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

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.