Дисертації з теми "Fragmentation des liquides"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-32 дисертацій для дослідження на тему "Fragmentation des liquides".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
Néel, Baptiste. "Déstabilisation, rupture et fragmentation spontanées et stimulées de films liquides." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0578/document.
This thesis deals primarily with liquid films fragmentation. It consists, thanks to quantitative and original experiments, in the transformation of a free suspended film into a collection of droplets: destabilization, rupture, and fragmentation.In a prologue, notions of capillarity, momentum transfer and viscosity are introduced by the Marangoni-driven destabilization of a thin thread of viscous oil on water. The difference of surface tension feeds an accelerated, critical, self-similar cascade which ends up with the complete dilution of oil into water. When applied to a free film, the Marangoni effect driven by a localized deficit of surface tension, whose carrier (temperature or a solute) is diffusing into the liquid, destabilizes it (chapter two). The linear instability analysis points out the crucial role of an inertial timescale based on the surface shear stress. Experiments validate the prediction of an interstitial flow, which digs out the film in the case of a surface tension deficit. These observations offer new insights into a long-standing problem, namely the spontaneous nucleation of holes on planar liquid films.The third chapter investigates the consequences of the linear instability, as far as the film final stability is concerned, reviewing possible regularizations. The rupture dynamics is described within the framework of shocks. In the final chapter, the collision of liquid cylinders is identified as an individual mechanism for liquid fragmentation. The impact dynamics is analyzed, leading to two principal fragmentation regimes. The onset to the splashing one, which produces fine and fast droplets, is described
Vu, Trung-Thanh. "Processus d'atomisation des nappes liquides turbulentes : analyse expérimentale et développements numériques." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMR053/document.
Liquid fuel atomization is crucial for the performance of internal combustion engines. Through an injector, the liquid is delivered into the combustion chamber and breaks down into droplets. The finer the drops, the quicker their evaporation and the more proper their mixing with air. A proficient combustion could hence be expected, with low pollutant emissions. Atomization quality is primarily affected by the injector design and the operating conditions which shape the internal flow structure, the turbulence level, the velocity profile at the nozzle outlet, the cavitation and so forth. All these features are determinants of the breakup of the external liquid flow. Another key parameter to optimize the atomization process is the fuel physical properties. One can think of, among others, the dynamic surface tension controlled by the diffusion of the surfactants on the liquid-gas interface or the extensional viscosity which makes a liquid to become more resistant to the stretching, thereby affecting the breakup. Effects of the injector design, the operating conditions and the liquid properties on the atomization are inter-dependent. Analyses of experimental data help us to understand the involved mechanisms and their interactions. On the one hand, this is useful for the numerical developments which should be carried out depending upon the configuration. On the other hand, quantitative criterion could be established to validate the simulation results. Following the above research methodology, we aim to study the disintegration of planar turbulent liquid sheets produced by a triple-disk injector. Experimental measurements provide the sheet images, used as input for a multi-scale analysis. We investigate, thanks to the latter, the behaviours of the liquid sheet, the ligaments appearing on its edges and the resulting droplets. Moreover, two immersed boundary methods are developed, aiming to simultaneously solve the nozzle flow and the breakup process. We carry out two applications, the first one on a liquid jet ejected by a cylindrical nozzle and the other a planar sheet issuing from a triple-disk injector
Zainoun, Najib. "Contrôle de la fragmentation des jets liquides issus d'un disque tournant." Paris, CNAM, 2005. http://www.theses.fr/2005CNAM0520.
On a new generator of controlled aerosols, based on the fragmentation of the jets resulting from a disc in rotation, which we developed and automated, two models were developed and automated, two models were developed in order to determine the trajectory of the jets and the exact conditions of their break-up. The first model determines the trajectory of the jets with good precision thanks to the introduction of an ampirical law predicting the aerodynamic force of trail. The second model, approaching the jet by a succession of cylindrical sections, makes it possible to show that the disturbance which spreads and develops along the jet is a purely progressive wave advancing with a speed equal to the sum of the velocity of the flow and the celirity of capillary waves in a rest liquind. Thus, it is possible to predict the distances of natural and forced break-up, the most-unstable frequency, the zone in which the break-up of a jet induce an aerosol monodispersed without satellite and the size of the drops according to the physical properties of the liquid to be dispersed. The study also showed that, in the case of the smooth dics, the jets turn slower than the disc. When the dics present regularly distributed teeth at its periphery, we observe, according to the relative size of teeth and jets, or a periodic disturbance of the jets created by the jets crossing over the teeth. This disturbance constitutes a source of vibration, which controls the break-up in a similar way when starting the vibration of the disc by using a piezoelectric cell. The kinematics and granulometrics measurements were realised by using the photographs of the flow and a specific numerical granulometer presented in the document
Hadj, Achour Miloud. "Fragmentation de métal liquide dans l'eau." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0215/document.
The phenomenon of dispersion/fragmentation of corium remains one of the most complex and uncertain elements of nuclear accident modeling. In order to validate the sub-mesh models implemented in the MC3D software (developed by IRSN), an experiment without vapor explosion has been conceived. It consists of a low-melting liquid metal jet (Field metal) interacting with a stagnant water in a large tank. This thesis is divided into two parts ; the first one is related to the study of the so-called secondary fragmentation of an isolated drop of Field’s metal, for low Weber number. To this end, we designed an experimental device, GaLaD (drop-on-demand droplet generator). In this part, a literature review on liquid-liquid fragmentation is conducted with a quantitative comparison of the secondary fragmentation for a single drop in the liquid-liquid and the gas-liquid cases. The second part concerns the study of a jet of Field’s metal. For this purpose, GaLaD was modified, so as to be able to generate small jet of liquid metal in water. The obtained results allowed a better understanding of the physical phenomena involved in two-phase turbulent jet fragmentation. In the framework of this thesis, an additional experimental device designated by JaLaD is developed. Subsequently, this device will be dedicated to the study of metal jet in water and must allow us to reinterpret the data of classical experiments via new innovative measurement techniques
Castrillon, Escobar Sebastian. "Instabilité et dispersion de jets de corium liquides : analyse des processus physiques et modélisation dans le logiciel MC3D." Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0102/document.
In the case of a severe accident in a nuclear power plant, the molten core may flow into water and interact with it. The consequences of this fuel-coolant interaction (FCI) for the follow-up of the accident may be numerous so the phenomenon needs to be described accurately, one of them called “steam explosion” can lead to the failure of the nuclear reactor containment. FCI is a complex multiphase interaction involving several physical phenomena. The premixing phase of the interaction consists in the fragmentation and dispersion of corium in the coolant pool. This phase is driven by the fragmentation process which modifies heat transfers (coolant boiling dynamics) and chemical reactions (corium oxidation and hydrogen generation). This thesis brings new elements about the corium jet and droplet breakup with the main goal of improve fragmentation models on the MC3D multiphase code, developed by the IRSN. Our study is based on a multi-scale fragmentation process where the jet fragmentation rate and final droplet dimensions are not coupled themselves. We suppose a fragmentation process resulting from a primary instability (mass transfer within jet and big droplets) depending on the large flow scales and a secondary instability depending on the small flow scales (leading to final droplet breakup). This model has been implemented in MC3D in combination with the MUSIG method recently added to MC3D. In this method, droplets are represented using several classes, each of them with their own droplet diameter, mass and energy fields. Despite new improvements on modeling corium fragmentation, there is still a lack on the comprehension and characterization on the liquid droplet fragmentation, particularly on liquid/liquid configurations. In this thesis, we study in detail droplet breakup using the computational fluid dynamics software GERRIS. As a result, we find a new droplet breakup classification in liquid/liquid configurations, we improve the droplet breakup dynamics comprehension and we analyze the droplet-vortex interaction to determine breakup regime transition
CHICHEPORTICHE, JEAN-MARC. "Etude de la fragmentation commandee des jets liquides issus d'un disque en rotation et realisation d'un generateur de gouttelettes monodispersees." Paris 6, 1993. http://www.theses.fr/1993PA066057.
Lhuissier, Henri. "Nappes, trous, ligaments et gouttes." Phd thesis, Université de Provence - Aix-Marseille I, 2011. http://tel.archives-ouvertes.fr/tel-00600229.
Kewalramani, Gagan Vikram. "Experimental and theoretical analysis of a turbulent two-phase jet." Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0012.
The objective of the present thesis is to study two-phase liquid-liquid jets. Someof the features of a two-phase jet (distinct from single phase jet) are fragmentation ofthe injected fluid and energy exchange between fluids. Experimental measurementof the velocity dynamics in a two-phase jet is challenging because it's opacity. Tooptically access the dynamics of a two-phase jet, a transparent fluid with refractiveindex equal to water (referred as Cargille fluid) but with density twice as water isinjected into water tank. By adding a fluorescent dye to the transparent fluid andseeding particles to water, the dynamics of both the fluid are accessible opticallywhen illuminated by laser. A procedure to obtain information of the dynamics ofthe drops and its relation with velocity of the carrier fluid using high speed imagesis detailed in this thesis. To study two phase jets, two experimental setup (i) JaLaDand (ii) JeDi are developed. The work in this thesis can be categorized into severalparts that are explained as follows.Part-I: PTV analysis: Particle Tracking Velocimetry (PTV) algorithm Track isused on JaLad experiments. With PTV software Track, the Lagrangian trajectoriesof the fragmented liquid are analyzed. A procedure to detect primary fragmentation,secondary fragmentation and collision is developed. The methodology of fragmentationand collision detection is also verified with synthetically generated images.Part II: Single phase jet analysis: Before stating the measurement of a twophasejet, single-phase jets are studied on JeDi experiments. Relations to describeReynolds turbulent stress are developed to obtain a mathematical expression forturbulent kinetic energy dissipation and its dissipation.Part III: Simultaneous PTV-PIV measurement and analysis: In JeDi experiments,simultaneous measurement of both the fluids is perfomed. Optical flow and ParticleImage Velocimetry (PIV) are used for measuring dispersed phase (Cargille) andcarrier fluid (water) velocity respectively. For this part of the thesis, two lasers andtwo cameras are used. Camera 1 with a high pass filter (λ > 530 nm) and Camera 2with a low pass filter (λ < 530 nm) are synchronized with two lasers. Both systemsrecord images at the same instant in time and view the same plane. With the followingarrangement, Camera 1 only records the LIF signal in Cargille and Camera2 only records the PIV signal in water. The recorded images are processed to obtainthe average velocity of both phases. A simple integral model for entrainment andatomization based on Eulerian mass weighted average quantities is finally developedand validated against experimental results
Meignen, Renaud. "Modélisation de la fragmentation d'un jet liquide à très haute température dans un liquide froid volatil." Grenoble INPG, 1995. http://www.theses.fr/1995INPG0181.
Miller, Catherine Elizabeth. "Characterization of ion Cluster fragmentation in ionic liquid ion sources." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122372.
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2019
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 273-281).
Ion electrospray propulsion is a cutting-edge micropropulsion technology that could revolutionize the capabilities of microsatellites. Ion electrospray thrusters could also be used on large spacecraft for precision attitude control applications such as gravity wave detection and exoplanet imaging. Novel room temperature molten salts, called ionic liquids, are used as propellant, which are composed purely of positive and negative molecular ions. When exposed to strong electric fields, ions and metastable clusters of ions are evaporated from the bulk liquid surface. The free ions and ion clusters can be accelerated to high velocities, producing thrust at high specific impulse. The performance of ion electrospray thrusters is affected by the composition of the ion beam and the amount of ion clusters that break apart during the acceleration phase. To improve thruster performance, a better understanding of the fundamental physics of ion evaporation and cluster break-up is needed.
The break-up of ion clusters, also called fragmentation, is not a well understood phenomenon. It has been observed in past experiments, but the rates of break-up have not been measured. The focus of this work is to experimentally investigate fragmentation more deeply than ever before. To accomplish this, a specialized instrumentation suite has been designed, built, and tested to measure fragmentation characteristics in unprecedented detail. A full-beam, spherical geometry retarding potential analyzer is used to measure the rates of fragmentation of ion clusters both outside the thruster and within the acceleration region for the first time. A narrow-beam, high time-resolution time of flight mass spectrometer is used to measure the beam composition. Single emitters based on resorcinol formaldehyde carbon xerogels were used as ion sources. Four ionic liquids spanning a wide range of liquid properties were characterized: EMI-FAP, EMI-Im, EMI-BF4, and BMI-I.
Analytical models were also developed to enhance the interpretation of the experimental results. The experimental measurements show that the amount of fragmentation increases with distance from the thruster and follows a constant rate equation. The mean lifetimes of ion clusters outside of the thruster range from 1-6 [mu]s, indicating that these clusters are quite unstable. It is observed that the fragmentation throughout most of the acceleration region is linear with respect to electric potential, which can be understood using analytical models. Rapid fragmentation likely occurs immediately after evaporation due to the strong electric fields near the emission site, which has significant implications for thruster performance. It is also observed that clusters of complex molecular ions which consist of many atoms tend to be the most stable. The initial temperature of ion clusters, which range from 520 K - 790 K, were estimated using analytical methods.
The effect of liquid temperature on the rates of fragmentation was also investigated. In conclusion, the work in this thesis provides a greatly enhanced understanding of ion cluster fragmentation, particularly how it is affected by ionic liquid properties, liquid temperature, and electric fields.
This research was supported by a NASA Space Technology Research Fellowship
by Catherine Elizabeth Miller.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Aeronautics and Astronautics
Moghaddam, Amir. "Dynamics of transformation and fragmentation of composite liquid nano-particles." Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/31776/1/Amir_Moghaddam_Thesis.pdf.
Bissagou, Koumba Gaelle. "Fragmentations chimique et physique de plastiques et microplastiques en eau douce sous irradiation UV-visible." Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAC016/document.
The question of marine litter and their environmental impact gains importance. It was shown that 80% of plastics results from terrestrial sources, while 20% come from coastlines and seas. Many authors point to a serious environmental problem involved to the absorption of POPs (persistent organic pollutants) by plastic detritus, thus initiating a potential source of contamination of the food chain. All authors attribute the fragmentation to "microplastic" (size < 5mm) to phenomena related to degradation, under UV without ever having demonstrated or analysed it. The rivers constituting then a privileged vector of transport of the terrestrial waste towards the seas and oceans, we decided to highlight (and quantify) the presence of microplastics in a river known as "wild" as the Allier. At the laboratory, we develop simulation protocols for the fragmentation of plastics under UV irradiation of various plastic materials in fresh water. We analyse both the chemical molecules resulting from the degradation of plastics and transferred to the aqueous medium as well as the molecular changes that can undergo the material
Redding, Jeremy. "Deformation, Fragmentation and Vaporization of Volatile Liquid Droplets in Shock-Laden Environments." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1613745275535815.
BOYER, DENIS. "Theorie statistique de l'adsorption irreversible aux interfaces liquide-solide et de la fragmentation sequentielle." Paris 6, 1995. http://www.theses.fr/1995PA066550.
Caruyer, Céline. "Modélisation de nanomatériaux injectés par voie liquide dans un jet de plasma pour la fabrication de nanostructures." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14329/document.
The study of the plasma spraying process is investigated in this work, in particular the interaction between a liquid phase and a plasma flow. Different physical phenomena occureas the jet fragmentation, the liquid vaporization and the particles fusion. The numerical simulation is used to better understand the physical phenomena and is an alternative to experimental measurements, which could be locally difficult to perform because of the measurement techniques limitations and the particular characteristics of the plasma. A compressible two-phase model is developped to take into account the compressible effects of the plasma flow. Validations are realized on academic test cases and on a argonjet. Good agreements are obtained between simulations and theory or experiments. Then different mixtures of plasmagen gas, classically used in plasma spraying, are studied :argon/hydrogen and argon/helium. An analysis of unsteady and turbulent character isled and allows seeing the importance of unsteady effects in these flows. Numerical simulations of the injection of a liquid phase into the plasma flow are realized. The influence of the plasmagen gas nature and the injection type is anlysed. Structures observed by experiments are also obtained by the simulations
Fedkiw, Timothy Peter. "Characterization of an iodine-based ionic liquid ion source and studies on ion fragmentation." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62488.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 71-73).
Electrosprays are a well studied source of charged droplets and ions. A specific subclass is the ionic liquid ion source (ILIS), which produce ion beams from the electrostatically stressed meniscus of ionic liquids. ILIS have several applications, two of which include space propulsion and focused ion beam technologies. An ILIS using the 1-butyl-3-methylimidazolium iodide (BMI-I) is characterized with a focus on those properties that would impact its performance in a focused ion beam (FIB) system. The currents obtained in the negative mode from this ILIS are on the order of 100 nA, and composed of nearly 50% pure iodine ions with the remainder composed of solvated ions. The energy deficit of the ion beam is seen to be on the order of 15 eV, with full width at half maximum of about 12 eV. The angular intensity is estimated to be 0.65 tA sr- 1 . The energy signal from the BMI-I ILIS contained several features that suggested a significant amount of ion fragmentation in the acceleration region. This prompted a secondary study using the the ionic liquid 1-methyl-3-methylimidazolium tetrafluoroborate (EMI-BF 4). The amount of fragmentation was seen to be up to 25% of the ion beam. The impact of such fragmentation on the performance of an ILIS thruster is examined. The effects are integrated into the definition of the polydispersive efficiency by characterizing the fragmentation products as two discrete populations of ions and neutrals. This adjusted polydispersive efficiency is seen to be about 88%, about 6% lower than values not taking into account the fragmentation.
by Timothy Peter Fedkiw.
S.M.
Camplese, Davide. "An experimental and numerical study on liquid fragmentation induced by an accidental industrial explosion." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022.
Savoire, Raphaëlle. "Etude multi-échelles de la séparation solide-liquide dans la trituration du lin oléagineux." Compiègne, 2008. http://www.theses.fr/2008COMP1760.
The actual linseed trituration process is based on a mechanical pressing followed by a filtration. This process is in agreement with the considerations of sustainable development. The aim of this work was to study the link between the raw material composition (seed or linseed oil) and the process efficiency. The results have shown that mucilage (polysaccharides from the seed cuticule) was not a parameter influencing the linseed cold pressing. In the seed, the mucilage and reserve substances (as oil) accumulation was highly influenced by the meteorological conditions. The expression of seed before maturity had confirmed that the best harvesting period was at the end of the maturation (after 700 growing degree days). A similarity between the expression performances at laboratory scale on 3 g of seeds and at pilot scale (5 kg/h) was highlighted. This could be a sign of a possible transposition towards industrial scale. A strong effect of phospholipids on expressed oil filtration was displayed. An optimal concentration of 2% of lecithin was identified for oil filtration. The suspension stirring during filtration is not necessary to improve the process. But a filtration at 50°C allowed a very significative increase of the filtration rate. The pursuit of this work on pilot and industrial scale should permit to benefit from a method to determine pressability of the seed in the laboratory. This pressability could allow the prediction of the process industrial efficiency during the seed breeding
Audette, Marilyne. "Modifications radio-induites dans les protéines, étude de la fragmentation et de la polymérisation en solutions aqueuses liquide et gelée." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ60584.pdf.
Wacheul, Jean-Baptiste. "Étude de la fragmentation de métal liquide en chute libre dans un environnement visqueux : application à la formation des planètes." Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0184.
The accretion of terrestrial planets like Earth proceeds partly by impacts of proto-planets already differentiated in a silicate mantle and an iron core. Those impacts result in a two phase flow where the two main components of the planets partially mix for the last time. In order to study the conditions of diffusive transfer of heat and elements during this flow, we have performed experiments using an analog system of fluids. A gallium alloy is used to represent the molten iron core and a viscous fluid is used to represent the molten silicatemantle. Video recordings of the fall of liquid metal spheroids through the viscous fluid areanalyzed as a way to study the dynamics of the post impact flow. Measurements of the temperature of the liquid metal before and after its fall are performed in order to probe the conditions of the diffusive transfer between the two phases integrated along the fall.The diapir is found to dilute by entraining ambient fluid during its fall in a manner thatis well described by the entrainment hypothesis. The fragmentation of the liquid metal is quantified in terms of the break up distance, the mean radius of the droplets as a function of the spheroid’s initial radius andthe distribution of sizes of the droplets. The mean radius of the droplets is marked by the large scale falling speed which we interpret as a sign of a continuous break up process. The distribution of sizes is given by a Bessel function. The data on the dynamics, on the fragmentation and on the temperature are then used to test the existing thermal equilibration models between the two phases
AUDETTE, MARILYNE. "Modifications radio-induites dans les proteines : etude de la fragmentation et de la polymerisation en solutions aqueuses liquide et gelee." Paris 11, 1999. http://www.theses.fr/1999PA112092.
Landeau, Maylis. "Deux aspects de la dynamique des fluides des noyaux planétaires." Paris, Institut de physique du globe, 2013. https://tel.archives-ouvertes.fr/tel-01472508.
Cook, Shannon L. "Metastable Atom-Activated Dissociation (MAD): A Novel Dissociation Method Employed within a Quadrupole Ion Trap Mass Spectrometer." Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1331325173.
McLaughlin, Jacob Ryan. "Control of swelling, electrochemical, and elongation properties of photopolymers through the modification of structure." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6205.
Biasiori-Poulanges, Luc. "Fragmentation aérodynamique d’une goutte liquide induite par une onde de choc plane High-magnification shadowgraphy for the study of dropbreakup in a high-speed gas flow On the formation and recurrent shedding of ligaments in droplet aerobreakup Data on eosin y solutions for laser-induced fluorescence in water flows Multimodal imaging for intra-droplet gas-cavity observation during droplet fragmentation." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2021. http://www.theses.fr/2021ESMA0002.
This thesis proposed a groundbreaking description of the shock-induced aerodynamic fragmentation of a water droplet at the transition of the Rayleigh-Taylor Piercing and the Shear-Induced Entrainment regimes. An experimental facility consisting of a shock tube and high-speed imaging diagnostics is used to investigate the fragmentation processes. Experimental results are supported with numerical simulations performed with the open-source code ECOGEN dedicated to multiphase compressible flows. The shock wave effect on the droplet is assessed by a theoretical modelling based on geometrical acoustics which allows for the description of the wave spatio-temporal dynamics and enables to predict the time-dependent location of the highest energy density. Pressure fields are determined using numerical simulations. It appears that the water tensile rupture is reached for a shock wave Mach number of 1.7 from which bubble cloud cavitation may occur by causing signification changes in the fragmentation dynamics. As regards to the interfacial dynamics, both experiments and numerical simulations show the development of a transverse azimutal modulation resulting in the periodic ligament structure at the droplet surface. Contrary to the modulation growth, its initiation seems to be independent of the capillary effects as revealed by a Fourier analysis of the 3-D numerical results. The ligament dynamics is a cyclic process driven by the vortex shedding process in the wake of the droplet. Four cycles have been observed before the residual droplet core breaks up owing to the growth of an air cavity inside the droplet that acts as weak spot, and thus facilitating the droplet split-off
De, Luca Magali. "Contribution à la modélisation de la pulvérisation d'un liquide phytosanitaire en vue de réduire les pollutions." Phd thesis, Université de la Méditerranée - Aix-Marseille II, 2007. http://tel.archives-ouvertes.fr/tel-00195424.
Cheng, Shijing. "Synthesis and Characterization of Cation-Containing and Hydrogen Bonding Supramolecular Polymers." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/77185.
Ph. D.
Forny, Laurent. "L'eau en poudre." Compiègne, 2007. http://www.theses.fr/2007COMP1701.
Water-rich powders, also called "dry water", containing up to 98% (by weight) of water and still maintaining the same flow properties as a dry powder were prepared by a simple mixing process. Dry water particles are a very convenient carrier system that can be easily produced at industrial scale. Water can be released by evaporation or under mechanical stress. The structure of individual particles bas been studied by electronic microscopy after freeze fracture or water sublimation. Each particle consist in a micrometric water droplet (average diameter of 150 μm) surrounded by a network build up by association of hydrophobic fumed silica particles. Two types of mixing processes were used: high shear processes and atomization processes such as granulators. The quality of the final product depends on the energetic contribution of the process and on the solid/liquid contact angle (evaluated by water intrusion). Potential applications are numerous in the food, pharmaceutical, and cosmetics industry
Belhadef, Abdelhak. "Contribution à la modélisation Eulérienne de l'atomisation pour la pulvérisation agricole." Phd thesis, Université de Provence - Aix-Marseille I, 2010. http://tel.archives-ouvertes.fr/tel-00663344.
Collin, Olivier L. "Development of a Novel Tandem Mass Spectrometry Technique for Forensic and Biological Applications." View abstract, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3292877.
Rossi, Dario. "Fracton phases: analytical description and simulations of their thermal behavior." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23919/.
Verhaegen, Julien. "Modélisation multiphasique d'écoulements et de phénomènes de dispersion issus d'explosion." Thesis, Aix-Marseille 1, 2011. http://www.theses.fr/2011AIX10028/document.
This work focuses on modeling the formation and the dispersion of a cloud of droplets, induced by ejection of a liquid, resulting from an external aggression or an accidental situation. The goal is to build a model able to reproduce simultaneously the conditions which generate the cloud formation and the cloud evolution in time (dispersion). The main difficulty lies in the differences between the already existing models adapted to the description of flows which are able to characterize each stage of the global phenomenon: initially a multiphase flow model with compressible phases (Continuum), then the atomization and the formation of a cloud of droplets dispersed in a carrier phase (dilute flow model). We propose a new approach to achieve an effective coupling between these two models. The problem of the formation and the dispersion of the liquid requires to take into account several physical phenomena: atomization, heat and mass transfers and drag between phases. These phenomena are included in the global model through interaction terms involved in the systems of equations. The construction of this model has permited the realization of calculations describing the formation and dispersion of a cloud of droplets which may occur during, for axample, in accidental situations at industrial sites