Fuel concentration in isothermal Diesel sprays through structured planar laser imaging measurements

Payri, Raúl; Marti, Paula; Manin, Julien

doi:10.1016/j.ijheatfluidflow.2011.12.007

Cited by 6 publications

(12 citation statements)

References 31 publications

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“…In the setup used here the instantaneous LIF/Mie ratio is available only for conventional illumination since SLIPI used here requires three images obtained for different modulation phases of the structured light sheet. Interesting option for instantaneous imaging is two-pulse SLIPI based only on two phases as discussed by Payri et al [21] and Kristensson et al [22]. This approach however requires a dual cavity laser.…”

Section: Discussionmentioning

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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Section: Discussionmentioning

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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“…The governing equations (18), (20) were solved by Schlichting [24] for the single phase axisymmetric jet. A solution for the fuel volumetric fraction can then be obtained by using the equation of conservation of mass for the fuel phase (equation (19)).…”

Section: Solution For Steady State Two-phase Laminar Jetmentioning

confidence: 99%

“…Equations (18), (20) can be solved by defining a stream function Ψ similarly to the case of the single-phase laminar jet [24], where: Similarly to the single phase jet, the stream function will be assumed to have the following functional form: (26) where η =r / x and F is a function to be determined. Substituting the velocity components into equation 20with expressions derived from equations (25), (26), an ordinary differential equation for F is obtained: (27) The general solution of equation 27which satisfies the necessary boundary conditions is [24]: (28) where ξ = γη and γ is a constant to be determined below.…”

Section: Solution For Steady State Two-phase Laminar Jetmentioning

confidence: 99%

“…Experimental correlations also exist for the radial distributions of mixture velocity and fuel concentration. Commonly [14], [18] a Gaussian profile is assumed for both the velocity and fuel concentration: Where x, r are the axial and radial coordinates within the jet, Sc is the droplets' Schmidt number (see definition below) and a constant λ was determined experimentally.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

An Analytical Model of a Two-Phase Jet with Application to Fuel Sprays in Internal Combustion Engines

Tenenbaum¹,

Shapiro²,

Tartakovsky³

2014

SAE Int. J. Engines

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The paper presents an analytical two-dimensional model of two-phase turbulent jets with focus on fuel sprays in internal combustion engines. The developed model allows prediction of the fuel spray parameters including local fuel concentration and mixture velocity. The model proposed in this paper is based on the single-phase steady-state laminar axisymmetric jet flow field solution by Schlichting. This solution is amended to include transport of the discontinuous fuel phase in a stagnant air in the limit of a dilute fuel concentration. This two-phase jet flow model admits a closed form analytical solution for the fuel concentration distribution. This solution is then applied to turbulent jet flow as per the approach described by Schlichting and in other studies, and used to predict point-wise properties of fuel sprays in internal combustion engines. The results of model simulations are compared with the available experimental data. It was found that the analytical model predicts satisfactorily spray properties without additional assumptions or fitting coefficient. The advantage of the developed model is in its simplicity and rigor in comparison with empirical and numerical models.

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“…Internal flow studies deal with the influence of the injector geometry on the flow pattern [1], the cavitation phenomena [2], the needle lift [3] and eccentricity and other manufacturing issues relevance, etc. ; and external flow studies deal with fuel break-up [4,5], atomization and fuel-air mixing processes [6]. This division is made because of the different flow nature: in the internal part the flow is continuous, mono-phase liquid (or multi-phase if cavitation is considered); and in the external part far from the injector exit the flow is dispersed multi-phase.…”

Section: Introductionmentioning

confidence: 99%

Verification of a new CFD compressible segregated and multi-phase solver with different flux updates-equations sequences

Payri

Ruíz

Martí-Aldaraví

2015

Applied Mathematical Modelling

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Elsevier Payri, R.; Ruiz Rosales, S.; Gimeno, J.; Marti-Aldaravi, P. (2015) AbstractA new solver capable of calculating liquid and/or gas problems has been developed, verified and validated. Compressible solvers in Computational Fluid Dynamics use both mass flux and volumetric fluxes through the cell surface to calculate derivative terms. These fluxes depend on density and velocity fields, therefore the stability of the solver is affected by "how" and "where" density and velocity are calculated or updated. In addition to verification and validation, this paper deals with how different flux updates -equations sequences change the computational solution, reaching the conclusion that for mono-phase solvers no extra-updates should be used in order to minimize computational cost, but for multi-phase solvers with high density gradients an extra-update should be implemented to improve the stability of the solver.

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Fuel concentration in isothermal Diesel sprays through structured planar laser imaging measurements

Cited by 6 publications

References 31 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

An Analytical Model of a Two-Phase Jet with Application to Fuel Sprays in Internal Combustion Engines

Verification of a new CFD compressible segregated and multi-phase solver with different flux updates-equations sequences

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