Session: Poster Session

Paper Number: 152785

Characterization of a Toroidal Jet-Stirred Reactor for Ammonia/hydrogen Combustion at Jet Engine Conditions 

Great research interest in alternative fuels has arisen due to the detrimental ecological impact of carbon-based combustion. Commercial aviation is a great emission contributor, the U.S Environmental Protection Agency attributes 10 percent of the U.S transportation emissions to commercial airplanes and large business jets, accounting for three percent of the nation’s total greenhouse gas production. Hydrogen (H₂) has been identified to be a potential surrogate to carbon-based fuels. Many companies have started to take steps towards the use of H₂ in ground base gas turbines, however, the use of H₂ as a fuel requires a large storage infrastructure, in addition to increased explosive safety measures due to H₂ high reactivity. Ammonia’s (NH₃) properties as a carbon-free hydrogen carrier, in addition to its phase characteristics and widely used infrastructures present a solid case as a potential surrogate to carbon-based aviation fuels.

Several groups have investigated NH₃-H₂ using burners which aim at simplifying gas turbine combustors, providing great insight into the feasibility of this fuel. However, results obtained in these types of combustors are heavily affected by reactor geometry and recirculation rates. There exists a need to study these alternative fuel blends in ideal combustion devices, allowing for the observation of different flame phenomena in reactions assumed to be chemistry dominant, permitting a fundamental study on the effects of different conditions such as fuel composition and residence times on stability limits. The use of a Toroidal Jet-Stirred Reactor (TJSR) which is an experimental approximation of a Well Stirred Reactor (WSR) provides a near ideal environment; characterized by a very low Damköhler number, indicating high mixing rates compared to those of chemical timescales. This allows for neglection of gas transports effects, and the creation and measurement of a chemically dominant flame. The induced ideality of the facility allows for validation of chemical kinetic mechanisms.

University of Central Florida’s (UCF) TJSR facility will be used to perform lean blowoff experiments at different NH₃-H₂ blends at atmospheric pressure conditions and low residence times, comparable to those of aviation gas turbine combustors. The reactor of use was designed following Nenniger’s improved TJSR, which has shown capable of reaching lower residence times and better homogeneity compared to other WSR’s. The 250 cm³ reactor is made of sintered ceramic. Premixed reactants are introduced radially through 32 nozzles by a Jet-Ring. The assembly is sealed by the use of gasketed sealing rings compressed by two flanges. Mass flow values will be controlled by three Alicat mass flow controllers through a fully electronic manifold system. Experiments will start by igniting a particular blend by the use of a removable spark plug. After flame stabilization is completed, transition to the fuel blend of interest will occur gradually. Each specific blend will be studied starting at a near stochiometric value, gradual decrease of the equivalence ratio will be achieved by changing mass flow rates values such that residence times remain constant.

Initially, the TJSR will be characterized by using methane lean blowout measurements and benchmarking it against values reported in literature. Upon successful characterization, lean blow off data will be collected for different NH₃-H₂ blends ranging from 0-50% H₂ content at atmospheric pressure and residence times relevant to aviation gas turbines. Since TJSR’s are close to ideal stirred reactors, we anticipate sustainment of these flames at lower equivalence ratios compared to those of previous efforts. The data collected will be compared against the predictions by state-of-the-art chemical kinetic models and discussion will be provided on their performance. Accurate characterization of lean blow out for NH₃/H₂ mixtures will aid in the design and development of advanced zero emissions gas turbines.

Presenting Author: Guillermo Barrios Cadenas University of Central Florida

Presenting Author Biography: Guillermo is an Aerospace Engineering PhD student at the University of Central Florida, he was born and raised in Caracas, Venezuela, and moved to the United States when he was 13 years old, he is particularly interested in alternative sustainable fuels for use in gas turbines. His work is funded by the NASA University Leadership Initiative for zero-emission aviation.

Authors:

Guillermo Barrios Cadenas University of Central Florida
Oli Marquez Valenzuela University of Central Florida
Marzuqa Ahmed University of Central Florida
Amanda Maia University of Central Florida
Gihun Kim University of Central Florida
Ramees Khaleel Rahman University of Central Florida
Subith Vasu Sumathi University of Central Florida