Turbulence effects on ignition flame kernel growth

Conference · Sat Dec 31 04:00:00 EST 1988

OSTI ID:10115561

Santavicca, D A

Spark ignition in most combustion systems occurs in highly turbulent flows, where practical ignition limits are not so much determined by the ignitability of the fuel-air mixture as by the subsequent growth of the ignition flame kernel [1]. For example, in spark ignition engines, charge dilution, which increases thermodynamic efficiency and reduces NO{sub x} emissions, also leads to unacceptable cycle-to-cycle variations in peak cylinder pressure [2]. This can be attributed to large variations in the initial flame kernel growth rate caused by the turbulent flow [3]. Similar arguments can be made for other combustion systems regarding the effect of turbulence on ignition limits due to changes in the ignition limits due to changes in the ignition flame kernel growth rate. The effect of turbulence on the ignition flame kernel growth process is particularly complex due to the fact that it is a transient process with time and length scales which are the same order as those of the turbulent flow. Therefore, the effect of turbulence changes both with time and with increasing size of the ignition flame kernel. In addition, since the susceptibility of the ignition flame kernel to the effects of turbulence depends on its initial temperature and chemical composition, the details of the spark ignition process are also important. 25 refs.

• Research Organization: Pennsylvania State Univ., University Park, PA (United States). Dept. of Mechanical Engineering
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AS04-86AL38027
• OSTI ID: 10115561
• Report Number(s): CONF-881215--4; ON: DE92006774
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330101
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800
BREAKDOWN
COMBUSTION KINETICS
COMBUSTION, PYROLYSIS, AND HIGH-TEMPERATURE CHEMISTRY
ELECTRIC ARCS
FLAME PROPAGATION
GLOW DISCHARGES
IGNITION SYSTEMS
SPARK IGNITION ENGINES
SPARK-IGNITION
TURBULENCE