Transpiration Cooling Systems for Jet Engine Turbines and Hypersonic Flight

这项资助将使英国在对下一代冷却系统的理解和可预测性方面发生重大变化，使英国能够在喷气发动机和高超音速飞行器冷却技术方面建立全球领先地位。我们的目标是使被公认为终极对流冷却系统的蒸发冷却在英国生产的喷气发动机和欧洲高超音速飞行器上成为现实。涡轮增压器有可能实现更高的循环温度（根据热力学第二定律提高效率），但总是会引入涡轮机级损失（降低效率）。冷却系统的改进必须能够提高涡轮机入口温度（泰特），同时使用最小量的冷却液流量来实现所需的部件寿命。对于高速飞行，热传递主要是空气动力学加热，重返大气层时的气体温度超过太阳表面的温度。热防护系统传热的任何减少都将最终导致更低的质量，从而降低发射成本。此外，更低的温度可以成为目前温度受限的更高性能技术的推动力。喷气发动机和高超音速飞行可达到的最高温度受到所使用的材料和冷却技术的限制。蒸发流动的冷却效益是公认的，但在英国，由于缺乏合适的多孔材料以及精确模拟空气动力学和机械应力场的挑战，这项技术在航空航天领域的应用一直受到阻碍。我们的方法将enale之间的耦合流，热和应力场的研究同时在一个跨学科的方法，我们认为是必不可少的，以达到最佳的蒸腾系统。该项目资助将使各自领域的世界领导者能够共同解决蒸发冷却应用中出现的跨学科问题，从而推动该技术的快速创新。该应用是及时的，因为拟议的研究将使英国航空航天工业利用最近的发展，在材料，制造能力，实验设施/测量技术和计算方法，以发展科学的应用发汗冷却。高温研究中心在伯明翰大学将提供的手段，铸造超合金涡轮机翼型的孔隙度。拟议的赠款将允许创新的铸造系统相结合的铸造专业知识与航空航天和应力建模在最近的EPSRC资助的研究计划。它还建立在超高温陶瓷和碳复合材料的材料开发上，这些材料是在EPSRC资助的研究中进行的，通过使用可控孔隙率和多层复合材料。它还将首次提供在真实飞行条件和材料温度下进行流动与材料（多孔和非多孔）直接耦合的机会。最近在牛津大学和帝国理工学院的NWTF计划（EPSRC/ATI资助）下对英国风洞的投资将允许直接复制飞行中看到的温度和热通量，并使用先进的激光技术进行询问。最近发展的傅立叶叠加在CFD网格模拟薄膜冷却，现在可以扩展到提供一个突破性的方法来预测冷却流和高孔隙率/发汗冷却systems.The欧洲航天局最近确定了迫切需要的替代品，一次烧蚀热防护系统的高超音速飞行的有效性。在这方面的投资是显着的，发汗冷却已被确定为一个有前途的冷却技术。罗尔斯·罗伊斯公司已开始加速对未来喷气发动机新技术的投资，包括ADVANCE

This grant will deliver a step change in the understanding and predictability of next generation cooling systems to enablethe UK to establish a global lead in jet engine and hypersonic vehicle cooling technology.We aim to make transpiration cooling, recognised as the ultimate convective cooling system, a reality in UK produced jetengines and European hypersonic vehicles. Coolant has the potential to enable higher cycle temperatures (improving efficiency following the 2nd law of thermodynamics) but invariably introduces turbine stage losses (reducing efficiency). Cooling system improvement must enable higher Turbine Entry Temperature (TET) while using the minimum amount of coolant flow to achieve the required component life. For high speed flight, heat transfer is dominated by aerodynamic heating with gas temperatures on re-entry exceeding those at the surface of the sun. Anyreduction in heat transfer to the Thermal Protection System will ultimately lead to lower mass, allowing for decreased launch costs Furthermore, the lower temperatures could serve as an enabler for higher performance technologies which are currently temperature limited.The highest temperatures achievable for both jet engines and hypersonic flight are limited by the materials and coolingtechnology used. The cooling benefits of transpiration flows are well established, but the application of this technology to aerospace in the UK has been prevented by the lack of suitable porous materials and the challenge of accurately modelling both the aerothermal and mechanical stress fields. Our approach will enale the coupling between the flow, thermal andstress fields to be researched simultaneously in an interdisciplinary approach which we believe is essential to arrive at the best transpiration systems. This Progreamme Grant will enable world leaders in their respective fields to work together to solve the combination of cross-disciplinary problems that arise from the application of transpiration cooling, leading to rapid innovations in this technology. Theapplication is timely since the proposed research would enable the UK aerospace industry to capitalise on recentdevelopments in materials, manufacturing capability, experimental facilities/measurement techniques and computationalmethods to develop the science for the application of transpiration cooling.The High Temperature Research Centre at Birmingham University will provide the means to cast super alloy turbine aerofoils with porosity. Theproposed grant would allow innovation in the cast systems arising from combining casting expertise with aerothermal andstress modelling in recent EPSRC funded research programmes. It also builds upon material development of ultra-hightemperature ceramics and carbon composites undertaken in EPSRC funded research, by use of controlledporosity and multilayer composites. It will also provide the first opportunity to undertake direct coupling of the flow with thematerials (porous and non-porous) at true flight conditions and material temperatures.Recent investment in the UK's wind tunnels under the NWTF programme (EPSRC/ATI funded) at both Oxford University andat Imperial College will allow for direct replication of temperatures and heat fluxes seen in flight and interrogated usingadvanced laser techniques. Recent development of Fourier superposition in CFD grids for modelling film cooling can nowbe extended to provide a breakthrough method to predict cooling flow and metal effectiveness for highporosity/transpiration cooling systems.The European Space Agency has recently identified the pressing requirement for alternatives to one-shot ablative ThermalProtection Systems for hypersonic flight. Investment in this area is significant and transpiration cooling has been identifiedas a promising cooling technology. Rolls-Royce has embarked upon accelerated investment in new technologies for future jet engines including the ADVANCE