Planar Droplet Sizing for Characterization of Automotive Sprays in Port Fuel Injection Applications Using Commercial Fuel

Bareiss, Stefan; Fuhrmann, N.; Dreizler, Andreas; Bacher, Heinz; Höffner, J.; Weishäupl, Ronald; Kügler, Dietmar

doi:10.1007/978-94-007-5320-4_15

Cited by 2 publications

(3 citation statements)

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“…The accuracy of SMD measurements from LIF/Mie ratios is also governed by the calibration procedure. The majority of calibration schemes are made using PDA measurements while a few calibration approaches are reported that use a monodisperse droplet generator [38]. Calibration with a monodisperse droplet is preferred because droplets are recorded and evaluated identically to the LIF/Mie ratio scheme (see details in subsection 2B).…”

Section: Introductionmentioning

confidence: 99%

3D mapping of droplet Sauter mean diameter in sprays

et al. 2019

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In this study, we report on the 3D (three-dimensional) characterization of a spray in terms of its droplet SMD (Sauter Mean Diameter) using the LIF (Laser-Induced Fluorescence)/Mie ratio technique. The spray structure is analyzed for a multi-hole DISI (Direct-Injection Spark Ignition) injector. A calibration curve to convert LIF/Mie ratio to droplet diameter is deduced using LIF/Mie imaging and analysis of single droplets generated by a droplet generator. The DISI spray investigated here is optically sectioned by means of two-phase SLIPI (Structured Laser Illumination Planar Imaging) to suppress the intensity of multiple light scattering from LIF and Mie images prior to their ratio. A series of calibrated LIF/Mie ratio images of spray is then recorded at several depths along the Z-direction following the light sheet scanning of the spray. The droplet SMD is ranging from less than 5 µm up to a maximum of 50 µm in single-shot images. The averaged SMD results (1-30 µm) obtained by using the calibration curve from the droplet generator are compared with measurement results from Phase-Doppler Anemometry (PDA). Finally, a 3D map is reconstructed from the successive 2D layers generated from spray scanning. The resulting 3D representation of the droplet SMD shows a non-symmetric spray structure produced by the studied multi-hole injector, which cannot be resolved by analyzing only one central plane.

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Section: Introductionmentioning

confidence: 99%

3D mapping of droplet Sauter mean diameter in sprays

et al. 2019

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“…LIF/Mie technique can be an attractive alternative to discussed methods as it allows a rapid determination of droplet size distribution across the spray at the same time providing information on global spray parameters, specifically the spray angle. It has been successfully used for port fuel injection studies [10] where injection pressure is very similar to the one in SCR systems. The advantage of this method in reduced measuring times comes along with various challenging issues, such as accuracy limited by multiple-scattering, absorption effects and calibration procedures [10].…”

Section: Introductionmentioning

confidence: 99%

“…It has been successfully used for port fuel injection studies [10] where injection pressure is very similar to the one in SCR systems. The advantage of this method in reduced measuring times comes along with various challenging issues, such as accuracy limited by multiple-scattering, absorption effects and calibration procedures [10]. The calibration procedure is especially difficult for 90 deg detection angle since increase of the scattered light intensity with the droplet diameter is irregular [11].…”

Section: Introductionmentioning

confidence: 99%

LIF/Mie Droplet Sizing of Water Sprays from SCR System Injector using Structured Illumination

Kapusta

2017

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

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Recent trends in SCR (Selective Catalytic Reduction) systems development increase requirements for UWS (Urea Water Solution) injection. Close-coupled SCR system designs decrease the distance available for water evaporation and urea decomposition. Due to that, much effort is put into static mixing elements design improvement and injection process enhancement. So far, most experimental studies on UWS spray formation were based on Mie scattering visualization using global illumination and shadowgraphy imaging. High speed imaging of Mie signal with global illumination allows to determine global spray parameters such as penetration and angle but does not give information on droplet sizes. Droplet size determination, due to relatively large droplets generated by SCR injectors, can be done with Mie scattering or backlight imaging methods. Then the visualized area becomes narrowed since high magnification is required. Determination of droplet size distribution across whole spray in such arrangement requires number of measurements. LIF/Mie (Laser Induced Fluorescence/Mie scattering) technique provides an attractive alternative for rapid determination of droplet size distribution across the whole spray. This method however suffers from multiple scattering effects which might affect droplet size distribution results even in relatively dilute sprays. In this study, LIF/Mie ratio distribution across sprays from commercial automotive injector for SCR systems was determined by simultaneous LIF and Mie detection using structured illumination. Moreover, the results were compared with conventional LIF/Mie imaging. Nd:YAG pulse laser was used as a light source. Second harmonic beam of 532 nm was used to illuminate the sprays. Instead of UWS pure water doped with Eosin Y was used. The results showed that conventional images exhibited much stronger background signal. Moreover, the conventional imaging was sensitive to reflections from experimental setup elements, specifically reflections from LIF camera filter. These two observations prove the importance of using SLIPI for LIF/Mie droplets sizing in sprays for SCR systems. At the same time the obtained results showed that under certain conditions (no accidental reflections in the background) conventional imaging provides similar LIF/Mie ratio as structured illumination. The results showed that the LIF/Mie ratio remains unchanged over the spray cloud. This suggests that SMD remains unchanged as well. The slight increase of LIF/Mie ratio far from the injector outlet could be caused by absence of small droplets due to lower momentum and thus lower penetration distance. This assumption however should be verified with PIV measurement.

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Planar Droplet Sizing for Characterization of Automotive Sprays in Port Fuel Injection Applications Using Commercial Fuel

Cited by 2 publications

References 20 publications

3D mapping of droplet Sauter mean diameter in sprays

3D mapping of droplet Sauter mean diameter in sprays

LIF/Mie Droplet Sizing of Water Sprays from SCR System Injector using Structured Illumination

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