Net-Zero Aircraft Design Optimisation

尽管飞机燃油效率在过去三十年中提高了约50%，但航空旅行需求的不断增长导致二氧化碳排放量仅在过去五年就增加了34%。氢燃料电池飞机提供了真正零飞行的机会，飞行距离比电池电动飞机远得多。它们特别适合欧洲航空市场，欧洲航空市场的平均航程为983公里，但目前由空客A320和波音737主导，设计航程超过4000公里。以前氢气飞机概念的谬误是它们遵循既定的煤油飞机设计实践，正如Torenbeek、Roskam和Raymer的作品中总结的那样。结果，现有的机身被重复使用，当前的任务轨迹被考虑，新的空气动力学技术被改造，并采用了错误的设计目标。因此，需要一种基于物理的、多层次的尺寸确定方法，该方法能够公正地看待设计空间。这将允许回答以下三个问题：控制燃料电池最佳尺寸的基本设计参数是什么？应该如何修改当前的飞机操作实践，以发挥燃料电池的优势？协同推进机身一体化能否缩小氢气和煤油飞机之间的重量和阻力差距？CDT MREs阶段进行的初步工作展示了全系统方法的力量，在飞机层面上做出的设计决策的影响可以追溯到动力总成部件层面，反之亦然。博士学位第一年的目的是加深对FC飞机尺寸问题的物理性质的理解。该项目的一个重要中期目标是确定管理FC飞机设计空间的无维组；这一点很重要，因为当前研究得出的结论严重依赖于假设的技术水平，有可能对多维设计空间施加错误的约束。博士学位的其余部分可能会建立在三个支柱上：更高保真度的建模、实验设计和与其他机构的合作，然而，详细的计划尚未制定。总而言之，该项目旨在在现实主义和最小气候影响之间取得平衡，从零开始，但遵守物理学定律，以实现中短途净零航空旅行；不是到2050年，而是到2035年，因为威尔士亲王在2020年挑战了全球航空界。

Although aircraft fuel efficiency improved by around 50% over the past three decades, rising demand for air travel led to a 34% increase in CO2 emissions just over the past five years. Hydrogen fuel cell aircraft offer the opportunity for truly net-zero flight over much longer distances than battery-electric aircraft. They are particularly suited for the European aviation market, which has an average range of 983 km, but is currently dominated by the Airbus A320 and Boeing 737 with design ranges above 4000 km.The fallacy of prior hydrogen aircraft concepts was that they followed established kerosene aircraft design practices, as summarised in the works of Torenbeek, Roskam, and Raymer. As a result, existing airframes were reused, current mission trajectories were considered, novel aerodynamic technologies were retrofitted, and wrong design objectives were applied. Hence, there is a need for a physics-based, multi-level sizing method giving an unprejudiced view of the design space.This will allow the following three questions to be answered: Which are the fundamental design parameters governing the optimum size of a fuel cell? How should current aircraft operating practices be modified to play to fuel cells' strengths? Could a synergistic propulsion airframe integration close the weight and drag gap between hydrogen and kerosene aircraft?The preliminary work conducted during the MRes phase of the CDT demonstrated the power of a whole-system approach, where the impact of design decisions taken at aircraft level could be tracked down to powertrain component level and vice versa. The purpose of the first year of the PhD is to further the understanding of the physical nature of the FC aircraft sizing problem. An important interim goal of this project is to identify the non-dimensional groups governing the FC aircraft design space; this is important insofar as the conclusions drawn by current studies heavily depend on the assumed technology levels, with the risk of imposing false constraints on the multi-dimensional design space. The remainder of the PhD will likely be built on three pillars: higher-fidelity modelling, experimental design, and collaboration with other institutions, however, a detailed plan is yet to be developed.In summary, this project aims to strike a balance between realism and minimum climate impact, starting with a clean slate, yet keeping to the laws of physics, in order to realise short- to medium-haul net-zero air travel; not by 2050, but by 2035 as HRH The Prince of Wales challenged the global aviation community in 2020.