Advanced vibration control measures for high performance rotating machines

概述：航空发动机转子动力学在现代航空发动机设计中始终扮演着核心角色，随着旧的基于规则的设计方法逐渐消失，随着即将离任的一代转子动力学即将退休，新一代设计方法将面临巨大的机遇。背景概述在某些激励频率可能与系统共振重合的所有振动环境中，阻尼是一种非常有价值的工具。在航空发动机的背景下，这意味着当发动机转子的旋转速度等于所谓的“临界速度”时。现有的主要减振方法是利用挤压油膜阻尼器(SDF)。工程师对于其他振动问题自然会采取的许多选择并不适用于航空发动机，因为阻尼器必须能够承受合理的高温，并且在数千小时的操作中不能退化。目的：本博士研究的主要研究目标是：更好地了解现有SFD的运行情况，更好地了解SFD内在的高度非线性行为是如何在航空发动机的振动特性中表现出来的。基于几何和材料特性的微小变化，深入了解单个发动机设计可能产生的振动响应的分布，提出并分析SFD或其他减振条款的设计演变/旋转，通过提供更一致的性能来提高未来航空发动机设计的稳健性。获得支持上述结论的进一步实验证据。方法和时间这项研究将在诺丁汉大学的燃气轮机和变速器研究中心进行--一个由50人组成的研究小组。它将得到劳斯莱斯专家的积极支持。该项目目前基本上是及时的，因为正在设计的新一代航空发动机将在正常运行速度范围内具有更多的临界速度。因此，这项工作有很大的空间来真正改变未来的设计。

Overview: Aero-Engine Rotor Dynamics invariably plays a central role in modern aero-engine design and there is a tremendous opportunity for a new-generation of approaches as the old rule-based design methods fade away and as an outgoing generation of rotordynamics is retiring. Background summary Damping is an invaluable tool in all vibration contexts where it is possible that some excitation frequency may coincide with system resonance. In the context of aero-engines, that means when the engine rotor spin speed is the same as a so-called "critical speed". The main existing approach to damping is to exploit squeeze-film dampers (SDFs). Many of the options that engineers would naturally take for other vibration problems are not applicable in aero-engines because the dampers must be tolerant to reasonably high temperatures and they must not degrade over thousands of hours of operation. Aim The key research objectives of this PhD study are: Understand the operation of existing SFDs better Develop an improved insight into how the intrinsic highly non-linear behaviour of SFDs manifests itself inside the vibration characteristics of aero-enginesAchieve insight into the distribution of vibration responses that can arise from a single engine design based on small variations in geometry and material properties Propose and analyse design evolutions / revolutions for SFDs or other damping provisions that will improve the robustness of future aero-engine designs by delivering more consistent performanceObtain further experimental evidence to support the above. Methods and timescale The research will be conducted at the University of Nottingham within the Gas Turbines and Transmissions research centre - a research group of 50 people. It will be supported actively by experts from Rolls-Royce. The project is essentially timely at present because a new generation of aero-engines is being engineered that will have more critical speeds within the range of normal running speeds. As such, there is significant scope for this work to make a real difference to future designs.