58923 - On the Forced Response Predictions and Life Improvements of an Industrial Axial Compressor Rotor Blade 

Improvements made to the high cycle fatigue life of an industrial compressor rotor blade for tip active modes through aerodynamic design changes and aero-mechanical computations are presented in this paper. Typical aero-mechanical computations involved utilising an in-house linear-harmonic solver to compute the aero damping. In parallel, a novel hybrid model with whole-anulus domain for the blade rows of interest followed by a single passage domain for the rest of the compressor was used to compute the modal forcing within the time frame of a rapid design cycle using TurboStream,  a GPU based non-linear time domain unsteady solver. In addition to the standard blade passing resonances, low engine order excitations due to vane number differences made possible by the large-scale hybrid time domain computations were analysed. The low engine order resonance was found to be influenced by beating due to vane number difference and a harmonic of upstream blade passing. The reserve factors that represents the life were then calculated for both the old and the new design signifying up to two times improvements for the tip modes of interest. The subsequent engine tests carried out with tip timming agreed closely with the predictions thus validating not only the design but also the forced response prediction process and its continued application.