Experimental Investigation of a Forced-Response Condition in a Multistage Compressor

摘要

It is nearly impossible to remove all resonant crossings from the operating range of a multistage compressor; thus, designers rely on models to predict the resonant response amplitude to determine if the crossing is acceptable. An accurate model can reduce unexpected forced-response problems encountered during engine testing. Although work has been done to improve such models, the confidence in these models comes from validation with quality test data including both the aerodynamic forcing function and the response of the blade row. Recent trends in turbomachinery, including higher blade loadings and use of integrally bladed rotors, lead to increased potential for forced-response issues. The Campbell diagram crossing for the excitation associated with the upstream and downstream vane rows on the embedded rotor first torsion vibratory mode is measured. The rotor response will be characterized with tip-timing measurements and the aerodynamic forcing functions measured. Unsteady casing pressures over the vibrating rotor are also acquired. This represents one of the few datasets detailing a forced-response condition in a multistage compressor, and the understanding gained from these experiments will be valuable in developing robust compressor designs.