Dynamic Analysis Of The Framed Foundation For The Steam Turbine-generator Set

The large-framed machine foundation is commonly used in supporting the steam turbine-generator set in power stations, and the vibration of the foundation is the key element of the whole foundation design. This thesis analyses the present research on dynamic theory of the steam turbine-generator set, and sets up a finite element model of framed foundation based on finite element theory. Based on this model, the dynamic characteristics of the foundation are calculated and analysed The dynamic characteristics are also analysed by using the 'Two Degrees of Freedom' method, which is permissible in 'Regulations on Machine Foundation Design', and is compared with the results obtained form the finite element method, It is concluded that some problems exist in the present design, and some solutions are put forward. This will provide some useful references for future steam turbine-generator set foundation design.Firstly, the meaning of dynamic analysis on the steam turbine-generator set foundation is pointed out. Review and comment on the present research on dynamic analysis of domestic and international steam turbine-generator sets are presented Then a dynamic calculating model of the framed foundation of the steam turbine-generator set is set up based on finite element theory. Then dynamic analysis methods are put forward based on dynamics theory. The dynamic design of the foundation of the specific 12,000KW steam turbine-generator set is carried out. The style of the foundation is confirmed as framed foundation. According to the model of foundation dynamic responses are calculated by large-scale analysis software, SAP90, Finally, multiple designs of the foundation are compared to gain some useful conclusions.The dynamic analysis is conducted by using the Two Degrees of Freedom' method, which is permissible in 'Regulations on Machine Foundation Design' (GB50040-96). The result from the Two Degrees of Freedom' method by simplifying calculation are compared with the result from the finite element. Although the Two Degrees of Freedom' method calculating by plane frame considers theeffect of space, it still has considerable error. Therefore, designing by simplified method is no longer preferable today due to highly popularised computer technologies. The characteristics of the intrinsic frequency distribution of the framed steam turbine-generator set foundation are summarized; it can been seen that the base plate of the framed foundation does not have much effect on the dynamic response of the foundation, and that the 'Amplitude Method' is better than the 'Resonance Method' among dynamic analysis methods. When designing a framed foundation, as long as the load-bearing capacity and stability is ensured, a flexible pillar is better, the amplitude of vibration can be controlled through adjusting the particle quality in foundation design.