An experimental method for studying combustion of an unsupported fuel droplet at reduced gravity

Thesis/Dissertation · Mon Jan 01 04:00:00 EST 1990

OSTI ID:5563571

Yang, J C

An experimental method to study combustion of free fuel droplets at reduced gravity was developed. Reduced gravity environment was achieved by performing the experiments in a drop tower. The experimental technique was based on the parabolic projectile motion of a fuel droplet. A test fuel droplet was propelled almost vertically upward from a droplet generator in a combustion chamber. As soon as the droplet reached the apex of its trajectory, the droplet was ignited, and simultaneously the camera which was positioned at the apex of the droplet trajectory and which was used to obtain photographic record of the burning droplet, the combustion chamber, and the associated instrumentation were released into free fall. In this way the burning droplet would experience reduced gravity, and at the same time the droplet was levitated with respect to the free falling package. Fuels studied were heptane (moderately sooting), toluene (highly sooting), methanol (non-sooting), and heptane-hexadecade mixtures. A soot shell was observed for heptane and toluene. No disruptive burning was observed. The flames front stand-off ratio was found to increase with time. Transmission electron micrographs of the collected soot samples showed that the size of the soot particles obtained under reduced gravity appear to be slightly larger than those obtained under the normal gravity of the Earth. Extinction of methanol droplets was consistently observed. Extinction diameters obtained from the present study ranged from 0.16 to 0.19 mm for a range of initial diameters from 0.04 to 0.43 mm. For heptane-hexadecane mixtures, micro-explosions were not observed. Mixture droplets appeared to burn to completion without extinction whereas the one hexadecane drop studied extinguished.

• Research Organization: Cornell Univ., Ithaca, NY (United States)
• OSTI ID: 5563571
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
ALCOHOLS
ALKYLATED AROMATICS
AROMATICS
CHEMICAL REACTION KINETICS
COMBUSTION KINETICS
DROPLETS
FUELS
GRAVITATIONAL FIELDS
HYDROCARBONS
HYDROXY COMPOUNDS
IGNITION
KINETICS
LIQUID FUELS
METHANOL
ORGANIC COMPOUNDS
PARTICLES
REACTION KINETICS
SOOT
TOLUENE