Cryogenic Flow Physics to Advance Liquid Hydrogen-Based Aviation

商业航空每年向大气中排放超过9亿吨二氧化碳（CO2），占人为CO2排放总量的3%。如果它是一个国家，商业航空将排在德国之前，成为第六大二氧化碳排放国。航空业必须紧急脱碳，以避免灾难性的气候影响。超过70%的排放来自中程飞行（2000-4000公里），在可预见的未来，电池电气化仍然不可行。氢为航空业的脱碳提供了一种替代途径它具有很大的质量能量密度;它可以由风能和太阳能等可再生能源产生;它可以在飞机发动机中燃烧，只需很少的修改;它可以直接通过燃料电池发电。然而，氢的低体积能量密度意味着它必须作为加压气体或低温（超冷）液体储存。每单位能量，液态氢需要大约一半的体积，使其最适合航空。采用液氢作为低碳航空燃料将需要对航空技术进行重大的重新设计，主要是由于其低温状态的复杂性。尽管低温条件对燃料储存条件、燃料系统布局以及最终对飞机安全性和效率有重大影响，但对低温条件与流动湍流、相变、热不平衡、几何复杂性和界面效应的相互作用了解甚少。没有对低温流动的深入物理理解，液氢航空就无法发展。我的研究计划将通过三个平行的活动推进液氢途径，使航空业脱碳。首先，我们将生成新的计算流体动力学方法，这些方法将专门针对低温流动物理的精确和鲁棒模拟而定制，特别是建立在非连续方法（如晶格玻尔兹曼方法）的优势上。其次，我们将使用开发的工具来解决有关液氢低温行为的基本问题。最后，利用这些调查所产生的见解，我们将开发简单而物理现实的模型来预测工程设计中使用的液氢的热工水力行为。我的研究计划将直接影响航空业，实现低碳航空系统的创新，并支持航空业脱碳的理想氢气途径。它还将促进其他难以脱碳的行业的氢基技术的发展，包括重型卡车运输，铁路和海上运输。因此，拟议的计划将支持加拿大国内的经济和能源多样化努力，同时帮助加拿大实现其紧迫的环境和气候目标。

Commercial aviation emits more than 900 million tonnes of carbon dioxide (CO2) each year into the atmosphere, accounting for 3% of total anthropogenic CO2 emissions. If it were a country, commercial aviation would rank just ahead of Germany as the sixth largest emitter of CO2. Aviation must urgently decarbonize to avoid catastrophic climate impacts. Over 70% of emissions come from medium-range flights (2000-4000 km) for which battery electrification remains infeasible for the foreseeable future. Hydrogen presents an alternative route for decarbonizing aviation-it has a large energy density by mass; it can be generated from renewable sources such as wind and solar; it can be combusted in aircraft engines with few modifications; and it can generate electricity directly via a fuel cell. However, hydrogen's low volumetric energy density means that it must be stored as a pressurized gas or cryogenic (ultra-cold) liquid. Per unit energy, liquid hydrogen requires about half the volume, making it most suitable for aviation. Adopting liquid hydrogen as a low-carbon aviation fuel will require significant re-engineering of aviation technologies, mainly due to the complexity associated with its cryogenic state. The interactions of cryogenic conditions with flow turbulence, phase transition, thermal non-equilibrium, geometrical complexities, and interfacial effects are poorly understood, despite the major impacts these processes have on the fuel storage conditions, fuel system layout, and ultimately the aircraft safety and efficiency. Without an in-depth physical understanding of cryogenic flows, liquid hydrogen-based aviation cannot advance. My research program will advance the liquid hydrogen pathway for decarbonising the aviation sector through three parallel activities. First, we will generate new computational fluid dynamics approaches that will be specifically tailored for accurate and robust simulation of cryogenic flow physics, building especially on the strengths of non-continuum approaches such as the lattice Boltzmann method. Second, we will use the developed tools to address fundamental questions that remain unanswered regarding the cryogenic behaviour of liquid hydrogen. Finally, using the insights produced by such investigations, we will develop simple yet physically-realistic models to predict the thermohydraulic behaviour of liquid hydrogen for use in engineering design. My research program will directly impact the aviation industry, enabling innovations in low-carbon aviation systems and supporting the aspirational hydrogen pathway for decarbonizing the aviation sector. It will also promote the development of hydrogen-based technologies in other hard-to-decarbonize sectors, including heavy-duty trucking, rail, and marine transportation. Therefore, the proposed program will support economic and energy diversification efforts within Canada while simultaneously helping Canada reach its urgent environmental and climate goals.