Simultaneous Imaging of Fuel and Hydroxyl Radicals in an In-Line Four Cylinder SI Engine

Arnold, A.; Buschmann, Anke; Cousyn, B.; Decker, Michael; Vannobel, F.; Sick, Volker; Wolfrum, J.

doi:10.4271/932696

Cited by 25 publications

(4 citation statements)

References 5 publications

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“…This is a possible mixture for optical engine studies addressing fuel mixing and temperatures. 10,11 For the particular mixture under study, the absorption and emission bands of the tracer do not overlap. Also, no other absorbers are present in the fuel-tracer mixture.…”

Section: B Signal Attenuationmentioning

confidence: 99%

Attenuation effects on imaging diagnostics of hollow-cone sprays

Sick¹,

Stojkovic²

2001

Appl. Opt.

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Detrimental effects to quantitative interpretation of Mie and laser-induced fluorescence images of hollow-cone sprays were investigated. The attenuation of the laser beam leads to locally unknown intensities rendering it impossible to obtain high-fidelity images of these sprays. Two strategies that use bidirectional illumination of the spray are discussed and evaluated. Conditions for which a bidirectional illumination, single-image detection will allow good recovery of the spray structure are identified. Furthermore, the attenuation of laser-induced fluorescence signals on their path through the spray is quantified.

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Section: B Signal Attenuationmentioning

confidence: 99%

Attenuation effects on imaging diagnostics of hollow-cone sprays

Sick¹,

Stojkovic²

2001

Appl. Opt.

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“…Previous measurements to simultaneously detect OH and acetone used excitation in the OH (0,0) band with XeCl lasers at 308 nm by Yip et al [9] and dye lasers in the (1,0) band by Seitzman et al [10]. Similarly, the simultaneous detection of OH and 3-pentanone was used in engine studies by Arnold et al [11] using a KrF excimer laser (248 nm) to excite OH in the (3,0) band and a XeCl excimer laser (308 nm) for 3-pentanone and by Rothamer and Ghandhi [12], who used a dye laser to excite 3-pentanone and OH in the (1,0) band.…”

Section: Introductionmentioning

confidence: 99%

Single-shot imaging of OH radicals and simultaneous OH radical/acetone imaging with a tunable Nd : YAG laser

Sick

Wermuth

2004

Appl Phys B

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Single shot imaging capability for OH radical distributions in various atmospheric pressure methane flames upon excitation with a tunable frequencyquadrupled Nd : YAG laser is demonstrated. The laser wavelength can be tuned with an intra-cavity etalon to produce laser-induced fluorescence (LIF) signals from OH via absorption in the OH AX (2,0) P 1 (10) line. Simultaneous single-shot imaging of the burnt and unburnt zones in laminar nonpremixed, premixed and turbulent flames is presented. The unburnt areas are visualized with LIF of acetone that is seeded to the methane fuel. Acetone levels are set to match signal intensities to that of the OH signals to allow imaging on a single intensified CCD camera.

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“…A fluorescent tracer is added in percentage concentrations to act as a marker for fuel molecules. Ketones, like acetone and 3-pentanone are frequently used for this purpose [Arnold 1993]. We have chosen to investigate toluene as a tracer because of its unique quenching properties that yield a fluorescence signal that is directly proportional to the fuel/air ratio.…”

Section: Figure 3: Distribution Of Relative Droplet Diameters Of An Imentioning

confidence: 99%

Mixture Preparation and Nitric Oxide Formation in a GDI Engine studied by Combined Laser Diagnostics and Numerical Modeling

Sick¹,

Assanis²

2002

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Project objectives:Through the combination of advanced imaging laser diagnostics with multidimensional computer models, a new understanding of the performance of directinjection gasoline engines is pursuit. The work focuses on the fuel injection process, the breakup of the liquid into a fine spray and the mixing of the fuel with the in-cylinder gases. Non-intrusive laser diagnostics will be used to measure the spatial distribution of droplets and vaporized fuel with very high temporal resolution. These data along with temperature measurements will be used to validate a new spray breakup model for gasoline direct-injection. Experimental data on near wall fuel distributions will be used for comparison with a model that predicts the spray-wall interaction and the dynamics of the liquid film on the surface. Quantitative measurements of local nitric oxide concentrations inside the combustion chamber will provide a critical test for a numerical simulation of the nitric oxide formation process. This model is based on a modified flamelet approach and will be used to study the effects of exhaust gas recirculation. Experimental Approaches and Achievements:A direct-injection fuel spray rig was designed and installed to study a wellcharacterized spray and provide data for comparison with a new breakup and impingement model. Measurements of the spatial and temporal structure of sprays were conducted with a combination of planar laser-induced fluorescence and planar Mie scattering. This gives access to fuel distribution as well as to relative droplet diameters. A single KrF excimer laser beam was employed to illuminate the spray and the signals were separated with a newly designed filter-beam splitter setup. This filter allows a complete separation of the signals and produces two parallel images that can then be recorded with a single ICCD camera. Other features of the setup are on-line single-shot energy referencing and flexible wavelength selection.Two sets of experiments were conducted. A first series addressed issues of background signals that occur in engine environments when a reflecting surface lies behind the illuminating laser light sheet. This background signal was determined to be strongly wavelength dependent and an effective suppression is primarily possible when the surface is treated with high pressure water blasting and by optically narrowing the depth-offield for observation by using a large-aperture imaging lens without additional apertures.

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Simultaneous Imaging of Fuel and Hydroxyl Radicals in an In-Line Four Cylinder SI Engine

Cited by 25 publications

References 5 publications

Attenuation effects on imaging diagnostics of hollow-cone sprays

Attenuation effects on imaging diagnostics of hollow-cone sprays

Single-shot imaging of OH radicals and simultaneous OH radical/acetone imaging with a tunable Nd : YAG laser

Mixture Preparation and Nitric Oxide Formation in a GDI Engine studied by Combined Laser Diagnostics and Numerical Modeling

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