Abstract
To avoid resonance of steam turbine blades during operation, it is necessary to establish a prediction method for the natural frequencies of blades. Therefore, a calculation method of the natural frequencies is developed for structures with blades bound on the entire disk circumference. Five natural frequencies exist within the range below 500 Hz in calculations of the natural frequencies of a single blade with turbine. Vibration characteristics for these natural frequencies are shown systematically by taking the direction of the vibration into account when moment of inertia is small at the middle of the blade between blade root and blade tip. The relation between the natural frequencies of all bound blades and those of a bound group consisting of several blades, and variations of the natural frequencies according to variation in blade dimensions are also discussed.
