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Title: Internal structure of a premixed turbulent flame

A pulsed laser and a multielement detector have been used to make instantaneous Rayleigh profiles along a line through a turbulent flame front thus eliminating the effects of flame front motion. The flame front in a premixed turbulent flame moves randomly about a mean position, giving rise to the visually observed flame brush or time-averaged flame thickness which is larger than the instantaneous thickness of the reaction zone. The physical characteristics and statistical properties of such turbulent flames reported previously were deduced from the time histories of Rayleigh scattered laser light at one or two points within the reaction zone. The study was conducted on a premixed propane-air flame stabilized on a rod at the exit plane of a square burner. Turbulence-producing screens below the burner exit controlled turbulent length scales while intensity was controlled with inlet mixture velocity. Turbulence properties of the cold reactants were determined by hot-wire anemometry. Mean and fluctuating velocity in the unburnt and burnt gases were measured using laser Doppler velocimetry. At the low level of turbulence studied, the instantaneous flame front thickness was found to be only slightly greater than the laminar flame thickness, and the magnitude of the density fluctuations only slightly greatermore » than the cold flow turbulence intensity. Mean and rms values of density and velocity; density and velocity probability density functions; spatial density correlations; and comparison of data with the Bray-Moss-Libby model are presented.« less
Authors:
; ;
Publication Date:
OSTI Identifier:
6710933
Report Number(s):
SAND-82-8865; CONF-821035-7
ON: DE83001948
DOE Contract Number:
AC04-76DP00789
Resource Type:
Conference
Resource Relation:
Conference: Combustion Insitute symposium on western states section, Livermore, CA, USA, 11 Oct 1982
Research Org:
Southern Illinois Univ., Carbondale (USA); Sandia National Labs., Albuquerque, NM (USA)
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; FLAMES; DENSITY; FLAME PROPAGATION; TURBULENCE; PROPANE; COMBUSTION; ANEMOMETERS; COMBUSTION KINETICS; EXPERIMENTAL DATA; LASERS; THEORETICAL DATA; VELOCIMETERS; ALKANES; CHEMICAL REACTION KINETICS; CHEMICAL REACTIONS; DATA; HYDROCARBONS; INFORMATION; KINETICS; MEASURING INSTRUMENTS; NUMERICAL DATA; ORGANIC COMPOUNDS; OXIDATION; PHYSICAL PROPERTIES; REACTION KINETICS; THERMOCHEMICAL PROCESSES 420400* -- Engineering-- Heat Transfer & Fluid Flow