Simultaneous formaldehyde PLIF and high-speed schlieren imaging for ignition visualization in high-pressure spray flames

Skeen, Scott A.; Manin, Julien; Pickett, Lyle M.

doi:10.1016/j.proci.2014.06.040

Cited by 252 publications

(150 citation statements)

References 22 publications

(31 reference statements)

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“…Planar laser-induced fluorescence images of PAH formation at the Spray A condition also indicate that the formation of these precursors takes place downstream of 30 mm [57]. The soot observed at more upstream locations in the ANL and POL may thus illustrate a weakness of simplified soot models yielding particulates directly from acetylene.…”

Section: Skeen Et Al / Sae Int J Engines / Volume 9 Issue 2 (June mentioning

confidence: 91%

A Progress Review on Soot Experiments and Modeling in the Engine Combustion Network (ECN)

Skeen

Manin

Pickett

et al. 2016

SAE Int. J. Engines

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The 4th Workshop of the Engine Combustion Network (ECN) was held September 5-6, 2015 in Kyoto, Japan. This manuscript presents a summary of the progress in experiments and modeling among ECN contributors leading to a better understanding of soot formation under the ECN “Spray A” configuration and some parametric variants. Relevant published and unpublished work from prior ECN workshops is reviewed. Experiments measuring soot particle size and morphology, soot volume fraction (fv), and transient soot mass have been conducted at various international institutions providing target data for improvements to computational models. Multiple modeling contributions using both the Reynolds Averaged Navier-Stokes (RANS) Equations approach and the Large-Eddy Simulation (LES) approach have been submitted. Among these, various chemical mechanisms, soot models, and turbulence-chemistry interaction (TCI) methodologies have been considered

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Section: Skeen Et Al / Sae Int J Engines / Volume 9 Issue 2 (June mentioning

confidence: 91%

A Progress Review on Soot Experiments and Modeling in the Engine Combustion Network (ECN)

Skeen

Manin

Pickett

et al. 2016

SAE Int. J. Engines

Self Cite

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“…The experimental data is provided via the ECN data platform [2]. A detailed description of the experimental setup can be found in [28][29][30]. The experimental initial and boundary conditions are summarized in Table 1.…”

Section: Simulation Casesmentioning

confidence: 99%

“…Comparison of baseline mechanism and reduced mechanism with experimental ignition delay measurements. The model performance is evaluated by comparison with experimental results from Skeen et al [30], who simultaneously measured schlieren and the formaldehyde distribution. The schlieren technique visualizes gradients of the refractive index, which is directly correlated with the density, in a line-of-sight view.…”

Section: Inert Casementioning

confidence: 99%

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LES of n-Dodecane Spray Combustion Using a Multiple Representative Interactive Flamelets Model

Davidovic

Falkenstein

Bode

et al. 2017

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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-A single-hole n-dodecane spray flame is studied in a Large-Eddy Simulation (LES) framework under Diesel-relevant conditions using a Multiple Representative Interactive Flamelets (MRIF) combustion model. Diesel spray combustion is strongly affected by the mixture formation process, which is dominated by several physical processes such as the flow within the injector, break-up of the liquid fuel jet, evaporation and turbulent mixing with the surrounding gas. While the effects of nozzle-internal flow and primary breakup are captured within tuned model parameters in traditional Lagrangian spray models, an alternative approach is applied in this study, where the initial droplet conditions and primary fuel jet breakup are modeled based on results from highly resolved multiphase simulations with resolved interface. A highly reduced chemical mechanism consisting of 57 species and 217 reactions has been developed for n-dodecane achiving a good computational performance at solving the chemical reactions. The MRIF model, which has demonstrated its capability of capturing combustion and pollutant formation under typical Diesel conditions in Reynolds-Averaged Navier-Stokes (RANS) simulations is extended for the application in LES. In the standard RIF combustion model, representative chemistry conditioned on mixture fraction is solved interactively with the flow. Subfilter-scale mixing is modeled by the scalar dissipation rate. While the standard RIF model only includes temporal changes of the scalar dissipation rate, the spatial distribution can be accounted for by extending the model to multiple flamelets, which also enables the possibility of capturing different fuel residence times. Overall, the model shows good agreement with experimental data regarding both, low and high temperature combustion characteristics. It is shown that the ignition process and pollutant formation are affected by turbulent mixing. First, a cool flame is initiated at approximately stoichiometric mixture and propagates towards the rich side. Hence, heat and radicals are transported away from the most reactive mixture and thus the ignition is delayed. At the same time, the transported heat and radicals increase the reactivity of rich mixtures, which strongly affects the CO formation. NO was found to increase compared to the no transport case due to enhanced mixing, which is related to a broader high-temperature zone and the additional transport of oxygen from lean into high-temperature regions.

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“…The formation of formaldehyde (CH2O) shown in Figure 1 appears at low-temperature region (<1,000 K), but at a very wide range of ϕ. As an intermediate species, CH2O has been known to formed at a very initial stage ignition reaction (prior to premixed combustion) and is usually seen in upstream region of CI combustion and consumed downstream of the flame lift-off length (Idicheria and Pickett, 2006;Skeen et al, 2015;Cung et al, 2016). With some amount of low-temperature reaction during premixed combustion in GCI, it is expected a high concentration of CH2O prior to high-temperature diffusion flame.…”

Section: Introductionmentioning

confidence: 99%

Low-Temperature Combustion of High Octane Fuels in a Gasoline Compression Ignition Engine

et al. 2017

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Gasoline compression ignition (GCI) has been shown as one of the advanced combustion concepts that could potentially provide a pathway to achieve cleaner and more efficient combustion engines. Fuel and air in GCI are not fully premixed compared to homogeneous charge compression ignition (HCCI), which is a completely kinetic-controlled combustion system. Therefore, the combustion phasing can be controlled by the time of injection, usually postinjection in a multiple-injection scheme, to mitigate combustion noise. Gasoline usually has longer ignition delay than diesel. The autoignition quality of gasoline can be indicated by research octane number (RON). Fuels with high octane tend to have more resistance to autoignition, hence more time for fuel-air mixing. In this study, three fuels, namely, aromatic, alkylate, and E30, with similar RON value of 98 but different hydrocarbon compositions were tested in a multicylinder engine under GCI combustion mode. Considerations of exhaust gas recirculating (EGR), start of injection, and boost were investigated to study the sensitivity of dilution, local stratification, and reactivity of the charge, respectively, for each fuel. Combustion phasing (location of 50% of fuel mass burned) was kept constant during the experiments. This provides similar thermodynamic conditions to study the effect of fuels on emissions. Emission characteristics at different levels of EGR and lambda were revealed for all fuels with E30 having the lowest filter smoke number and was also most sensitive to the change in dilution. Reasonably low combustion noise (<90 dB) and stable combustion (coefficient of variance of indicated mean effective pressure <3%) were maintained during the experiments. The second part of this article contains visualization of the combustion process obtained from endoscope imaging for each fuel at selected conditions. Soot radiation signal from GCI combustion were strong during late injection and also more intense at low EGR conditions. Soot/temperature profiles indicated only the high-temperature combustion period, while cylinder pressure-based heat release rate showed a two-stage combustion phenomenon.

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Simultaneous formaldehyde PLIF and high-speed schlieren imaging for ignition visualization in high-pressure spray flames

Abstract: The authors DO NOT agree to pay charges for color reproduction of figures. All figures to be printed in grey scale. *ManuscriptClick here to view linked References

Cited by 252 publications

References 22 publications

A Progress Review on Soot Experiments and Modeling in the Engine Combustion Network (ECN)

A Progress Review on Soot Experiments and Modeling in the Engine Combustion Network (ECN)

LES of n-Dodecane Spray Combustion Using a Multiple Representative Interactive Flamelets Model

Low-Temperature Combustion of High Octane Fuels in a Gasoline Compression Ignition Engine

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