Wake-induced unsteady aerodynamic interactions in a multistage compressor

Abstract

The effects of steady loading and the detailed aerodynamic forcing function on airfoil row unsteady aerodynamics are investigated and quantified at high reduced frequency values. For the first time, both parallel and normal gust components of the forcing function are considered. This is accomplished by a series of experiments that quantify the unsteady aerodynamics of the first stage vane row of a research compressor. The effects of steady vane aerodynamic loading with both nonconstant and constant aerodynamic forcing functions are quantified. These data show that the steady loading affects only the magnitude of the complex dynamic pressure coefficient, whereas the ratios of the maximum amplitudes of the parallel and normal components of the aerodynamic forcing function affect both the magnitude and the phase lag. The relative effects of the two components of the time-variant inlet velocity field on the resulting vane row unsteady aerodynamics are also investigated, showing that the parallel component of the aerodynamic forcing function affects only the dynamic pressure coefficient phase lag. The correlation of the dynamic pressure coefficient data with flat plate predictions is also considered. The level and chordwise distribution of the steady aerodynamic loading, not the incidence angle, are revealed to be the key parameters to obtain good correlation with such mathematical models.