Session: Poster Session

Paper Number: 162873

High-Pressure Laser Absorption Measurements and Combustion Chemical Kinetic Modeling of Natural Gas/ammonia/hydrogen 

 

Hydrogen (H2) and ammonia (NH3) are two alternative fuels that could decarbonize the energy sector, which currently produces most power through combusting natural gas (NG). Both H2 and NH3 exhibit non-favorable combustion properties, such as flame flashback and blowout, and complex storage properties due to their incompatibilities with other metals, NH3’s toxicity, and H2’s small molecular size. By blending these alternative fuels with NG, a much more stable flame can be achieved while also lowering carbon emissions. There is also an already extensive infrastructure for transporting NG, which blends of these fuels can be utilized. Hydrogen cyanide (HCN) formation and nitrogen oxide (NOx) emissions are also major concerns when blending these fuels, which can be reduced or eliminated through various techniques such as combustion chamber sizing or selective catalytic reduction. To first simulate emission reduction techniques in fluid dynamic programs, the underlying combustion chemistry must be correct. Through fundamental experimental data such as ignition delay times (IDTs), laminar burning velocities (LBVs), and species time histories, fluid dynamics effects can be decoupled to purely study chemistry and compared to detailed chemical kinetic models. For this study, species time history measurements for lean mixtures of NG/H2/Air and NG/NH3/Air were collected at conditions relevant to gas turbine combustion chamber conditions (25 bar, 1300-2000 K). Time histories of methane (CH4), NH3, water (H2O), nitric oxide (NO), and carbon monoxide (CO) were studied and compared to the 2018 Glarborg et al. and the 2021 NUIGMech models.

The mixtures were pressurized and heated using a high-pressure shock tube with an inner diameter of 7.62 cm. Located 1 cm away from the end wall of the tube were eight optical access ports for data collection. Wedged magnesium fluoride (MgF2) windows were used to allow transmission of the wavelengths of 200 nm to 6 μm, and wedged AR-coated germanium (Ge) windows were used to allow 6 to 12 μm transmission. The experimental data was collected using infrared tunable diode laser absorption spectroscopy (IR-TDLAS). The laser intensities were measured using high-sensitivity VIGO Photonics HgCdTe photovoltaic IR detectors and converted to mole fraction using the Beer-Lambert equation. The mixtures were highly diluted in argon (Ar) (95%) to prevent a large temperature rise during the ignition process. Research grade gases (99.999% purity) were used in all mixtures and supplied from Nexair. All mixtures were made based on Dalton’s law of partial pressure and mixed using a Teflon-coated high-pressure mixing tank. The shock tube was passivated with 100 torr of the gaseous mixture for 5 mins to prevent NH3 adsorption onto the stainless-steel shock tube. A modified and reduced model is also presented for uses in combustion modeling, which will, in turn, help reduce carbon emission in power generation gas turbines.

Presenting Author: Michael Pierro University of Central Florida

Presenting Author Biography: Michael Pierro is a current Aerospace Engineering doctoral student from the University of Central Florida, where he received his Mechanical and Aerospace Engineering bachelor’s degrees in 2020 and his Aerospace Engineering master's degree in 2023. He performs combustion diagnostic research at the High-Pressure Extended Range Shock Tube for Advanced Research laboratory under the advisement of Subith Vasu, Ph.D. He is a member of the Center for Advanced Turbomachinery and Energy Research, and his work investigates next-generation fuel blends for gas turbine engines. He has performed research on blends of natural gas/hydrogen and natural gas/ammonia as well as liquid methane oxidation at 200 bar for rocket engine thrust chamber conditions. He also spent a summer working at the German Aerospace Center Institute of Combustion Technologies (DLR) in Stuttgart, Germany, promoting international collaboration of scientists.

Authors:

Michael Pierro University of Central Florida
Justin Urso University of Central Florida
Ramees Rahman University of Central Florida
Subith Vasu University of Central Florida