PSI - Issue 6

Valerii P. Zolotarevich et al. / Procedia Structural Integrity 6 (2017) 224–227 V.P. Zolotarevich, A.E. Salienko, A.I. Frumen, N.V. Yugov / Structural Integrity Procedia 00 (2017) 000–000

226

3

Fig. 1. Mesh for blade of runner Kaplan turbine.

Fig. 2. Fist and second modes blade.

Fig. 3. 3th and 4th modes blade.

shaft. As can be seen from table 1, for the second and third mode shapes is observed in good agreement with the experimental data. Contrast to the experiment values of natural frequencies for the first mode shapes require additional studies of the conditions of the experiment (electronic circuits, errors of the sensors and preamplifiers, as well as the types of used vibrators or vibration measuring hammers).

Table 1. Results for natural frequencies. #

in Air, × f 0 26.9 (29.9) 39.0 (38.8) 61.3 (61.8)

in Water, × f 0 15.9 (12.1) 25.7 (23.7) 42.2 (41.2)

1 2 3 4

76.8

51.1

The developed approach also was used to analyze the causes of the destruction of the runner of a Francis turbine of one of the modernized HPP. Calculation studies of natural frequencies and vibration modes of the runner in air and water have been performed. A comparison of the available experimental vibration data on the runner bearing with the results of calculating the natural frequencies of the runner in the water showed that they were in good agreement. Analysis of the natural frequencies of the runner in the ”water” and the frequency spectrum of the exciting dynamic forces has shown that the critical occurrence of resonance oscillations as a result of the coincidence of the natural frequencies of the runner with the revolution frequencies of the disturbing forces determines the characteristics of the strength blades of the runner and the nature of their destruction.