Assessing the relative importance of flame regimes in Raman/Rayleigh line measurements of turbulent lifted flames

Journal Article · Fri Jul 06 00:00:00 EDT 2018 · Proceedings of the Combustion Institute

DOI:https://doi.org/10.1016/j.proci.2018.06.067· OSTI ID:1497649

Hartl, S. ^[1]; Van Winkle, R. ^[2]; Geyer, D. ^[3]; Dreizler, A. ^[4]; Magnotti, G.  ^[5]; Hasse, C.  ^[6]; Barlow, R. S.  ^[7]

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1. Univ. of Applied Sciences, Darmstadt (Germany). Thermodynamics and Alternative Propulsion Systems; TU Darmstadt (Germany). FG Simulation of Reactive Thermo-Fluid Systems
2. Univ. of the Pacific, Stockton, CA (United States)
3. Univ. of Applied Sciences, Darmstadt (Germany). Thermodynamics and Alternative Propulsion Systems
4. TU Darmstadt (Germany). FG Reactive Flows and Diagnostics. Center of Smart Interfaces
5. Sandia National Lab. (SNL-CA), Livermore, CA (United States). Combustion Research Facility; King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia). Clean Combustion Research Center
6. TU Darmstadt (Germany). FG Simulation of Reactive Thermo-Fluid Systems
7. Sandia National Lab. (SNL-CA), Livermore, CA (United States). Combustion Research Facility

Understanding and quantifying the relative importance of premixed and non-premixed reaction zones within turbulent partially premixed flames is an important issue for multi-regime combustion. The recently-developed method of gradient-free regime identification (GFRI) is applied to instantaneous 1D Raman/Rayleigh measurements of temperature and major species from two turbulent lifted methane/air flames. Local premixed and non-premixed reaction zones are identified using criteria based on the mixture fraction, the chemical explosive mode, and the heat release rate, the latter two being calculated from an approximation of the full thermochemical state of each measured sample. A chemical mode (CM) zero-crossing is a previously documented marker for a premixed reaction zone. Results from the lifted flames show strong correlations among the mixture fraction at the CM zero-crossing, the magnitude of the change in CM at the zero-crossing, and the local heat release rate at the CM zero-crossing compared to the maximum heat release rate. The trends are confirmed through a comparable analysis of numerical simulations of two laminar triple flames. These newly documented trends are associated with the transition from dominantly premixed flame structures to dominantly non-premixed flames structures. The methods introduced for assessing the relative importance of local premixed and non-premixed reactions zones have potential for application to a broad range of turbulent flames.

• Research Organization: Sandia National Lab. (SNL-CA), Livermore, CA (United States); Univ. of Applied Sciences, Darmstadt (Germany); TU Darmstadt (Germany)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Workforce Development for Teachers and Scientists (WDTS); German Research Foundation (DFG)
• Grant/Contract Number: NA0003525; DR 374/15-1; DR 374/18-1; GE 2523/3-1; HA 4367/5-1
• OSTI ID: 1497649
• Report Number(s): SAND2017-13160J; 672178
• Journal Information: Proceedings of the Combustion Institute, Vol. 37, Issue 2; ISSN 1540-7489
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
GFRI
combustion regime
heat release rate
CEMA
Raman/Rayleigh