Aeroelastic Investigation of a Transonic Compressor Rotor with Multi-Row Effects

According to the modern turbomachinery design trend, blades are getting more and more flexible and loaded, and therefore prone to vibration issues due to forced response and flutter phenomena. For this reason, the flutter stability assessment has become a key aspect to avoid high cycle fatigue (HCF) blade failures. The aim of this paper is to numerically evaluate the influence of unsteady aerodynamic effects, due to upstream and downstream rows, on flutter predictions using an uncoupled method. Both CFD aeroelastic and modal analyses have been carried out for a one and half compressor stage in transonic conditions. Flutter results are reported for the classic single-row approach and then for the multi-row model which includes rotor/stator unsteady interactions: a good agreement with measured data is shown for both cases and also a no negligible impact of adjacent rows can be observed.