Hydrodynamic cavitation of binary liquid mixtures in laminar and turbulent flow regimes

Mossaz, Stéphane; Colombet, Damien; Ayela, Frédéric

doi:10.1016/j.expthermflusci.2016.08.001

Cited by 20 publications

(18 citation statements)

References 24 publications

(38 reference statements)

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“…Each mixture was characterised at three different weight percentages. The whole results have just been published elsewhere [17], and we recall here only the main results. Concerning the water -isopropanol mixture, it has been observed that a small amount of isopropanol lead to a dramatic increase of the viscosity.…”

Section: Hydrodynamic Cavitation Of Binary Mixtures and The Anomalousmentioning

confidence: 87%

“…Data recorded with 2-butanol and isopropanol were the first ever published experimental evidences of a transition from a laminar liquid single phase flow towards a cavitating one [17]. The onset of cavitation is perfectly monitored by the drop of the pressure, as a consequence of the Bernoulli law.…”

Section: Hydrodynamic Cavitation Of Binary Mixtures and The Anomalousmentioning

confidence: 99%

“…The value of the dynamic viscosity influences Re values and so the flow regime (laminar or turbulent) present at the onset of cavitation. The viscosity and the pressure vapour of the blends were experimentally determined [17]. Each mixture was characterised at three different weight percentages.…”

Section: Hydrodynamic Cavitation Of Binary Mixtures and The Anomalousmentioning

confidence: 99%

See 2 more Smart Citations

Hydrodynamic Cavitation through “Labs on a Chip”: From Fundamentals to Applications

Ayela

Cherief

Colombet

et al. 2017

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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-Monitoring hydrodynamic cavitation of liquids through "labs on a chip" (i.e. microchannels with a shrinkage, such as microdiaphragms or microventuris) is an improvement in experimental approaches devoted to study the mechanisms involved in these multiphase flows. The small sizes of the reactors do not require big substructures. Flow rates of around 1 L/h make possible the characterisation of rare, toxic or expensive pure fluids or mixtures. Moreover, because of that microfluidic approach, an unique inception of the cavitation from a laminar flow regime is also possible, that provides precious databases for simulation or modelisation. Lastly, "labs on a chip" are an extremely versatile solution to perform novel experiments, as they are embeddable in tools basically designed to proceed with small samples (confocal microscopy, spectroscopy). We present here a summary of the former experiments performed by our team, concerning the fundamental aspects of hydrodynamic cavitation in a microchannel. We have recorded, with thermosensitive nanoparticles dispersed in water, the thermal signature of the growth and collapse of bubbles. We were also able to monitor the cavitation flow regime from a laminar single liquid phase. We are currently involved in applicative studies of hydrodynamic cavitation in microchannels, and preliminary results concerning liquid phase exfoliation of graphene will be also presented.Résumé -Cavitation hydrodynamique "sur puce" : Aspects fondamentaux et appliqués -L'émergence de la cavitation hydrodynamique 'sur puce' (cavitation dans des microcanaux comportant une réduction localisée de leur section de passage) est un atout pour l'étude des mécanismes impliqués dans ce type d'écoulements diphasiques. Les dimensions réduites des réacteurs s'affranchissent de l'utilisation d'infrastructures lourdes. Des débits de l'ordre du litre par heure rendent possible l'étude de fluides rares, toxiques ou coûteux, ainsi que l'étude de mélanges. De plus, cette approche microfluidique est la seule qui permet sous certaines conditions l'apparition de la cavitation à partir d'un régime d'écoulement laminaire, ce qui fournit des données expérimentales intéressantes pour la modélisation. Enfin, la dimension réduite des "laboratoires sur puce" leur permet de s'intégrer dans des schémas expérimentaux (microscopes confocaux, spectrométrie) inenvisageables à plus grande échelle. Nous présentons ici un récapitulatif de résultats récemment obtenus par notre équipe, concernant des aspects fondamentaux et appliqués au génie des procédés de la cavitation hydrodynamique sur puce. Nous avons pu détecter la signature thermique de l'évaporation et de la condensation de bulles, grâce à des nanoparticules thermofluorescentes dispersées dans l'écoulement. Nous avons également piloté la transition vers la cavitation à partir d'un écoulement laminaire. Nous présentons enfin les premiers résultats de nos travaux en cours, concernant l'exfoliation en phase liquide du graphène assistée par microcavitation.

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Section: Hydrodynamic Cavitation Of Binary Mixtures and The Anomalousmentioning

confidence: 87%

Section: Hydrodynamic Cavitation Of Binary Mixtures and The Anomalousmentioning

confidence: 99%

Section: Hydrodynamic Cavitation Of Binary Mixtures and The Anomalousmentioning

confidence: 99%

See 1 more Smart Citation

Hydrodynamic Cavitation through “Labs on a Chip”: From Fundamentals to Applications

Ayela

Cherief

Colombet

et al. 2017

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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“…These kind of channels have been used extensively by our team [8][9][10] and others [11][12][13][14]. Channel geometries most used are micro diaphragms (figure 1b) and micro Venturis.…”

Section: Bodymentioning

confidence: 99%

Luminescence Based Measurements in Micro Cavitating Flow

Podbevšek

Colombet

Ayela

et al. 2018

Proceedings of the 10th International Symposium on Cavitation (CAV2018)

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Microchannels are often used to study fluid dynamics. For steady state problems like cavitating flow, fluorescent microscopy, with the addition of temperature sensitive nanoprobes into the observed fluid, can be used to determine the temperature at a chosen point, averaged over the integration time. Coupled with a confocal microscope setup, we are able to produce two and three dimensional temperature maps of the flow in the microchannel by the use of ratiometric intensity measurements. The nanometric scale of the probes assures fast thermalization of the probes and below certain concentrations does not modify the properties of the studied liquid. Since the probes are not present in the vapor phase, the relative intensity map also corresponds to the average void fraction in the flow. These nanoprobes are composed of a gold core and a polysiloxane shell containing fluorescent dyes (FITC, RBITC). Organic dyes were chosen due to their compatibility with the shell and primarily for the fast luminescence lifetime, which is essential due to the rapid flow in the microchannel and the consequent short dwell time of an individual nanoprobe in the excitation volume. The temperature information in each measured point is obtained from the temperature sensitive spectrum of the dye. The shell protects the dye from the environment and allows for the functionalization of the surface to prevent agglomeration, while the gold core mitigates photo bleaching. The technic allowed us to observe temperature gradients in microfluidic two-phase flow and observe the thermal effect associated with phase transition. Typically, a region of decreased temperature is observed downstream the orifice in the liquid-vapor stream, attributed to the cooling of the liquid due to the latent heat of the phase change. However, small changes in the diaphragm geometry can induce recirculating vortices, where the vapor bubbles condensate and induce a region of increased temperature.

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“…There are a few studies addressing the application of other working fluids and its effect on flow patterns. For example, Mossaz et al [20] reported that the mixture of isopropanol and water could change the cavitation inception from turbulent regime to laminar regime. Low percentage of isopropanol in water is likely to increase the dynamic viscosity so that cavitation inception corresponding to laminar flow could be more easily achieved.…”

Section: Introductionmentioning

confidence: 99%

Engineered Lateral Roughness Element Implementation and Working Fluid Alteration to Intensify Hydrodynamic Cavitating Flows on a Chip for Energy Harvesting

et al. 2019

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Hydrodynamic cavitation is considered an effective tool to be used in different applications, such as surface cleaning, ones in the food industry, energy harvesting, water treatment, biomedical applications, and heat transfer enhancement. Thus, both characterization and intensification of cavitation phenomenon are of great importance. This study involves design and optimization of cavitation on chip devices by utilizing wall roughness elements and working fluid alteration. Seven different microfluidic devices were fabricated and tested. In order to harvest more energy from cavitating flows, different roughness elements were used to decrease the inlet pressure (input to the system), at which cavitation inception occurs. The implemented wall roughness elements were engineered structures in the shape of equilateral triangles embedded in the design of the microfluidic devices. The cavitation phenomena were also studied using ethanol as the working fluid, so that the fluid behavior differences in the tested cavitation on chip devices were explained and compared. The employment of the wall roughness elements was an effective approach to optimize the performances of the devices. The experimental results exhibited entirely different flow patterns for ethanol compared to water, which suggests the dominant effect of the surface tension on hydrodynamic cavitation in microfluidic channels.

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Hydrodynamic cavitation of binary liquid mixtures in laminar and turbulent flow regimes

Cited by 20 publications

References 24 publications

Hydrodynamic Cavitation through “Labs on a Chip”: From Fundamentals to Applications

Hydrodynamic Cavitation through “Labs on a Chip”: From Fundamentals to Applications

Luminescence Based Measurements in Micro Cavitating Flow

Engineered Lateral Roughness Element Implementation and Working Fluid Alteration to Intensify Hydrodynamic Cavitating Flows on a Chip for Energy Harvesting

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