On the Intact Core of Full-Cone Sprays

Chehroudi, B.; Chen, Shih‐Hsiung; Bracco, F. V.; Onuma, Yoshiaki

doi:10.4271/850126

Cited by 78 publications

(39 citation statements)

References 5 publications

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“…12(a) and (b) are the inverse of each other. The DLR data are at or below the lower bound of the Chehroudi et al (1985) model (i.e., solid curves in Fig. 12(b)) which was proposed based on the liquid spray data in various atomization regimes.…”

Section: Jet Decay 321 Visualization Of Jet Core Lengthmentioning

confidence: 99%

“…Also, according to Chehroudi et al (1985) the intact core length of the liquid sprays similar to the ones used in diesel engines is given by Cd j (ρ l /ρ g ) 1/2 where ρ l and ρ g are liquid injectant and chamber gas densities respectively, " d j " is an effective jet exit diameter and C is a constant between 3.3 to 11. This translates to an intact core length between 33 to 110 injector diameters for the chamber-to-injectant density ratio of 0.01 and between 16.5 to 55 diameters for the chamber-to-injectant density ratio of 0.04.…”

Section: Jet Decay 321 Visualization Of Jet Core Lengthmentioning

confidence: 99%

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Injection of Fluids Into Supercritical Environments

Oschwald

Smith

Branam

et al. 2006

Combustion Science and Technology

305

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Section: Jet Decay 321 Visualization Of Jet Core Lengthmentioning

confidence: 99%

Section: Jet Decay 321 Visualization Of Jet Core Lengthmentioning

confidence: 99%

Injection of Fluids Into Supercritical Environments

Oschwald

Smith

Branam

et al. 2006

Combustion Science and Technology

305

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“…Note that, according to Abramovich [19] the length of the potential core in isothermal uniform-density axisymmetric and two-dimensional jets are estimated to be about 16 to 18 injector diameters whereas for nonisothermal cold-into-hot jets it can reach up to about 50 injector diameters. Also, accoring to Chehroudi et al [20] the intact core of the liquid sprays similar to the ones used in diesel engines is C.d^/pg)" 2 where p, and p g are liquid injectant and chamber gas densities, respectively, d is the effective jet exit diameter and C is a constant between 3.3 to 11. This reflects to an intact core length of between 33 to 110 injector diameters for the chamber-toinjectant density ratio of 0.01 and 16.5 to 55 diameters for the chamber-to-injectant density ratio of 0.04.…”

Section: Jet Spreading Anglementioning

confidence: 99%

“…To separate effects of the compressibility, following Bogdanoff [26], Papamoschou and Roshko [1] define a convective velocity (U c ) and a convective Mach number (M =(U-U c )/a; a is speed of sound) to be more appropri ate ^^t he individual streams' Mach numbers in the mixing layer due to the coherent structures observed by Brown and Roshko [20]. It is shown that in a convective system there is a common stagnation saddle point for both streams (first proposed to be considered by Dimotakis).…”

Section: Papamoschou and Roshkomentioning

confidence: 99%

Initial growth rate and visual characteristics of a round jet into a sub- to supercritical environment of relevance to rocket, gas turbine, and diesel engines

Chehroudi

Talley

Coy

1999

37th Aerospace Sciences Meeting and Exhibit

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Public reporting burden lor this eolation of information is estimated to average 1 hour per respo-se n-udrg ~e . ~e ■-• revewng instructions, searching existing datasources gathering and maintaining the data needed, and completing and reviewing this collection of information Send ccmme-fs recarcna tr s ouroen estimate or any other aspect of this collection of information including suggestions for reducing this burden to Department of Defense. Washington Headquarters Se vices Directorate tor Info-mation AbstractThe combustion chamber temperature and pressure in many liquid rocket, gas {urbin|, and diesel engines are quite high and can reach above the critical point *¥ the injected fuels and/or oxidizers. A high pressure chamber is used to investigate and understand the nature of the interaction between the injected fluid and the environment under such conditions. Pure N 2 , He, and 0 2 fluids are injected. Several chamber media are selected including, N 2 , He, and mixtures of CO+N 2 . The effects of chamber pressure ranging from a subcritical (i.e.*elative pressure, P r = P/Pinjeoantcridca! 1) value|"at a supercritical chamber temperature (i.e.^ relative temperature T r = TAr injectam critical >1) are photographically observed and documented near the injector hole exit region using a CCD camera illuminated by a shortduration back-lit strobe light. At low subcritical chamber pressures, the jets exhibit surface irregularities that amplify downstream, lookjggintact, shiny, but wavy (sinuous) on the surface mimS evenwglly break up into irregularly-shaped small entities./^urther increase of chamber pressure causes formation of many small droplets on the surface of the jet ejecting away only within a narrow region below the critical pressure of the injected fluid similar to a second wind-induced liquid jet breakup regime. Raising the chamber pressure, transition into a full atomization regime is inhibited by rejghing near, but slightly lower than, ^"critical pressure «fthe injectant where both surface tension and heat of vaporization are sufficiently reduced. The jet appearance changes abruptly at this point and remains the same «ter resemb}£a?turbulent gas jet injection. In this region, and within the imaging resolution limitation, no droplets are seen forming and/or departing from the jet. The jet initial total divergence angle, indicating initial growth or spreading rate, is extracted from a large set of images and plotted along with ^"available data on liquid fuel injection in £ diesel engine environment, turbulent incompressible, supersonic, and variable-density jets and for incompressible but variable-density turbulent mixing layers, thus quantitatively strengthening the gas-jet like appearance. Considering this agreement, the inhibition of Tfc*-transition to atomization regime and its confirmation through the examined atomization criteria, and the visual lack of any drop; the relevancy of current injection models and some drop vaporization/combustion results under conditions where...

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“…Cheroudi et al [15] have estimated the nozzle diameter (d) normalized distance the liquid core survives primary atomization (lc) to be ⁄ = ( ⁄ ) 1 2 ⁄…”

Section: Introductionmentioning

confidence: 99%

An Optical Characterization of Atomization in Non-Evaporating Diesel Sprays

Lockett

Jeshani

Makri

et al. 2016

SAE Technical Paper Series

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High-speed planar laser Mie scattering and Laser Induced Fluorescence (PLIF) was employed for the determination of Sauter Mean Diameter (SMD) distribution in non-evaporating diesel sprays. The effect of rail pressure, distillation profile, and consequent fuel viscosity on the drop size distribution developing during primary and secondary atomization was investigated.Samples of conventional crude-oil derived middle-distillate diesel and light distillate kerosene were delivered into an optically accessible mini-sac injector, using a customized high-pressure common rail diesel fuel injection system. Two optical channels were employed to capture images of elastic Mie and inelastic LIF scattering simultaneously on a high-speed video camera at 10 kHz.Results are presented for sprays obtained at maximum needle lift during the injection. These reveal that the emergent sprays exhibit axial asymmetry and vorticity. An increase in the rail pressure was observed to lead to finer atomization, with larger droplets observable in the neighbourhood of the central axis of the spray, decreasing with radius towards the spray boundaries. Finally, the light kerosene was observed to produce smaller droplets (as measured by Sauter mean diameter), relative to the conventional diesel, suggesting a correlation between distillation profile and viscosity, and mean spray droplet size.

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On the Intact Core of Full-Cone Sprays

Cited by 78 publications

References 5 publications

Injection of Fluids Into Supercritical Environments

Injection of Fluids Into Supercritical Environments

Initial growth rate and visual characteristics of a round jet into a sub- to supercritical environment of relevance to rocket, gas turbine, and diesel engines

An Optical Characterization of Atomization in Non-Evaporating Diesel Sprays

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