Reducing aviation's impact on climate change - understanding effects of fuel and engine characteristics on formation of contrails

对气候强迫的贡献(由于尾迹和二氧化碳)将是塑造航空业未来的主要驱动力。目前，似乎还没有可行的原动机来取代燃气轮机，成为中远程商用飞机的首选发动机。在可预见的未来，这些发动机最有可能的燃料是从可持续来源获得的液态碳氢化合物，即可持续航空燃料。尾迹的形成是发动机排气中的烟尘气溶胶作为冰核形成的结果。目前的理解是，当羽流中的水蒸气由于与周围冷空气混合并迅速冷却而变得过饱和时，烟尘气溶胶、排气中形成的任何含水气溶胶以及带入羽流中的环境气溶胶作为核形成冰晶。关于轨迹形成过程中涉及的这些过程的细节还不是很清楚，而且存在几个知识空白。由于缺乏对冰粒成核的了解，与模拟其辐射强迫相关的不确定性很高。在物理描述导致真实模型的水平上理解这些过程对于模拟飞机诱导的轨迹特性以预测其行为是至关重要的。拟议的项目旨在通过冰成核和增长的理论发展所支持的综合实验和模拟工作来解决知识差距，从而促进在轨道形成方面的知识的进步。这项研究计划的成果将是更好的物理描述和改进的轨道形成模型，这些模型可以用于轨道辐射强迫模拟，减少气候模拟中的不确定性。研究结果将帮助加拿大燃气轮机发动机制造商预测发动机尾气和尾气对环境的影响，并为未来航空技术(如混合动力、氢气和可持续航空燃料飞机)的潜力做出决策和制定战略。

Contributions to climate forcing (due to contrails and carbon dioxide) will be the main drivers that will shape the future of the aviation. Currently, there seems to be no viable prime mover that will replace the gas turbine as the preferred engine for the medium to long range commercial aircraft. It is most likely that for the foreseeable future these engines will be fueled by liquid hydrocarbons obtained from sustainable sources, i.e., sustainable aviation fuels. Contrail formation is a result of the soot aerosol in the engine exhaust acting as the nuclei to form ice particles. The current understanding is that the soot aerosols, any aqueous aerosols formed in the exhaust, and the ambient aerosols entrained into the plume act as nuclei to form ice crystals when water vapour in the plume becomes supersaturated because of the plume mixing with ambient cold air and cooling rapidly. The details of these processes involved in contrail formation are not known well, and there exist several knowledge gaps. The uncertainty associated with modelling its radiative forcing is very high due to a lack understanding nucleation of ice particles. Understanding these processes at a level that physical descriptions leading to realistic models is essential to simulate the aircraft induced contrail properties to predict their behaviour. The proposed project aims to contribute to the advancement of knowledge in contrail formation by addressing the knowledge gaps by means of a combined experimental and modelling effort supported by theoretical development of ice nucleation and growth. The deliverables of this research program will be a better physical description and improved models of contrail formation that can be used in contrail radiation forcing simulations decreasing the uncertainties in climate modelling. Results will help the Canadian gas turbine engine manufacturers to predict the impacts of engine exhaust and contrails on the environment and facilitate the decision-making and strategies for the potential of future aviation technologies such as hybrid electric, hydrogen, and sustainable aviation fuels aircraft.