Dynamic Characteristics Calculation Study of a Gas Turbine Rod Fastening Rotor

Stiffness design of rod fastening rotors is seriously concerned about by manufacturers. In order to reflect dynamic characteristics of rod fastening rotors accurately, elastic contact model is established on the axial contact surfaces between discs for rod fastening rotor firstly. This model assumes that a layer of uniform springs distribute on the contact surfaces and rod fastening rotor is a set of discs joint together by these springs. Then large numbers of rod fastening rotor models are designed and manufactured keeping main physical parameters such as contact stress between discs and contact surfaces roughness consistent with a certain actual gas turbine rotor. Natural frequencies and modes of these rotor models are studied through experimental measuring and finite element calculating methods. After that, mathematical relationship between contact stress and contact stiffness is established and verified using data of these rotor models. Finally, using this relationship, dynamic characteristics of the actual gas turbine rotor are calculated with finite element software and the calculated results coincide with experimental measured values very well. So the elastic contact model and the relationship of contact stress and contact stiffness is recommendable and contact stiffness determining method presented in this paper could be a good reference for stiffness design of rod fastening rotors.