Quantitative measurements of thermo-chemical states in turbulent lean and rich premixed NH₃/H₂/N₂-air jet flames

Schultheis, Robin1; Li, Tao1; Shi, Shuguo1; Barlow, Robert S.2; Zhou, Bo3; Geyer, Dirk4; Dreizler, Reas1

2024

10.1016/j.proci.2024.105571

PROCEEDINGS OF THE COMBUSTION INSTITUTE   影响因子和分区

1540-7489

1873-2704

Premixed piloted jet flames are an ideal generic configuration to examine the impact of turbulence on thermochemical states for staged-combustion systems, like rich-quench-lean technologies, which have been proposed for ammonia combustion to minimize emissions. The current study aims to gain fundamental insights on the internal scalar structure of such premixed and rich-lean stratified ammonia-hydrogen flames. Turbulent premixed NH3/H-2/N-2-air jet flames, stabilized by a large, lean pilot flame (phi= 0.57), were investigated over a range of lean to rich global equivalence ratios (phi(global) = 0.8, 1.2, and 1.6), employing simultaneous 1D Raman/Rayleigh spectroscopy with a novel calibration approach for NH3. The quantitative scalar data of instantaneous flame structures and thermo-chemical states are analyzed with emphasis on the NH3-H-2 interaction and its effects on differential diffusion. In the transition from lean to rich jet flames, the spatial flame structures reveal the presence of residual H-2 in the products, while a significant minimization of the NH3 slip is observed. The remaining H-2 undergoes turbulent mixing with the hot exhaust gas causing additional heat release and elevated temperatures compared to 1D adiabatic flame simulations. The local oxygen concentration is found to be a determining factor in the interaction between thermal cracking and oxidation of NH3. Due to the formation of H-2 as a result of NH3 cracking on the one hand and the oxidation reactions and diffusion of H-2 on the other hand, a relatively high H-2 concentration is still observed at relatively high temperatures despite the presence of O-2. This interplay between in situ cracking, diffusion, turbulent mixing, and oxidation reactions leads to a zone of stratified combustion, so that overall a two-stage combustion characteristic is observed, showing premixed combustion primarily within the jet flow and stratified combustion in the mixing zone with the pilot exhaust gas.

Ammonia/hydrogen combustion Turbulence-chemistry interaction Raman/Rayleigh scattering Internal flame structures Quantitative thermo-chemical states

SCI ; EI

英语

其他

DFG, Germany[503997890] ; NSFC, China[52206150] ; European Regional Development Fund (ERDF)[FPG968]

Thermodynamics ; Energy & Fuels ; Engineering

Thermodynamics ; Energy & Fuels ; Engineering, Chemical ; Engineering, Mechanical

WOS:001281351800001

ELSEVIER SCIENCE INC

ENGINEERING

Web of Science

1.Tech Univ Darmstadt, Dept Mech Engn, React Flows & Diagnost RSM, Otto Berndt Str 3, D-64287 Darmstadt, Germany
2.Barlow Combust Res, Livermore, CA USA
3.Southern Univ Sci & Technol SUSTech, Dept Mech & Aerosp Engn, Shenzhen 518055, Peoples R China
4.Darmstadt Univ Appl Sci, Opt Diagnost & Renewable Energies ODEE, Schofferstr 3, D-64295 Darmstadt, Germany

Schultheis, Robin,Li, Tao,Shi, Shuguo,et al. Quantitative measurements of thermo-chemical states in turbulent lean and rich premixed NH₃/H₂/N₂-air jet flames[J]. PROCEEDINGS OF THE COMBUSTION INSTITUTE,2024,40(1-4).

Schultheis, Robin.,Li, Tao.,Shi, Shuguo.,Barlow, Robert S..,Zhou, Bo.,...&Dreizler, Reas.(2024).Quantitative measurements of thermo-chemical states in turbulent lean and rich premixed NH₃/H₂/N₂-air jet flames.PROCEEDINGS OF THE COMBUSTION INSTITUTE,40(1-4).

Schultheis, Robin,et al."Quantitative measurements of thermo-chemical states in turbulent lean and rich premixed NH₃/H₂/N₂-air jet flames".PROCEEDINGS OF THE COMBUSTION INSTITUTE 40.1-4(2024).