Optical measurements of soot formation in premixed flames

Conference · Fri Oct 01 04:00:00 EDT 1982

OSTI ID:6859823

Flower, W L

The growth of soot particles in rich premixed flames was measured using the diffusion-broadening particle-sizing technique. This dynamic-light-scattering technique eliminates the strong dependence of size measurements on particle complex index of refraction which is a problem with most light-scattering size measurements. Size measurements were made in fuel-rich premixed methane-oxygen flat flames with fuel-oxidizer ratios ranging from 2.2 to 2.9 times stoichiometric values and in propane-oxygen flames at an equivalence ratio of 2.6. Particles as small as 23 nm in diameter were observed 5 mm above the burner surface (within about a millimeter of the flame front), growing to 60 to 120 nm (depending on the equivalence ratio) 14 mm above the burner. Measurements of the intensity of scattered light were used in conjunction with the size measurements to determine the soot number density in the methane-oxygen flames, which was found to be decreasing with height above the burner at positions 5 mm above the burner and higher. The soot volume fraction in the methane-oxygen flame, determined from the size and number-density measurements, continually increased in this region, although apparently starting to level off 12 mm above the burner surface. The temperature history of the soot particles was determined using optical pyrometry. Near the flame front, the measured particle temperature was slightly higher than the adiabatic flame temperature, decreasing below this level further downstream. 9 figures.

• Research Organization: Sandia National Labs., Livermore, CA (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6859823
• Report Number(s): SAND-82-8812; CONF-821035-2; ON: DE83002212
• Country of Publication: United States
• Language: English

Related Subjects

090110* -- Hydrocarbon Fuels-- Properties-- (1979-1989)
10 SYNTHETIC FUELS
ALKANES
COMBUSTION PRODUCTS
DATA
DENSITY
DIFFUSION
ELEMENTS
EXPERIMENTAL DATA
FLAMES
HYDROCARBONS
INFORMATION
LIGHT SCATTERING
MEASURING INSTRUMENTS
MEASURING METHODS
METHANE
NONMETALS
NUMERICAL DATA
OPTICAL PYROMETERS
ORGANIC COMPOUNDS
OXYGEN
PARTICLE SIZE
PARTICLES
PHYSICAL PROPERTIES
PROPANE
PYROMETERS
SCATTERING
SIZE
SOOT
TEMPERATURE MEASUREMENT