Fundamental mechanisms in premixed turbulent flame propagation via flame-vortex interactions part I: Experiment

Citation
Jm. Samaniego et T. Mantel, Fundamental mechanisms in premixed turbulent flame propagation via flame-vortex interactions part I: Experiment, COMB FLAME, 118(4), 1999, pp. 537-556
Citations number
44
Categorie Soggetti
Mechanical Engineering
Journal title
COMBUSTION AND FLAME
ISSN journal
00102180 → ACNP
Volume
118
Issue
4
Year of publication
1999
Pages
537 - 556
Database
ISI
SICI code
0010-2180(199909)118:4<537:FMIPTF>2.0.ZU;2-5
Abstract
A combined experimental and numerical study of the interaction of a two-dim ensional vortex with planar laminar premixed flames has been carried out. I n such a flaw, the flame is subjected to time-varying strain and curvature and, hence, the interaction may be viewed as a model of fundamental process es occurring in premixed turbulent flames. Part I of the paper describes th e experimental facility and diagnostics employed and presents results from the experimental investigation of effects of Lewis number, radiative heal l osses, and unsteadiness on the interaction. A two-dimensional V-shaped lami nar premixed flame is stabilized on a heated wire in a constant-area square duct. A two-dimensional vortex pair, generated from a slot in the duct wal l, eventually interacts with one of the flame fronts. Schlieren and smoke f low visualization indicate that the flow field remains two-dimensional over a significant part of the flame-vortex interaction. This feature allows us e of line-of-sight diagnostics, and, in particular, a CO2* emission imaging technique for determination of quantitative heat release rates. Several fu el and oxidizer mixtures are employed in order to vary the Lewis number fro m 0.8 to 1.6 and to increase the heat loss parameter by a factor of 2.6. Fo r the conditions investigated, the Lewis and Damkohler numbers are importan t controlling parameters in the evolution of the heat release rate and radi ative losses may be neglected. In Part II of the paper, results from direct numerical simulations of a flame-vortex pair interaction are presented. Th e simulations were performed using a two-dimensional Navier-Stokes solver i n which variable density and temperature-dependent transport coefficients a re considered. The simulations utilize the initial conditions of the experi ment and were used to investigate the role of multistep chemistry in the fl ame-vortex interaction. (C) 1999 by The Combustion Institute.