Structure of a stratified CH4 flame with H2 addition
- TU Darmstadt (Germany). Dept. of Reactive Flows and Measurement Technology
- Darmstadt Univ. of Applied Sciences (Germany)
- King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia). Clean Combustion Research Center
- Univ. of Sydney, NSW (Australia). The School of Aeronautical, Mechanical and Mechatronic Engineering
- Sandia National Lab. (SNL-CA), Livermore, CA (United States). Reacting Flow Research Dept.
To explore the effect of H2 addition (20 percent by volume) on stratified-premixed methane combustion in a turbulent flow, an experimental investigation on a new flame configuration of the Darmstadt stratified burner is conducted here. Major species concentrations and temperature are measured with high spatial resolution by 1D Raman-Rayleigh scattering. A conditioning on local equivalence ratio (range from φ = 0.45 to φ = 1.25) and local stratification is applied to the large dataset and allows to analyze the impact of H2 addition on the flame structure. The local stratification level is determined as Δφ/ΔT at the location of maximum CO mass fraction for each instantaneous flame realization. Due to the H2 addition, preferential diffusion of H2 is different than in pure methane flames. In addition to diffusing out of the reaction zone where it is formed, particularly in rich conditions, H2 also diffuses from the cold reactant mixture into the flame front. For rich conditions (φ = 1.05 to φ = 1.15) H2 mass fractions are significantly elevated within the intermediate temperature range compared to fully-premixed laminar flame simulations. This elevation is attributed to preferential transport of H2 into the rich flame front from adjacent even richer regions of the flow. Additionally, when the local stratification across the flame front is taken into account, it is revealed that the state-space relation of H2 is not only a function of the local stoichiometry but also the local stratification level. In these flames H2 is the only major species showing sensitivity of the state-space relation to an equivalence ratio gradient across the flame front.
- Research Organization:
- Sandia National Lab. (SNL-CA), Livermore, CA (United States); Darmstadt Univ. of Applied Sciences (Germany); TU Darmstadt (Germany)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE National Nuclear Security Administration (NNSA); German Research Foundation (DFG)
- Grant/Contract Number:
- NA0003525
- OSTI ID:
- 1497651
- Report Number(s):
- SAND--2017-13162J; 672180
- Journal Information:
- Proceedings of the Combustion Institute, Journal Name: Proceedings of the Combustion Institute Journal Issue: 2 Vol. 37; ISSN 1540-7489
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Fuel Stratification Influence on NOx Emission in a Premixed Axial Reacting Jet-in-Crossflow at High Pressure
Direct numerical simulation of a high Ka CH4/air stratified premixed jet flame