Thermal modelling for Clean Sky Aircraft

随着航空业面临越来越大的减少对化石燃料依赖的压力，人们正在探索新的能源储存和转换途径。电池、氢电(燃料电池)和氢气燃烧都将不得不应对新的热管理挑战。热管理系统是评估燃料电池结构重量和可行性的关键。该项目将结合航空工程的顶级要求，以及对压力降和热传递之间的权衡的流体动力学理解。飞机上的换热器是受压降约束的，前部区域的包装和集成是决定重量和阻力的关键。此外，关键的尺寸点是在炎热的日子里起飞，这需要能够模拟瞬时响应和不同的巡航热管理策略，以实现最佳设计。研究将包括研究基本的换热和压降分布，如横流中的平板和管子，并将这些与全热交换器的工程等价物联系起来。将开发一种如何对热管理部件的重量进行建模的通用方法，以及一种估计单次飞行中的热循环和飞机寿命的工具。将特别注意尝试并包含可能对热膨胀和氢脆等设计至关重要的高保真效果。总体目标将能够评估和质疑乐观飞机概念的关键假设，并评估错误的热假设在哪里可能是关键的。

As the aviation industry is increasingly under pressure to reduce it's dependence on fossil fuels, new energy storage and conversion pathways are being explored. Battery-electric, hydrogen-electric (fuel cell) and hydrogen combustion all will have to deal with new thermal management challenges. The thermal management system is key in assessing weight and viability of fuel cell architectures. The project will bring together the engineering top-level requirements of aviation and a fluid dynamic understanding of the trade-offs between pressure drop and heat transfer. Heat exchangers in aircraft are pressure drop constrained, the packaging and integration of frontal area is key to determining weight and drag. Furthermore the critical sizing point is at take-off on a hot day, requiring capability to model transient response and different cruise thermal management strategies for optimal design. Research will include investigating fundamental heat transfer and pressure drop profiles such as the flat plate and tubes in cross flow, and relating these to the engineering equivalents of full heat exchangers. A general methodology on how to model weight of thermal management components will be developed, as well as a tool to estimate thermal cycles across a single flight and the lifetime of an aircraft. Particular care will be taken to attempt and include high fidelity effects that may be critical to designs such as thermal expansion and hydrogen embrittlement. The overall goal will be able to assess and question the key assumptions of optimistic aircraft concepts and evaluate where erroneous thermal assumptions could be critical.