Turbulence effects on ignition flame kernel growth
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
- Resource Relation:
- Conference: 1988 Fall technical meeting of the Eastern states section of the Combustion Institute,Clearwater Beach, FL (United States),5-7 Dec 1988; Other Information: PBD: [1988]
- Country of Publication:
- United States
- Language:
- English
Similar Records
Ignition flame kernel growth under simulated idle conditions
Ignition flame kernel growth under simulated idle conditions