EPSRC ICASE/Rolls Royce - Hydrogen Fuel Flow Control for Zero Carbon propulsion systems

该项目属于EPSRC工程研究领域。该奖学金由牛津大学和劳斯莱斯公司在EPSRC iCASE奖励计划下联合提供。氢气作为飞机推进的燃料是实现碳减排的一个潜在途径。氢燃料航空推进的一大挑战是使用液氢来实现更高的有效载荷/航程。液氢需要压缩和加热，然后在进入燃烧室之前进行计量。在具有挑战性的工作温度和振动环境中，航空航天对准确、稳定和瞬时燃油流量计量的要求推动了对定制创新、可靠、低重量解决方案的需求。由于高温环境的影响，目前尚无解决方案，因此需要对单个燃烧器流量进行调制计量。本项目的主要目的是研究新型流体阀概念及其在氢燃料流量计量中的应用。流体设备利用流体机械现象来控制对象流体(如氢燃料)的行为，同时消除了对任何移动部件的需要。之前的工作着眼于射流转向器和切换涡流阀。这项工作将研究一种新型对置射流放大器的工作原理理论上，对置射流放大器的工作原理是将同一流体的两个射流对准对方，使用一个小但强大的射流来切断来自较大进气口的较小功率的射流。虽然众所周知，较小的喷嘴实际上可以切断较大喷口的流动(只要喷口速度不同)，但喷口大小和所需喷口速度之间的确切关系尚不清楚，可能会决定这类设备的生存能力。这项研究的第一个目的是描述该设备的规范版本在一系列条件下的性能。由于该装置使用的是本质上不稳定的相对喷流，因此将进行详细的计算和实验研究，以了解最佳性能。最后，将开发和测试更多发动机尺度的几何形状。通过这项研究，正在使用多种工程方法来确定和改进该装置的性能。3D打印被用于制作该设备的原型，并评估其初始性能。它与计算流体力学结合使用，以模拟无法用原型设备测试的条件下的性能(例如在非常高的压力下)。分析预测也在进行，以与实验和计算研究进行比较。因此，研究项目将包括：对向喷流流体动力学的研究设备运行的分析模型的研究典型设备行为的计算模型和低压设备上的实验验证。初步设计合适的发动机规模的设备和测试本项目属于EPSRC流体动力学、空气动力学和控制研究领域。

Project DescriptionThis project falls within the EPSRC Engineering research area.The studentship is jointly offered by the University of Oxford and Rolls-Royce under the EPSRC iCase award scheme.Hydrogen as a fuel in aircraft propulsion is one potential avenue in achieving carbon reduction. One of the big challenges for hydrogen fuelled aerospace propulsion is the use of liquid hydrogen to enable higher payload/range aircraft. Liquid Hydrogen requires compression and heating before being metered ahead of introduction in the combustion chamber. Aerospace requirements for accurate steady and transient fuel flow metering in challenging operating temperature and vibration environments drives the need for bespoke innovative reliable low weight solutions. There is also a potential need for modulated metering of individual combustor burner flows where there are few technological solutions present due to high temperature environment.The main objective of this project is to investigate novel fluidic valve concept with the application to hydrogen fuel flow metering. Fluidic devices utilize fluid mechanic phenomena to control the behaviour of a subject fluid (such as hydrogen fuel) while removing the need for any moving parts. Previous work has looked at fluidic diverters and switched vortex valves. This work will research the working principle of a novel opposed jet amplifier deviceThe Opposed Jet Amplifier theoretically works by pointing two jets of the same fluid at each other, using one small but powerful jet to cut off a less powerful jet coming from a larger inlet. While it is known that a smaller jet can in fact cut off the flow of a larger one (as long as the jet velocities are different), the exact relationship between the size of the jets and what jet velocities are required is not yet known and will likely determine the viability of such class of devices. The first aim of this research is to characterise performance of a canonical version of the device under series of conditions. As the device utilises opposing jets that are inherently unstable and so detailed computational and experimental studies will be carried out to understand optimum performance. Finally a more engine scale geometry will be developed and tested.Throughout this research a multitude of engineering methodologies are being used to determine and improve the performance of the device. 3D printing is being used to prototype the device and evaluate initial performance. This is being used in conjunction with computational fluid dynamics to simulate performance at conditions that can't be tested with a prototype device (such as at very high pressures). Analytical predictions are also being carried out to compare with experiments and computational studies. The research project will therefore include:Research into fluid dynamics of opposed jetsInvestigation into analytical modelling of the device operation Computational modelling of the canonical device behaviour and experimental validation on low pressure facilities.Preliminary design of a suitable engine scale device and testingThis project falls within the EPSRC Fluid dynamics, aerodynamics and control research areas.