Influence of acoustic streaming on thermo-diffusion in a binary mixture under microgravity

Charrier-Mojtabi, Marie-Catherine; Fontaine, A.; Mojtabi, Abdelkader

doi:10.1016/j.ijheatmasstransfer.2012.06.009

Cited by 11 publications

(14 citation statements)

References 13 publications

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“…The crudest propagation model is to consider a uniform beam of cylindrical shape, which is to say without any diffraction, nonlinearity nor attenuation 3,29,[45][46][47][48][49] ; in this case, attenuation is neglected in the propagation problem and is only accounted for through the attenuation coefficient appearing in the acoustic force expression (Eq. (12)).…”

Section: A An Explanation Based On Time-scales Discriminationmentioning

confidence: 99%

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Scaling and dimensional analysis of acoustic streaming jets

et al. 2014

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This paper focuses on acoustic streaming free jets. This is to say that progressive acoustic waves are used to generate a steady flow far from any wall. The derivation of the governing equations under the form of a nonlinear hydrodynamics problem coupled with an acoustic propagation problem is made on the basis of a time scale discrimination approach. This approach is preferred to the usually invoked amplitude perturbations expansion since it is consistent with experimental observations of acoustic streaming flows featuring hydrodynamic nonlinearities and turbulence. Experimental results obtained with a plane transducer in water are also presented together with a review of the former experimental investigations using similar configurations. A comparison of the shape of the acoustic field with the shape of the velocity field shows that diffraction is a key ingredient in the problem though it is rarely accounted for in the literature. A scaling analysis is made and leads to two scaling laws for the typical velocity level in acoustic streaming free jets; these are both observed in our setup and in former studies by other teams. We also perform a dimensional analysis of this problem: a set of seven dimensionless groups is required to describe a typical acoustic experiment. We find that a full similarity is usually not possible between two acoustic streaming experiments featuring different fluids. We then choose to relax the similarity with respect to sound attenuation and to focus on the case of a scaled water experiment representing an acoustic streaming application in liquid metals, in particular, in liquid silicon and in liquid sodium. We show that small acoustic powers can yield relatively high Reynolds numbers and velocity levels; this could be a virtue for heat and mass transfer applications, but a drawback for ultrasonic velocimetry.

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Section: A An Explanation Based On Time-scales Discriminationmentioning

confidence: 99%

“…Acoustic streaming can be seen as a tool to enhance heat and mass transfer in a number of applications. [1][2][3][4][5] For instance, several studies show that ultrasounds used during solidification process can improve final material properties. [6][7][8][9][10][11][12] However, it can also unwillingly affect some processes.…”

Section: Introductionmentioning

confidence: 99%

Scaling and dimensional analysis of acoustic streaming jets

et al. 2014

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“…However, the case of streaming associated with acoustic beams has by far been the more studied case since celebrated pioneering works [8]. Ultrasonic acoustic streaming is in particular considered for its interest in a very broad variety of applications and processes, including acoustic velocimetry [9,10], sonochemistry applications [11][12][13][14], medical applications [15][16][17][18], acoustically assisted mixing, phase change, and blend separation [19][20][21][22][23], and metallic and semiconducting material processing [14,[24][25][26][27][28]. In these applications, acoustic streaming is usually considered with an objective to better control the flow dynamics and/or improve its mixing properties.…”

Section: Introductionmentioning

confidence: 99%

From flying wheel to square flow: Dynamics of a flow driven by acoustic forcing

et al. 2017

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Acoustic streaming designates the ability to drive quasisteady flows by acoustic propagation in dissipative fluids and results from an acoustohydrodynamics coupling. It is a noninvasive way of putting a fluid into motion using the volumetric acoustic force and can be used for different applications such as mixing purposes. We present an experimental investigation of a kind of square flow driven by acoustic streaming, with the use of beam reflections, in a water tank. Time-resolved experiments using particle image velocimetry have been performed to investigate the velocity field in the reference plane of the experiments for six powers: 0.5, 1, 2, 4, 6, and 8 W. The evolution of the flow regime from almost steady to strongly unsteady states is characterized using different tools: the plot of time-averaged and instantaneous velocity fields, the calculation of presence density maps for vortex positions and for the maximal velocity and vorticity crest lines, and the use of spatiotemporal maps of the waving observed on the jets created by acoustic streaming. A transition is observed between two regimes at moderate and high acoustic forcing.

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“…This phenomenon is, willingly or not, present in a number of applications ranging from ultrasoundbased velocimetry [2,3] to medical applications [4,5] and from heat and mass transfer [6][7][8][9][10] to sonochemistry [11], It can also be used to move particles [12] or droplets [13] or to generate jets in small and even microsize domains [14]. It can be seen as a coupling between acoustic propagation and fluid motion [15], This coupling is often accounted for by an additional force term in the Navier-Stokes equations for a viscous incompressible flow.…”

Section: Introductionmentioning

confidence: 99%

Near-field acoustic streaming jet

et al. 2015

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A numerical and experimental investigation of the acoustic streaming flow in the near field of a circular plane ultrasonic transducer in water is performed. The experimental domain is a parallelepipedic cavity delimited by absorbing walls to avoid acoustic reflection, with a top free surface. The flow velocities are measured by particle image velocimetry, leading to well-resolved velocity profiles. The theoretical model is based on a linear acoustic propagation model, which correctly reproduces the acoustic field mapped experimentally using a hydrophone, and an acoustic force term introduced in the Navier-Stokes equations under the plane-wave assumption. Despite the complexity of the acoustic field in the near field, in particular in the vicinity of the acoustic source, a good agreement between the experimental measurements and the numerical results for the velocity field is obtained, validating our numerical approach and justifying the planar wave assumption in conditions where it is a priori far from obvious. The flow structure is found to be correlated with the acoustic field shape. Indeed, the longitudinal profiles of the velocity present a wavering linked to the variations in acoustic intensity along the beam axis and transverse profiles exhibit a complex shape strongly influenced by the transverse variations of the acoustic intensity in the beam. Finally, the velocity in the jet is found to increase as the square root of the acoustic force times the distance from the origin of the jet over a major part of the cavity, after a strong short initial increase, where the velocity scales with the square of the distance from the upstream wall.

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Influence of acoustic streaming on thermo-diffusion in a binary mixture under microgravity

Cited by 11 publications

References 13 publications

Scaling and dimensional analysis of acoustic streaming jets

Scaling and dimensional analysis of acoustic streaming jets

From flying wheel to square flow: Dynamics of a flow driven by acoustic forcing

Near-field acoustic streaming jet

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