JET IGNITION OF AN ULTRA-LEAN MIXTURE

A preliminary study was conducted of jets of active radicals used as igniters for lean fuel mixtures. Jets were generated by combustion or electric discharge. Experiments were performed in a cylindrical steel vessel, 9 centimeters in diameter and 9 centimeters in length, filled initially with air or an ultra-lean methane-air mixture (equivalence ratio of 0.5) at atmospheric pressure and room temperature. Observations were made by streak photography of light emitted by the jets taken with a rotating mirror camera and by schlieren photography, using a submicrosecond spark discharge in air as a point light source. Gas dynamic properties of jets were primarily governed by their initial velocity, while the particular process by which they were formed had a secondary role. Jets of radicals invariably appeared as turbulent plumes which were embedded in blast waves headed by hemispherical shock fronts. Three interesting properties of jet ignition are examined: controllable depth of penetration so that combustion can be started at any desired location within the charge; zonal pre-turbulization enhancing the combustion process; and wide dispersion resulting in multipoint ignition so that combustion is initiated throughout a relatively large segment of the medium rather than in the form of a small, laminar flame kernel as it does in an unconfined spark discharge.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/01487191
• Supplemental Notes:
  • Presented at SAE Passenger Car Meeting, Troy, Michigan, 5-9 June 1978. Supported by Department of Energy.
• Corporate Authors:

  Society of Automotive Engineers (SAE)

  400 Commonwealth Drive
  Warrendale, PA  United States  15096
• Authors:
  • OPPENHEIM, A K
  • Teichman, K
  • Hom, K
  • STEWART, H E
• Publication Date: 1978

Media Info

• Features: References;
• Pagination: 16 p.
• Serial:
  • SAE Technical Paper
  • Publisher: Society of Automotive Engineers (SAE)
  • ISSN: 0148-7191
  • EISSN: 2688-3627
  • Serial URL: http://papers.sae.org/

Subject/Index Terms

• TRT Terms: Experiments; Lean fuel mixtures
• Old TRIS Terms: Jet ignition
• Subject Areas: Safety and Human Factors;

Filing Info

• Accession Number: 00396331
• Record Type: Publication
• Source Agency: National Highway Traffic Safety Administration
• Report/Paper Numbers: SAE 780637, HS-025 536U
• Files: HSL, USDOT
• Created Date: Aug 31 1985 12:00AM