Conditional analysis of lifted hydrogen jet diffusion flame experimental data and comparison to laminar flame solutions

Journal Article · Sat Sep 15 04:00:00 EDT 2007 · Combustion and Flame

DOI:https://doi.org/10.1016/J.COMBUSTFLAME.2007.04.013· OSTI ID:20919404

Cheng, T S ^[1]; Wehrmeyer, J A ^[2]; Pitz, R W ^[3]

---

1. Department of Mechanical Engineering, Chung Hua University, Hsinchu 300 (China)
2. Aerospace Testing Alliance, Arnold Air Force Base, TN 37389 (United States)
3. Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235 (United States)

Simultaneous point measurements of temperature, mixture fraction, major species, and OH concentrations in a lifted turbulent hydrogen jet flame are reprocessed to obtain the Favre average and conditional mean profiles. Large discrepancies between the Favre average and the ensemble average temperature, H{sub 2}O, and OH mole fractions are found at the lifted flame base, due to density weighting of fairly large samples of unreacted mixtures. Conditional statistics are used to reveal the reaction zone structure in mixture fraction coordinates. The cross-stream dependence of conditional reactive scalars, which is most notable at the lifted flame base and decreases to negligible levels with increasing streamwise positions, could be attributed to radial differences in both the Damkoehler number and the level of partial premixing. Conditional results indicate that the lifted flame is stabilized at the outer region of the jet characterized by low strain rates and lean mixtures. Comparison of the measured conditional mean OH vs H{sub 2}O with a series of stretched laminar partially premixed flame and diffusion flame calculations reveals that strong partial premixing takes place at the lifted flame base and the strain rates vary from a=14,000 to 100 s{sup -1}. The level of partial premixing and the strain rate decrease with increasing downstream locations. The range of estimated scalar dissipation rates ({chi}{approx}1-0.13 s{sup -1}) at a further downstream location (x/D=33.3) is in agreement with reported values and the flame composition reaches an equilibrium condition at x/D=194.4. These results combined with previously reported data provide a benchmark data set for evaluation and refinement of turbulent combustion models for lifted hydrogen jet flame predictions. (author)

• OSTI ID: 20919404
• Journal Information: Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 4 Vol. 150; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
BENCHMARKS
CHEMICAL COMPOSITION
COMBUSTION
DIFFUSION
EQUILIBRIUM
EXPERIMENTAL DATA
FORECASTING
HYDROGEN
HYDROXYL RADICALS
JETS
LAMINAR FLAMES
MATHEMATICAL SOLUTIONS
SCALARS
STABILIZATION
STATISTICS
STRAIN RATE
TURBULENCE
WATER
ZONES