scholarly journals Planar droplet sizing for studying the influence of ethanol admixture on the spray structure of gasoline sprays

2020 ◽  
Vol 61 (10) ◽  
Author(s):  
Matthias Koegl ◽  
Yogeshwar Nath Mishra ◽  
Kevin Baderschneider ◽  
Chris Conrad ◽  
Bastian Lehnert ◽  
...  
Keyword(s):  
Direct Injection ◽  
Mie Scattering ◽  
Gasoline Direct Injection ◽  
Spray Structure ◽  
Start Of Injection ◽  
Droplet Sizes ◽  
Cyclic Variations ◽  
Direct Injection Spark Ignition ◽  
Surrogate Fuel ◽  
Fuel Effects

Abstract A novel planar droplet sizing (PDS) technique based on laser-induced fluorescence (LIF) and Mie-scattering is utilized for the characterization of the spray structure under gasoline direct-injection spark-ignition (DISI) conditions. Fuel effects on the spray structure and cyclic variations are studied for a gasoline surrogate fuel (Toliso, consisting of 65 vol.% isooctane and 35 vol.% toluene) and the gasoline-ethanol blend E20 (20 vol.% ethanol admixture). Sauter mean diameter (SMD) results are compared with those from phase-Doppler anemometry (PDA) measurements showing good agreement especially at early points in time (up to 1.2 ms after start of injection). The liquid spray propagation and SMD are very similar for both fuels indicating similar atomization behavior. Both investigated fuels show comparable cyclic variations of the spray shape. A larger width and slightly larger droplet sizes are observed for the E20 spray when stronger evaporation occurs (at 2 ms). At these later points in time, the PDS-measured droplet sizes differ from the PDA-results. Here the limitation of the PDS-technique becomes obvious as a partial evaporation of the droplets may lead to large systematic errors. A numerical simulation of single droplets is provided for clarification of issues of droplet evaporation in PDS. Graphic abstract

scholarly journals Impingement characteristics of an early injection gasoline direct injection engine: A numerical study

2016 ◽  
Vol 18 (4) ◽  
pp. 378-393 ◽  
Author(s):  
Nicholas J Beavis ◽  
Salah S Ibrahim ◽  
Weeratunge Malalasekera
Keyword(s):  
Liquid Film ◽  
Film Formation ◽  
Direct Injection ◽  
Cylinder Liner ◽  
Gasoline Direct Injection ◽  
Intake Valve ◽  
Direct Injection Engine ◽  
Gasoline Direct Injection Engine ◽  
Start Of Injection ◽  
Early Injection

This article describes the use of a Lagrangian discrete droplet model to evaluate the liquid fuel impingement characteristics on the internal surfaces of an early injection gasoline direct injection engine. This study focuses on fuel impingement on the intake valve and cylinder liner between start of injection and 20° after start of injection using both a single- and a multi-component fuels. The single-component fuel used was iso-octane and the multi-component fuel contained fractions of iso-pentane, iso-octane and n-decane to represent the light, medium and heavy fuel fractions of gasoline, respectively. A detailed description of the impingement and liquid film modelling approach is also provided. Fuel properties, wall surface temperature and droplet Weber number and Laplace number were used to quantify the impingement regime for different fuel fractions and correlated well with the predicted onset of liquid film formation. Evidence of film stripping was seen from the liquid film formed on the side of the intake valve head with subsequent ejected droplets being a likely source of unburned hydrocarbons and particulate matter emissions. Differences in impingement location and subsequent location of liquid film formation were also observed between single- and multi-component fuels. A qualitative comparison with experimental cylinder liner impingement data showed the model to well predict the timing and positioning of the liner fuel impingement.

Transient Fuel Spray Structure for Simulated Injection Strategies in Direct Injection, Spark Ignition Engines

2001 ◽  
Author(s):  
P. A. Hutchison ◽  
R. B. Wicker
Keyword(s):  
Flow Visualization ◽  
Cross Section ◽  
Direct Injection ◽  
Fuel Spray ◽  
Spark Ignition Engines ◽  
Rail Pressure ◽  
Fuel Injectors ◽  
Spray Structure ◽  
Image Velocimetry ◽  
Direct Injection Spark Ignition

Abstract For two production DISI fuel injectors, flow visualization and particle image velocimetry (PIV) were utilized to illustrate the effect of fuel rail pressure and in-cylinder density (using in-cylinder pressure) on instantaneous fuel spray structure. Studies were performed within a non-motored research cylinder for two fuel rail pressures (3 MPa and 5 MPa) and two in-cylinder pressures (2 atm and 6 atm). Instantaneous flow visualization demonstrated the effects of changes in fuel rail pressure and in-cylinder density on transient spray structure. Increased fuel rail pressure resulted in increased narrowing of the spray cross-section and increased spray penetration distance. Increased in-cylinder density produced sprays with increased narrowing of the spray cross-section and shorter penetration distances. Spray velocities were shown to increase with increased fuel rail pressure and decrease with increased in-cylinder density.

scholarly journals Analysis of the LIF/Mie Ratio from Individual Droplets for Planar Droplet Sizing: Application to Gasoline Fuels and Their Mixtures with Ethanol

2019 ◽  
Vol 9 (22) ◽  
pp. 4900 ◽  
Author(s):  
Matthias Koegl ◽  
Kevin Baderschneider ◽  
Florian J. Bauer ◽  
Bernhard Hofbeck ◽  
Edouard Berrocal ◽  
...  
Keyword(s):  
Direct Injection ◽  
Nile Red ◽  
Mie Scattering ◽  
Droplet Generator ◽  
Sauter Mean Diameter ◽  
Fuel Droplets ◽  
Calibration Curves ◽  
Fluorescence Dye ◽  
Direct Injection Spark Ignition

In this work, the possibility of using planar droplet sizing (PDS) based on laser-induced fluorescence (LIF) and Mie scattering was investigated within the framework of measuring the droplet Sauter mean diameter (SMD) of direct-injection spark-ignition (DISI) spray systems. For this purpose, LIF and Mie signals of monodisperse fuel droplets produced by a droplet generator were studied at engine relevant diameters (20–50 µm). The surrogate gasoline fuel Toliso (consisting of 65 vol. % isooctane, 35 vol. % toluene) and the biofuel blend E20 (consisting of 80 vol. % Toliso, 20 vol. % ethanol) were used and which were doped with the fluorescence dye “nile red”. The effects of ethanol admixture, dye concentration, laser power, and temperature variation on the LIF/Mie ratio were studied simultaneously at both macroscopic and microscopic scale. The deduced calibration curves of the LIF and Mie signals of both fuels showed volumetric and surface dependent behaviors, respectively, in accordance with the assumptions in the literature. The existence of glare points and morphology-dependent resonances (MDRs) lead to slightly higher LIF and Mie exponents of E20 in comparison to Toliso. In principle, these calibration curves enable the determination of the SMD from LIF/Mie ratio images of transient fuel sprays.

scholarly journals Time-dependent line-of-sight extinction tomography for multi-hole GDI injectors

2016 ◽  
Vol 9 (3) ◽  
pp. 199-211 ◽  
Author(s):  
Yudaya Sivathanu ◽  
Jongmook Lim ◽  
Varun Kulkarni
Keyword(s):  
Ambient Temperature ◽  
Direct Injection ◽  
Injection Pressure ◽  
Gasoline Direct Injection ◽  
Time Dependent ◽  
Line Of Sight ◽  
Experimental Measurements ◽  
Fuel Injectors ◽  
Factors Affecting ◽  
Spray Structure

Finely atomized sprays from multi-hole gasoline direct injection (GDI) fuel injectors make them an ideal choice for automobile applications. A knowledge of the factors affecting the performance of these injectors is hence important. In the study presented here, we employ statistical extinction tomography to examine the transient characteristics of two GDI fuel injectors with five and six holes. Two axial locations, 25 mm and 35 mm from the injector exit, are chosen for experimental measurements, and the dependence of injection pressure and ambient temperature on plume locations and angles is examined from these measurements. A pressure chamber with opposing windows is used which permits the nozzle to be rotated 12 times (30° each rotation) to obtain information on the complete spray structure. Additionally, the plume centroid locations are measured and compared with those obtained with a mechanical patternator. The centroid locations from the two instruments compare favorably.

An experimental study of the spray from an air-assisted direct fuel injector

2008 ◽  
Vol 222 (10) ◽  
pp. 1883-1894 ◽  
Author(s):  
S H Jin ◽  
M Brear ◽  
H Watson ◽  
S Brewster
Keyword(s):  
Laser Sheet ◽  
Direct Injection ◽  
Ambient Air ◽  
Mie Scattering ◽  
Fuel Injector ◽  
Strongly Coupled ◽  
Transient Behaviour ◽  
Constant Volume Chamber ◽  
Planar Images ◽  
Direct Injection Spark Ignition

The transient behaviour of the fuel spray from an air-assisted direct-injection spark ignition (DISI) fuel injector has been investigated experimentally in a constant-volume chamber. As the chamber and injection pressures were varied, ensemble-averaged planar images of the laser-induced fluorescence (LIF) and Mie scattering from the spray were obtained to measure the Sauter mean diameter (SMD) using the laser sheet drop-sizing (LSD) technique. The root mean square (r.m.s.) SMD was also calculated by combination of the r.m.s. LIF and r.m.s. Mie scattering signals. The effect of the injection and chamber pressures and the ambient air density on the SMD, spray tip penetration, and dispersion of the air-assisted fuel injector are determined. In keeping with recent numerical studies by the group, vortex structures appear to be shed from the injector tip in back-illuminated images, indicating that the air and liquid motion are strongly coupled. These results also show that the spray penetration and SMD vary significantly with injection and chamber density, and scalings of the spray's overall SMD and penetration are proposed that achieve reasonable clustering in the experimental results.

Fuel Effects on Knock in a Highly Boosted Direct Injection Spark Ignition Engine

2012 ◽  
Vol 5 (3) ◽  
pp. 1048-1065 ◽  
Author(s):  
Amer Amer ◽  
Hassan Babiker ◽  
Junseok Chang ◽  
Gautam Kalghatgi ◽  
Philipp Adomeit ◽  
...  
Keyword(s):  
Direct Injection ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Direct Injection Spark Ignition ◽  
Fuel Effects

In-cylinder air flow and cyclic variations in gasoline direct injection engines

MTZ worldwide ◽  
2005 ◽  
Vol 66 (3) ◽  
pp. 15-17
Author(s):  
Jürgen Fischer ◽  
Maurice Kettner ◽  
Ulrich Spicher ◽  
Amin Velji
Keyword(s):  
Direct Injection ◽  
Air Flow ◽  
Gasoline Direct Injection ◽  
Direct Injection Engines ◽  
Cyclic Variations

scholarly journals Analysis of ethanol and butanol direct-injection spark-ignition sprays using two-phase structured laser illumination planar imaging droplet sizing

2018 ◽  
Vol 11 ◽  
pp. 175682771877249 ◽  
Author(s):  
Matthias Koegl ◽  
Yogeshwar Nath Mishra ◽  
Michael Storch ◽  
Chris Conrad ◽  
Edouard Berrocal ◽  
...  
Keyword(s):  
Direct Injection ◽  
Spark Ignition ◽  
Mie Scattering ◽  
Laser Induced Fluorescence ◽  
Planar Imaging ◽  
Sauter Mean Diameter ◽  
Two Phase ◽  
Laser Illumination ◽  
Mean Diameter ◽  
Direct Injection Spark Ignition

This paper reports on the spray structure of the biofuels, ethanol, and butanol generated by a multihole direct-injection spark-ignition injector, which is studied in a constant volume chamber. The spray shape and structure are analyzed using two-phase structured laser illumination planar imaging where both laser-induced fluorescence and Mie-scattering light are recorded simultaneously for the extraction of instantaneous laser-induced fluorescence/Mie-scattering ratio images. Quantitative planar measurements of the droplet Sauter mean diameter are conducted, using calibration data from phase-Doppler anemometry. The resulting Sauter mean diameters are presented for ethanol and butanol at various fuel temperatures at different times after the start of injection. It is found that an increase in fuel temperature results in a faster atomization and higher evaporation rate, which leads to reduced spray tip penetration and smaller droplet Sauter mean diameter. At equivalent conditions, butanol consistently showed larger spray tip penetration in comparison to ethanol. This behavior is due to the higher surface tension and viscosity of butanol resulting in the formation of larger droplets and larger Sauter mean diameters in the whole spray region. Finally, the butanol injection also shows larger cyclic variations in the spray shape from injection to injection which is explained by the internal nozzle flow that is influenced by larger fuel viscosity as well. The Sauter mean diameter distribution is also compared to phase-Doppler anemometry data showing good agreement and an uncertainty analysis of the structured laser illumination planar imaging-laser-induced fluorescence/Mie-scattering technique for planar droplet sizing in direct-injection spark-ignition sprays is presented.

scholarly journals Light sheet fluorescence microscopic imaging for high-resolution visualization of spray dynamics

2017 ◽  
Vol 10 (1) ◽  
pp. 86-98 ◽  
Author(s):  
Edouard Berrocal ◽  
Elias Kristensson ◽  
Lars Zigan
Keyword(s):  
Near Field ◽  
Direct Injection ◽  
Light Sheet ◽  
Mie Scattering ◽  
Depth Of Field ◽  
Microscopic Imaging ◽  
Swirl Atomizer ◽  
Direct Injection Spark Ignition ◽  
Dynamics Models ◽  
Pressure Swirl

In this study, the use of light sheet fluorescence microscopic imaging is demonstrated for viewing the dynamic of atomizing sprays with high contrast and resolution. The technique presents several advantages. First, liquid fluorescence gives a more faithful representation of the structure of liquid bodies, droplets, and ligaments than Mie scattering does. The reason for this is that the signal is emitted by the fluorescing dye molecules inside the liquid itself and not generated at the air–liquid interfaces. Second, despite the short depth of field (∼200 µm) obtained when using the long range microscope, the contribution of out-of-focus light is much smaller on a light sheet configuration than for line-of-sight detection, thus providing more clearly sectioned images. Finally, by positioning the light sheet on the spray periphery, toward the camera objective, the effects due to multiple light scattering phenomena can be reduced to some extent. All these features provide, for many spray situations, good fidelity images of the liquid fluid, allowing the extraction of the velocity vectors at the liquid boundaries. Here, double frame images were recorded with a sCMOS camera with a time delay of 5 µs between exposures. A typical pressure-swirl atomizer is used producing a water hollow-cone spray, which was imaged in the near-nozzle region and further downstream for injection pressures between 20 bar and 100 bar. Furthermore, near-nozzle spray shape visualization of a direct-injection spark ignition injector was conducted, describing the disintegration of the liquid fuel and droplet formation. Such data are important for the validation of computational fluid dynamics models simulating liquid breakups in the near-field spray region.

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