Performance of a Plasma Jet Igniter

Conference · Tue Jan 01 00:00:00 EST 1980

OSTI ID:5523685

Cetegen, B. ^[1]; Teichman, K. Y. ^[2]; Weinberg, F. J. ^[3]; Oppenheim, A. K. ^[4]

---

1. California Institute of Technology (CalTech), Pasadena, CA (United States)
2. Univ. of Minnesota, Minneapolis, MN (United States)
3. Imperial College, London (United Kingdom)
4. University of California, Berkeley, CA (United States)

The main advantage of jet igniters lies in their ability to provide distributed ignition sources that are capable of initiating and enhancing combustion in lean mixtures. This is achieved principally by two mechanisms, i.e., the provision of a high concentration of free radicals, enhancing ignition at lower temperatures, and of the extended highly turbulent igniting surface, yielding larger flame front areas and hence increased burning rates. Experimental and analytical procedures that were developed to determine the performance of a jet igniter with particular emphasis on the fluid mechanic effects are described. To de-emphasize the thermochemical effects, the plasma medium and energy were maintained without change for all the tests. Thus the only variables pertained just to the volume of the cylindrical plasma cavity and the area of the orifice discharging the jet. The results are based on high speed schlieren cinematography of the combustion process in a cylindrical bomb, and simultaneous pressure transducer measurements. The penetration depth is shown to be proportional to the square root of the characteristic length - the ratio of the volume of igniter cavity to its orifice area. The capability to ignite lean mixtures is demonstrated by the repeatibility of results attained with the use of methane-air mixtures at an equivalence ratio of 0.6, initially at atmospheric pressure and room temperature. Under these conditions the observed enhancement of the rate of combustion could be accounted for entirely by the fact that the flame surface was enlarged due to ignition by a highly turbulent jet. While the laminar burning velocity was well within the range reported in the literature, the corresponding turbulent burning velocity was about three times greater, the ratio between the two remaining nearly constant throughout the process.

• Research Organization: University of California, Berkeley, CA (United States). Lawrence Berkeley Laboratory (LBL)
• Sponsoring Organization: USDOE; National Science Foundation (NSF)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5523685
• Report Number(s): LBL--10365; CONF-800202--3
• Resource Type: Conference paper
• Conference Information: SAE automotive engineering congress and exposition, Detroit, MI (United States), 25-29 Feb 1980
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330100* -- Internal Combustion Engines
AUTOMOBILES
CHEMICAL REACTION KINETICS
COMBUSTION KINETICS
ENGINES
IGNITION SYSTEMS
INTERNAL COMBUSTION ENGINES
KINETICS
MATHEMATICAL MODELS
PERFORMANCE
PLASMA JETS
REACTION KINETICS
VEHICLES