The growth of instabilities in annular liquid sheets

Duke, Daniel J.; Honnery, Damon; Soria, Julio

doi:10.1016/j.expthermflusci.2015.04.013

Cited by 15 publications

(5 citation statements)

References 32 publications

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“…Duke et al , performed an instability analysis for a nozzle with flow configuration (iii) and noted two physical instabilities: the Kelvin–Helmholtz instability (shear layer) and a nonlinear rupturing instability. As observed by Duke et al, the primary Kelvin–Helmholtz instability is only formed in the presence of a sufficiently high relative velocity of the outer gas stream v gas,o and liquid sheet v liq .…”

Section: Theoretical Backgroundmentioning

confidence: 99%

Comparison of Central Jet and Annular Sheet Atomizers at Identical Gas Momentum Flows

Wachter

Jakobs

Kolb

2021

Ind. Eng. Chem. Res.

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This study compares three different nozzle flow configurationscentral liquid jet with surrounding gas phase, liquid sheet with central gas phase, and liquid sheet with inner and outer gas phases. To guarantee constant velocities, as well as momentum flows at the nozzle orifice, a nozzle with identical orifice areas (a central tube with inner and outer slits) was utilized in the experiments. The influence of gas velocity (GLR), dynamic viscosity of the liquid, and nozzle configuration on the resulting droplet sizes (D 32, ID 32,m) and primary breakup was investigated at constant liquid mass flow. A high-speed camera (HSC) was used for the detection of primary breakup, whereas droplet size measurements were performed with a phase Doppler anemometer. The variation of nozzle configuration exhibited distinct influence on the resulting breakup morphology and droplet size. Especially, for atomizing high-viscosity liquids, application of sheet configurations led to smaller droplet sizes compared to liquid jet configuration.

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Section: Theoretical Backgroundmentioning

confidence: 99%

Comparison of Central Jet and Annular Sheet Atomizers at Identical Gas Momentum Flows

Wachter

Jakobs

Kolb

2021

Ind. Eng. Chem. Res.

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“…It can be clearly seen in Equation ( 28) that the temperature difference ∆T * is a factor that affects the temperature gradient in an annular liquid jet. Although temperature difference ∆T * variation will change the Weber number, the temperature gradient also affects the instability of an annular liquid jet through the energy balance equation (Equation (10)). Hence, the Weber numbers of the inner and outer interfaces are assumed unchanged with temperature difference ∆T * variation by modifying the program.…”

Section: Effect Of Temperature Gradientmentioning

confidence: 99%

“…Chen and Lin [6] investigated the instability of an annular jet surrounded by a viscous gas in a pipe. Considering practical spray applications [7,8], aerodynamic and swirling effects were also studied [9][10][11][12][13]. Due to a smaller Mach number, the compressibility of gas is usually neglected.…”

Section: Introductionmentioning

confidence: 99%

Thermal Effect on the Instability of Annular Liquid Jet

Cui

Jia

2021

Aerospace

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The linear instability of an annular liquid jet with a radial temperature gradient in an inviscid gas steam is investigated theoretically. A physical model of an annular liquid jet with a radial temperature gradient is established, dimensionless governing equations and boundary conditions are given, and numerical solutions are obtained using the spectral collocation method. The correctness of the results is verified to a certain extent. The liquid surface tension coefficient is assumed to be a linear function of temperature. The effects of various dimensionless parameters (including the Marangoni number/Prandtl number, Reynolds number, temperature gradient, Weber number, gas-to-liquid density ratio and velocity ratio) on the instability of the annular liquid jet are discussed. A decreasing Weber number destabilizes the annular liquid jet when the Weber number is lower than a critical value. It is found that the effects of the Marangoni effect are related to the Weber number. The Marangoni effect enhances instability when the Weber number is small, while the Marangoni effect weakens instability when the Weber number is large. In addition, because the thermal effect is considered, a decreasing Reynolds number enhances the instability when the Weber number is lower than a critical value, which is similar to the results of a viscous liquid sheet with a temperature difference between two planar surfaces. Furthermore, the effects of other dimensionless parameters are also investigated.

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“…Liquid sheet flows issuing into a gaseous environment have being studied since the middle of the last century [1], due to their wide scientific and industrial interest, which involves fuel atomization, coating deposition, paper making, and other applications. The literature includes a wide variety of geometrical and physical configurations, which span both planar [2] and round [3] geometries, both high [4] and low speed (gravitational) [5] flows, both quiescent [6] and co-flowing air [7] ambients. Notwithstanding the large amount of research efforts, some aspects of the unsteady dynamics of liquid sheet flows are the object of ongoing studies and some are still open.…”

Section: Introductionmentioning

confidence: 99%

Unsteady Dynamics of Free-Interface Gravitational Liquid Sheet Flows

Pia¹,

Chiatto²,

Luca³

2021

14th WCCM-ECCOMAS Congress

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Numerical simulations of gravitational planar liquid sheet flows, interacting with unconfined gaseous environments located on both sides of the liquid phase, are performed through Volume-of-Fluid (VOF) technique. The global unsteady dynamics of the non-parallel flow is analyzed by perturbing the initial steady configuration by means of a Gaussian bump in the transverse velocity component of relatively very small amplitude, thereby exciting sinuous modes. Thanks to the development of a theoretical linear one-dimensional model, more physical insights are gained on the flow system. It is found that surface tension plays a stabilizing role for the gravitational sheet, and for relatively high values of density ratio r ρ of gaseous-to-liquid phases it becomes unstable. An analogy is shown between the global unstable behavior exhibited by the liquid sheet as r ρ increases, and the shear-induced global instability found by Tammisola et al. ["Surface tension-induced global instability of planar jets and wakes", J. Fluid Mech. 713, 632-658 (2012)] for planar jet and wake flows of two immiscible fluids in the presence of surface tension.

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The growth of instabilities in annular liquid sheets

Cited by 15 publications

References 32 publications

Comparison of Central Jet and Annular Sheet Atomizers at Identical Gas Momentum Flows

Comparison of Central Jet and Annular Sheet Atomizers at Identical Gas Momentum Flows

Thermal Effect on the Instability of Annular Liquid Jet

Unsteady Dynamics of Free-Interface Gravitational Liquid Sheet Flows

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