Hydrogen fuel technologies for future propulsion and power (HOPE)

当前和未来的能源政策越来越多地着眼于减少动力和电力部门的碳排放。化石燃料的燃烧释放出二氧化碳(CO2)形式的碳，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)和碳质烟尘或颗粒物(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，但电动总成目前只适用于轻型应用，如乘用车。目前有几种对能源要求很高的应用(飞机、军事和建筑中的越野车、火力发电)，目前还没有合适的内燃机替代品。氢气(H2)有可能成为下一代零碳排放燃烧系统的主要能源载体。以氢为燃料的燃气轮机有可能在没有碳排放的情况下提供非常高效的能源转换，并将能够跨越陆地发电和航空推进的功率和重量要求。与碳氢燃料相比，氢气可以提供显著的好处；其宽广的可燃性范围允许非常稀薄的燃烧，低点火能量确保快速点火，高扩散率有助于高效的空气-燃料混合。然而，氢的燃烧利用受到相当大的挑战的阻碍。其高火焰速度会加剧火焰不稳定和回火的风险，对运行产生不利影响，高放热率(导致高热负荷)，加上H2‘S的腐蚀性，可能会导致燃烧室损坏。这意味着，目前的燃气轮机燃烧室不适合纯氢气燃烧，必须重新设计。复杂的反应、湍流条件和复杂的几何形状意味着传统的氢气燃烧设计技术(如模拟工具)需要修改。需要开展全面的实验活动，以填补我们对基本H2燃烧的理解上的空白，并确定实际H2燃烧系统中高效和接近零排放的运行模式。为了制定H2燃烧器的新设计和操作原则，拟议的研究将(A)确定H2喷射和与空气有效混合的策略，以产生均匀分布的H2-空气混合物，(B)确定适当的操作条件，以产生良好的火焰行为和抑制NOx排放，(C)确定适合在高压和高温下与H2一起使用的材料，(D)了解声边界条件对燃烧不稳定性的影响，(E)调查将a-d中研究的概念转化为在实际条件下运行的大型系统的影响。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来开发和评估，然后在两种不同类型的半工业规模燃烧系统中实施，(I)代表用于发电的工业小型燃气轮机，(Ii)军刀火箭发动机预燃器组件的缩小版本。在这些半工业系统上进行的实验将为后续研究(在本奖学金的4年之后)在全尺寸工业多管燃气轮机和全尺寸火箭发动机中集成H2燃料燃烧室奠定基础。研究成果将为项目合作伙伴西门子工业涡轮机械有限公司和反应发动机有限公司(REL)提供关于氢气燃烧的基础科学知识，使他们能够直接参与这项研究。

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.