Summary & Conclusions

This paper presents an extension to the traditional Panovsky-Kielb for flit­ter analysis of LPT blades that considers the cyclic symmetry mode shapes. As demonstrated in the example problems this new cyclic symmetry method produces aerodynamic damping results that are in reasonable agreement with those of complete three-dimensional viscous CFD method. It does not require any additional input information or CFD analysis. The work due to the interac­tion effects of the cosine and sine modes was generally found to be significant, even for some nearly pure real modes. In addition, the work associated with the steady pressure was also found to be significant.

Acknowledgement

The authors wish to acknowledge GE Aircraft Engines for financial support and for the permission to publish this work. The authors also express gratitude to Francesco Poli (University of Florence) and Claudia Schipani (Fiat Avio) for their cooperation on the test cases.

References

Arnone, A, Poli, F., and Shipani, C., 2003, A Method to Assess Flutter Stability of Complex Modes, Accepted for Presentation at the 10th ISUAAAT, Duke University, September 2003

Chernycheva, O. V., Fransson, T. H., Kielb, R. E., and Barter, J., 2001, ’’Comparative anal­ysis of blade mode shape infhence on flitter of two-dimensional turbine blades”, ISABE – 2001-1243, XVISOABE conference, September 2-7, Bangalore, India

Kielb, R. E., and Barter, J., Chernycheva, O. V., and Fransson, T. H., 2003, ’Flutter of Low Pressure Turbine Blades with Cyclic Symmetric Modes – A Preliminary Design Method”, presented at ASME Turbo Expo 2003, June 2003, Atlanta, Georgia, accepted for publica­tion in the ASME Journal of Turbomachinery.

Panovsky J., and Kielb R. E., 1998, “A Design Method to Prevent Low Pressure Turbine Blade Flutter”, 98-GT-575, ASME Gas Turbine Conference and Exhibition, Stockholm, Sweden