Kabannik S. Determination of stability limit of GTE axial compressors against subsonic flutter at large attack angles

The thesis presents the technique of experimental and calculation determination of the dynamic stability limit of the blade assembly against subsonic flutter. The procedure of modernization of the existing aerodynamic test bench is described to determine the non-stationary aerodynamic loads at large positive and negative attack angles. Also, the refined procedure of their determination has been developed allowing one to consider the systematic errors caused by strains and displacements of the setup elements. The results of tests of the plane cascade of the blade airfoils in the wide range of variation of the attack angle and reduced frequency of vibrations are provided, which were used to perform the calculations and develop the database of critical values of the reduced vibration frequency for the first flexural mode of blade vibrations. The obtained results were employed to develop the algorithm of the mathematical implementation of the express-method and software to predict the stability of the GTE compressor cascade unshrouded blades against subsonic flutter, which were approbated on some types of modern AGTE.