High speed Schlieren visualization of flame initiation in a lean operating S. I. engine

Conference · Thu Jan 01 04:00:00 EST 1987

OSTI ID:5201518

Baritaud, T A

High speed Schlieren cinematography along with flame contour analysis is used to study the early flame propagation, from spark to a 4 mm flame radius. This is done for lean propane-air mixtures, and up to 1500 RPM. For normal engine speeds, the flame is turbulent immediately after initiation, with no laminar phase. The burnt kernel is first driven by the electric ignition source. After about 0.5 ms, the effect of engine speed (i.e. turbulence) is very strong, the kernel expansion rate increasing with engine speed. Increasing the equivalence ratio also increase the propagation speed. The rate of flame growth measured in the engine is shown to go through a minimum for a burnt kernel radius of about 2 mm which varies with the equivalence ratio. The minima of the flame velocity at this radius depend on mixture strength and turbulence level. The simultaneous recording of the pressure trace shows a correlation between the early flame behavior and the overall combustion speed.

• OSTI ID: 5201518
• Report Number(s): CONF-871142-
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
025000* -- Petroleum-- Combustion
33 ADVANCED PROPULSION SYSTEMS
330101 -- Internal Combustion Engines-- Spark-Ignition
ALKANES
AUTOMOTIVE FUELS
CHEMICAL REACTION KINETICS
COMBUSTION KINETICS
ENGINES
FLAME PROPAGATION
FLAMES
FLUID FLOW
FUEL-AIR RATIO
FUELS
HEAT ENGINES
HYDROCARBONS
IGNITION
INTERNAL COMBUSTION ENGINES
KINETICS
LAMINAR FLOW
MONITORING
ORGANIC COMPOUNDS
PHOTOGRAPHY
PROPANE
REACTION KINETICS
SPARK IGNITION ENGINES
TURBULENCE
VELOCITY