Effect of pressure on soot formation in laminar diffusion flames
The formation of soot in laminar methane-air diffusion flames was studied at atmospheric and elevated pressures. A high-pressure chamber was constructed surrounding a two-slot burner, which was designed to produce a single-surface, two-dimensional diffusion flame. The reacting gases were isolated from the environment by quartz windows. Laser light scattering and extinction were measured to determine soot particle diameter, volume fraction, and number density at different heights in the flame and at pressures up to 3.0 atm. The flame temperatures were determined by measuring the intensity distribution of rotational bands of the ultraviolet spectrum of OH. A computer program was written to calculate the intensity distribution of these bands in thermodynamic equilibrium for various temperatures until agreement with the experimentally determined distribution was obtained. The flame temperature increased slightly with pressure. The soot-laden region lies in the fuel side of the reaction zone, within a temperature range of 1000 to 1600/sup 0/K. Its thickness increases with height above the burner and decreases with pressure. Maxima in the soot mean diameter and volume fraction are found to occur a few millimeters from the maximum temperature zone. Soot size and volume fraction increase with height above the burner, and logarithmically with an increase in pressure.
- Research Organization:
- Ohio State Univ., Columbus (USA)
- OSTI ID:
- 5571006
- Country of Publication:
- United States
- Language:
- English
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