Academic literature on the topic 'Bubbler condenser'
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Journal articles on the topic "Bubbler condenser"
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Khazanov, A. L. "Conditions for cessation of complete steam condensation during passage of a steam-air mixture through the water layer in a condenser-bubbler." Power Technology and Engineering 43, no. 4 (July 2009): 251–55. http://dx.doi.org/10.1007/s10749-010-0106-3.
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Lu, Jiacai, and Gretar Tryggvason. "Dynamics of nearly spherical bubbles in a turbulent channel upflow." Journal of Fluid Mechanics 732 (August 30, 2013): 166–89. http://dx.doi.org/10.1017/jfm.2013.397.
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AbstractThe dynamics of bubbles in upflow, in a vertical channel, is examined using direct numerical simulations (DNS), where both the flow and the bubbles are fully resolved. Two cases are simulated. In one case all the bubbles are of the same size and sufficiently small so they remain nearly spherical. In the second case, some of the small bubbles are coalesced into one large bubble. In both cases lift forces drive small bubbles to the wall, removing bubbles from the channel interior until the two-phase mixture is in hydrostatic equilibrium, and forming a bubble-rich wall layer. The same evolution has been seen in earlier DNS of bubbly upflows, but here the friction Reynolds number is higher (${\mathit{Re}}^{+ } = 250$). In addition to showing that the overall structure persists at higher Reynolds numbers, we show that the bubbles in the wall layer form clusters. The mechanism responsible for the clustering is explained and how bubbles move into and out of the wall layer is examined. The dynamics of the bubbles in the channel core is also compared with results obtained in fully periodic domains and found to be similar. The presence of the large bubble disrupts the wall layer slightly, but does not change the overall picture much, for the parameters examined here.
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SMEREKA, PETER. "A Vlasov equation for pressure wave propagation in bubbly fluids." Journal of Fluid Mechanics 454 (March 10, 2002): 287–325. http://dx.doi.org/10.1017/s002211200100708x.
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The derivation of effective equations for pressure wave propagation in a bubbly fluid at very low void fractions is examined. A Vlasov-type equation is derived for the probability distribution of the bubbles in phase space instead of computing effective equations in terms of averaged quantities. This provides a more general description of the bubble mixture and contains previously derived effective equations as a special case. This Vlasov equation allows for the possibility that locally bubbles may oscillate with different phases or amplitudes or may have different sizes. The linearization of this equation recovers the dispersion relation derived by Carstensen & Foldy. The initial value problem is examined for both ideal bubbly flows and situations where the bubble dynamics have damping mechanisms. In the ideal case, it is found that the pressure waves will damp to zero whereas the bubbles continue to oscillate but with the oscillations becoming incoherent. This damping mechanism is similar to Landau damping in plasmas. Nonlinear effects are considered by using the Hamiltonian structure. It is proven that there is a damping mechanism due to the nonlinearity of single-bubble motion. The Vlasov equation is modified to include effects of liquid viscosity and heat transfer. It is shown that the pressure waves have two damping mechanisms, one from the effects of size distribution and the other from single-bubble damping effects. Consequently, the pressure waves can damp faster than bubble oscillations.
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Mori, Y. H. "Artificial Transformation of the Direct-Contact Condensation Pattern of Steam Bubbles in a Hydrophobic Liquid Medium." Journal of Heat Transfer 109, no. 4 (November 1, 1987): 1007–12. http://dx.doi.org/10.1115/1.3248170.
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When steam bubbles are released into a medium of a hydrophobic coolant, the condensate is scattered through the coolant in the form of tiny droplets. This condensation pattern is unfavorable for direct-contact condensers because it is difficult to separate the condensate and the coolant. This paper proposes a novel bubble-release device by which the condensation pattern is so transformed that the condensate remains within the confines of the bubble wall. An experimental examination with single steam bubbles released into a medium of liquid paraffin is demonstrated.
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Sun, T. Y., R. N. Parthasarathy, and G. M. Faeth. "Structure of Bubbly Round Condensing Jets." Journal of Heat Transfer 108, no. 4 (November 1, 1986): 951–59. http://dx.doi.org/10.1115/1.3247040.
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A theoretical and experimental study of turbulent bubbly condensing jets is reported. Tests involved initially monodisperse carbon dioxide bubbles in water (∼ 1 mm diameter bubbles with initial gas volume fractions of 2.4 and 4.8 percent) injected vertically upward in still water. Measurements were made of mean and fluctuating phase velocities, mean bubble diameters, mean bubble number intensities, and mean concentrations of dissolved carbon dioxide. Three theoretical methods were used to interpret the measurements: (1) locally homogeneous flow analysis, assuming infinitely fast interphase transport rates; (2) deterministic separated flow analysis, where finite interphase transport rates are considered but bubble/turbulence interactions are ignored; and (3) stochastic separated-flow analysis where both finite interphase transport rates and bubble/turbulence interactions are considered using random-walk methods. Both finite interphase transport rates and the turbulent dispersion of bubbles were important for present test conditions; therefore, only the stochastic separated flow analysis provided reasonable agreement with measurements.
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Oliveira, de, Machado Ochoski, Conrado Chiarello, Dos Nunes, Silva da, Dos Dias, and Alves Antonini. "Experimental study of hydrodynamic parameters regarding on geyser boiling phenomenon in glass thermosyphon using wire-mesh sensor." Thermal Science, no. 00 (2021): 221. http://dx.doi.org/10.2298/tsci201008221o.
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The thermosyphon is a type of heat exchanger that has been widely used in many applications. The use of thermosyphons has been intensified in recent years, mainly in the manufacture of solar collectors and various industrial activities. A thermosyphon is a vertical sealed tube filled with a working fluid, consisting of, from bottom to top, by an evaporator, an adiabatic section, and a condenser. The study of geyser-boiling phenomena, which occurs inside the thermosyphon is of extreme importance, therefore the experimental analysis of the parameters related to the two-phase flow (liquid-steam), such as void fraction, bubble frequency, bubble velocity, and bubble length are necessary, since these parameters have a significant influence on heat transfer. In this work, a pair of wire mesh sensors was used, a relative innovative technology to obtain experimental values of the reported quantities for measuring these parameters of slug flow in thermosyphons. An experimental setup is assembled and the sensors are coupled to the thermosyphon enabling the development of the experimental procedure. Here is presented an experimental study of a glass thermosyphon instrumented with two Wire-Mesh Sensors, in which the aforementioned slug flow hydrodynamic parameters inherent to the geyser type boiling process are measured. It was measured successfully, as a function of the heat load (110, 120, 130, 140, and 150W), the void fraction (instantly and average), liquid film thickness, translation velocity of the elongated bubbles, lengths of the bubbles, and the liquid slug (displaced by the bubble rise up). It was observed that the higher the heat load, the lower is the bubble translation velocity. For all heat loads, based on the measured length of liquid slug (consequent displacement of liquid volume), caused by bubbles rise from evaporator to condenser, it could be affirmed to some extent that both boiling regime (pool and film) exist in the evaporator. The measured average void fraction (80%) and liquid film thickness (around 2.5mm) during the elongated bubble passages were approximately constant and independent of the heat load.
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Smereka, Peter, and Graeme W. Milton. "Bubbly flow and its relation to conduction in composites." Journal of Fluid Mechanics 233 (December 1991): 65–81. http://dx.doi.org/10.1017/s0022112091000393.
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Following Wallis, the relation between non-viscous bubbly flow and conduction in composites is examined. The bubbles are treated as incompressible and correspond to non-conducting inclusions. A simple relation is found between the effective conductivity and the energy coefficient which is agreement with previous calculations. It is shown that the energy coefficient is frame dependent and, in the frame of zero volumetric flux, is equal to the virtual mass density. Zuber's virtual mass density corresponds to the conductivity of the Hashin–Shtrikman coated-sphere geometry. This connection is exploited to extend Zuber's result to ellipsoidal bubbles. The hyperbolicity of effective equations derived from a variational principle is analysed for various bubble configurations. Without bubble clustering the equations are ill-posed (unstable). However, when the bubbles group into ellipsoidal clusters the resulting effective equations are well-posed for a wide range of parameter values.
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RASTELLO, MARIE, JEAN-LOUIS MARIÉ, NATHALIE GROSJEAN, and MICHEL LANCE. "Drag and lift forces on interface-contaminated bubbles spinning in a rotating flow." Journal of Fluid Mechanics 624 (April 10, 2009): 159–78. http://dx.doi.org/10.1017/s0022112008005399.
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The equilibrium position of a spherical air bubble in a solid body rotating flow around a horizontal axis is investigated experimentally. The flow without bubbles is checked to be solid body rotating. The area of influence of the bubble is characterized to determine for each bubble whether the incoming flow is perturbed or not. The demineralized water used is shown to Tbe contaminated, and spinning of the bubble's interface is observed and measured. From the measurement of the bubble's equilibrium position, drag and lift coefficients are determined. They appear to be dependent on two dimensionless numbers. Eo the Eötvös number and Rω the rotational Reynolds number (or Taylor number Ta) can be varied independently by changing the control parameters, and for that reason are the convenient choice for experiments. (Re, Ro) with Ro the Rossby number is an equivalent choice generally adopted in the literature for numerical simulations, and Re denotes the Reynolds number. When using this second representation, the Ro number appears to be an indicator of the influence on the force coefficients of the shear, of the curvature of the streamlines of the flow and of the bubble's spinning. The bubble's spinning effect on the lift force is far from trivial. Its contribution explains the important gap between lift values for a bubble (not spinning) in a clean fluid and for a bubble (spinning) in a contaminated fluid as present.
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Lelouvetel, J., T. Tanaka, Y. Sato, and K. Hishida. "Transport mechanisms of the turbulent energy cascade in upward/downward bubbly flows." Journal of Fluid Mechanics 741 (February 13, 2014): 514–42. http://dx.doi.org/10.1017/jfm.2014.24.
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AbstractThe turbulent energy cascade in an upward or downward bubbly pipe flow with a Reynolds number of 1.5 × 104 was experimentally investigated in order to examine the effects of the flow direction on the turbulence modifications by bubbles. The bubble diameter was approximately 1 mm. The combination of a particle tracking velocimetry (PTV) system with Kolmogorov-order spatial and temporal resolutions and a shape projection imaging (SPI) system was used to simultaneously capture the liquid and bubble motions. The physical mechanisms of turbulence modification at each length scale, or in wavenumber space, were investigated by introducing a filtering-based scaling analysis, in which the filtering techniques derived from large eddy simulation (LES) were applied to the PTV measurements. The analysis can be used to examine the turbulent kinetic energy (TKE) exchange between bubbles and flows at each wavenumber. We observed significant differences in the flow statistics and turbulent energy budget of upward and downward flows, which are due to the sign of the relative velocity of bubbles. A negative relative velocity (downward flow) induces greater modifications in the energy budget than a positive relative velocity (upward flow), which suggests that the bubble-transport term of the turbulent energy is greater when the flow has to push down the bubbles. The flow provides more energy to the bubbles when it pushes them in the downward direction. The flow will also receive and dissipate more energy from the bubbles in a downward flow compared with an upward flow due to the greater transverse motion of the bubbles. The analysis introduced in the present study shows that the energy transfer from large to small scales is decreased in an upward flow and is increased in a downward flow. Similarly, the sign of the bubble term indicates that turbulent flow receives energy from bubbles in an upward flow, while it transfers energy to bubbles in a downward flow. We also observed that this energy transport is approximately 10 times larger in a downward flow than in an upward flow.
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ZERAVCIC, ZORANA, DETLEF LOHSE, and WIM VAN SAARLOOS. "Collective oscillations in bubble clouds." Journal of Fluid Mechanics 680 (June 6, 2011): 114–49. http://dx.doi.org/10.1017/jfm.2011.153.
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In this paper the collective oscillations of a bubble cloud in an acoustic field are theoretically analysed with concepts and techniques of condensed matter physics. More specifically, we will calculate the eigenmodes and their excitabilities, eigenfrequencies, densities of states, responses, absorption and participation ratios to better understand the collective dynamics of coupled bubbles and address the question of possible localization of acoustic energy in the bubble cloud. The radial oscillations of the individual bubbles in the acoustic field are described by coupled linearized Rayleigh–Plesset equations. We explore the effects of viscous damping, distance between bubbles, polydispersity, geometric disorder, size of the bubbles and size of the cloud. For large enough clusters, the collective response is often very different from that of a typical mode, as the frequency response of each mode is sufficiently wide that many modes are excited when the cloud is driven by ultrasound. The reason is the strong effect of viscosity on the collective mode response, which is surprising, as viscous damping effects are small for single-bubble oscillations in water. Localization of acoustic energy is only found in the case of substantial bubble size polydispersity or geometric disorder. The lack of localization for a weak disorder is traced back to the long-range 1/r interaction potential between the individual bubbles. The results of the present paper are connected to recent experimental observations of collective bubble oscillations in a two-dimensional bubble cloud, where pronounced edge states and a pronounced low-frequency response had been observed, both consistent with the present theoretical findings. Finally, an outlook to future possible experiments is given.
Dissertations / Theses on the topic "Bubbler condenser"
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Studýnka, Radim. "Modely a analýzy v kontejnmentovém systému s potlačením tlaku při haváriích s únikem chladiva." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231495.
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This diploma thesis deals with a pressure suppression system containment during the loss of coolant accidents. It is focused on the containment systems of the nuclear power plants with VVER-440/V-213 reactors. There is described the process of loss of coolant accident. There was designed input model which consists of the zones representing the areas which are connected with junctions and heat structures. Were then selected input parameters for the model calculations. And finally, there have been several calculations for the selected parameters.
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Apte, Pankaj A. "Phase equilibria and nucleation in condensed phases a statistical mechanical study /." Columbus, Ohio : Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1135876018.
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Levine, Edlyn Victoria. "Extreme Liquid Superheating and Homogeneous Bubble Nucleation in a Solid State Nanopore." Thesis, Harvard University, 2016. http://nrs.harvard.edu/urn-3:HUL.InstRepos:33493497.
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This thesis explains how extreme superheating and single bubble nucleation can be achieved in an electrolytic solution within a solid state nanopore. A highly focused ionic current, induced to flow through the pore by modest voltage biases, leads to rapid Joule heating of the electrolyte in the nanopore. At sufficiently high current densities, temperatures near the thermodynamic limit of superheat are achieved, ultimately leading to nucleation of a vapor bubble within the nanopore.
A mathematical model for Joule heating of an electrolytic solution within a nanopore is presented. This model couples the electrical and thermal dynamics responsible for rapid and extreme superheating of the electrolyte within the nanopore. The model is implemented numerically with a finite element calculation, yielding a time and spatially resolved temperature distribution in the nanopore region. Temperatures near the thermodynamic limit of superheat are predicted to be attained just before the explosive nucleation of a vapor bubble is observed experimentally.
Knowledge of this temperature distribution is used to evaluate related phenomena including bubble nucleation kinetics, relaxation oscillation, and bubble dynamics. In particular, bubble nucleation is shown to be homogeneous and highly reproducible. These results are consistent with experimental data available from electronic and optical measurements of Joule heating and bubble nucleation in a nanopore.Engineering and Applied Sciences - Applied Physics
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Apte, Pankaj A. "Phase equilibria and nucleation in condensed phases: a statistical mechanical study." The Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=osu1135876018.
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Kocarkova, Helena. "Stability of glass foams : experiments at the bubble scale and on vertical film." Phd thesis, Université Paris-Est, 2011. http://tel.archives-ouvertes.fr/tel-00664444.
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For investigating glass foams stability, experiments with a single bubble rising towards the free surface of molten glass and with vertical films are performed for several values of glass chemical composition, viscosity, bubble size and gas nature. The glass lamella on top of the bubble is observed by video-recording and its thickness evolution is measured by optical interferometry. The lamella thins as a result of buoyancy and capillary forces and then it ruptures. Actually the lamella thinning occurs in two steps. In the first step, the drainage is regular and the thinning rate depends on Bond number. In the second step a backward flow is observed above 1200°C for ordinary soda-lime-silica glass, which is explained as Marangoni counter flow due to evaporation of volatile species such as sodium. As the lamella ruptures tiny bubbles are created by the rupture of bubble lamella on the free surface for large bubbles and low viscosity of the melt
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Fang, Jieping. "New Methods to Create Multielectron Bubbles in Liquid Helium." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10673.
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An equilibrium multielectron bubble (MEB) in liquid helium is a fascinating object with a spherical two-dimensional electron gas on its surface. After it was first observed a few decades ago, a plethora of physical properties of MEBs, for example, a tunable surface electron density, have been predicted. In this thesis, we will discuss two new methods to create MEBs in liquid helium. Before the discussion, the way to generate a large number of electrons in a low temperature system will be discussed, including thermionic emission and field emission in helium. In the first new method to make MEBs, we used a dome-shaped cell filled with superfluid helium in which an MEB was created and confined at the dome. The lifetime of the MEB was substantially longer than the previously reported observations of MEBs. In the second method, MEBs were extracted from the vapor sheath around an electrically heated tungsten filament submerged in liquid helium, either by a high electric field (up to 15 kV/cm) or by a sudden increase of a negative pressure in liquid helium. High-speed photography was used to capture the MEB's motion. A method to determine the number of electrons was developed by monitoring the oscillations of the MEBs. Finally, an electromagnetic trap was designed to localize the MEBs created using the second method, which was important for future studies of the properties of MEBs.Physics
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Vincent, Olivier. "Dynamique de bulles de cavitation dans de l'eau micro-confinée sous tension. Application à l'étude de l'embolie dans les arbres." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00807749.
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Les liquides sont capables, comme les solides, de supporter des forces de traction. Ils sont alors à pression négative (c'est-à-dire en tension), dans un état qui est métastable. Le retour vers un état stable à pression positive peut se faire par la nucléation d'une bulle, un processus appelé cavitation. Dans cette thèse nous nous intéressons aux propriétés de la cavitation en milieu confiné, avec un accent particulier sur la dynamique des bulles. Ce sujet est motivé par l'étude du transport de l'eau dans les arbres dont une partie (la sève montante) se fait sous tension, dans des canaux micrométriques. La cavitation entraîne alors l'embolie des éléments conducteurs de sève, c'est-à-dire leur remplissage par du gaz. Une grande partie du manuscrit est consacrée à l'étude de la cavitation dans un milieu modèle, où de l'eau est confinée dans des inclusions sphériques micrométriques au sein d'un hydrogel. L'évaporation passive de l'eau à travers le gel permet de générer des pressions négatives, et la cavitation peut se produire spontanément ou être déclenchée à l'aide d'un laser. Nous résolvons la dynamique subséquente de la bulle à l'aide de diverses méthodes (caméra time-lapse ou caméra rapide, diffusion de la lumière, strobophotographie laser ...) et montrons qu'après une séquence inertielle ultra-rapide, la bulle atteint un état d'équilibre temporaire, puis grossit de manière quasi-statique sous l'effet des flux d'eau dans l'hydrogel, provoquant "l'embolie" de l'inclusion. Une place importante est accordée à un chapitre de théorie qui explore d'une part les propriétés thermodynamiques d'un liquide confiné à pression négative, et d'autre part la dynamique aux temps courts de bulles de cavitation dans de tels systèmes. Nous proposons ainsi une équation de Rayleigh-Plesset modifiée qui rend compte de l'accélération importante des oscillations radiales des bulles que nous avons observée expérimentalement. La compressibilité du liquide et l'élasticité du confinement sont des éléments-clés de ce modèle. Enfin, nous discutons l'application des résultats précédents dans le contexte des arbres, tout en proposant une nouvelle méthode expérimentale qui permet un suivi optique du processus d'embolie. Nous présentons quelques résultats obtenus sur des échantillons de pin sylvestre.
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Siedel, Samuel. "Bubble dynamics and boiling heat transfer : a study in the absence and in the presence of electric fields." Phd thesis, INSA de Lyon, 2012. http://tel.archives-ouvertes.fr/tel-00876630.
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Since boiling heat transfer affords a very effective means to transfer heat, it is implemented in numerous technologies and industries ranging from large power generation plants to micro-electronic thermal management. Although having been a subject of research for several decades, an accurate prediction of boiling heat transfer is still challenging due to the complexity of the coupled mechanisms involved. It appears that the boiling heat transfer coefficient is intimately related to bubble dynamics (i.e. bubble nucleation, growth and detachment) as well as factors such as nucleation site density and interaction between neighbouring and successive bubbles. In order to contribute to the understanding of the boiling phenomenon, an experimental investigation of saturated pool boiling from a single or two neighbouring artificial nucleation sites on a polished copper surface has been performed. The bubble growth dynamics has been characterized for different wall superheats and a experimental growth law has been established. The interaction between successive bubbles from the same nucleation site has been studied, showing the bubble shape oscillations that can be caused by these interactions. The forces acting on a growing bubble has been reviewed, and a complete momentum balance has been made for all stages of bubble growth. The curvature along the interface has been measured, and indications concerning the mechanism of bubble detachment have been suggested. The rise of bubble after detachment has been investigated, and the maximum velocity reached before a change of direction has been estimated and compared to existing models from the literature. The interaction between bubbles growing side by side has been studied: the generation and propagation of a wave front during the coalescence of two bubbles has been highlighted. As boiling heat transfer enhancement techniques are being imagined and developed, this study also focuses on the electrohydrodynamic enhancement technique. Boiling experiments have been performed in the presence of electric fields, and their effects on heat transfer and bubble dynamics have been characterized. Although the volume of the bubbles at detachment and the relationship between the bubble frequency and the wall superheat were not affected, the bubble growth curve was modified. The bubbles were elongated in the direction of the electric field, and this elongation was estimated and compared to other studies from the literature. The rising velocity of the bubble was reduced in the presence of electric field, and the behaviour of bubbles growing side by side was modified, the electric field causing the bubbles to repeal each other. These results, obtained in a fully controlled environment, provide compelling evidence that electric fields can be implemented to alter the bubble dynamics and subsequently heat transfer rates during boiling of dielectric fluids.
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Jomni, Fathi. "Étude des phénomènes hydrodynamiques engendrés dans les liquides diélectriques par un champ électrique très intense." Université Joseph Fourier (Grenoble ; 1971-2015), 1997. http://www.theses.fr/1997GRE10118.
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L'experience montre que tout liquide isolant soumis a une tension croissante est traverse par un courant qui croit rapidement jusqu'au claquage. La connaissance des mecanismes conduisant au claquage necessite une etude tres approfondie des phenomenes physiques qui le precedent. En effet, ces phenomenes sont d'une grande complexite, ils mettent en jeu aussi bien des processus electroniques dans un milieu dense et desordonne (injection et chauffage des electrons, ionisation, etc. ) que des processus thermodynamiques et hydrodynamiques (changement de phase, emission d'ondes de choc et formation de bulles, propagation d'un canal gazeux). C'est dans ce contexte que se situe notre travail avec un interet plus marque pour la comprehension des phenomenes hydrodynamiques. Nous presentons dans ce memoire une etude experimentale sur l'evolution des phenomenes hydrodynamiques (bulle, onde de choc) en fonction de la nature du liquide, de l'energie deposee suite a l'avalanche electronique (0,01-100nj), et de la pression hydrostatique appliquee dans un large domaine de pression (0,1-10mpa), etc. . Une analyse des rebonds successifs de la bulle et des mecanismes dissipatifs intervenant est egalement presentee. Tout d'abord, nous avons mis en evidence l'existence de la bulle bien au dela de la pression critique du liquide. Les phenomenes physiques observes dans nos experiences sont semblables (exception faite pour l'origine des electrons initiaux) a ceux decrits suite a un claquage optique et ils suivent la meme chronologie des evenements. Ce sont seulement les temps et les dimensions caracteristiques qui different suivant le mode de claquage. Ensuite, nos resultats experimentaux sur des liquides de viscosite croissante nous ont permis de mettre en evidence l'existence de deux regimes qui peuvent gouverner la dynamique de la bulle : le regime inertiel et le regime visqueux. Ce resultat est conforte par les resultats theoriques obtenus par integration numerique de l'equation de rayleigh-plesset.
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Templier, Claude. "Etude expérimentale de la précipitation dans les alliages à base d'aluminium obtenus par implantation ionique de Cu, Ag et Xe : demixtion et dissolution dans les alliages Al-Ag et Al-Cu, structure, formation et croissance des bulles de xenon." Poitiers, 1987. http://www.theses.fr/1987POIT2017.
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Analyse de la microstructure des alliages al-ag et al-cu fabriques par implantation ionique. Analyse des zones de guinier-preston et des phases intermediaires dans l'alliage al-cu irradie par des ions xenon de 300 kev. Mise en evidence des mecanismes de diffusion acceleree, diffusion balistique et precipitation. Pour les echantillons irradies avec des ions xenon, des bulles de xenon solide se forment. Etude de la demixion , du xenon dans des matrices d'aluminium: structure des bulles apres l'implantation , formation des bulles pendant l'implantation, evolution des bulles lors des traitements thermiques
Books on the topic "Bubbler condenser"
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United States. National Aeronautics and Space Administration., ed. Studies on pressure response of gas bubbles contributions of condensed droplets in bubbles generated by a uniform nucleation. Washington, DC: National Aeronautics and Space Administration, 1988.
Find full textBook chapters on the topic "Bubbler condenser"
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Kalia, Rajiv K., P. Vashishta, S. W. de Leeuw, and John Harris. "Quantum Molecular Dynamics Simulation of Electron Bubbles in a Dense Helium Gas." In Condensed Matter Theories, 71–76. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4613-0605-4_8.
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Portella-Oberli, M. T., C. Jeannin, and M. Chergui. "Subpicosecond Study of Bubble Formation upon Rydberg State Excitation in Condensed Rare Gases." In Advances in Chemical Physics, 711–18. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2007. http://dx.doi.org/10.1002/9780470141601.ch27.
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FENG, K. K., D. E. G. JONES, and S. K. CHAN. "SHOCK INITIATION OF BUBBLE SENSITIZED COMMERCIAL EXPLOSIVES." In Shock Compression of Condensed Matter–1991, 691–94. Elsevier, 1992. http://dx.doi.org/10.1016/b978-0-444-89732-9.50159-x.
Full textConference papers on the topic "Bubbler condenser"
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Kostka, Pal, Zsolt Techy, and James J. Sienicki. "Hydrogen Mixing Analyses for a VVER Containment." In 10th International Conference on Nuclear Engineering. ASMEDC, 2002. http://dx.doi.org/10.1115/icone10-22206.
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Hydrogen combustion may represent a threat to containment integrity in a VVER-440/213 plant owing to the combination of high pressure and high temperature. A study has been carried out using the GASFLOW 2.1 three-dimensional CFD code to evaluate the hydrogen distribution in the containment during a beyond design basis accident. The VVER-440/213 containment input model consists of two 3D blocks connected via one-dimensional (1D) ducts. One 3D block contains the reactor building and the accident localization tower with the suppression pools. Another 3D block models the air traps. 1D ducts represent the check valves connecting the accident localization tower with the air traps. The VVER pressure suppression system, called “bubbler condenser,” was modeled as a distributed heat sink with water thermodynamic properties. This model accounts for the energy balance. However, it is not currently possible to model dynamic phenomena associated with the water pools (e.g., vent clearing, level change). The GASFLOW 2.1 calculation gave detailed results for the spatial distribution of thermal-hydraulic parameters and gas concentrations. The range and trend of the parameters are reasonable and valuable. There are particularly interesting circulation patterns around the steam generators, in the bubbler tower and other primary system compartments. In case of the bubbler tower, concentration and temperature contour plots show an inhomogeneous distribution along the height and width, changing during the accident. Hydrogen concentrations also vary within primary system compartments displaying lower as well as higher (up to 13–20% and higher) values in some nodes. Prediction of such concentration distributions was not previously possible with lumped parameter codes. GASFLOW 2.1 calculations were compared with CONTAIN 1.2 (lumped parameter code) results. Apart from the qualitatively similar trends, there are, for the time being, quantitative differences between the results concerning, for example, pressure histories, or the total amount of steam available in the containment. The results confirm the importance of detailed modeling of the containment, as well as of the bubbler condenser and sump water pools. The study showed that modeling of hydrogen distribution in the VVER-440/213 containment was possible using the GASFLOW 2.1 code with reasonable results and remarkable physical insights.
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Hu, J. S., and Christopher Y. H. Chao. "Fluid Flow and Heat Transfer Characteristics of Slug Bubbly Flow in Micro Condensers." In 2007 First International Conference on Integration and Commercialization of Micro and Nanosystems. ASMEDC, 2007. http://dx.doi.org/10.1115/mnc2007-21102.
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Experiments were carried out to study the condensation flow pattern in silicon micro condenser using water as medium. Five flow patterns were identified under our experimental conditions. Slug-bubbly flow and droplet/liquid slug flow were found to be the two dominant flows in the micro condenser. These two flow patterns subsequently determined the heat transfer and pressure drop properties of the fluid. It was observed that only slug-bubbly flow existed in low steam mass flow and high heat flux conditions. When the steam mass flow rate increased or the heat flux dropped, mixed flow pattern occurred. An empirical correlation was obtained to predict when the transition of the flow pattern from slug-bubbly flow to mixed flow could appear. In the slug-bubbly flow regime, heat transfer coefficient and pressure drop in the micro condensers were studied. It was found that micro condensers with smaller channels could exhibit higher heat transfer coefficient and pressure drop. At constant heat flux, increasing the steam mass flow rate resulted in a higher heat transfer coefficient and also the pressure drop.
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Chen, Q., and R. S. Amano. "Experimental Study of Annular and Stratified Flows in Horizontal Micro-Fin Tubes." In ASME 4th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2006. http://dx.doi.org/10.1115/icnmm2006-96104.
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In this paper, a new kind of evaporative heat transfer experiment for the cooling process of coolers/condensers is conducted. The design of the test coils is immersed in an air-water bubbling layer. The air-water two-phase flow passes through the tubes of the coils. Due to the motion of the air bubbles in the water, a thin water film forms on the surface of the tube. As the air bubbles pass by the tube this water film is evaporated into the air. The tubes of coil reject heat to the water film, and the evaporation of the water film rejects heat to the air bubble stream. This heat transfer mode significantly increases the heat transfer coefficient between tubes and air. The consumption of the power of a water pump can be decreased. Moreover, the airflow rate required is less than that of an air-cooled condenser. The pressure drop of air through air-water bubbling layer and the heat transfer between the tube and water are experimentally investigated in this paper. The results show that the factors affecting the pressure drop and the heat transfer coefficient involve the pore geometry of sieve plate, the height of the air-water bubbling layer, the air flow rate through the sieve plate and the heat flux of tubes. The heat transfer coefficient between tube and water is two times larger than that of falling film of water on the outer surface of tube.
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Chen, Qinghua, R. S. Amano, Linli Zhou, and Yi Hou. "Evaporative Heat Transfer Experiment of Air-Water Bubbly Flow." In ASME 2003 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/detc2003/cie-48248.
Full textAbstract:
In this paper, a new kind of evaporative heat transfer experiment for the cooling process of coolers/condensers is conducted. The design of the test coils is immersed in an airwater bubbling layer. The air-water two-phase flow passes through the tubes of the coils. Due to the motion of the air bubbles in the water, a thin water film forms on the surface of the tube. As the air bubbles pass by the tube this water film is evaporated into the air. The tubes of coil reject heat to the water film, and the evaporation of the water film rejects heat to the air bubble stream. This heat transfer mode significantly increases the heat transfer coefficient between tubes and air. The consumption of the power of a water pump can be decreased. Moreover, the airflow rate required is less than that of an aircooled condenser. The pressure drop of air through air-water bubbling layer and the heat transfer between the tube and water are experimentally investigated in this paper. The results show that the factors affecting the pressure drop and the heat transfer coefficient involve the pore geometry of sieve plate, the height of the air-water bubbling layer, the air flow rate through the sieve plate and the heat flux of tubes. The heat transfer coefficient between tube and water is two times larger than that of falling film of water on the outer surface of tube.
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McQuillen, John, John Sankovic, and Nancy Rabel Hall. "Multiphase Flow Separators in Reduced Gravity." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-80764.
Full textAbstract:
Gas phase and liquid phase separation is necessary for one of two reasons. First, system-critical components are designed to specifically operate in a single phase mode only. Pumps, especially centrifugal pumps, lose their prime when gas bubbles accumulate in the impellor housing. Turbines and compressors suffer from erosion problems when exposed to vapor laden with liquid droplets. The second reason is that system performance can be significantly enhanced by operating in a single phase mode. The condensation heat transfer coefficient can be enhanced when the liquid of an entering two-phase stream is stripped thus permitting initial direct contact of the vapor with the cold walls of the condenser. High efficiency and low mass Environmental Control and Life Support Systems invariably require multiphase processes. These systems consist of water filtration and purification via bioreactors that encounter two phase flow at the inlets from drainage streams associated with the humidity condensate, urine, food processing, and with ullage bubble effluent from storage tanks. Entrained gases in the liquid feed, could have deleterious effects on the performance of many of these systems by cavitating pumps and poisoning catalytic packed bed bioreactors. Phase separation is required in thermal management and power systems whereby it is necessary to have all vapor entering the turbine and all liquid exiting the condenser and entering the pump in order to obtain the highest reliability and performance of these systems. Power systems which utilize Proton Exchange Membrane Fuel Cells generate a humidified oxygen exit stream whereby the water vapor needs to be condensed and removed to insure reliable and efficient system operation. Gas-liquid separation can be achieved by a variety of means in low gravity. Several active and passive techniques are examined and evaluated. Ideally, a system that functions well in all gravity environments that the system experiences is a requirement
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Cho, Yong Soo. "Interaction of two bubbles in water." In Shock compression of condensed matter. AIP, 2000. http://dx.doi.org/10.1063/1.1307304.
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Zhang, Wei, and Jinliang Xu. "Multichannel Effect of Condensation Flow and Heat Transfer in Horizontally Positioned Silicon Microchannels With the Channel Depth Down to Thirty Microns." In ASME 2008 First International Conference on Micro/Nanoscale Heat Transfer. ASMEDC, 2008. http://dx.doi.org/10.1115/mnht2008-52315.
Full textAbstract:
Multichannel effect is an important issue in micro condensers. In the present paper, we fabricated a silicon chip, consisting of three rectangular microchannels, with each width of 800 microns but depth down to 30 microns. Saturated vapor of water enters the entrance of microchannels which were horizontally positioned. There are two types of flow patterns: (1) the annular flow at high inlet pressures; (2) the quasi-stable bubble slug in the microchannel upstream followed by the isolated bubbles downstream, at moderate or low inlet pressures. For the second flow pattern, the downstream isolated bubble is formed by breaking up: (1) the single vapor thread connecting the upstream bubble slug and the detaching bubble; (2) the dual vapor threads synchronously in the center microchannel; (3) the dual vapor threads non-synchronously in the side microchannels. The flow patterns in the two side channels are symmetry against the center microchannel. The upstream bubble slug is shorter in the side channels than in the center channel. The temperature gradient across the chip width direction accounts for the non-synchronously break-up of the dual vapor threads connecting the bubble slug and the detaching bubble, in the side channels, indicating the multichannel effects.
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Sychev, A. I. "“Bubble” detonation." In HIGH-ENERGY PROCESSES IN CONDENSED MATTER (HEPCM 2020): Proceedings of the XXVII Conference on High-Energy Processes in Condensed Matter, dedicated to the 90th anniversary of the birth of RI Soloukhin. AIP Publishing, 2020. http://dx.doi.org/10.1063/5.0028338.
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Wu, Jinfeng, and Vijay K. Dhir. "Numerical Simulations of Dynamics and Heat Transfer Associated With a Single Bubble in the Presence of Noncondensables." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-43551.
Full textAbstract:
Under subcooled boiling conditions, the liquid may contain dissolved noncondensabe gases. During phase change at the bubble-liquid interface, noncondensable gases will be injected into the bubble along with vapor. Due to heat transfer into sub-cooled liquid, vapor will condense in the upper regions of the bubble and the bubble interface is impermeable to noncondensables. As a result, noncondensabe gases will accumulate at the top of bubbles. This existing gradient of noncondensable concentration inside bubble determines the saturation temperature gradient around the bubble surface. The nonuniform saturation temperature may cause a difference in surface tension which would give rise to thermocapillary convection in the vicinity of the interface. So far, this description is merely a hypothesis. It is felt that much inspection is in vital demand to clarify the uncertainty as to the role of noncondensables throughout this process. In this study, air is taken as noncondensable gas, and the aim is to investigate the effects of noncondensable air on heat transfer and bubble dynamics. The results from a numerical procedure coupling level set function with moving mesh method show the evidence of effects of noncondensable air imposed on heat transfer and the induced flow pattern is presented as well.
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Sakurai, Hisashi, Yasuo Koizumi, and Hiroyasu Ohtake. "Orientation-Free Micro Heat Pipe." In ASME 3rd International Conference on Microchannels and Minichannels. ASMEDC, 2005. http://dx.doi.org/10.1115/icmm2005-75066.
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A simple design micro-heat pipe was proposed. It was composed of a 20.0 × 20.0 mm square flow circuit which had two adjacent narrow-sides (1.0 × 1.0 mm2 or 0.5 × 1.0 mm2) and two adjacent wide-sides (5.0 × 1.0 mm2 or 2.5 × 1.0 mm2). A heating spot was at the narrow side and a cooling spot was at the wide side. Working fluid was ethanol. The flow circuit was placed horizontally. Bubbles generated at the heating spot migrated toward the wide side, the bubbles coalesced there to form a large bubble, and then the large bubble moved to the cooling spot. Finally, the large bubble was condensed at the cooling spot. This cycle repeated continuously. As a result of it, heat transport from the heating spot to the cooling spot was produced in the micro heat pipe even if it was arranged horizontally. It was confirmed that this simple device works as the heat pipe. An analysis of a flow mechanism was performed by solving a simple flow equation based on the flow resistance. It was proved that one-way circulation flow could be formed in the flow circuit. Predicted flow velocities were close to measured velocities. The heat transport performance of the proposed micro heat pipe was much better than the heat conduction of a stainless steel plate.