Evaluation of natural and tracer fluorescent emission methods for droplet size measurements in a diesel spray

Pastor, Javier; Payri, Raúl; Salavert, José Miguel; Manin, Julien

doi:10.1007/s12239-012-0070-z

Cited by 9 publications

(11 citation statements)

References 28 publications

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“…The observed phase results shown in Figures 4 and 5 exhibit much stronger signal on one side of the spray, right and left respectively (note that the images are mirrored due to opposite locations of the cameras). This signal enhancement is not the effect of laser signal extinction as observed in single nozzle sprays [12,17,19] but results from the fact that the spray cloud observed here is formed by three jets. The light sheet crosses one jet emerging from the injector (right side of the LIF image, and left side of Mie image) while going between two other jets.…”

Section: Resultsmentioning

confidence: 52%

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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Section: Resultsmentioning

confidence: 52%

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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“…It is also possible to use a single camera to record the fluorescence and elasticlight-scattering images in sequence [27,[42][43][44][45][46][47][48][49]. This approach provides reliable SMD measurements where there is reasonable confidence that the flow or spray characteristics do not change with time, steady spray [43,44].…”

Section: Sequential Imaging Of Plif and Mie Signalsmentioning

confidence: 99%

“…This approach provides reliable SMD measurements where there is reasonable confidence that the flow or spray characteristics do not change with time, steady spray [43,44]. This approach is used in the literature, and it is observed that results are consistent with SMD measurements from Phase Doppler Interferometry (PDI) [43][44][45][46].…”

Section: Sequential Imaging Of Plif and Mie Signalsmentioning

confidence: 99%

Planar Drop-Sizing in Dense Fuel Sprays Using Advanced Laser Diagnostic Techniques

Kulkarni¹,

Deshmukh²

2020

Diesel and Gasoline Engines

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A reliable measurement of drop sizes and liquid fuel distribution in a spray is essential for best combustion efficiency and exhaust emission from I.C. engines. The droplet size and fuel distribution control air-fuel mixture formation and, hence, combustion characteristics. The chapter gives a concise summary of recent advances and developments in the LSD technique as a planar drop-sizing technique. The LSD technique relies on the principle that a ratio of planar laser-induced fluorescence (PLIF) and Mie signals is proportional to Sauter mean diameter (SMD). PLIF signal can also be used to determine the distribution of liquid in a spray. This makes LSD an attractive technique in dense spray characterization that can also provide liquid volume fraction distributions. A brief review of laser-based drop-sizing methods and working principle of LSD measurements are first discussed. Different approaches and limitations of the LSD technique are also summarized. Further, sources of error and ways to compensate these errors are explained in detail. Previous studies on LSD measurements in different fuel sprays of stationary combustion devices and I.C. engines are summarized. Finally, improvements in the LSD techniques are suggested, including structured laser illumination planar imaging (SLIPI) measurements, for reliable measurements in dense sprays.

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“…Based on the obtained imaging diesel spray form and distribution of droplets in the gas phase were determined. Pastor et al (2012) used this method to determine the SMD, but to enhance the fluorescence effect, indicator Rhodamine B was added to the fuel. The method is widely used by other researchers - Li et al (2011) investigated the characteristics of the swirl spray.…”

Section: Introductionmentioning

confidence: 99%

Comparative Studies of the Biodiesel Fuel Jet Development Dynamics in Common Rail and Conventional Design Fuel Systems

Kulmanakov

Lebedevas

Kulmanakov³

et al. 2019

Transport

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The results of comparative diesel and biodiesel (Rapeseed oil Methyl Ester (RME) and Rapeseed Oil (RO)) fuel jet structure studies by optical scanning method are presented. There is an interrelation between the dynamics of fuel jet development by the Common Rail (CR) with single-phase injection and Conventional Design System (CDS) and the parameters of mixture formation, which are typical for transferring the operation of the Diesel Engine (DE) from mineral diesel to RME and RO. The structure of the Diesel Fuel (DF) jet is significantly more heterogeneous by the size and number of droplets in CDS in comparison with CR. From the moment of the injection the presence of zones less saturated with fuel contributes to a relatively short induction period – 5° ca. compared to 11…12° ca. in the CR system. Using RME in the CR system in comparison with DF, increases the heterogeneity of the fuel jet, thereby causing a shorter (by 1…2° ca.) induction period in the whole investigated range of injection pressures of 60…160 MPa. The injection of a non-heated RO is accompanied by the shape and structure fluctuations of the fuel jet. RO heating to 65 °C stabilizes the structure of the jet and increases the share of less saturated zones. Promising way of use for the optical scanning method in the mathematical modelling of the DE working process is proposed.

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Evaluation of natural and tracer fluorescent emission methods for droplet size measurements in a diesel spray

Cited by 9 publications

References 28 publications

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

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

Planar Drop-Sizing in Dense Fuel Sprays Using Advanced Laser Diagnostic Techniques

Comparative Studies of the Biodiesel Fuel Jet Development Dynamics in Common Rail and Conventional Design Fuel Systems

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