Thermal management of hydrogen-powered aircraft

该项目是与ZeroAvia合作的，ZeroAvia将氢电动力总成改装到支线和通用航空飞机上。在最高层次上，目标是从实验和数值上询问热管理系统周围的空气动力学特性。氢燃料电池在飞机上很少见，因此这项技术正在为汽车等其他行业进行优化。在试验台飞机上使用汽车衍生的热管理系统进行的早期测试显示，寄生阻力增加了，这是不受欢迎的。这需要对与这些改装相关的主要气动特性有更深层次的了解，特别是在技术可扩展到更高功率要求的情况下。主要目标/研究问题是：-什么气动特性，稳定或非稳定，主导改装设施？这些如何受关键设计变量(例如螺旋桨-冷却管道距离)的影响？-在这个参数研究中，将需要开发一个实验试验台(使用PIV/PLIF、冷/热钢丝、非定常探头)和CFD解算器(将现有的DNS代码与螺旋桨模型相适应)。-与突出的主要特征相关的性能损失是什么？-这将允许推导出航空航天特定的热管理系统设计指标/程序。-我们如何使用被动流动控制和/或几何优化来提高性能？-本节将利用在前两个阶段中获得的理解。该项目的应用与热管理和空气动力学结构这两个“技术砖”紧密结合在一起，航空航天技术研究所在其2022年的“FlyZero”报告中概述了这两个结构对氢气飞机的发展至关重要。尽管工作的重点是与ZeroAvia的改装相关的几何形状，但研究将适用于整个氢气飞机空间。寄生阻力的小幅减少将带来有价值的射程增加，有助于改善这项技术的商业化。一项参数研究，利用PIV/PLIF的高级空气动力学询问，以及根据主要空气动力学特性对系统范围内的惩罚进行量化，提出了一项新的研究。以前的工作大多提出了不适用于ZeroAvia所面临的挑战的简化和假设，例如，冷却管道中没有非稳定的空气动力学特征。文献中的这种偏差是由非稳定CFD模拟所需的高计算能力以及实验询问所产生的困难和费用产生的。此外，研究主要集中在涡扇装置上，导致文献中缺乏适用于新几何形状的研究。

This project is a collaboration with ZeroAvia who retrofits hydrogen-electric powertrains onto regional and general aviation aircraft. On the highest level, the aim is to experimentally and numerically interrogate aerodynamic features surrounding the thermal management system. Hydrogen fuel cells are rarely found on aircraft, leading to the technology being optimised for other industries such as automotive. Early tests using automotive-derived thermal management systems on testbed aircraft have shown undesirable parasitic drag increases. This requires a deeper level of understanding regarding dominant aerodynamic features associated with these retrofits, especially as the technology scales to higher power requirements. Key objectives/research questions are:- What aerodynamic features, steady or unsteady, dominate retrofitted installations? How are these affected by key design variables (e.g. prop-cooling duct distance)?- In this parametric study, development of an experimental test rig (using PIV/PLIF, cold/hotwires, unsteady probes) along with a CFD solver (adapting an existing DNS code with propeller model), will be required.- What are the performance penalties associated with the highlighted dominant features? - This will enable derivation of aerospace-specific thermal management system design metrics/procedures.- How can we improve performance using passive flow control and/or geometric optimisation?- This section will utilise the understanding derived in the first two stages. The applications of this project are closely coupled with two 'technology bricks', thermal management and aerodynamic structures, outlined as vital for the development of hydrogen aircraft by the Aerospace Technology Institute in their 2022 'FlyZero' report. Despite work being focussed on geometries associated with ZeroAvia's retrofits, research will be applicable to the hydrogen aircraft space as a whole. Small reductions in parasitic drag will present valuable range increases, helping improve the commercialisation of this technology. A parametric study, utilising high-level aerodynamic interrogation with PIV/PLIF, alongside quantification of the system-wide penalties from dominant aerodynamic features, presents as novel research. Prior works largely present simplifications and assumptions that are not applicable to the challenges ZeroAvia faces, for example, the absence of unsteady aerodynamic features in a cooling duct. This bias in the literature is generated from the high computing power required for unsteady CFD simulations, alongside the difficulties and expenses incurred with experimental interrogation. Additionally, research largely focusses on turbofan installations, leading to a lack of studies in the literature applicable to new geometries.