Autoignition of droplets in nondilute monodisperse clouds

Journal Article · Wed Sep 01 04:00:00 EDT 1993 · Combustion and Flame; (United States)

DOI:https://doi.org/10.1016/0010-2180(93)90122-J· OSTI ID:6131023

Wong, Shwin Chung; Chang, Jyh Cheng; Yang, Jyh Chyang ^[1]

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1. National Tsing Hua Univ. (Taiwan, Province of China). Dept. of Power Mechanical Engineering

The work investigates theoretically the transient autoignition processes of the droplets in nonconvective, nondilute, monodisperse clouds, including the evaporation of the droplet and the buildup of the fuel vapor concentration in the droplet vicinity from an initial state of concentration. Three different ignition modes are identified: local, global, and homogeneous ignition. Although the chemical reaction is confined to a narrow region in local ignition, it prevails in the interdrop space in global ignition due to the presence of significant fuel vapor. Homogeneous ignition, occurring after the droplets have vaporized completely, appears when initial droplet diameters are relatively small. Local ignition is favored when preexisting fuel vapor concentrations are low, initial droplet diameters are large, and ambient gas temperatures are high. The effects of droplet diameter, preexisting fuel vapor concentration, and ambient gas temperature on ignition modes and ignition delay times are examined. The different ignition modes correspond to the various flame propagation modes in sprays reported in previous experimental observations.

• OSTI ID: 6131023
• Journal Information: Combustion and Flame; (United States), Journal Name: Combustion and Flame; (United States) Vol. 94:4; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
AEROSOLS
ATOMIZATION
CHEMICAL REACTIONS
COLLOIDS
COMBUSTION
DISPERSIONS
DROPLETS
EVAPORATION
FLAME PROPAGATION
FLUIDS
FUELS
GASES
IGNITION
LIQUID FUELS
MATHEMATICAL MODELS
OXIDATION
PARTICLES
PHASE TRANSFORMATIONS
SIZE
SOLS
SPONTANEOUS COMBUSTION
SPRAYS
THERMOCHEMICAL PROCESSES
TIME DELAY
VAPORS