Flame stretch interactions of laminar premixed hydrogen/air flames at normal temperature and pressure

K. T. Aung, M. I. Hassan, G. M. Faeth

Research output: Contribution to journalArticlepeer-review

313 Scopus citations

Abstract

Effects of positive flame stretch on the laminar burning velocities of hydrogen/air flames were studied both experimentally and computationally, considering freely (outwardly) propagating spherical laminar premixed flames. Measurements were based on motion picture shadowgraphy, while numerical simulations were based on typical contemporary chemical reaction mechanisms. Flame conditions studied included hydrogen/air flames having fuel-equivalence ratios in the range 0.3-5.0 at normal temperature and pressure. Both measured and predicted ratios of unstretched (plane flames) to stretched laminar burning velocities varied linearly with Karlovitz numbers over the test range (Karlovitz numbers up to 0.4), yielding Markstein numbers that were independent of Karlovitz numbers for a particular reactant mixture. Markstein numbers were in the range -1 to 6, with unstable (stable) preferential- diffusion conditions observed at fuel-equivalence ratios below (above) roughly 0.7. Present stretch-corrected laminar burning velocities were in reasonably good agreement with other determinations of laminar burning velocities at fuel-lean conditions where Markstein numbers, and thus effects of stretch, are small. In contrast, the stretch-corrected laminar burning velocities generally were smaller than other measurements in the literature at fuel-rich conditions, where Markstein numbers, and thus effects of stretch, are large. Finally, predicted unstretched laminar burning velocities and Markstein numbers were in reasonably good agreement with measurements, although additional study to improve the comparison between predictions and measurements at fuel-rich conditions should be considered.

Original languageBritish English
Pages (from-to)1-24
Number of pages24
JournalCombustion and Flame
Volume109
Issue number1-2
DOIs
StatePublished - Apr 1997

Fingerprint

Dive into the research topics of 'Flame stretch interactions of laminar premixed hydrogen/air flames at normal temperature and pressure'. Together they form a unique fingerprint.

Cite this