Research on the Vibration Characteristic of Composite Rotor for Halfspeed Nuclear Power Turbine-Generator

Shafting is one of the key units of large steam turbine generator set, its dynamic characteristics directly affect the technical level and operation effect of the new type large capacity Turbine-generator unit. The forces acting on the disc and the shaft are complex in operation. A composite rotor has various dynamic characters for a large capacity nuclear power Turbine-generator comparing with general rotor for its different structure. Numerical simulation was carried out to a composite rotor for a large capacity nuclear power T-G set, so as to analyze the influence of different length to diameter ratio on the vibration characteristics of the low pressure rotor and to study the effect of Interference Amount Between disc and shaft by using the three-dimensional finite element analysis in order to meet the requirements of the good vibration characteristics of the rotor. Firstly, the geometric model of the rotor is set up, and then the element model of the shafting is built, finally natural frequency of the rotor is calculated by using the mechanical module. Vibration characters such as the natural frequency and corresponding mode were obtained by analysis of vibration for the disc and shaft. The effect of the interference fit on critical speeds of the rotors are analyzed preliminarily. The results show that critical speeds of T-G rotor vary sensitively with magnitude of interference. (CSPE).