Simulation of long blades and calculation of critical speeds of the steam turbine rotor by 3D finite element methods

The critical speed of the low-pressure rotor of a 150MW steam turbo-generator set has been calculated by the 3D finite element method. Two ways of simulating long blades, used in the mentioned calculation, are proposed. Comparing the calculation results with those obtained by traditional methods, and also with data obtained on site, prove that both ways of simulation are feasible and may thus serve to a certain extent, as a reference for 3D modeling concrete bodies, when using finite element methods for vibration calculating of rotors with long blades.