Hydrogen fuel technologies for future propulsion and power (HOPE)

当前和未来的能源政策越来越多地旨在减少推进和动力部门的碳排放。化石燃料的燃烧以二氧化碳（CO2）的形式释放碳，并且人们一致认为，化石结合碳的快速人为排放正在导致全球气候变化。与此同时，人们越来越意识到化石燃料燃烧产生的有毒废气污染物，如氮氧化物（NOx）和含碳烟灰或颗粒物（PM）对城市人口健康的负面影响。虽然电气化提供了化石燃料的潜在替代品，但电动动力系统目前仅适用于轻型应用，例如乘用车。有几个高能量需求的应用（飞机，军用和建筑中的越野车辆，火力发电），目前还没有合适的替代内燃机存在。氢（H2）有潜力成为下一代零碳排放燃烧系统的主要能量载体。氢燃料燃气轮机可能能够提供非常有效的能量转换，而不会产生碳排放，并能够满足陆基发电和航空推进的功率和重量要求。H2可以提供比碳氢化合物燃料显著的益处;其宽的可燃性范围允许非常稀薄的燃烧，低点火能量确保迅速点火，高扩散性促进有效的空气-燃料混合。然而，利用H2进行燃烧受到相当大的挑战的阻碍。它的高火焰速度会加剧火焰不稳定和回火的风险，对操作产生不利影响，并且高放热速率（导致高热负荷）与H2的腐蚀性相结合，会导致燃烧室损坏。这意味着目前的燃气涡轮机燃烧器不适合纯H2燃烧，必须重新设计。复杂的反应、湍流条件和复杂的几何结构意味着传统的设计技术（如模拟工具）需要针对H2燃烧进行修改。需要进行全面的实验活动，以填补我们对基本H2燃烧理解的空白，并确定实际H2燃烧系统中高效和近零排放运行的机制。所提出的研究将（a）确定H2注入和与空气有效混合以产生均匀分布的H2-空气混合物的策略，（B）确定导致具有抑制的NOx排放的有利的火焰行为的合适的操作条件，（c）确定在升高的压力和温度下与H2一起使用的合适的材料，（d）了解声学边界条件对燃烧不稳定性的影响;（e）研究a-d中研究的概念从实验室规模到大型规模的转化效果。在实际条件下操作的规模系统。与氢气燃烧相关的基本原理将通过实验室规模的严格实验进行开发和评估，然后在两种不同类型的半工业规模燃烧系统中实施，（i）用于发电的工业小型燃气涡轮机的代表，和（ii）SABRE火箭发动机预燃室部件的缩小版本。在这些半工业系统上进行的实验将为后续研究奠定基础（超过本研究金的4年），以将氢燃料燃烧室集成到全尺寸工业多套管燃气轮机和全尺寸火箭发动机中。研究成果将为项目合作伙伴西门子工业涡轮机有限公司和反应发动机有限公司（REL）提供有关H2燃烧的基础科学知识，为他们提供直接的研究路线。

Current and future energy policies are increasingly aiming to reduce carbon emissions from the propulsion and power sector. The combustion of fossil fuels releases carbon, in the form of carbon dioxide (CO2), and there is consensus that the rapid anthropogenic emission of fossil bound carbon is resulting in global climate change. Co-currently, there is growing awareness of the negative impacts of toxic exhaust pollutants from fossil fuel combustion, such as nitrogen oxides (NOx) and carbonaceous soot or particulate matter (PM), on the health of urban populations. While electrification offers a potential replacement for fossil fuels, the electric powertrain is currently only suitable for light duty applications, such as passenger vehicles. There are several high energy requirement applications (aircraft, off-road vehicles in military and construction, thermal power generation) for which currently no appropriate alternative to combustion engines exists.Hydrogen (H2) has the potential of emerging as the leading energy carrier for the next generation of zero-carbon emission combustion systems. H2 fuelled gas turbines are potentially capable of providing very efficient energy conversion with no carbon emissions, and will be able to span the power and weight requirements of land-based power generation and aero-propulsion. H2 can offer significant benefits over hydrocarbon fuels; its wide flammability range allows very lean combustion, low ignition energy ensures prompt ignition and high diffusivity facilitates efficient air-fuel mixing. However, the utilisation of H2 for combustion is hindered by considerable challenges. Its high flame speed can intensify risks of flame instability and flashback, adversely affecting operation, and high rates of heat release (leading to high thermal loading), combined with H2's corrosive properties, can lead to combustor damage. This means that current gas turbine combustors are not suitable for pure H2 combustion and will have to be re-designed. Complex reactions, turbulent conditions and complicated geometries means that conventional design techniques (such as simulation tools) need to be revised for H2 combustion. Comprehensive experimental campaigns are required to fulfil the gaps in our understanding of fundamental H2 combustion, and to identify regimes for high efficiency and near-zero emission operation in practical H2 combustion systems.In order to set out new design and operation principles for H2 combustors, the research proposed will (a) identify strategies for H2 injection and efficient mixing with air to create a uniformly distributed H2-air mixture, (b) identify suitable operating conditions that result in favourable flame behaviour with suppressed NOx emissions, (c) identify suitable materials for use with H2 at elevated pressures and temperatures, (d) understand the influence of acoustic boundary conditions on combustion instabilities and (e) investigate the effects of translating concepts studied in a-d vary from lab-scale to large-scale systems operating at practical conditions. The fundamental principles associated with H2 combustion will be developed and evaluated through rigorous experimentation at laboratory scale, and then implemented in two different types of semi-industrial scale combustion systems, (i) representative of industrial small gas turbine for power generation, and (ii) scaled down version of the pre-burner component of the SABRE rocket engine. The experiments performed on these semi-industrial systems will lay the foundations for the follow-on research (beyond the 4 years of this fellowship) to integrate H2-fuelled combustors in full-scale industrial multi-cannular gas turbines and in full-scale rocket engines. The research outcomes will provide underpinning scientific knowledge on H2 combustion for the project partners, Siemens Industrial Turbomachinery Ltd. and Reaction Engines Ltd. (REL), giving them a direct uptake route for this research.