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Campbell, Goodman, and SAFE Diagrams for Steam Turbine Blades 201
Figure 11.10 Campbell plane. (Dresser-Rand Company, Wellsville, N.Y.)
F = F 0 + F 1 sin (ωt +θ 1 ) + F 2 sin (2ωt +θ 2 ) + . . . (11.2)
The frequency (ω) of dynamic forces experienced by the blading is
expressed mathematically as follows:
(M)(N)
ω= (11.3)
60 Hz
where ω= frequency, Hz
M = number of nozzles, number of interruptions
N = turbine speed, r/min
