Abstract
A full 3D rotor/stator FE model with CMS-based superelement modal reduction is developed. The method enables a high fidelity and efficient rotordynamic analysis for a newly designed power turbine (PT) with a slim spoke frame stator. In parallel, the stator support structure dynamic stiffness is quickly assessed using the FE simulated frequency response functions (FRF) data on the requirement of API standard. The results of the dynamic stiffness of the stator shows lower than the API standard recommended. The derived support dynamic stiffness is directly applied to the unbalance response analysis of the PT rotor incorporating the bearing characteristics. The comparison of the unbalance response shows that the rotor with FRF representation of stator structure and the full 3D FE superelement model are very well cross validated. Finally, the rotordynamic analysis of full FE model shows that with the slim spoke frame, the PT still meets all the API requirements.
