ELTE Eötvös Loránd University
1117 Budapest Pázmány Péter sétány 1/A, Hungary
room 637 extension 1108
room 638 extension 1109
room 643 extension 1909
e-mail: turanyi@chem.elte.hu
Comprehensive optimization of a detailed NH3/H2 combustion kinetic mechanism
András György Szanthoffer, Máté Papp, Tibor Nagy, Chao Zhou, Tamás Turányi
Over the last decade, numerous detailed NH3/H2 combustion kinetic mechanisms have been published, but none of the available models are accurate enough across a wide range of experimental conditions. In our previous study (Szanthoffer et al., 2026), the NUIG-2024 mechanism (Zhu et al., 2024) exhibited the best overall performance against a large collection of NH3 and NH3/H2 indirect experimental data, including shock tube ignition delay times, laminar burning velocities, and concentration data measured in various reactors. However, even NUIG-2024 could not reproduce the data points within their 3σ uncertainty limits, on average, where σ is the standard deviation of the experimental data. This study focuses on optimizing a modified NUIG-2024 mechanism against our collection of NH3/H2 indirect experimental data (7,259 data points in 578 data series) using a mean-squared objective function. The most impactful reactions in the initial mechanism were identified using local sensitivity analysis results and uncertainties of rate coefficients and indirect experimental data. The model parameters selected for optimization comprise 25 sets of Arrhenius parameters (A, n, E) and the third-body collision efficiency of NH3 for the H + O2 (+M) = HO2 (+M) reaction. These parameters were optimized within their prior uncertainty ranges, estimated from the available direct data and previous optimization studies. The optimized mechanism outperforms all currently available NH3/H2 combustion mechanisms. Also, it can reproduce all types of the investigated experimental data within or very close to their 3σ uncertainty limits, whereas none of the currently available NH3/H2 mechanisms can achieve this.
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 Cantera, FlameMaster, OpenSMOKE++ and ZeroRK. Also, Chemkin Pro is coming soon.
ReSpecTh is an information system of the ELKH-ELTE Complex Chemical Systems Research Group, prepared in collaboration with the ELTE Laboratory of Molecular Structure and Dynamics and the ELTE Chemical Kinetics Laboratory. ChemKinLab maintains the Reaction Kinetics (Re) branch. Currently this combustion chemistry database contains 162026 data points in 3641 XML-format data files and it has 913 registered users.
ReSpecTh Kinetics Data Format Specification v2.5
A series of tutorial videos were created on the efficient creation combustion data files, validation of combustion mechanisms, and using our codes on computer clusters. Also, a Hungarian language video describes the research opportunities in our lab for ELTE undergraduate students.
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.