Investigation of Secondary Waves Dynamics in Annular Gas–Liquid Flow

Алексеенко, С. В.; Cherdantsev, Andrey V.; Cherdantsev, Mikhail V.; Маркович, Д. М.

doi:10.1007/s12217-009-9145-5

Cited by 11 publications

(4 citation statements)

References 9 publications

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“…Ring waves were found to be faster and have higher amplitudes than ripples, and it was observed that ring waves absorb overtaken ripples. Moreover, the velocity values of primary and secondary waves measured in our experiments (see Alekseenko et al 2009b) agree very well with the data on the velocity of ring waves and ripples measured by Ohba and Nagae for close gas and liquid flow rates. We suppose that Ohba and Nagae described the same types of waves as those observed in our experiments.…”

Section: Experimental Setup and Measurement Techniquesupporting

confidence: 90%

Application of a high-speed laser-induced fluorescence technique for studying the three-dimensional structure of annular gas–liquid flow

Алексеенко

Cherdantsev

et al. 2011

Exp Fluids

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The wavy structure of liquid film in annular gas-liquid flow was studied using a high-speed modification of the laser-induced fluorescence (LIF) technique, which was adapted for three-dimensional measurements. The three-dimensional structure of different types of waves in regimes with and without liquid entrainment was investigated. A comparison of the circumferential size of different types of waves was performed. Disturbance waves at high liquid Reynolds numbers were shown to be circumferentially non-uniform, and it was shown that this non-uniformity affects the generation of ripples.

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Section: Experimental Setup and Measurement Techniquesupporting

confidence: 90%

Application of a high-speed laser-induced fluorescence technique for studying the three-dimensional structure of annular gas–liquid flow

Алексеенко

Cherdantsev

et al. 2011

Exp Fluids

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“…Liu and co-workers [14][15][16][17], for example, investigated the evolution of interfacial instabilities in aqueous-glycerol solution films by calibrating the fluorescence intensity emitted by the dye-doped liquid bulk. Using rhodamine 6G and the same measurement approach, Alekseenko and co-workers conducted experiments over a broad range of unsteady gasliquid flows, such as downwards annular-flows [41][42][43] and gas shear-driven flows [44]. Focusing on the dynamics of the larger waves (referred to some times as "disturbance waves"), their aim was to uncover the underlying mechanism that potentially links these waves to liquid entrainment phenomena.…”

Section: Experimental Methodsmentioning

confidence: 99%

Detailed hydrodynamic characterization of harmonically excited falling-film flows: A combined experimental and computational study

et al. 2017

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We present results from the simultaneous application of planar laser-induced fluorescence (PLIF), particle image velocimetry (PIV) and particle tracking velocimetry (PTV), complemented by direct numerical simulations, aimed at the detailed hydrodynamic characterization of harmonically excited liquid-film flows falling under the action of gravity. The experimental campaign comprises four different aqueous-glycerol solutions corresponding to four Kapitza numbers (Ka = 14, 85, 350, 1800), spanning the Reynolds number range Re = 2.3-320, and with forcing frequencies f w = 7 and 10 Hz. PLIF was employed to generate spatiotemporally resolved film-height measurements, and PIV and PTV to generate two-dimensional velocity-vector maps of the flow field underneath the wavy film interface. The latter allows for instantaneous, highly localized velocity-profile, bulk-velocity, and flow-rate data to be retrieved, based on which the effect of local film topology on the flow field underneath the waves is studied in detail. Temporal sequences of instantaneous and local film height and bulk velocity are generated and combined into bulk flow-rate time series. The time-mean flow rates are then decomposed into steady and unsteady components, the former represented by the product of the mean film height and mean bulk velocity and the latter by the covariance of the film-height and bulk-velocity fluctuations. The steady terms are found to vary linearly with the flow Re, with the best-fit gradients approximated closely by the kinematic viscosities of the three examined liquids. The unsteady terms, typically amounting to 5%-10% of the mean and peaking at approximately 20%, are found to scale linearly with the film-height variance. And, interestingly, the instantaneous flow rate is found to vary linearly with the instantaneous film height. Both experimental and numerical flow-rate data are closely approximated by a simple analytical relationship with only minor deviations. This relationship includes terms such as the wave speed c and mean flow rate Q, which can be obtained by relatively simple and inexpensive methods, thus allowing for spatiotemporally resolved flow-rate predictions to be made without requiring explicit knowledge of the full flow-field information underneath the wavy interface.

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“…Other groups have also employed the same measurement technique, for example Vlachogiannis and Bontozoglou [20] and Alekseenko et al [21]. Using Rhodamine 6G as the fluorescent marker, high-speed imaging and continuous-wave lasers, Alekseenko and co-workers have carried out extensive fluorescence-based investigations over a wide range of downwards annular flows (Alekseenko et al [22], Alekseenko et al [23], Alekseenko et al [24]). For the upper range of the liquid Re range examined (Re = 18 -350), the authors captured the formation of disturbance waves (primary waves) with non-uniform height along the circumference of a pipe, and deduced that this non-uniformity affects the generation of ripples (secondary waves).…”

Section: Review Of Experimental Methodsmentioning

confidence: 99%

A simultaneous planar laser-induced fluorescence, particle image velocimetry and particle tracking velocimetry technique for the investigation of thin liquid-film flows

Charogiannis

Markides

2015

Experimental Thermal and Fluid Science

108

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A simultaneous measurement technique based on planar laser-induced fluorescence imaging (PLIF) and particle image/tracking velocimetry (PIV/PTV) is described for the investigation of the hydrodynamic characteristics of harmonically excited liquid thin-film flows. The technique is applied as part of an extensive experimental campaign that covers four different Kapitza (Ka) number liquids, Reynolds (Re) numbers spanning the range 2.3 -320, and inlet-forced/wave frequencies in the range 1 -10 Hz. Film thicknesses (from PLIF) for flat (viscous and unforced) films are compared to micrometer stage measurements and analytical predictions (Nusselt solution), with a resulting mean deviation being lower than the nominal resolution of the imaging setup (around 20 μm). Relative deviations are calculated between PTV-derived interfacial and bulk velocities and analytical results, with mean values amounting to no more than 3.2% for both test cases. In addition, flow rates recovered using LIF/PTV (film thickness and velocity profile) data are compared to direct flowmeter readings. The mean relative deviation is found to be 1.6% for a total of six flat and nine wavy flows. The practice of wave/phase locked flow-field averaging is also implemented, allowing the generation of highly localized velocity profile, bulk velocity and flow rate data along the wave topology. Based on this data, velocity profiles are extracted from 20 locations along the wave topology and compared to analytically derived ones based on local film thickness measurements and the Nusselt solution. Increasing the waviness by modulating the forcing frequency is found to result in lower absolute deviations between experiments and theoretical predictions ahead of the wave crests, and higher deviations behind the wave crests. At the wave crests, experimentally derived interfacial velocities are overestimated by nearly 100%. Finally, locally non-parabolic velocity profiles are identified ahead of the wave crests; a phenomenon potentially linked to the cross-stream velocity field.

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Investigation of Secondary Waves Dynamics in Annular Gas–Liquid Flow

Cited by 11 publications

References 9 publications

Application of a high-speed laser-induced fluorescence technique for studying the three-dimensional structure of annular gas–liquid flow

Application of a high-speed laser-induced fluorescence technique for studying the three-dimensional structure of annular gas–liquid flow

Detailed hydrodynamic characterization of harmonically excited falling-film flows: A combined experimental and computational study

A simultaneous planar laser-induced fluorescence, particle image velocimetry and particle tracking velocimetry technique for the investigation of thin liquid-film flows

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