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，氨和氢等燃料作为替代能源受到关注。利用纯氢作为能源载体受到昂贵的储存和运输技术的限制，而且与碳氢化合物相比，纯氢的体积能量较低。另一方面，氨作为一种无碳高密度氢能源很有吸引力。然而，作为直接燃料的氨存在燃烧速度低、可燃性限制窄、氮氧化物排放量高等缺点。研究表明，非热等离子体具有控制燃料点火/燃烧特性的潜力。到目前为止，大多数研究都是从其他应用中借来的等离子体源，这些源不适合燃烧，现实的工程限制使它们不切实际。本项目的目的是利用一种新型等离子体源研究氨的燃烧特性。考虑到目前全球近80%的能源消耗来自化石燃料的燃烧，这将对环境和减少化石燃料的消耗产生重大影响。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。提出的研究目标是研究由旋转电场产生的等离子体源来控制氨的点火和燃烧动力学。等离子体源符合燃烧器的几何形状，并有效地产生控制氨燃烧特性所需的前驱体。本文提出的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，该方法可导致体积电能耦合和自由基电子冲击产生。该项目将有助于更好地理解等离子体辅助燃烧的机理，以及控制电能释放对火焰速度和LBO范围的影响。这将导致预测工具的发展，用于设计等离子辅助点火/燃烧系统。与其他正在研究的技术不同，由于其符合燃烧几何形状且简单，因此在实际设备中实现的机会更大。这项调查还将为包括高超音速运输在内的先进发动机概念的发展提供信息。提出的工作将推进等离子体辅助燃烧在高海拔和低动压和温度下稳定点火和燃烧的知识。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。

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.