Unbalance response analysis of the circumferential tie-rod combined rotor considering different support

The combined circumferential tie rod rotor with the advantages of light weight, good cooling effect and easy assembly is widely used in gas turbines, especially in heavy-duty gas turbines. In this paper, a circumferential tie-rod combined rotor was investigated using two-dimensional finite element model and three-dimensional finite element model with ANSYS. The critical speed of the rotor were calculated by finite element method and compared with experiments. The dynamic characteristics and stability of rotor are closely related to the supporting performance of bearing. The unbalance response analysis of the tie-rod rotor supported by elliptical pad bearing and tilting pad bearings which are loads acting on the tile pad and loads acting between the tiling pads are investigated respectively. The results show that the critical speed calculates with two-dimensional finite element model is closer to the experimental value. Selecting different support bearing has a great influence on the critical speed and vibration amplitude of the rotor. In addition, the tie-rod rotor supporting by tilting-pad bearing have a better stability when the load is between the pads.