Ph.D. Proposal

Yuzhe Peng
 

(Advisor: Prof. Wenting Sun)

"Investigation of Ammonia Kinetics using Shock Tube and Laser Absorption Spectroscopy"

Friday, April 21

10:00 a.m.
 

Ben T. Zinn Combustion Laboratory 107
635 Strong St., Atlanta, GA 30318

Abstract
Access to clean and affordable energy is one of the key sustainable development goals recognized by the United Nation. The implementation of carbon-free chemical fuels, such as hydrogen and ammonia, is expected to facilitate the sustainable transition in two major aspects. The synthesis of green ammonia provides an economical storage and transport vector for hydrogen and renewable electricity that is used to power the process. At the point of consumption, ammonia and its fuel blends could replace fossil fuels and accelerate the decarbonization of combustion-based energy systems. Challenges surrounding the low reactivity and high emissions of nitrogen oxides, however, remain an impediment to the implementation of ammonia as an engine and gas turbine fuel. An improved understanding of detailed combustion chemistry is fundamental to the development of ammonia-fueled combustion systems, and the need for reliable experimental data to support kinetic modeling is critical.

The proposed doctoral work aims to experimentally investigate the chemical kinetics of ammonia using a high-pressure shock tube and laser absorption spectroscopy. Measurements of the autoignition delay time and ammonia profile, from both oxidation and pyrolysis experiments, will be obtained for ammonia and its blends, covering a wide range of fuel concentrations and equivalence ratios, and at elevated pressures relevant to gas turbine conditions. An assessment of currently available kinetic mechanisms applicable to ammonia combustion will be performed through comparison of measurements and model predictions, with reaction paths and sensitivity analyses conducted on selected mechanisms. The purpose is to identify important features that help explain the observed discrepancies, and to use experimental and analytical findings to provide recommendations on model improvement. The work also includes the development of a diode-laser absorption sensor near 2.2 μm for ammonia detection, with spectroscopic parameters determined from static absorption cell measurements, and capability demonstrated in shock tube measurements of ammonia oxidation and pyrolysis. Results from this study will provide important evidence to support kinetic modeling and help advance the development of ammonia-fueled applications.

Committee

• Prof. Wenting Sun – School of Aerospace Engineering (advisor)
• Prof. Ellen Y. C. Mazumdar – School of Mechanical Engineering
• Prof. Adam M. Steinberg – School of Aerospace Engineering