Combined-Simultaneous Gust and Oscillating Compressor Blade Unsteady Aerodynamics

Abstract

Experiments are performed in a 3-stage axial flow research compressor to investigate and quantify the simultaneous-combined gust and motion induced unsteady aerodynamic response of compressor 1st stage rotor blades. The gust response unsteady aerodynamics are experimentally modeled with a 2/rev forcing function. The torsion mode unsteady aerodynamics are investigated utilizing an experimental influence coefficient technique in conjunction with a unique drive system. Combined gust and oscillating unsteady aerodynamics are obtained by superposition of the separate oscillating blade row and the gust response unsteady aerodynamics. Simultaneous gust and motion induced unsteady aerodynamic response are obtained by driving the torsion mode oscillation in the presence of the 2/Rev forcing function. The effects of steady loading are quantified, with airfoil oscillation amplitude effects also studied. The combined unsteady aerodynamics establish the applicability limitations of the superposition principle at high oscillation amplitudes and high loading. In addition, the gust-blade motion phase angle is identified as a key parameter, with the accuracy of forced response prediction and the alteration of blade row stability due to gust interaction dependent on the gust-blade motion phase.