Flame propagation in heterogeneous mixtures of fuel drops and air

Technical Report · Tue May 01 04:00:00 EDT 1984

OSTI ID:7121080

Myers, G D; Lefebvre, A H

Photographic methods are used to measure flame speeds in flowing mixtures of fuel drops and air at atmospheric pressure. The fuels employed include a conventional fuel oil plus various blends JP 7 with stocks containing single-ring and multi-ring aromatics. The results for stoichiometric mixtures show that flame propagation cannot occur in mixtures containing mean drop sizes larger than 300 to 400 microns, depending on the fuel type. For smaller drop sizes, down to around 60 microns, flame speed is inversely proportional to drop size, indicating that evaporation rates are limiting to flame speed. Below around 60 microns, the curves of flame speed versus mean drop size flatten out, thereby demonstrating that for finely atomized sprays flame speeds are much less dependent on evaporation rates, and are governed primarily by mixing and/or chemical reaction rates. The fuels exhibiting the highest flame speeds are those containing multi-ring aromatics. This is attributed to the higher radiative heat flux emanating from their soot-bearing flames which enhances the rate of evaporation of the fuel drops approaching the flame front.

• Research Organization: Purdue Univ., Lafayette, IN (USA)
• DOE Contract Number: AI01-81CS50006
• OSTI ID: 7121080
• Report Number(s): DOE/NASA-0266-1; NASA-CR-174644; ON: DE84009884
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330100* -- Internal Combustion Engines
42 ENGINEERING
421000 -- Engineering-- Combustion Systems
AROMATICS
DISPERSIONS
DROPLETS
FLAME PROPAGATION
FUEL OILS
FUEL-AIR RATIO
FUELS
LIQUID FUELS
MIXTURES
OILS
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
PARTICLES
PETROLEUM PRODUCTS
STOICHIOMETRY