Vibration due to Rotordynamics in Rolls-Royce UltraFan Architecture

这项研究的目的是提高对新的劳斯莱斯UltraFan架构中转子动力学的理解，并开发新的解决方案来应对新架构带来的挑战。重点关注的两个领域主要是风扇系统中的波速一致性，以及与长高压转子设计（由10级压缩机和2级涡轮机组成）相关的各种转子动力学问题。一旦建立了更好的理解，除了通常的解决方案，如阻尼器，将从更基本的方法探索解决方案。初步评估将利用现有的数据，并在需要时进行一些初步评估，以比较转子动力学风险的影响和概率，并相应地确定优先级。这可能包括波速重合、转子内部阻尼、托马斯/阿尔福德力、不平衡、转子弯曲（主要是由于停机后变形）、轴承支撑刚度不对称和叶尖摩擦的影响。根据初步评估，将优先解决将为UltraFan开发增加最大价值的原因。现有的分析或实验方法可以选择和修改后的文献综述，或新的方法，如果需要，以量化对发动机性能的影响。然后将与劳斯莱斯设计团队合作开发设计解决方案，然后进行分析和选择。

The purpose of this research is to improve the understanding of rotordynamics in the new Rolls-Royce UltraFan architecture, and develop novel solutions to tackle the challenges presented by the new architecture. The two areas of focus will primarily be wave speed coincidence in the fan system, and various rotordynamic issues associated with the long high pressure rotor design (consisting of a 10 stage compressor and 2 stage turbine). Once a better understanding is established, solutions other than the usual fixes, such as dampers, will be explored from a more fundamental approach.An initial assessment will make use of existing data, and some preliminary assessment if required, to compare the impact and probability of the risks in rotordynamics and prioritise accordingly. This may include the effects of wave speed coincidence, rotor internal damping, Thomas/Alford forces, unbalance, rotor bow (mainly due to post-shutdown distortion), asymmetries in bearing support stiffness and tip rubs.Based on the preliminary assessment, priorities will be placed to address the causes which will add the most value to the UltraFan development. Existing analytical or experimental methods can be chosen and modified following a literature review, or new methods produced if required, to quantify the impact on engine behaviour. Design solutions will then be developed, in collaboration with the Rolls-Royce design teams, which are then analysed and down-selected.