Page 247 - Steam Turbines Design, Applications, and Rerating
P. 247
226 Chapter Twelve
segments by welding the shroud portions together. The effect of joining
the blades is allowed for mathematically by means of the bonding fac-
tor described later. Figure 12.5 shows how the dynamic loading on the
blades, i.e., the cyclic stress, can be drastically reduced by this segment
arrangement.
Figure 12.5 Vibration amplitudes of a control-stage blade due to
partial admission through nozzle segments A, C, and D: (a) individ-
ual blades; (b) groups of blades; y = deflection; y s = static deflection;
U = periphery. (Asea Brown-Boveri, Baden, Switzerland)
