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

Old Dominion University Research Foundation, Norfolk VA

Investigators

Abstract

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.