Influence of tip leakage flow on the aerodynamic damping of compressor blade torsional vibration

Abstract

Based on harmonic balance calculation technology with a single-passage phase-lag periodic boundary, the influence of tip gap size on the aerodynamic damping characteristics of rotor for first-order torsional vibration is analyzed with energy method. This research shows that the aerodynamic damping coefficient of the blade has a parabolic distribution law of first decreasing and then increasing with the increase of the tip clearance size. There is a most dangerous clearance value of torsional flutter characteristics in the blade, and the aerodynamic damping under this clearance is 12.67 % lower than the maximum damping value. The influence of the leakage flow on the time-averaged flow field near the blade tip leads to significant differences in the local aerodynamic work. In addition, the effect of leakage flow on the amplitude and phase of the local first-order unsteady pressure also bring about a significant influence on local aerodynamic work near blade tip.