Combustion characteristics in the transition region of liquid fuel sprays. Final Report, January 1983-September 1985

Technical Report · Wed Jan 01 04:00:00 EST 1986

OSTI ID:5629255

Cernansky, N P; Namer, I; Tidona, R J

A number of important effects have been observed in the droplet size transition region in spray combustion systems. In this region, where the mechanism of flame propagation is transformed from diffusive to premixed dominated combustion, the following effects have been observed: (1) maxima in burning velocity; (2) extension of flammability limits; (3) minima in ignition energy; and (4) minima in NOx formation. A monodisperse aerosol generator has been used to form and deliver a well controlled liquid fuel spray to the combustion test section where measurements of ignition energy have been made. The ignition studies were performed on monodisperse n-heptane sprays at atmospheric pressure over a range of equivalence ratios and droplet diameters. A capacitive discharge spark ignition system was used as the ignition source, providing independent control of spark energy and duration. Preliminary measurements were made to optimize spark duration and spark gap, optimum conditions being those at which the maximum frequency or probability of ignition was observed. Using the optimum electrode spacing and spark duration, the frequency of ignition was determined as a function of spark energy for three overall equivalence ratios (0.6, 0.8, and 1.0) and for initial droplet diameters of 25, 40, 50, 60, and 70 micro m.

• Research Organization: Drexel Univ., Philadelphia, PA (USA)
• OSTI ID: 5629255
• Report Number(s): N-86-20517
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
AEROSOLS
ALKANES
CHALCOGENIDES
CHEMICAL REACTION KINETICS
COLLOIDS
COMBUSTION KINETICS
COMBUSTION PROPERTIES
DATA
DISPERSIONS
EXPERIMENTAL DATA
FLAME PROPAGATION
FLAMMABILITY
FUELS
HEPTANE
HYDROCARBONS
IGNITION
INFORMATION
KINETICS
LIQUID FUELS
NITROGEN COMPOUNDS
NITROGEN OXIDES
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
SOLS
SPRAYS