CAREER: From Flamelet to Full-Scale: Advancing Plasma-Assisted Combustion for Low-Emission Sustainable Fuels

应对气候变化需要创新的解决方案，以减少以燃烧为基础的能源生产和运输（包括航空）产生的二氧化碳和其他污染物。该项目旨在推进等离子体辅助燃烧（PAC）技术，重点是在现实场景中提高细焰稳定性和减少污染物。目前对PAC的了解，包括其对排放的影响及其可扩展性，是不完整的。先前的工作已经证明，纳秒重复脉冲等离子体可以延长碳氢化合物和氨火焰的稀薄井喷极限，并减轻不稳定性。然而，对氮氧化物排放的影响仍不清楚，特别是考虑到稀薄燃烧和等离子体本身产生的排放的竞争效应。基础化学动力学研究与实际应用之间存在显著差距，行业相关平台的研究往往采用试错方法。该项目旨在弥合这一鸿沟，将一维层流系统的知识与工业参数联系起来，包括精益井喷极限、燃烧动力学开始和排放。该项目的目标是加深我们对等离子体辅助稀薄火焰稳定和NOx产生的理解，并将这些知识应用于无二氧化碳燃料，包括氢和氨。更具体地说，该项目将评估等离子体策略的有效性，以确保湍流火焰的静态和动态稳定性，这与等离子体对基本火焰参数（如层流火焰速度和熄灭应变率）的影响有着内在的联系。该项目将开发等离子体辅助火焰的数值模型，并将等离子体驱动的涡流稳定燃烧器的稀薄井喷扩展和燃烧动力学抑制实验数据与基本火焰参数相关联，适用于一系列燃料（NH3， H2和CH4混合物）和操作条件。第二个目标是优化这些系统中的氮氧化物排放。该项目采用1D火焰平台，提出了直接的排放优化，而不是简单地延长贫化吹出限制。参数探索将确定使用等离子体减少排放的最佳区域。第三个目标是通过考虑高维效应来补充一维图景。该项目整合了一个教育和扩大参与计划，利用了麻省理工学院系和研究所层面的内部项目。重点是为航空航天推进本科课程开发数字教育内容，并为本科生提供研究机会。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Addressing climate change necessitates innovative solutions to reduce CO2 and other pollutants from combustion-based energy production and transportation, including aviation. This project targets advancing plasma-assisted combustion (PAC) technology, focusing on enhancing lean-flame stability and reducing pollutants in real-world scenarios. Current understanding of PAC, including its impact on emissions and its scalability, is incomplete. Prior work has demonstrated that nanosecond repetitively pulsed plasmas can extend the lean blowout limit of hydrocarbon and ammonia flames and mitigate instabilities. However, the impact on NOx emissions remains unclear, especially considering the competing effects of lean-burning and emission production by the plasma itself. A significant gap exists between fundamental chemical kinetic studies and practical applications, with research on industry-relevant platforms often resorting to trial-and-error approaches. This project aims to bridge this divide, connecting knowledge from 1D laminar systems to industrial parameters, including lean blowout limit, combustion dynamics onset, and emissions. The goal of the project is to deepen our understanding of plasma-assisted lean flame stabilization and NOx production and apply this knowledge to CO2-free fuels, including hydrogen and ammonia. More specifically the project will evaluate the hypothesis that the efficacy of plasma strategies for ensuring the static and dynamic stability of turbulent flames is intrinsically linked to the impact of plasma on fundamental flame parameters, such as the laminar flame speed and the extinction strain rate. The project will develop numerical models for plasma-assisted flamelets, and correlate experimental data on lean blowout extension and suppression of combustion dynamics of plasma-actuated swirl-stabilized burners to fundamental flame parameters, for a range of fuels (NH3, H2 and CH4 blends) and operational conditions. The second goal focuses on optimizing NOx emissions in these systems. Rather than simply extending the lean blow-out limit, the project proposes direct emissions optimization, using the 1D flamelet platforms. A parametric exploration will identify optimal regions for emissions reduction using plasma. A third goal complements the 1D picture by considering higher-dimensional effects. The project integrates an education and broadening participation plan, leveraging internal programs at the department and institute level at MIT. The focus is on developing digital educational content for an undergraduate course on Aerospace Propulsion and providing research opportunities for undergraduate students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.