The potential of on- and off-resonant formaldehyde imaging combined with bootstrapping in diesel sprays

P.C. Bakker, N. Maes, N. Dam

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Formaldehyde (CH2O) is an important intermediate in spray combustion of diesel-like fuels. Experimentally, its spatial distribution is often assessed by means of planar Laser-Induced Fluorescence (PLIF), using a frequency-tripled Nd:YAG laser for excitation and spectrally-filtered fluorescence detection. Especially in soot-laden spray flames, however, considerable spectral interference cannot be avoided, which renders interpretation of the fluorescence distribution challenging. We introduce a more selective strategy, involving dye laser excitation and background subtraction by means of off-resonant excitation in combination with a bootstrap evaluation of sets of individual events. The latter extracts persistent features out of non-simultaneously recorded snapshots of stochastic events, thereby mitigating possible interpretation issues related to the turbulent nature of the process under study. Following this approach, recurrent patterns can be distinguished from random high-intensity events (allegedly due to turbulent fluctuations). We demonstrate our method on the Engine Combustion Network (ECN) “Spray A”-benchmark, with 15 vol-% and 21 vol-% ambient oxygen; we also present spatially well-delimited CH2O fluorescence distributions, and compare these to simultaneously recorded OH* chemiluminescence intensities.
Originele taal-2Engels
Pagina's (van-tot)20-27
TijdschriftCombustion and Flame
Volume182
DOI's
StatusGepubliceerd - aug 2017

Vingerafdruk

formaldehyde
Formaldehyde
sprayers
Fluorescence
Imaging techniques
fluorescence
excitation
diesel fuels
chemiluminescence
soot
Soot
subtraction
dye lasers
laser induced fluorescence
Laser excitation
Chemiluminescence
Dye lasers
engines
Lasers
YAG lasers

Citeer dit

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title = "The potential of on- and off-resonant formaldehyde imaging combined with bootstrapping in diesel sprays",
abstract = "Formaldehyde (CH2O) is an important intermediate in spray combustion of diesel-like fuels. Experimentally, its spatial distribution is often assessed by means of planar Laser-Induced Fluorescence (PLIF), using a frequency-tripled Nd:YAG laser for excitation and spectrally-filtered fluorescence detection. Especially in soot-laden spray flames, however, considerable spectral interference cannot be avoided, which renders interpretation of the fluorescence distribution challenging. We introduce a more selective strategy, involving dye laser excitation and background subtraction by means of off-resonant excitation in combination with a bootstrap evaluation of sets of individual events. The latter extracts persistent features out of non-simultaneously recorded snapshots of stochastic events, thereby mitigating possible interpretation issues related to the turbulent nature of the process under study. Following this approach, recurrent patterns can be distinguished from random high-intensity events (allegedly due to turbulent fluctuations). We demonstrate our method on the Engine Combustion Network (ECN) “Spray A”-benchmark, with 15 vol-{\%} and 21 vol-{\%} ambient oxygen; we also present spatially well-delimited CH2O fluorescence distributions, and compare these to simultaneously recorded OH* chemiluminescence intensities.",
keywords = "Engine Combustion Network (ECN); , n-Dodecane, bootstrap, Fuel spray, LIF, Formaldehyde",
author = "P.C. Bakker and N. Maes and N. Dam",
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The potential of on- and off-resonant formaldehyde imaging combined with bootstrapping in diesel sprays. / Bakker, P.C.; Maes, N.; Dam, N.

In: Combustion and Flame, Vol. 182, 08.2017, blz. 20-27.

Onderzoeksoutput: Bijdrage aan tijdschriftTijdschriftartikelAcademicpeer review

TY - JOUR

T1 - The potential of on- and off-resonant formaldehyde imaging combined with bootstrapping in diesel sprays

AU - Bakker, P.C.

AU - Maes, N.

AU - Dam, N.

PY - 2017/8

Y1 - 2017/8

N2 - Formaldehyde (CH2O) is an important intermediate in spray combustion of diesel-like fuels. Experimentally, its spatial distribution is often assessed by means of planar Laser-Induced Fluorescence (PLIF), using a frequency-tripled Nd:YAG laser for excitation and spectrally-filtered fluorescence detection. Especially in soot-laden spray flames, however, considerable spectral interference cannot be avoided, which renders interpretation of the fluorescence distribution challenging. We introduce a more selective strategy, involving dye laser excitation and background subtraction by means of off-resonant excitation in combination with a bootstrap evaluation of sets of individual events. The latter extracts persistent features out of non-simultaneously recorded snapshots of stochastic events, thereby mitigating possible interpretation issues related to the turbulent nature of the process under study. Following this approach, recurrent patterns can be distinguished from random high-intensity events (allegedly due to turbulent fluctuations). We demonstrate our method on the Engine Combustion Network (ECN) “Spray A”-benchmark, with 15 vol-% and 21 vol-% ambient oxygen; we also present spatially well-delimited CH2O fluorescence distributions, and compare these to simultaneously recorded OH* chemiluminescence intensities.

AB - Formaldehyde (CH2O) is an important intermediate in spray combustion of diesel-like fuels. Experimentally, its spatial distribution is often assessed by means of planar Laser-Induced Fluorescence (PLIF), using a frequency-tripled Nd:YAG laser for excitation and spectrally-filtered fluorescence detection. Especially in soot-laden spray flames, however, considerable spectral interference cannot be avoided, which renders interpretation of the fluorescence distribution challenging. We introduce a more selective strategy, involving dye laser excitation and background subtraction by means of off-resonant excitation in combination with a bootstrap evaluation of sets of individual events. The latter extracts persistent features out of non-simultaneously recorded snapshots of stochastic events, thereby mitigating possible interpretation issues related to the turbulent nature of the process under study. Following this approach, recurrent patterns can be distinguished from random high-intensity events (allegedly due to turbulent fluctuations). We demonstrate our method on the Engine Combustion Network (ECN) “Spray A”-benchmark, with 15 vol-% and 21 vol-% ambient oxygen; we also present spatially well-delimited CH2O fluorescence distributions, and compare these to simultaneously recorded OH* chemiluminescence intensities.

KW - Engine Combustion Network (ECN);

KW - n-Dodecane

KW - bootstrap

KW - Fuel spray

KW - LIF

KW - Formaldehyde

U2 - 10.1016/j.combustflame.2017.03.032

DO - 10.1016/j.combustflame.2017.03.032

M3 - Article

VL - 182

SP - 20

EP - 27

JO - Combustion and Flame

JF - Combustion and Flame

SN - 0010-2180

ER -