularly from 30 l/min to 75 l/min, significantly reduces the extent of high-loss areas and markedly decreases loss intensity.