The continuous trend in gas turbine design towards lighter, more powerful and more reliable engines on one side and use of alternative fuels on the other side renders flutter problems as one of the 

/pdf/experimental-investigation-of-three-dimensional-mechanisms-4tma3p9690.pdf

Experimental Investigation of Three-Dimensional Mechanisms in Low-Pressure Turbine Flutter

A review of the field of turbomachinery aeroelasticity is presented. Developments over the past decade are emphasized, and an assessment of possible future directions of research is offered. The paper reviews the areas of unsteady cascade flows, structural modeling, and flutter prediction methods. Representative results for unsteady flow calculations and flutter boundary predictions in subsonic, transonic, and supersonic flows are discussed, including recent calculations based on the methods of computational fluid mechanics. Results from current attempts to correlate experimental data with theoretical predictions are discussed briefly. It is recommended that future research include investigations of novel approaches to flutter calculations that can take full advantage of parallel processing supercomputers. The feasibility of using mistuning and aeroelastic tailoring as passive flutter suppression techniques should also be pursued.

Aeroelastic problems in turbomachines

Aeroelastic stability of cascades in turbomachinery

PSO-LSSVR: A surrogate modeling approach for probabilistic flutter evaluation of compressor blade

Flutter analysis of bending–torsion coupling of aero-engine compressor blade with assembled clearance

A study of the effects of bending-torsion interaction of the flutter boundaries of turbomachinery blading is presented. The blades are modeled as equivalent sections, and the equations of motion allow for the general case of structural, inertial and aerodynamic coupling, in the presence of structural damping. Two different speed regimes are investigated: incompressible flow, and supersonic flow with a subsonic leading edge locus. Flutter boundaries are presented for cascade design parameters representative of current technology fan rotors. These results illustrate that bending-torsion interaction has a pronounced effect on the flutter boundaries for both speed regimes, although the mode frequencies show no appreciable tendency to coalesce as flutter is approached. Several cases of bending branch instability were observed, without incorporating the effects of finite mean lift or strong shocks in the analysis.

P. P. Friedmann

Papers

The Effect of Bending-Torsion Coupling on Fan and Compressor Blade Flutter