Thematische Bibliographien / Cavitation nuclei

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Auswahl der wissenschaftlichen Literatur zum Thema „Cavitation nuclei“

Autor: Grafiati

Veröffentlicht am 28. Juni 2021

Zuletzt aktualisiert am 1. Februar 2022

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Zeitschriftenartikel zum Thema "Cavitation nuclei"

d’Agostino, L., T. Pham und S. Green. „Comparison of a Cavitation Susceptibility Meter and Holography for Nuclei Detection in Liquids“. Journal of Fluids Engineering 111, Nr. 2 (01.06.1989): 197–203. http://dx.doi.org/10.1115/1.3243623.

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This work compares the results obtained from a Cavitation Susceptibility Meter (CSM) and from direct holographic observations for the detection of cavitation nuclei in tap water samples. The CSM uses a cavitating venturi tube to measure the concentration of active cavitation nuclei as a function of the pressure at the venturi throat, while the holographic system measures the nuclei concentration size distribution. Microbubbles are used as the dominant type of cavitation nuclei. The data from the two nuclei detection methods are then compared and interpreted in view of the expected dynamic behavior of microbubbles in the CSM venturi throat. Both results show that the concentration of active cavitation nuclei initially increases exponentially with the applied tension, reaches a maximum and remains nearly constant thereafter when few additional nuclei are left to cavitate. In its current configuration the CSM tends to underestimate the concentration of active cavitation nuclei and to overestimate the value of the nuclei critical pressure as a consequence of sensitivity limitations and interference effects between the cavities.

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Strasberg, M. „Cavitation nuclei and cavitation noise“. Journal of the Acoustical Society of America 83, S1 (Mai 1988): S39. http://dx.doi.org/10.1121/1.2025338.

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d’Agostino, L., und A. J. Acosta. „Separation and Surface Nuclei Effects in a Cavitation Susceptibility Meter“. Journal of Fluids Engineering 113, Nr. 4 (01.12.1991): 695–98. http://dx.doi.org/10.1115/1.2926536.

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This work is concerned with the effects of flow separation and surface nuclei on the operation of a fixed geometry Cavitation Susceptibility Meter (CSM) with laminar flow. Cavitation is induced under controlled conditions at the throat of a glass venturi tube for the measurement of the active nuclei concentration in water samples as a function of the applied tension. Both cavitation and flow velocity are monitored optically by a Laser Doppler Velocimeter. The throat pressure is determined indirectly from the upstream pressure and the local flow velocity. The results show that laminar flow separation and surface nuclei effects are the most stringent operational limitations. Separation in the diffuser increases the minimum attainable throat pressure above the susceptibility of most cavitation nuclei commonly found in technical waters. Surface nuclei can generate extensive sheet or spot cavitation at relatively high tensions even on optically finished glass surfaces. These phenomena are difficult to eliminate and bring therefore into question the practical utility of CSM’s with laminar flow and fixed geometry for the measurement of the dependence of the cavitating nuclei concentration over wide ranges of the applied tension, as required for cavitation studies.

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Fu, Qiang, Mengyuan Li, Xiuli Wang, Jianen Yu und Rongsheng Zhu. „Nanoscale bubble study of cavitation inception on a platinum surface using molecular dynamics simulation“. Thermal Science 24, Nr. 5 Part A (2020): 2953–63. http://dx.doi.org/10.2298/tsci180212019f.

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The transient properties of liquid argon cavitation nuclei in platinum surface were studied by means of molecular dynamics simulation. The bubble nucleation, with a certain size and stability on the wall surface, was studied by different tensile distances and different wall wettabilities. Also the parameters of cavitation nuclei development, the system pressure, and the total pressure were analysed. The stability of cavitating nucleus growth is closely related to the metastable degree of the system and the wettability of the wall. The tensile distance of the wall surface has a critical value, and stretching greater than the critical value will induce a greater degree of instability in the system, which is conducive to the growth of the cavitation nucleus. A hydrophobic wall is more conducive to the growth of a cavitation nucleus, which is beneficial to spontaneous growth among cavitated nuclei, whereas a hydrophobic exerts has an inhibitory influence on cavitation nuclei.

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Qiang, Fu, Zhang Benying, Zhao Yuanyuan, Zhu Rongsheng, Liu Gang und Li Mengyuan. „The Cavitation Nuclei Transient Characteristics of Lennard-Jones Fluid in Cavitation Inception“. Polish Maritime Research 25, s2 (01.08.2018): 75–84. http://dx.doi.org/10.2478/pomr-2018-0077.

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Abstract In the field of ocean engineering, cavitation is widespread, for the study of cavitation nuclei transient characteristics in cavitation inception, we applied theoretical analysis and molecular dynamics (MD) simulation to study Lennard-Jones (L-J) fluid with different initial cavitation nuclei under the NVT-constant ensemble in this manuscript. The results showed that in cavitation inception, due to the decrease of liquid local pressure, the liquid molecules would enter the cavitation nuclei, which contributed to the growth of cavitation nuclei. By using molecular potential energy, it was found that the molecular potential energy was higher in cavitation nuclei part, while the liquid molecular potential energy changes greatly at the beginning of the cavitation nuclei growth. The density of the liquid and the surface layer changes more obvious, but density of vapor in the bubble changes inconspicuously. With the growth of cavitation nuclei, the RDF peak intensity increased, the peak width narrowed and the first valley moved inner. When cavitation nuclei initial size reduced, the peak intensity reduced, the corresponding rbin increased. With the decrease of the initial cavitation nuclei, the system pressure and total energy achieved a balance longer, and correspondingly, they were smaller. In addition, at the beginning of the cavitation nuclei growth, the total energy and system pressure changed greatly.

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d’Agostino, Luca, und S. I. Green. „Simultaneous Cavitation Susceptibility Meter and Holographic Measurements of Nuclei in Liquids“. Journal of Fluids Engineering 114, Nr. 2 (01.06.1992): 261–67. http://dx.doi.org/10.1115/1.2910025.

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Cavitation Susceptibility Meter (CSM) and holographic measurements of cavitation nuclei distributions are compared in this paper. The CSM optically detects cavitation in water samples flowing through a venturi and relates the unstable nuclei concentration to the applied tension in the fluid. A ruby laser holographic system measures the nuclei size distribution directly. Microbubbles have been used as the dominant nuclei source. The data from the two detection schemes are correlated by accounting for the dynamic response of the cavities in the venturi throat. The active nuclei distributions predicted by the holographic data compare favorably with those measured by the CSM. Both detection methods show that the nuclei concentration rises approximately exponentially as the applied tension is increased and then, with further reduction in the pressure, tends to a nearly constant maximum due to the shortage of remaining cavitatable nuclei. The CSM consistently underestimates the concentration of active cavitation nuclei, due to limited electro-optical resolution and mutual interference effects between cavities in the venturi. The good qualitative agreement of the two techniques supports the validity of the data correlation model and clearly indicates that any practical interpretation of measured nuclei size distributions for cavitations predictions is highly dependent of the specific flow conditions. Attempts to cavitate saturated water of the California Institute of Technology Low Turbulence Water Tunnel in the CSM were unsuccessful even at the lowest attainable CSM throat pressures (about −40kPa). This is thought to be due to insufficient throat tension and, at least partially, to the short time available for cavity growth in the CSM.

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ITO, Yukio, Makoto YAMADA, Risaburou OBA, Yoshiaki ONISHI und Keiichi IIDAKA. „Cavitation tunnel characterized by stable cavitation-nuclei-distributions.“ Transactions of the Japan Society of Mechanical Engineers Series B 54, Nr. 502 (1988): 1222–25. http://dx.doi.org/10.1299/kikaib.54.1222.

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Hall, Timothy L., Alex Duryea und Hedieh Tamaddoni. „Control of cavitation through coalescence of cavitation nuclei“. Journal of the Acoustical Society of America 136, Nr. 4 (Oktober 2014): 2301. http://dx.doi.org/10.1121/1.4900326.

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Gindroz, B., und M. L. Billet. „Influence of the Nuclei on the Cavitation Inception for Different Types of Cavitation on Ship Propellers“. Journal of Fluids Engineering 120, Nr. 1 (01.03.1998): 171–78. http://dx.doi.org/10.1115/1.2819643.

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In order to relate nuclei size distributions with inception cavitation in cavitation facilities, a test program was conducted at the Grand Tunnel Hydrodynamique (GTH) of the Bassin d’Essais des Care`nes. The GTH, which has a complete air control system including dissolved gas and nuclei (microbubbles) control, offers the opportunity to answer this question. The tests were conducted on the three 34 mm diameter propellers used by Kuiper (1981), each of these propellers being characterized by a different cavitation type: bubble, sheet and vortex cavitation. The water nuclei content correspond to strong degassed water (maximum tension), low injection of medium size nuclei (medium tension-low content), large injection of medium size nuclei (medium tension-high content) and large injection of large nuclei (minimum tension). By injecting medium size nuclei for a low content and a high content, we can examine the influence of the number of nuclei on the cavitation inception characteristic. During all the tests, the dissolved air content was kept constant. The GTH online Cavitation Nuclei Counter (Centerbody Venturi) was used to measure both the water nuclei distribution and the liquid tension. Comparisons are made with the calibrated Centerbody Venturi, a Phases Doppler Particles Analyzer (PDPA) and Holographic measurements.

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Mørch, K. A. „Cavitation inception from bubble nuclei“. Interface Focus 5, Nr. 5 (06.10.2015): 20150006. http://dx.doi.org/10.1098/rsfs.2015.0006.

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The tensile strength of ordinary water such as tap water or seawater is typically well below 1 bar. It is governed by cavitation nuclei in the water, not by the tensile strength of the water itself, which is extremely high. Different models of the nuclei have been suggested over the years, and experimental investigations of bubbles and cavitation inception have been presented. These results suggest that cavitation nuclei in equilibrium are gaseous voids in the water, stabilized by a skin which allows diffusion balance between gas inside the void and gas in solution in the surrounding liquid. The cavitation nuclei may be free gas bubbles in the bulk of water, or interfacial gaseous voids located on the surface of particles in the water, or on bounding walls. The tensile strength of these nuclei depends not only on the water quality but also on the pressure–time history of the water. A recent model and associated experiments throw new light on the effects of transient pressures on the tensile strength of water, which may be notably reduced or increased by such pressure changes.

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Dissertationen zum Thema "Cavitation nuclei"

Graham, Susan M. „Ultrasound-triggered drug release from liposomes using nanoscale cavitation nuclei“. Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:510ab12d-74c9-4c07-a621-4dc388b14f7a.

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Side effects of current chemotherapeutics limit their use in cancer therapy. Although many current drugs are highly toxic and potent, the effects they have on non-cancerous tissue are unbearable for patients. Targeting these drugs may provide a means to restrict their toxic effects to only cancer tissue while leaving healthy tissue unaffected. This approach requires that the drug is only available in cancer tissue, which has been achieved here by encapsulating drugs into liposomal nano-capsules which are capable of passively accumulating in cancerous tissue via the enhanced permeability and retention effect (EPR). In addition to localisation, a threshold dose must be achieved to deliver the desired toxic effect to the target tumour tissue. Previous strategies have relied on passive 'leaching' of the drug from liposomes, however this 'leaching' does not necessarily achieve the threshold dose required. In the present work, a new generation of liposomes has been developed whereby release is solely achieved in the presence of ultrasound triggered cavitation. Instigation of such cavitation events would normally require the target tissue be exposed to high and possibly damaging ultrasound pressures. To remove the need for these high pressures, cavitation nuclei have been developed to lower the cavitation threshold of surrounding media. To allow for improved co-localisation and treatment deeper into cancer tissue, cavitation nuclei were developed to be in the nanoscale size range. Two types of novel cavitation nuclei were produced, a rough surfaced carbon nanoparticle (CNP, ~180 nm) and smooth shaped polymeric nano-cup particle (NC, ~150, 470, or 770 nm). Both types of particle are solid nanoparticles with gas entrapped on their surface which was capable of cavitating in response to ultrasound without greatly affecting the particle itself. These particles are classified as cavicatalytic nanoparticles due to their ability to reduce the cavitation threshold of their surrounding media without being destroyed themselves. Finally, an entirely nanoscale release system was developed and tested in vitro and in vivo. The drug carrier (the liposome) and effector agent (the cavicatalytic nanoparticle) were used to demonstrate ultrasound triggered drug release, specifically in response to the generation of cavitation events. These cavitation events could be non-invasively monitored and characterised, adding to the potential clinical utility of the technologies developed and described here.

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Myers, Rachel. „Ultrasound-enhanced delivery of therapeutic agents to tumours using submicron cavitation nuclei“. Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:cb82814d-cb45-40e4-b859-5b171895e817.

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Cancer therapy is severely hampered by the poor delivery of agents out of the blood vessels and into tumours. This is due to the irregular vasculature, high interstitial pressure and dense extracellular matrix associated with tumour tissue. As a consequence, high doses of agents must be administered intravenously for effective accumulation in the tumour. This leads to a low therapeutic index, necessitates multiple administrations of the same drug, and for many cancer drugs, also leads to toxic side-effects. Increasingly complex therapeutics, such as antibodies and viruses, only exacerbate this delivery problem as their greater size leads to lower coefficients of diffusion and, consequently, even greater portions of the tumour remain untreated. There have been studies aimed at improving therapeutic outcomes using microbubble-nucleated, ultrasound-induced cavitation, which provides a mechanical impetus to drive drugs out of the vasculature and into tumours. However, microbubbles are limited by their large size, their instability in the blood and their destruction upon cavitation. This thesis details the formulation of two alternative cavitation nuclei to overcome the limitations of microbubbles: mesoporous carbon particles and polymer cups. These are solid, submicron particles that contain crevices into which nanobubbles can be stabilised. Initial studies of their biocompatibilty have indicated that these formulations may be safe for intravenous administration. A tumour mimicking phantom was first used to quantify drug delivery caused by cavitation. Both polymer cups and mesoporous carbon particles were found to significantly enhance delivery of a model therapeutic agent by this method. In vivo the polymer cups were used to enhance the delivery of an oncolytic vaccinia virus: intravenous administration of 1x105 pfu vaccinia virus, polymer cups and ultrasound treatment was shown to cause a 780-fold increase in genome copies in the tumours of a SKOV-3 tumour model, and 5,700-fold, in the tumours of a HEPG2 tumour model 20 days after the treatment. In mice treated with 1x106 pfu of virus cavitation caused by cups and ultrasound was shown to cause regression in 7 of the 8 tumours in comparison to just 1 of the 8 tumours that were treated with virus alone.

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Bohunský, Tomáš. „Kavitace na mikrofluidické clonce“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-444292.

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This diploma thesis deals with cavitation flow in the microscale, which remains an area with a lack of sufficient description of this phenomenon. At the same time, microfluidics is a field experiencing a dramatic rise in numerous biochemical applications, which underlines the relevance of researches of this type. In theoretical part of the thesis, cavitation was described in detail. In the practical part, a microfluidic device with a cavitation orifice was designed and manufactured. The ANSYS program was used for this design. An experiment was performed with the designed microchip, the aim of which was to observe a cavitating flow on the orifice. This measurement took place at the microfluidic laboratory at Victor Kaplan Department of Fluid Engineering. Due to the failure of the experiment, a CFD model of two-phase cavitation flow was built. The conclusions of the thesis were compiled from the findings of measurement and the results of modeling.

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Pham, Tuyet Mai. „La mesure des populations de germes de cavitation : qualification et optimisation d'un compteur dynamique à ogive centrale“. Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10235.

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Le present travail est consacre a la realisation d'un appareil de mesure dynamique de populations de germes de cavitation. L'objectif de l'etude est de definir une conception de reference du compteur a ogive centrale la mieux caracterisee possible, tant sur le plan de la geometrie de l'appareil que sur le plan des limites de fonctionnement et des precisions de mesure. Notre etude s'articule autour de deux themes: la conception et la qualification de l'appareil. Une premiere etape consiste a optimiser le capteur hydrodynamique compte-tenu des contraintes imposees par les interactions entre la cavitation et la couche limite. Les innovations essentiellement apportees concernent la compensation des effets visqueux dans la section du col, ainsi que l'utilisation de dispositifs d'excitation de la turbulence pour eviter le decollement laminaire dans le divergent. Une qualification de l'appareil optimise est ensuite menee: des visualisations de l'ecoulement sous eclairage stroboscopique, des mesures de pressions statique et fluctuante permettent de valider la conception retenue. On etablit egalement les limites de fonctionnement du compteur conditions extremes de prelevement des echantillons, concentrations maximales de germes mesurables, taille des plus gros germes mesurables, et ses performances precision de mesure de la pression critique des germes et de leur nombre. La possibilite theorique de detecter acoustiquement les germes est discutee et aucune limitation en taille de germes n'a ete trouvee. En revanche, l'analyse par cinematographie rapide du fonctionnement du venturi a mis en evidence l'existence d'une valeur limite du parametre de cavitation en deca de laquelle le nombre de germes est surestime

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Briançon-Marjollet, Laurence. „Couches-limites, germes et cavités en interaction : étude physique“. Grenoble 1, 1987. http://www.theses.fr/1987GRE10119.

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Etude en tunnel hydrodynamique de l'influence de la teneur en germes libres de l'eau sur la cavitation se developpant sur un profil bidimensionnel en ecoulement permanent. On etudie le type de cavitation (poche attachee ou bulle separee) et son developpement en fonction de l'incidence du profil, du nombre de reynolds, du parametre de cavitation et de la concentration en germes libres. On determine des zones d'influence des germes. On montre l'importance de la couche limite et du nombre de germes actifs dans la determination du debut de cavitation et du type de cavitation. Application aux machines tournantes

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Liu, Zhenhuan. „Nuclei population dynamics and cavitation“. Thesis, 1995. https://thesis.library.caltech.edu/4217/1/Liu_z_1995.pdf.

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The effect of the nuclei population in water on cavitation has not been investigated thoroughly due to the difficulties of measuring the microbubbles in water. In this thesis, a Phase Doppler Anemometer (PDA) was calibrated by a holographic method and used to measure the micro-bubble distribution in water. Substantial agreement was achieved between the PDA and the holographic method. After the calibration, the PDA was used to study the nuclei population dynamics in two water tunnels. It was also employed in a study of cavitation on an axisymmetric Schiebe body in which the cavitation on the headform and the upstream nuclei population were simultaneously observed. Substantial changes in the nuclei number density distributions were found in these two water tunnels. The nuclei population in each water tunnel can also vary significantly, sometimes by as much as an order of magnitude. The nuclei population dynamics are complicated and are affected by the tunnel design, the tunnel operating condition and the air content. The cavitation event rate on the Schiebe headform is mainly determined by the cavitation number. It increases dramatically as the cavitation number is decreased. It also varies with the magnitude and the shape of the nuclei number distribution. As the upstream nuclei population increases, the cavitation event rate increases. During the experiments, cavitation acoustic emissions were also measured and analyzed. An analytical model based on the spherical bubble assumption and the Rayleigh-Plesset theory is developed to relate the free stream nuclei population to the cavitation event rate and the acoustic noise on an axisymmetric body. Complications, such as the effect of the boundary layer flow rate, of the bubble screening, of the bubble/bubble interactions and of the observable bubble size are examined and included in the model. The predicted cavitation event rate and acoustic impulse are compared with the experimental observations. It is shown that the predicted event rates agree with the observations when the population is small, but that increasing discrepancies occur at lower cavitation numbers when the bubble density becomes larger. The predicted noise qualitatively agrees with the observations, but is generally larger than the observations, mainly due to the fact that the spherical bubble assumption usually departs from the observed bubble shape.

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O'Hern, Timothy John. „Cavitation Inception Scale Effects: I. Nuclei Distributions in Natural Waters. II. Cavitation Inception in a Turbulent Shear Flow“. Thesis, 1987. https://thesis.library.caltech.edu/1246/2/OHern_tj_1987.pdf.

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Cavitation scale effects can be grouped into two major categories: susceptibility of the water to cavitation, i.e., the amount, size, and type of microbubbles or microparticulates in the water acting as inception nuclei, and flow field effects due to such factors as velocity and pressure distributions, body size and shape, viscous effects, and turbulent phenomena. Experimental investigations into these two aspects of scale effects were performed in the present study.

Field investigations of marine nuclei populations were made using underwater holography to observe microbubbles and particulates, including microplankton in oceanic waters of Los Angeles Harbor, San Pedro Channel and near Santa Catalina Island. Holographic detection was shown to be a reliable method of measuring the nuclei number concentration density distributions. Overall, very high concentrations of the various types of potential cavitation nuclei were observed at all of the test sites and depths examined, although the statistical significance of these results is strong only in the smaller size ranges (less than 50 µm), where a significant number of counts were made. Relatively high bubble concentrations during calm sea conditions, and their population inversion below the thermocline where organism activity was high, indicate a possible biological source of bubble production rather than the usual surface mechanisms of breaking waves and whitecaps. The measured population of particulates is somewhat higher than comparable data in the ocean or in cavitation test facilities, and the number density distribution of particulates decreases approximately as the fourth power of the particle size, as often reported in the literature. An increase in particle concentration near the bottom of the thermocline in clear coastal waters is observed. The total concentration of particles and bubbles in a liquid provides an upper bound on the number of potentially active cavitation nuclei. The measured bubble sizes can be used to indicate that the average tensile strength of the ocean waters examined in this study should be on the order of a few thousand Pascals, with a minimum expected value of about one hundred Pascals. The present results support the recommendation of Billet (1985), that a concentration of at least 3 bubbles per cm³ in the 5 to 20 µm radius range is needed in test facility water in order to model marine conditions.

Experimental studies were also made on the inception processes in a large turbulent free shear layer generated by a sharp edged plate in a water tunnel at Reynolds numbers up to 2 x 10⁶. Two distinct types of vortex motion were evident in the shear layer, the primary spanwise and the secondary longitudinal vortices. Cavitation inception occurs consistently in the secondary shear layer vortices and more fully developed cavitation is visible in both structures, with the streamwise cavities primarily confined to the braid regions between adjacent spanwise vortices. A Rankine vortex model indicates that the secondary vortex strength is always less than 10% of that of the primary structure. Measurements of fluctuating pressures in the turbulent shear layer are made by holographically monitoring the size of air bubbles injected into the non-cavitating flow, showing that pressure fluctuations were much stronger than previously reported, with positive and negative pressure peaks as high as 3 times the freestream dynamic pressure, sufficient to explain the occurrence of cavitation inception at high values of the inception index. Cavitation inception indices display a strong dependence on the dissolved air content and thus on the availability of freestream bubble cavitation nuclei. The present inception data do not display a clear dependence on freestream velocity (or Reynolds number) but do fall into the overall range of data of previous bluff body investigations. The occurrence of inception in the secondary vortices of the shear layer, and previous reports of velocity dependence of these cores (Bernal 1981) may provide the key to explaining the commonly observed Reynolds number scaling of the inception index in shear flows.

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Hopkins, Stephen Day. „Exploring the limits of cavitation /“. 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3223617.

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Thesis (Ph. D.)--University of Illinois at Urbana-Champaign, 2006.
Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3843. Adviser: Kenneth S. Suslick. Includes bibliographical references. Available on microfilm from Pro Quest Information and Learning.

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Hooper, David Alan. „Cavitation of Mercury in a Centrifugal Pump“. 2007. http://trace.tennessee.edu/utk_gradthes/139.

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Cavitation is a significant concern for the reliable operation of a centrifugal pump. Liquid metal flow loops are used in nuclear, chemical, metal forming, and liquid metal dynamo applications. Understanding of the cavitation characteristics of liquid metals is increasingly important to the design and operation of these facilities. One recent field of cavitation research has developed for mercury flow in spallation targets used in neutron sources. To further the understanding of mercury cavitation, a review of the existing literature on water cavitation, liquid metal cavitation, and mercury cavitation is performed. The mechanics of cavitation and the analytical methods applied to cavitation problems are discussed and analyzed. Acoustic data from the centrifugal pump for the mercury flow loop at the Spallation Neutron Source in Oak Ridge National Laboratory are examined.

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Bücher zum Thema "Cavitation nuclei"

Tullis, J. Paul. Cavitation guide for control valves. Washington, DC: Division of Engineering, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 1993.

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Buchteile zum Thema "Cavitation nuclei"

Akulichev, Victor A. „Cavitation nuclei and thresholds of acoustic cavitation in ocean water“. In Fluid Mechanics and Its Applications, 171–78. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-0938-3_16.

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Saiki, K., T. Iikura, K. Matsumoto, H. Komita, M. Kobayashi, T. Saito und H. Tanaka. „Performance Comparison of Nuclear Reactor Recirculation Pumps Tested under Large Reynolds Number Difference“. In Hydraulic Machinery and Cavitation, 1083–92. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-010-9385-9_110.

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Tianyou, Sheng, Ma Rubing, Yuan Yidan und Ma Weimin. „Numerical Simulation of Cavitation Phenomenon in Thin and Long Orifices“. In Proceedings of The 20th Pacific Basin Nuclear Conference, 453–59. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-2311-8_42.

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Liu, Changliang, Sheng Meiling, Jingmeng Qiu und Wenhong He. „Calculation and Analysis of Cavitation for Low-Head Safety Injection Pump“. In Proceedings of The 20th Pacific Basin Nuclear Conference, 85–92. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-2314-9_7.

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Washio, Seiichi. „Review of cavitation nuclei“. In Recent Developments in Cavitation Mechanisms, 1–44. Elsevier, 2014. http://dx.doi.org/10.1533/9781782421764.1.

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„Cavitation Nuclei and Tensile Strength of Water“. In Proceedings of the 10th International Symposium on Cavitation (CAV2018), 233–38. ASME Press, 2018. http://dx.doi.org/10.1115/1.861851_ch45.

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„Behaviors of Free Bubble Nuclei in Inception of Sheet Cavitation“. In Proceedings of the 10th International Symposium on Cavitation (CAV2018), 140–43. ASME Press, 2018. http://dx.doi.org/10.1115/1.861851_ch28.

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„Size and Concentration Measurements of Cavitation Nuclei in the Wake of a Ship Model“. In Proceedings of the 10th International Symposium on Cavitation (CAV2018), 934–38. ASME Press, 2018. http://dx.doi.org/10.1115/1.861851_ch178.

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Yang, Qing, Guang-qing Dai, Jian-ming Zhang, Hai-yun Wang und Jian-qiang Wu. „Influence of gas nucleus on scale effect of cavitation“. In Environmental Hydraulics and Sustainable Water Management, Two Volume Set, 1787–91. CRC Press, 2004. http://dx.doi.org/10.1201/b16814-292.

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Konferenzberichte zum Thema "Cavitation nuclei"

Heinke, H. J., C. Johannsen, W. KrÖger, P. Schiller und E. A. Weitendorf. „On Cavitation Nuclei in Water Tunnels“. In 8th International Symposium on Cavitation. Singapore: Research Publishing Services, 2012. http://dx.doi.org/10.3850/978-981-07-2826-7_270.

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Xu, Lianghao, Xiaoxing Peng und Guoping Zhang. „Nuclei Measurement by Interferometric Laser Imaging“. In 8th International Symposium on Cavitation. Singapore: Research Publishing Services, 2012. http://dx.doi.org/10.3850/978-981-07-2826-7_044.

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HÖhne, Stephan, Stefan Borchert, Willfried KrÖger und Nils Damaschke. „Optical Methods for Nuclei Spectra Characterization in Cavitation Tunnels“. In 8th International Symposium on Cavitation. Singapore: Research Publishing Services, 2012. http://dx.doi.org/10.3850/978-981-07-2826-7_263.

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Raiton, Benjamin, James R. McLaughlan, Peter R. Smith, David M. J. Cowell und Steven Freear. „Non-invasive cavitation nuclei trap for Histotripsy“. In 2012 IEEE International Ultrasonics Symposium. IEEE, 2012. http://dx.doi.org/10.1109/ultsym.2012.0249.

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Wang, Tzu-Yin, Timothy L. Hall, Zhen Xu, J. Brian Fowlkes und Charles A. Cain. „Local cavitation suppression using cavitation nuclei preconditioning for precise treatment in histotripsy“. In 2010 IEEE Ultrasonics Symposium (IUS). IEEE, 2010. http://dx.doi.org/10.1109/ultsym.2010.5935735.

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Hsiao, Chao-Tsung, und Georges L. Chahine. „Scaling of Tip Vortex Cavitation Inception Noise With a Bubble Dynamics Model Accounting for Nucleus Size Distribution“. In ASME/JSME 2003 4th Joint Fluids Summer Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/fedsm2003-45315.

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A Surface-Averaged Pressure (SAP) spherical bubble dynamics model accounting for a statistical nuclei size distribution was used to model the acoustic signals generated by cavitating bubbles near inception in a tip vortex flow. The flow field generated by finite-span elliptic hydrofoils is obtained by Reynolds-Averaged Navier-Stokes computations. An “acoustic” criterion which defines the cavitation inception by counting the number of acoustical signal peaks that exceed a certain level per unit time was applied to deduce the cavitation inception number for different scales. It was found that the larger scale results in more cavitation inception events per unite time because more nuclei are excited by the tip vortex at the larger scale. The nuclei size was seen to have an important effect on cavitation inception number with scaling effects due to nuclei increasing as nuclei sizes decreases.

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Park, Kwangkun, Hanshin Seol und Soogab Lee. „Numerical Analysis of Tip Vortex Cavitation Behavior and Noise on Hydrofoil“. In ASME 2006 2nd Joint U.S.-European Fluids Engineering Summer Meeting Collocated With the 14th International Conference on Nuclear Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/fedsm2006-98510.

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In this study, tip vortex cavitation behavior and noise are numerically analyzed. Eulerian-Lagrangian approach is used to simulate the tip vortex cavitation on the hydrofoil. In this approach, the flow field and cavitation behavior are computed by Eulerian and Lagrangian point of view, respectively. The vortex flow field is simulated by combining Moore and Saffman’s vortex core radius variation equation with Sculley vortex model. The tip vortex cavitation behavior is analyzed by coupled Rayleigh-Plesset equation and trajectory equation based on Newton’s 2nd law. Kamiirisa’s experimental nuclei data are adopted to produce computational cavitation nuclei population and the nuclei are released in the vortex flow field. The tip vortex cavitation trajectories and radius variations of the nuclei are calculated according to the initial sizes of the nuclei. Noise is analyzed using time dependent cavitation bubble position and radius variation data. When the acting pressure on the nucleus goes down below the vapor pressure, the nucleus grows into a cavitation bubble. And, the cavitation bubble emits very high amplitude noise during collapse stage. This study may become a foundation of the vortex cavitation study.

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Duryea, Alexander P., Charles A. Cain, William W. Roberts, Hedieh A. Tamaddoni und Timothy L. Hall. „Active removal of residual bubble nuclei following a cavitation event“. In 2013 IEEE International Ultrasonics Symposium (IUS). IEEE, 2013. http://dx.doi.org/10.1109/ultsym.2013.0462.

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Sato, Keiichi, Kouji Hachino und Yasuhiro Saito. „Inception and Dynamics of Traveling-Bubble-Type Cavitation in a Venturi“. In ASME/JSME 2003 4th Joint Fluids Summer Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/fedsm2003-45322.

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The inception of cavitation is basically caused by a bubble nucleus which flows into the low pressure region in the liquid flow. Therefore the phenomenon is dependent on the tensile strength or the nuclei concentration of tested water. The cavitation susceptibility of water which controls the cavitation inception point has been made clear though various methods were proposed to measure the nuclei concentration. Cavitation susceptibility meter using a small venturi tube is also one of the methods to measure the nuclei concentration. It is pointed out that this method can be directly related to active nuclei for cavitation inception and gives a useful and simple device to estimate the tensile strength of water. In the present paper, to establish a measurement method of cavitation susceptibility using a venturi tube, the following points are investigated, such as; the relation between the occurrence, count rate of cavitation bubbles and cavitation number, the measurement of positions and local pressure of bubble occurrence and the high-speed video observation of bubble aspects from inception to collapse. As the result, the main points obtained are as follows. A traveling-bubble cavitation appears dominantly in a nozzle-type venturi tube with little possibility of flow separation. Cavitation aspects and the bubble occurrence count rate change with cavitation number and water quality (dissolved gas content). Unstable sheet cavitation can be also observed near the venturi diffuser and at relatively low cavitation number. The various behaviors of traveling bubble cavitation in a venturi are observed from inception to collapse using a high-speed video camera system.

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Farhat, Mohamed, Faic¸al Gennoun und Franc¸ois Avellan. „The Leading Edge Cavitation Dynamics“. In ASME 2002 Joint U.S.-European Fluids Engineering Division Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/fedsm2002-31000.

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In the present paper, we present an experimental investigation of the onset and detachment of a leading edge cavitation over a 2-D and 3-D hydrofoils. An insight of the flow field in the vicinity of the main cavity detachment is reached with the help of a miniature sensor fitted in a NACA009 hydrofoil suction side close to the leading edge stagnation point. Owing to theses experiments, we have demonstrated how the water may withstand negative pressure as low as −0.8 bar without any visible cavitation. As soon as the leading edge cavitation takes place, the pressure upstream to the cavity detachment rises significantly but remains negative while the measured pressure in the cavity is almost equal to the vapor pressure. This result confirms the assumption already stated by former studies according to which the liquid is in tension just upstream to the detachment point. Furthermore, flow visualization clearly shows that a well developed leading edge cavitation turns into bubble cavitation in a continuous way when the surrounding pressure is gradually increased. Owing to those results, we have introduced a physical model of the cavitation detachment in which, no laminar separation of the boundary layer is required to ensure its mechanical equilibrium as already stated by former studies. The nuclei in the vicinity of the blade surface explode as they cross the liquid-vapor interface, which is not a material surface. The main cavity is thus continuously fed with exploding bubbles at its detachment location. The negative pressure measured upstream to the cavity detachment may thus be explained by the dynamic delay of exploding nuclei due to inertia.

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