Various forms of drop fractionation in shock waves and their special characteristics

Gel’fand, B. E.; Gubin, S. A.; Kogarko, S. M.

doi:10.1007/bf00827632

Cited by 25 publications

(17 citation statements)

References 7 publications

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“…As argued in the introduction, most of these experiments were performed in conditions such that the density contrast was typically larger than 500 and the viscosity contrast r v typically in the 100 − 1000 range. In this context, the selection of a particular deformation mode was found to be determined by the Weber number [4,13,15,21,31,36,39], with additional influence of the Ohnesorge number whenever the latter exceeds 0.1. At low Ohnesorge numbers (i.e.…”

Section: A Deformation At High Density Contrasts ; Comparison With Bmentioning

confidence: 99%

Density contrast matters for drop fragmentation thresholds at low Ohnesorge number

Marcotte

Zaleski

2019

Phys. Rev. Fluids

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We address numerically the deformation and fragmentation dynamics of a single liquid drop subject to impulsive acceleration by a unidirectional gas stream. The density ratio between the liquid and gaseous phases is varied in the 10 − 2000 range and comparisons are made with recent drop breakup experiments. We show for low Ohnesorge numbers that the liquid-gas density contrast significantly modifies the critical Weber number for the transition between bursting and stripping fragmentation regimes on the one hand, for drop fragmentation on the other hand. We suggest a simple theoretical argument to predict the transitional Weber number as a function of the density contrast and show that the stabilising influence of small contrasts can be explained by the effect of inertia in the nonlinear coupling between drop stretching and centroid acceleration.

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Section: A Deformation At High Density Contrasts ; Comparison With Bmentioning

confidence: 99%

Density contrast matters for drop fragmentation thresholds at low Ohnesorge number

Marcotte

Zaleski

2019

Phys. Rev. Fluids

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“…The following discussion of past research on secondary breakup is brief, see Hsiang & Faeth (1992), Wierzba & Takayama (1987), Giffen & Muraszew (1953), Hinze (1955), Krzeczkowski (1980), and references cited therein, for more complete reviews. High-speed photography has been used to identify secondary breakup regimes for shock-wave disturbances (Hinze 1955;Hanson et al 1963;Reinecke & McKay 1969;Reinecke & Waldman 1970;Ranger & Nicholls 1969;Gel'fand et al 1974;Krzeczkowski 1980;Wierzba & Takayama 1988). Bag breakup is observed at the onset of secondary breakup.…”

Section: Introductionmentioning

confidence: 99%

“…In comparison to other breakup properties, available information about the outcome of secondary breakup is rather limited. Nevertheless, measurements of drop size distributions for shock-wave disturbances at Pu/Pc > 500 have been reported by Gel'fand et al (1974) and Hsiang & Faeth (1992). Gel'fand et al (1974) observed a bimodal drop size distribution for bag breakup, and suggested that the small drops largely resulted from breakup of the bag and the large drops from breakup of the liquid ring at the base of the bag.…”

mentioning

confidence: 99%

“…Nevertheless, measurements of drop size distributions for shock-wave disturbances at Pu/Pc > 500 have been reported by Gel'fand et al (1974) and Hsiang & Faeth (1992). Gel'fand et al (1974) observed a bimodal drop size distribution for bag breakup, and suggested that the small drops largely resulted from breakup of the bag and the large drops from breakup of the liquid ring at the base of the bag. However, the later measurements of Hsiang & Faeth (1992) did not confirm this finding.…”

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confidence: 99%

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Drop properties after secondary breakup

Hsiang

Faeth

1993

International Journal of Multiphase Flow

169

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Drop properties during and after secondary breakup in the bag, multimode and shear breakup regimes were observed for shock-wave-initiated disturbances in air at normal temperature and pressure. Test liquids included water, n-heptane, ethyl alcohol and glycerol mixtures to yield Weber numbers of 15-600, Ohnesorge numbers of 0.0025-0.039, liquid/gas density ratios of 579-985 and Reynolds numbers of 1060-15080. Measurements included pulsed shadowgraphy and double-pulsed holography to find drop sizes and velocities after breakup. Drop size distributions after breakup satisfied Simmons' universal root normal distribution in all three breakup regimes, after removing the core (or drop-forming) drop from the drop population for shear breakup. The size and velocity of the core drop after shear breakup was correlated separately based on the observation that the end of drop stripping corresponded to a constant Ertvrs number. The relative velocities of the drop liquid were significantly reduced during secondary breakup, due both to the large drag coet~cients caused by drop deformation and the reduced relaxation times of smaller drops. These effects were correlated successfully based on a simplified phenomenological theory.

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“…This is usually reconciled by invoking shattering or other break-up mechanisms. Theoretical studies that include such effects have also been conducted [7]. They concluded that the stripping mechanism (shearing of the outer layer of liquid from droplets due to the high speed flow) is beneficial to droplet breakup and stripping.…”

Section: B Effect Of Velocitymentioning

confidence: 99%

Numerical Simulation of Injection and Mixing on New Power Systems of Liquid-Fueled Pulse Detonation Engines

Guo

2010

2010 Asia-Pacific Power and Energy Engineering Conference

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Pulse detonation engines (PDE) have received significant attention in recent years due to their potential advantages over conventional propulsion systems, including high thermodynamics cycle efficiency,high thrust/weight and specific impulse. The fuelair injection and mixing is one of important research issues. To optimize the fuel-air injection and mixing, a three-dimensional computation model of PDE is established. The mixing process for twin-fluid air-assisted atomizers for air supplied with tangential inlet and axial inlet is numerically analyzed by using the software Fluent as platform to solve the three-dimensional Navier-Stokes equations, and the relationship beween drop size and air mass and gasoline/air ratio is arrived at. Numeric simulations results of the process with different inlets show that well mixing but bad concentration distribution occurs with tangential inlet especially along the central axis which makes PDE difficult to work in high frequency, while bad mixing but well-proportioned distribution occurs through axial inlet. And with the same gasoline/air ratio initialized, as the air mass increases, the droplet size decreases, and the result is also correct for the case in which the gasoline/air ratio decreases with the same air mass initialized. These results are found to be in good agreement with the limited experimental data that is currently available. The conclusions are available for the design of liquid-fueled PDE.

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Various forms of drop fractionation in shock waves and their special characteristics

Cited by 25 publications

References 7 publications

Density contrast matters for drop fragmentation thresholds at low Ohnesorge number

Density contrast matters for drop fragmentation thresholds at low Ohnesorge number

Drop properties after secondary breakup

Numerical Simulation of Injection and Mixing on New Power Systems of Liquid-Fueled Pulse Detonation Engines

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