Structure, propagation, and stabilization of turbulent flames at aircraft engine conditions

飞机发动机条件下湍流火焰的结构、传播和稳定性

• 批准号: RGPIN-2021-02676
• 负责人: Chaudhuri, Swetaprovo
• 金额: $ 2.33万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=743274
• 关键词: Structure; propagation; stabilization; turbulent; flames

Climate change poses an existential threat to life on earth. While most greenhouse gas (GHG) emitters have some possible alternatives; commercial, long-range aircraft engines powered by easily accessible liquid fuels of exceptional energy density, are yet to realize zero GHG-emission solutions. Such a situation underscores the urgent need to maximize efficiency, thereby reduce fuel consumption and emissions from aircraft engines. A step increase in efficiency can be achieved by correspondingly increasing the pressure and temperature in the combustor by increasing the overall pressure ratio. H2 is also being seriously considered as a zero GHG-emission aviation fuel. Either solution involves extreme engineering which behooves fundamental research inputs to ensure safe operation by enabling sustained, stable combustion, and flame stabilization without autoignition, flashback, or blowoff, which would be exacerbated in the extreme and widely varying engine thermodynamic states. The required measurements for turbulence modified flame speeds, flame structure, propagation modes, and blowoff mechanisms at such high pressure-temperature, engine operating conditions remain elusive. The proposed program will provide comprehensive measurements, scientific underpinnings, and modeling of local and global flame speeds and structure, flame propagation modes and regimes, and blowoff mechanisms of swirl-stabilized, turbulent premixed flames at aircraft engine conditions. To this end, experiments will be conducted at pressure up to 25 bar, inlet temperature up to 700 K, and at turbulence Reynolds numbers up to 68000 with both subcritical, supercritical jet fuels, and H2. Unique in Canadian universities and only very few of its kind around the world - the newly constructed High-Pressure Combustion Research Facility (HPCRF) at UTIAS enables the proposed research program. This will address some of the most profound questions of turbulent combustion, all the while serving design inputs for next-generation aircraft engines. Specifically, high-speed tomographic particle image velocimetry, chemiluminescence imaging, and the recently developed Flame Particle Tracking algorithms will be utilized to measure the local and global flame speeds. Turbulent diffusivity obtained by Lagrangian Fluid Particle Tracking at small scales, combined with high-speed laser induced fluorescence and Raman scattering will yield the turbulent flame structure. High fidelity computation aided experimental diagnostics will delineate the different flame propagation modes and corresponding regimes. Finally, H2-air turbulent combustion experiments and the insights gleaned will culminate into new combustors for zero GHG-emission aircraft engines. Alongside the far-reaching engineering impact, the highly qualified personnel trained in this program will have an unmatched research experience at HPCRF, which will prepare them to emerge as next-generation leaders of carbon-neutral aerospace propulsion.

气候变化对地球上的生命构成了生存威胁。虽然大多数温室气体 (GHG) 排放者都有一些可能的替代方案；由易于获取的具有卓越能量密度的液体燃料驱动的商用远程飞机发动机尚未实现零温室气体排放解决方案。这种情况凸显了迫切需要最大限度地提高效率，从而减少飞机发动机的燃油消耗和排放。通过增加总压力比相应地增加燃烧器中的压力和温度，可以实现效率的逐步提高。 H2 也被认真考虑作为一种零温室气体排放的航空燃料。这两种解决方案都涉及极端工程，需要基础研究投入，通过实现持续、稳定的燃烧和火焰稳定来确保安全运行，而不会出现自燃、回火或吹气，而在极端和广泛变化的发动机热力学状态下，这种情况会加剧。在如此高的压力温度、发动机工作条件下，对湍流改变的火焰速度、火焰结构、传播模式和吹气机制所需的测量仍然难以捉摸。 拟议的计划将提供全面的测量、科学基础以及对局部和全局火焰速度和结构、火焰传播模式和状态以及飞机发动机条件下涡流稳定、湍流预混火焰的吹灭机制的建模。为此，实验将在高达 25 bar 的压力、高达 700 K 的入口温度和高达 68000 的湍流雷诺数下使用亚临界、超临界喷气燃料和氢气进行。 UTIAS 新建的高压燃烧研究设施 (HPCRF) 使拟议的研究项目得以实现，这在加拿大大学中是独一无二的，在世界各地也只有极少数。这将解决一些最深刻的湍流燃烧问题，同时为下一代飞机发动机提供设计输入。具体来说，将利用高速层析粒子图像测速、化学发光成像和最近开发的火焰粒子跟踪算法来测量局部和全局火焰速度。通过小尺度拉格朗日流体粒子跟踪获得的湍流扩散率，结合高速激光诱导荧光和拉曼散射，将产生湍流火焰结构。高保真度计算辅助实验诊断将描述不同的火焰传播模式和相应的状态。最后，氢气空气湍流燃烧实验和收集到的见解将最终形成零温室气体排放飞机发动机的新型燃烧器。 除了深远的工程影响之外，在该项目中接受培训的高素质人员还将在 HPCRF 获得无与伦比的研究经验，这将使他们成为下一代碳中和航空航天推进领域的领导者。