Internal structure of a premixed turbulent flame

Conference · Fri Oct 01 00:00:00 EDT 1982

OSTI ID:6710933

Rajan, S; Smith, J R; Rambach, G D

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 greater 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.

• Research Organization: Southern Illinois Univ., Carbondale (USA); Sandia National Labs., Albuquerque, NM (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6710933
• Report Number(s): SAND-82-8865; CONF-821035-7; ON: DE83001948
• Resource Relation: Conference: Combustion Insitute symposium on western states section, Livermore, CA, USA, 11 Oct 1982
• Country of Publication: United States
• Language: English

Related Subjects

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