The Faculty of Engineering at the University of Nottingham and Rolls-Royce plc are seeking an enthusiastic and self-powered student with both excellent analytical skills and a good sense of what is practicable to undertake a PhD in Aero-Engine Rotordynamics. Rotordynamics 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 rotordynamicists is retiring.
Damping is an invaluable tool in all vibration contexts where it is possible that some excitation frequency may coincide with a 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 (SFDs). 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.
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-engines
- Achieve 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 performance.
- Obtain further experimental evidence to support the above.
The research will be conducted at the University of Nottingham within the Gas Turbines and Transmissions research centre – a research group with ~50 people. It will be supported actively by experts from Rolls-Royce. The project is especially 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.
The student will gain a broad range of experience and skills spanning the development and use of dynamic models, the design processes involved with critical hardware, some experimentation and modern techniques in data analysis.