Time-resolved investigation of hot spots in the end gas of an S. I. engine by means of 2-D double-pulse lif of formaldehyde

Bäuerle, Bettina; Warnat, J.; Behrendt, Frank

doi:10.1016/s0082-0784(96)80096-8

Cited by 32 publications

(12 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…and PLIF imaging of CH20 in an engine has been reported by Bauerle et al [9]. In both cases excitation was via the A'A,-X'A, 410 band (near 353 nm).…”

Section: Lif Measurements Of Native Ch20 In Flames Have Been Reportedmentioning

confidence: 70%

Planar laser-induced fluorescence imaging of flame heat release rate

Paul

Najm

1998

Symposium (International) on Combustion

240

View full text Add to dashboard Cite

“…and PLIF imaging of CH20 in an engine has been reported by Bauerle et al [9]. In both cases excitation was via the A'A,-X'A, 410 band (near 353 nm).…”

Section: Lif Measurements Of Native Ch20 In Flames Have Been Reportedmentioning

confidence: 70%

Planar laser-induced fluorescence imaging of flame heat release rate

Paul

Najm

1998

Symposium (International) on Combustion

240

View full text Add to dashboard Cite

“…[15]. The resulting signal was detected using a gated single-stage image intensifier coupled to a charge-coupled device (Santa Barbara Instrument Group ST6B).…”

Section: Experimental Methodsmentioning

confidence: 99%

An experimental study of vortex-flame interaction in counterflow spray diffusion flames

Santoro

Kyritsis

Gomez

2000

Proceedings of the Combustion Institute

View full text Add to dashboard Cite

The extinction behavior of methanol counterflow spray diffusion flames was investigated using a combination of formaldehyde planar laser-induced fluorescence (PLIF) and phase Doppler measurements. Extinction was brought about quasi-steadily, by progressively increasing the flow rates of both oxidizer and fuel side, and unsteadily, by generating a vortex on the oxidizer side. The unsteady experiments yielded values of extinction strain rates a factor of 2 larger than the quasi-steady values. The greater robustness of the spray flame under unsteady perturbation was explained phenomenologically by estimating the timescales involved in the process. It was found that the vortex introduces unsteady effects in the outer diffusiveconvective layer of the flame. The inner reactive-diffusive layer, on the other hand, behaves in a quasisteady manner, since the characteristic chemical time is much smaller than the characteristic unsteady time. As a result, even though the instantaneous strain rate is much larger than the quasi-steady extinction strain rate, the flame is subject to a damped strain rate through the outer layer. An estimate of the thickness of the mixing layer, based on formaldehyde PLIF, provided a convenient means to compare the scalar dissipation rate and the Damkö hler number between the two extinction modes, bypassing the need for detailed species measurements for the assessment of the mixture fraction and its gradient. Such a comparison showed that the difference between the two extinction modes was reduced to 25% on the average, consistent with expectations based on flame structure models from asymptotic theory. Spray flames exhibited longer time delays between the onset of extinction and reignition, as compared to gaseous flames. Estimates of the relevant Stokes number suggested that the difference may be attributed to droplet inertia effects.

show abstract

“…The dye laser option, however, results in lower available pulse energy compared to the Nd:YAG laser. The low pulse energies (∼2 mJ) used by Bäuerle et al [10] generally resulted in rather low signal-to-noise ratios of the presented images. Similar to our experiments Bäuerle et al observed a fluorescing end-gas region between the flame-front and the combustion chamber wall.…”

Section: Discussionmentioning

confidence: 89%

“…The detection of formaldehyde by laser-induced fluorescence has been performed in flames [5][6][7][8] as well as in internal combustion engines [9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

“…Hence, laser-based cycle-resolved studies generally require the use of setups with multiple lasers and detectors. Engine measurements on combustion intermediates using dual lasers and detectors have been presented in several papers [10,14,15]. These measurements were performed in a two-stroke research engine with a sidevalve configuration and optical access from the top.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Flame propagation visualization in a spark-ignition engine using laser-induced fluorescence of cool-flame species

Bladh¹,

Brackmann²,

Dahlander

et al. 2005

Meas. Sci. Technol.

View full text Add to dashboard Cite

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 nm 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.

show abstract

Time-resolved investigation of hot spots in the end gas of an S. I. engine by means of 2-D double-pulse lif of formaldehyde

Cited by 32 publications

References 7 publications

Planar laser-induced fluorescence imaging of flame heat release rate

Planar laser-induced fluorescence imaging of flame heat release rate

An experimental study of vortex-flame interaction in counterflow spray diffusion flames

Flame propagation visualization in a spark-ignition engine using laser-induced fluorescence of cool-flame species

Contact Info

Product

Resources

About