A possible solution to improve the combustion properties of ammonia is
to blend it with other fuels. Two of the most usually used co‑fuels are
hydrogen and syngas (H2/CO). To investigate the chemistry of
the co-combustion with these fuels, a large amount of indirect
experimental data for the combustion of neat NH3, and NH3/H2
and NH3/syngas fuel mixtures were collected from the literature
including ignition delay times measured in shock tubes, concentration
measurements in jet stirred and flow reactors, and laminar burning
velocity measurements. Altogether, 4898 data points (in 472 data series)
were recorded which cover wide ranges of equivalence ratio, temperature,
and pressure. These experimental data are available in data files in the
ReSpecTh site (http://respecth.hu). The
performances of 18 recently published detailed reaction mechanisms were
quantitatively assessed using the collected experiments. There are
significant differences between the performances of the models, and the
performance of a mechanism may also vary significantly with the different
types of experiments. The best‑performing mechanisms are POLIMI‑2020,
KAUST‑2021, and Otomo‑2018 for NH3/H2 fuel mixtures,
and Shrestha‑2021, Mei‑2021, and Mei‑2020 for NH3/syngas
systems. The results indicate that further mechanism development is needed
to reproduce the measurements more accurately. Local sensitivity analysis
was carried out on the kinetic and thermodynamic parameters of the
best‑performing mechanisms. Even though the investigated models have
different parameter sets, the most important reactions and thermodynamic
properties are similar. The most important reactions are not the same for
the different types of experiments but most of them include the NH3,
NH2, and/or NNH species. Among the thermodynamic parameters,
model outputs are most sensitive to the data of NH3 and NH2.
Optima++ is a general framework for manipulating experimental data related to combustion chemistry, carrying out simulations of such experiments, performing model optimization and analysis, and providing auxiliary features for the above tasks. Optima++ is able to handle simulation codes FlameMaster, OpenSMOKE++ and ZeroRK. Also, Cantera is coming soon.
An interactive web site, where the users may find Arrhenius parameters of gas phase elementary reactions determined in direct measurements, theoretical calculations or have been used in modelling studies. The users may recalculate the uncertainty limits of the rate coefficients. The editors have the right to upload data sheets for new reactions and to add, delete or modify existing data sheets. The editor status may be granted to any registered user upon request to the administrator.
Visit k-evaluation web page
Reaction fluxes of a combustion simulation can be visualized in the forms of still pictures and videos.
We maintain a collection of a series of Chemkin-format reaction mechanisms for the combustion of the following fuels:
hydrogen, syngas, methanol, ethanol, methane, butanol, fuels+NOx.