PSI - Issue 5

Jaroslav Václavík et al. / Procedia Structural Integrity 5 (2017) 1349–1354 Jaroslav Václavík et al. / Structural Integrity Procedia 00 (2017) 000 – 000

1354 6

1.0

2500

0 10 20 30 40 50 60 70

0.8

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500 torque amplitude M k, a [kNm] 1000 1500

sheer stress τ max, a [MPa]

0.6

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probability of occurence P [ ]

0.0

0

0

500

1000

1500

1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05

M k, a [kNm]

number of cyclesN [ ]

Fig. 8. Distribution of non-standard events (a) probability of occurrence; (b) rainflow matrix.

Spektrogram - odstavení 10.7.2015

250

Torsional, and blade frequencies

f [Hz]

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Rotation orders

100

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Subsynchronnous frequencies

0

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t [s]

Fig. 9. (a) amplitude spectra; (b) spectrogram during shut down of the turbine.

5. Conclusion

The system for long-term monitoring of torsional vibrations was introduced in this article. It has been found also with the support of FEM, that torsional responses are low enough to be able to excite the resonance frequencies of the LP blades. The second benefit of these measurements is now under investigations and that is the possibility to found the damaged blades due to the shift of their resonant frequencies in the torsional spectra. Acknowledgements The paper has originated in the framework of the solution of “Competence Centres” programme of the Technology Agency of the Czech Republic TE01020068.

References

ISO2226-1:2009 Mechanical vibration – Torsional vibration of rotating machinery – Part 1: Land-based steam and gas turbine generator sets in excess of 50 MW. Steam Turbine-Generator Torsional Vibration Interaction with the Electrical Network: Tutorial. EPRI, Palo Alto, CA: 2005. 1011679. Strain-Based Turbine Generator Torsional Vibration Monitoring System – Phase 3: Prototype Field Application. EPRI, Palo Alto, CA: 2015. 3002006234.