Flame propagation visualization in a spark-ignition engine using laser-induced fluorescence of cool-flame species
Author
Summary, in English
The flame propagation in a spark-ignition engine has been studied using laser-induced fluorescence (LIF) of species formed during the first ignition stage of hydrocarbon combustion. The detected two-dimensional LIF images showed the distribution of unburned regions. For the excitation, two Nd:YAG lasers operating at 355 mn were used for two consecutive measurements within the same engine cycle with adjustable time separation between the pulses. Two ICCD cameras that were synchronized to each of the laser pulses recorded pairs of fluorescence images, i.e. the movement of the flame front could be tracked. It is well known that formaldehyde is excited using a wavelength of 355 nm and a spectral signature of this species was also identified in engine LIF spectra. Programme routines were developed and used for evaluation of the flame propagation velocity from the fluorescence images. This paper presents the potential and the characteristics of the experimental technique as well as the evaluation procedure. The measurements of cool-flame intermediates have also been compared with measurements of fuel-tracer as an indicator of unburned fuel-air mixture. A good agreement between position and shape of the signal areas was obtained at crank angles where both fluorescence signal from cool-flame species excited at 355 nm and added 3-pentanone excited at 266 nm could be detected.
Department/s
Publishing year
2005
Language
English
Pages
1083-1091
Publication/Series
Measurement Science & Technology
Volume
16
Issue
5
Full text
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Document type
Journal article
Publisher
IOP Publishing
Topic
- Atom and Molecular Physics and Optics
Keywords
- combustion diagnostics
- spark-ignition
- engine
- flame propagation
- laser-induced fluorescence
Status
Published
ISBN/ISSN/Other
- ISSN: 0957-0233