Morphological Classification of Disintegration of Round Liquid Jets in a Coaxial Air Stream

Chigier, Norman; Farago, Zoltan

doi:10.1615/atomizspr.v2.i2.50

Cited by 207 publications

(46 citation statements)

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“…Thus, it has been recognized that atomization in such systems takes place in two stages, in the near field an initial or primary break up dominated by surface tension and a secondary one where a small liquid sheet and large droplets are broken down into a population of small droplets by viscous forces generated in the mean and turbulent motions of the turbulent air spray, see Lasheras et al (1998) and Varga et al (2003). For co-axial jet, the primary break up involves jet disintegration via membrane type (Farago and Chigier 1992) and/or annular sheets inclined at an angle to the flow before disintegration. The findings on the breakup processes in the near field of the liquid medium have been the result of flow visualization using fast photography.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…Previous studies focused on the effects of different configurations. Twin fluid atomization in which the gas kinetic energy is used to assist liquid jet fragmentation is probably the most widely used and a generic widely studied form is liquid jets in coaxial air streams (Chigier and Farago 1992;Hardalupas and Whitelaw 1996 ;Engelbert et al1995;Lasheras et al1998) or a liquid sheet between two air sheets (Mansour and Chigier 1990), or internal mixing atomizers as studied by Zaremba et al (2017).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Droplet size and velocity characteristics of water-air impinging jet atomizer

Xia

Khezzar

Alshehhi

et al. 2017

International Journal of Multiphase Flow

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Section: Accepted Manuscriptmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Droplet size and velocity characteristics of water-air impinging jet atomizer

Xia

Khezzar

Alshehhi

et al. 2017

International Journal of Multiphase Flow

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“…The successful atomization of the liquid jet into small droplets is essential for combustion, as it promotes evaporation and thorough mixing of the liquid fuel vapour with the surrounding gas. For this reason, the process of disintegration of the liquid jet by the high speed air co-flow is of great interest to combustion research and has been studied by a large number of researchers, including [1][2][3][4][5][6][7]. The main visualisation method of the liquid jet in these investigations is shadowgraphy.…”

Section: Introductionmentioning

confidence: 99%

Structure of the Continuous Liquid Jet Core during Coaxial Air-Blast Atomisation

Charalampous

Hardalupas

Taylor

2009

International Journal of Spray and Combustion Dynamics

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This paper investigates the structure of the continuous liquid jet of a coaxial air-blast atomiser over a range of Weber numbers 60-1040, Reynolds numbers of liquid jet 5400-21700 and air to liquid momentum ratios of the two streams of 1.7-335. A novel optical technique, based on internal illumination of the liquid jet through the jet nozzle by a laser pulse, which excites a fluorescing dye introduced in the atomizing liquid, was used to obtain instantaneous measurements of the breakup length and the three dimensional location of the liquid core of the continuous liquid jet. The latter was achieved by simultaneously imaging the liquid jet from two directions normal to each other. Such measurements are usually prevented by droplets surrounding the liquid jet at the dense spray near the nozzle exit. The measurements showed that the break-up length of the liquid jet scaled well with the air to liquid momentum ratio. The standard deviation of the temporal fluctuations of the break-up length was around 10% of the mean breakup length for each considered flow condition. The instantaneous jet surface does not develop axi-symmetric wave structures but the time-averaged liquid jet is axi-symmetric around the nozzle axis, while the maximum deflection of the liquid jet occurs close to the breaking point.

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“…Due to the unique combination of fluids and conditions, surface tension values are not available to the authors' knowledge. Based on the visualizations shown later and the results of Farago and Chigier 25 , the current experiments appear to be in the fiber-type regime and the Weber number is expected to be approximately 100 or higher.…”

Section: American Institute Of Aeronautics and Astronauticsmentioning

confidence: 60%

Receptivity of a Cryogenic Coaxial Gas-Liquid Jet to Acoustic Disturbances

Wegener¹,

Forliti²,

Leyva³

et al. 2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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An experimental study has been conducted at the Air Force Research Laboratory atEdwards Air Force Base to explore the receptivity of cryogenic coaxial jet flows to transverse acoustic disturbances. The shear coaxial jet flow employed liquid nitrogen in the inner jet and cooled helium in the outer annular jet to represent the nominal fluid dynamical conditions of an oxygen/hydrogen liquid rocket engine injector. The injector flow is submerged in a chamber that experiences a monotonic transverse acoustic resonance characteristic of a rocket chamber in the presence of combustion instability. The coaxial jet is exposed to a variety of acoustic conditions including different frequencies, amplitudes, and locations within the resonant mode shape. High-speed back-lit images were captured to record the behavior of the natural (unforced) and forced coaxial jets. Proper orthogonal decomposition and spectral analysis were used to extract natural and forced modes. Convective modes are extracted, and a new Strouhal number is used to characterize the dominant natural convective mode that is analogous to the preferred mode in free jets. The threshold of receptivity was found for a number of different injector flows and acoustic forcing conditions. The results indicate that the dimensionless frequency plays an important role, and there exists a finite forcing amplitude at which the threshold of receptivity occurs. The receptivity threshold and post receptivity response provides useful insight on the suitability of a given injector design for specific rocket combustion chamber conditions. NomenclatureAR = outer-to-inner area ratio c = speed of sound D = diameter f = frequency F = normalized frequency J = outer-to-inner momentum flux ratio m = mass p = pressure p' = pressure fluctuation amplitude St = Strouhal number t = inner jet post thickness U = mean velocity u' = velocity fluctuation amplitude ρ = density Subscripts c = convection meas = measured Dimotakis = the Dimotakis 1 convection velocity model 1 = inner jet fluid 2 = outer jet fluid

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Morphological Classification of Disintegration of Round Liquid Jets in a Coaxial Air Stream

Cited by 207 publications

References 0 publications

Droplet size and velocity characteristics of water-air impinging jet atomizer

Droplet size and velocity characteristics of water-air impinging jet atomizer

Structure of the Continuous Liquid Jet Core during Coaxial Air-Blast Atomisation

Receptivity of a Cryogenic Coaxial Gas-Liquid Jet to Acoustic Disturbances

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