Schlieren Measurements of the ECN-Spray A Penetration under Inert and Reacting Conditions

Pastor, Javier; Payri, Raúl; García-Oliver, José M; Nerva, Jean-Guillaume

doi:10.4271/2012-01-0456

Cited by 69 publications

(64 citation statements)

References 16 publications

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“…This parameter has been extensively used in many spray studies to characterize the inert spray radial spreading rate [8,25,32,35], in spite of some uncertainties related to the differences in definition among different groups and well-known limitations of the schlieren technique to objectively resolve the spray limit from a background flow [8]. Images in Figure 5 enable the identification of a sharp contour for the reacting case.…”

Section: Figure 3 Tomentioning

confidence: 99%

“…In previous works authors have investigated about the uncertainties and limitations on the particular schlieren optical set-up [25] as well on the final digital analysis and measurements [23]. In that sense, particularities on the collection section are briefly recalled here in order to empathize the fact of having a "controlled" schlieren system.…”

Section: Schlieren Imagingmentioning

confidence: 99%

“…The same arrangement as in previous works [23,25] has been used, namely a "focused single pass" schlieren setup, as sketched in Figure 1. This optical arrangement can be divided in two different sections, which are referred to as the illumination and collection sections.…”

Section: Schlieren Imagingmentioning

confidence: 99%

“…Both experiments and model results have been considered. Experimental injection data as well as ambient conditions are input for the 1D model, which has been calibrated in the same way as in [8,25] by fitting spray cone angle so that experimental inert penetration is adequately predicted. Considering the degree of accuracy in the prediction of inert spray penetration with similar 1D models, recent approaches have shown that spatial distribution of mixture fraction is also adequate [8].…”

Section: D Spray Modeling Considerations On Transient Flame Penetrationmentioning

confidence: 99%

See 3 more Smart Citations

An experimental analysis on the evolution of the transient tip penetration in reacting Diesel sprays

Desantes

Pastor

García-Oliver

et al. 2014

Combustion and Flame

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Schlieren imaging has helped deeply characterize the behavior of diesel spray when injected into an oxygen-free ambient. However, when considering the transient penetration of the reacting spray after autoignition, i.e. the Diesel flame, few studies have been found in literature. Differences among optical setups as well as among experimental conditions have not allowed clear conclusions to be drawn on this issue. Furthermore, soot radiation may have a strong effect on the image quality, which cannot be neglected.The present paper reports an investigation on the transient evolution of Diesel flame based upon schlieren imaging. Experimental conditions have spanned values of injection pressure, ambient temperature and density for typical Diesel engine conditions. An optimized optical setup has been used, which makes it possible to obtain results without soot interference. Based on observations for a long injection event (4 ms Energizing Time), the analysis has resorted to extensive comparison of inert and reacting sprays parameters, which have made it possible to define different phases after autoignition.Shortly after autoignition, axial and radial expansion of the spray have been observed in terms of axial penetration and radial cone angle. After that, during a stabilization phase, the reacting spray penetrates at a similar rate as the inert one. Later, the reacting spray undergoes an acceleration period, where it penetrates at a faster rate than the inert one. Finally, the flame enters a quasi-steady penetration phase, where the ratio of reacting and inert penetration stabilizes at a nearly constant value. The duration of the reacting spray penetration stages shows modifications when varying engine parameters such as air temperature, air density, injection pressure, and nozzle diameter. However, the proportionality between reacting and inert penetration has been observed to depend mainly on temperature, in agreement with observed reductions in entrainment when shifting from inert to reacting conditions.

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Section: Figure 3 Tomentioning

confidence: 99%

Section: Schlieren Imagingmentioning

confidence: 99%

Section: Schlieren Imagingmentioning

confidence: 99%

Section: D Spray Modeling Considerations On Transient Flame Penetrationmentioning

confidence: 99%

See 2 more Smart Citations

An experimental analysis on the evolution of the transient tip penetration in reacting Diesel sprays

Desantes

Pastor

García-Oliver

et al. 2014

Combustion and Flame

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“…It is not only fundamental knowledge to understand how boundary conditions affect these variables, but the experimental data is necessary to validate computational tools, such as 1-D models or computational fluid dynamics (CFD). The two most common Schlieren configurations are single-pass (SP) [2,[5][6][7][8][9] and double-pass (DP) [3,[10][11][12][13]. Typically, the first setup is used for axially drilled single-orifice nozzles, where vessels with multiple optical accesses allow line of sight visualization.…”

Section: Introductionmentioning

confidence: 99%

Vapor phase penetration measurements with both single and double-pass Schlieren for the same injection event

Payri

Salvador

Viera

2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

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Schlieren imaging has been adopted as a standard optical technique for the analysis of diesel sprays under engine like conditions. A single-pass Schlieren arrangement is typically used for the study of single-orifice nozzles, as vessels with multiple optical accesses regularly allow line of sight visualization. Contrarily, for multi-spray nozzles, measurements are commonly performed through a single optical access, in which case a double-pass arrangement is employed. As a consequence, the light beams pass through the test section twice, increasing the optical sensitivity of the Schlieren setup. However, the impact this has on the macroscopic spray characteristics is still unclear. The scope of this study is to analyze the differences in vapor phase penetration for the same injection event, through high-speed imaging, for both single and double-pass Schlieren configurations. Experiments were carried out with a three hole nozzle with a nominal orifice diameter of 90 µm, named Spray B from the Engine Combustion Network, using commercially available diesel fuel and in non-reactive conditions. The impact of different injection pressures and chamber densities on the spray captured by each setup was assessed. On the results, vapor phase penetration followed the expected trend found in the literature, as it increases with increasing injection pressure and decreasing chamber density. Comparing the optical setups, vapor phase penetration obtained with the double-pass arrangement was marginally higher. The deviation was observed throughout all tested conditions. Although the discrepancy was approximately constant for different injection pressures and chamber temperature, it increased with increasing density. These results highlight the importance of a proper understanding regarding the limitations of optical diagnostics, in particular for results used in calibration of computational models.

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Optical Diagnostics of Spray Development in Diesel Engines

Jena

2019

Energy, Environment, and Sustainability

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Schlieren Measurements of the ECN-Spray A Penetration under Inert and Reacting Conditions

Cited by 69 publications

References 16 publications

An experimental analysis on the evolution of the transient tip penetration in reacting Diesel sprays

An experimental analysis on the evolution of the transient tip penetration in reacting Diesel sprays

Vapor phase penetration measurements with both single and double-pass Schlieren for the same injection event

Optical Diagnostics of Spray Development in Diesel Engines

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