Structure of a methanol/air coaxial reacting spray near the stabilization region
- Sandia National Labs., Livermore, CA (United States)
- URA CNRS 230 CORIA, Mont Saint Aignan (France)
Planar laser Mie scattering, planar laser-induced fluorescence and two component phase-doppler interferometry have been used to study the reaction zone structure near the stabilization region of a coaxial methanol/air spray flame. The configuration of the experiment was chosen to approximate the atomizer geometry, surface tension and Weber number of a single coaxial rocket injector. The measurements are made in a water-cooled, optically accessible confinement chamber at a pressure of 1 atm. Data are reported for two atomizing air velocity conditions. One yields a flame length of approximately 1 m, the other, half that value. Both the Weber number (characterizing the atomization process) and the Reynolds number (characterizing the gas-phase mixing process) vary between the cases, but the data suggest that it is the Weber number which has the dominant effect. In both cases OH imaging shows that the reaction zone is confined to a narrow region, with the OH field being similar in appearance to that of a single-phase turbulent mixing-controlled (diffusion) flame. Size-classified mean velocity vectors derived from the phase-doppler data show striking differences in the flow pattern for low and high Stokes number droplets. Droplets 5 [mu]m in diameter and below (Stokes number less than 3) appear to follow the recirculating eddies that provide flame stabilization while droplets of large Stokes number travel ballistically through the flow. Increasing the Weber number by a factor of 2.5 decreased the Sauter mean diameter of the spray by as much as one-third, and the arithmetic mean diameter by as much as one-half. The authors believe that it is this decrease in the spray droplet diameter that is primarily responsible for the very different flame lengths in the two cases.
- OSTI ID:
- 7056931
- Journal Information:
- Combustion and Flame; (United States), Vol. 98:3; ISSN 0010-2180
- Country of Publication:
- United States
- Language:
- English
Similar Records
Structure of a methanol/air coaxial reacting spray near the stabilization region by OH fluorescence imaging and two-component phase-Doppler interferometry
Structure of a spray flame stabilized on a production engine combustor swirl cup
Related Subjects
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
FLAMES
MORPHOLOGY
METHANOL
COMBUSTION KINETICS
DROPLETS
HYDROXYL RADICALS
MEASURING METHODS
PARTICLE SIZE
SPRAYS
ALCOHOLS
CHEMICAL REACTION KINETICS
HYDROXY COMPOUNDS
KINETICS
ORGANIC COMPOUNDS
PARTICLES
RADICALS
REACTION KINETICS
SIZE
100400* - Synthetic Fuels- Combustion- (1990-)
400800 - Combustion
Pyrolysis
& High-Temperature Chemistry