EAGER: Enhancement of Ammonia combustion by spatiotemporal control of plasma kinetics

由于碳氢化合物燃烧释放温室气体，氨和氢等燃料作为一种替代能源引起了人们的兴趣。利用纯氢作为能源载体，除了与碳氢化合物相比体积能量较低外，还受到昂贵的储存和运输技术的限制。另一方面，氨作为一种无碳的高密度氢能源很有吸引力。然而，氨作为一种直接燃料，存在燃烧速度慢、可燃极限窄、氮氧化物排放量高等缺点。研究表明，低温等离子体具有控制燃料着火/燃烧特性的潜力。到目前为止，大多数研究都是渐进式的，从不适合燃烧的其他应用程序借来的等离子体源，以及现实的工程限制使其不切实际。本课题的目的是利用一种新型的等离子体源来研究氨的燃烧特性。考虑到目前全球近80%的能源消耗来自燃烧化石燃料，这将对环境和化石燃料消耗的减少产生重大影响。这项研究将有助于等离子体辅助燃烧科学关键领域的研究生和本科生的专业发展和培训。本研究的目标是研究一种通过旋转电场产生的等离子体源来控制氨的着火和燃烧动力学。等离子体源符合燃烧室的几何形状，并有效地产生控制氨燃烧特性所需的前体。该方法是目前已知的唯一一种实时控制电场空间分布的方法，可实现体积电能耦合和自由基电子碰撞产生。该项目将有助于更好地了解等离子体辅助燃烧的机理以及电能的控制释放对火焰速度和LBO范围的影响。这将导致开发用于等离子体辅助点火/燃烧系统设计的预测工具。与其他正在研究中的技术不同，由于它符合燃烧几何结构和简单性，因此更有可能在实际设备中实施。这项调查还将为包括高超声速运输在内的先进发动机概念的发展提供信息。建议的工作将促进等离子体辅助燃烧的知识，以稳定高海拔和低动态压力和温度下的点火和燃烧。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Due to the release of greenhouse gases from combustion of hydrocarbons, fuels such as ammonia and hydrogen are of interest as an alternative source of energy. Utilizing pure hydrogen as an energy carrier is limited by expensive storage and transportation technologies in addition to having a low volumetric energy in comparison to hydrocarbons. Ammonia on the other hand is attractive as a carbon-free high-density hydrogen energy source. However, ammonia as a direct fuel has several shortcomings including low burning velocity, narrow flammability limits, and high nitrogen oxides emissions. It has been shown that nonthermal plasmas have the potential to control ignition/combustion characteristics of fuels. Most research to date has been incremental with plasma sources borrowed from other applications which are not suitable for combustion and realistic engineering constraints make them impractical. The aim of this project is to study the combustion characteristics of ammonia with a novel plasma source. Considering that nearly 80% of the current worldwide energy consumption comes from burning fossil fuels, this will have a significant impact on the environment and reduction in the consumption of fossil fuels. The research will contribute to the professional development and training of graduate and undergraduate students in the critical area of plasma-assisted combustion science.The goal of the proposed research is to investigate a plasma source created by a rotating electric field to control ignition and combustion kinetics of ammonia. The plasma source conforms to the combustor geometry and efficiently produces the precursors needed to control the combustion characteristics of ammonia. The proposed method is the only known method of controlling the spatial distribution of electric field in real time resulting in volumetric electrical energy coupling and production by electron impact of radicals. The project will lead to a better understanding of the mechanism of plasma-assisted combustion and the effect of controlled release of electrical energy on the flame velocity and LBO range. This will lead to the development of predictive tools for design of plasma-assisted ignition/combustion systems. Unlike other techniques under investigation, this has a better chance of being implemented in actual devices due to its conformity to the combustion geometry and simplicity. This investigation will also inform the development of advanced engines concepts including hypersonic transportation. The work proposed will advance the knowledge of plasma assisted combustion to stabilize ignition and combustion at high altitudes and at low dynamic pressures and temperatures.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.