Aeromechanical Response of an Axial Compressor in Stall

Axial compressor stall causes unsteady aerodynamic loading that leads to blade vibration. Prolonged operation in stall can contribute to high cycle fatigue (HCF). The prediction of the impact stall has on HCF is a significant challenge. Information about the physics of stall is often obtained through the analysis of unsteady casing pressures, but no observed link has been shown between blade vibrations and unsteady casing pressures.

The present thesis describes the characteristics of blade vibration and examines the unsteady casing pressures of a single stage axial compressor in stall. Blade strains and unsteady casing pressures were measured during stall at various corrected speeds with two different inlet profiles. The unsteady casing pressures were found to be poorly correlated around the annulus, and not correlated to any of the first four modes of blade vibration.