Dynamical Analysis on Circumferential Rod Fastening Rotor System in Heavy-Duty Gas Turbine

Abstract

Circumferential rod fastening rotor system is widely used in heavy-duty gas turbines because of its advantages such as light weight, good cooling, easy assembly and so on. The force, torque or load between components in this type of rotor system must be transmitted depending on the contact interfaces. In this paper, the normal and tangential interface contact stiffness of rough surface are obtained according to the relationship between force and deformation of the finite element contact model which can reflect the surface topography. Then, the dynamic analysis method is presented and two models are built to analyze the dynamic performance of composite rod fastening rotor system. The effects of interface contact stiffness on the natural frequencies and unbalance responses of rotor system are studied. The results illustrate that the normal contact stiffness of rough surface linearly increase when the normal load rise, but the tangential contact stiffness decrease with the tangential pressure increasing. Furthermore, the contact stiffness has important effects on the natural frequencies and unbalance responses of rotor system. With the growth of contact stiffness, the natural frequencies increase, while the unbalance response amplitudes of rotor system decrease.