Visualization and measurement of jet breakup behavior using LIF

Saito, Shigemi; Abe, Yutaka; Koyama, Kazuya

doi:10.1299/transjsme.15-00395

Cited by 5 publications

(7 citation statements)

References 30 publications

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“…This breakup mode has been called wavy [5,10], screw symmetric or screwlike [13], bending [9], and sinuous [14][15][16][17], which is what we call it in this study. With even higher aerodynamic forces, short-wavelength, unstable waves grow on the jet surface breaking off as small droplets at the periphery and decreasing the jet diameter until the breakup reaches the axis [18,19]. This forms a conical spray of droplets with diameters much smaller than the jet diameter as shown in Fig.…”

Section: Introductionmentioning

confidence: 94%

Jet breakup in superfluid and normal liquid He4

et al. 2020

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Past studies have shown that liquid jet breakup behavior can be classified into five regimes: Rayleigh, first wind, sinuous, second wind, and atomization. By experimentally examining the breakup of superfluid and normal liquid 4 He in an atmosphere of its own vapor, we investigate the evolution of the jet behavior over a large range of the traditional three-dimensional parameter space of the Ohnesorge number [Oh l ∼ O(10 −5-10 −2)], Reynolds number [Re l ∼ O(10 2-10 6)], and gas-liquid density ratio [ρ g /ρ l ∼ O(10 −4-1)]. Using dimensional analysis we find that the transition from Rayleigh to first-wind breakup occurs at a constant liquid Weber number, and that the transitions from first wind to sinuous, and sinuous to second wind occur at constant gas Weber numbers. The proposed transitions, which differ from some previous studies, are well supported by our new experimental data that extend over all three dimensions of the parameter space. We do not observe any obvious effects of superfluidity on the breakup behavior. In addition, we examine the breakup length and comment on the transition of a liquid jet to a gaseous jet as the temperature passes through the critical point.

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Section: Introductionmentioning

confidence: 94%

Jet breakup in superfluid and normal liquid He4

et al. 2020

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“…The measured jet breakup length L scaled on the nozzle diameter Dj0 is plotted in Fig. 4 with the corresponding snapshots (Saito et al, 2015b). Note that the latter measurement results were processed based on vertical-plane images of the jet flow, and suggest that the Weber number dependence of the breakup length is no longer significant.…”

Section: Typical Breakup Regimes and Breakup-length Curvementioning

confidence: 99%

“…Liquid-liquid jet dynamics occur in fields such as chemical engineering (Das, 1997;Kitamura et al, 1982;Meister and Scheele, 1969a, 1969b, Takahashi and Kitamura, 1972, 1971) and ocean engineering (Riestenberg et al, 2004;Tang and Masutani, 2003). Experiments using a characteristic of liquid-liquid systems known as refractive index matching have also been reported to further understand jet breakup dynamics (Longmire et al, 2001;Milosevic and Longmire, 2002;S. Saito et al, 2014b;Saito et al, 2015b).…”

Section: Introductionmentioning

confidence: 99%

“…Experiments using a characteristic of liquid-liquid systems known as refractive index matching have also been reported to further understand jet breakup dynamics (Longmire et al, 2001;Milosevic and Longmire, 2002;S. Saito et al, 2014b;Saito et al, 2015b). Takahashi and Kitamura (1971) et al (2004) injected water into liquid CO2 and classified the data into three regimes similar to those of Ohnesorge (1936).…”

Section: Introductionmentioning

confidence: 99%

“…Jet breakup length versus ambient Weber number. Open circles (○) represent data obtained via planar LIF (laserinduced fluorescence) using the index-matching technique(Saito et al, 2015b). The three images on the right are of the vertical plane of the jet illuminated by a laser sheet.…”

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confidence: 99%

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Flow transition criteria of a liquid jet into a liquid pool

Saito

Abe

Koyama

2017

Nuclear Engineering and Design

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To better understand the fundamental interactions between melt jet and coolant during a coredisruptive accident at a sodium-cooled fast reactor, the jet breakup and droplet formation in immiscible liquid-liquid systems were studied experimentally. Experiments using two different pairs of test fluids were carried out at isothermal conditions. The observed jet breakup behavior was classified into characteristic regimes based on the classical Ohnesorge classification in liquid-gas systems. The variation in breakup length obtained in the present liquid-liquid system was similar to that in a liquidgas system. The droplet size distribution in each breakup regime was analyzed using image processing and droplet formation via pinch-off, satellite formation, and entrainment was observed. The measured droplet size was compared with those available from melt jet experiments. Based on the observation and analysis results, the breakup regimes were organized on a dimensionless operating diagram, with the derived correlations representing the criteria for regime boundaries of a liquid-liquid system. Finally, the experimental data were extrapolated to the expected conditions of a sodium-cooled fast reactor. From this, it was implied that most of the hydrodynamic conditions during an accident would be close to the atomization regime, in which entrainment is the dominant process for droplet formation. Nomenclature d droplet diameter Dj0 nozzle diameter

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Lattice Boltzmann modeling and simulation of liquid jet breakup

2017

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A three-dimensional color-fluid lattice Boltzmann model for immiscible two-phase flows is developed in the framework of a three-dimensional 27-velocity (D3Q27) lattice. The collision operator comprises the D3Q27 versions of three suboperators: a multiple-relaxation-time (MRT) collision operator, a generalized Liu-Valocchi-Kang perturbation operator, and a Latva-Kokko-Rothman recoloring operator. A D3Q27 version of an enhanced equilibrium distribution function is also incorporated into this model to improve the Galilean invariance. Three types of numerical tests, namely, a static droplet, an oscillating droplet, and the Rayleigh-Taylor instability, show a good agreement with analytical solutions and numerical simulations. Following these numerical tests, this model is applied to liquid-jet-breakup simulations. The simulation conditions are matched to the conditions of the previous experiments. In this case, numerical stability is maintained throughout the simulation, although the kinematic viscosity for the continuous phase is set as low as 1.8×10^{-4}, in which case the corresponding Reynolds number is 3.4×10^{3}; the developed lattice Boltzmann model based on the D3Q27 lattice enables us to perform the simulation with parameters directly matched to the experiments. The jet's liquid column transitions from an asymmetrical to an axisymmetrical shape, and entrainment occurs from the side of the jet. The measured time history of the jet's leading-edge position shows a good agreement with the experiments. Finally, the reproducibility of the regime map for liquid-liquid systems is assessed. The present lattice Boltzmann simulations well reproduce the characteristics of predicted regimes, including varicose breakup, sinuous breakup, and atomization.

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Visualization and measurement of jet breakup behavior using LIF

Cited by 5 publications

References 30 publications

Jet breakup in superfluid and normal liquid He4

Jet breakup in superfluid and normal liquid He4

Flow transition criteria of a liquid jet into a liquid pool

Lattice Boltzmann modeling and simulation of liquid jet breakup

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