The Effect of Nuclei on the Inception of Bubble and Sheet Cavitation on Axisymmetric Bodies

Kodama, Y.; Take, N.; Tamiya, Shin; Kato, Hiroharu

doi:10.1115/1.3241767

Cited by 18 publications

(10 citation statements)

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“…Actually, over the years, several researchers (e.g. Kodama 1981, Kuiper 2010 have observed that the presence of free field nuclei affected significantly the repeatability of the experimental results. In experiments where nuclei count was very low the value of the incipient cavitation number showed large scatter, whereas in water rich in nuclei the results were more repeatable and were not affected by further addition of nuclei.…”

Section: Introductionmentioning

confidence: 99%

Multiscale tow-phase flow modeling of sheet and cloud cavitation

Hsiao

Chahine

2017

International Journal of Multiphase Flow

116

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A multiscale two-phase flow model based on an Eulerian/Lagrangian coupled approach is applied to capture the sheet cavitation formation, development, unsteady breakup, and bubble cloud shedding on a hydrofoil. No assumptions are needed on mass transfer. Instead natural free field nuclei and solid boundary nucleation are modelled and enable capture of the sheet and cloud dynamics. The multiscale model includes a micro-scale model for tracking the bubbles, a macroscale model for describing large cavity dynamics and a transition scheme to bridge the micro and macro scales. With this multiscale model small nuclei are seen to grow into large bubbles, which eventually merge to form a large scale sheet cavity. A reentrant jet forms under the sheet cavity, travels upstream, and breaks the cavity, resulting in the emission of high pressure peaks as the broken pockets shrink and collapse while travelling downstream. The results for a 2D NACA0015 foil are in good agreement with published experimental measurements in terms of sheet cavity lengths and shedding frequencies. Sensitivity assessment of the model parameters and 3D effects on the predicted major cavity dynamics are also discussed.

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Section: Introductionmentioning

confidence: 99%

Multiscale tow-phase flow modeling of sheet and cloud cavitation

Hsiao

Chahine

2017

International Journal of Multiphase Flow

116

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“…Extensive research has been carried out on the topic over the years by numerous groups (see e.g. Harvey et al 1944;Fox & Herzfeld 1954;Apfel 1970;Kodama et al 1981;Atchley & Prosperetti 1989;Rood 1991;Meyer, Billet & Holl 1992;Milton & Arakeri 1992;Vinogradova et al 1995;Gindroz & Billet 1998;Liu & Brennen 1998;Arndt & Maines 2000;Mørch 2000;Hsiao, Chahine & Liu 2003). In the vast majority of engineering applications in which cavitation takes place, it can be argued that heterogeneous nucleation dominates, since all working fluids are expected to have a certain level of contamination and impurities.…”

Section: Bubble Nucleationmentioning

confidence: 99%

Modelling of cavitation in diesel injector nozzles

2008

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This is the unspecified version of the paper.This version of the publication may differ from the final published version. A computational fluid dynamics cavitation model based on the Eulerian-Lagrangian approach and suitable for hole-type diesel injector nozzles is presented and discussed. Permanent repository link Modelling of cavitation in diesel injector nozzles E. G I A N N A D A K I S, M. G A V A I S E S A N D C. A R C O U M A N I SThe model accounts for a number of primary physical processes pertinent to cavitation bubbles, which are integrated into the stochastic framework of the model. Its predictive capability has been assessed through comparison of the calculated onset and development of cavitation inside diesel nozzle holes against experimental data obtained in real-size and enlarged models of single-and multi-hole nozzles. For the real-size nozzle geometry, high-speed cavitation images obtained under realistic injection pressures are compared against model predictions, whereas for the largescale nozzle, validation data include images from a charge-coupled device (CCD) camera, computed tomography (CT) measurements of the liquid volume fraction and laser Doppler velocimetry (LDV) measurements of the liquid mean and root mean square (r.m.s.) velocities at different cavitation numbers (CN) and two needle lifts, corresponding to different cavitation regimes inside the injection hole. Overall, and on the basis of this validation exercise, it can be argued that cavitation modelling has reached a stage of maturity, where it can usefully identify many of the cavitation structures present in internal nozzle flows and their dependence on nozzle design and flow conditions.

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“…We notice that in most experimental studies the flow velocity and the dissolved gas content are not mentioned, and only rarely the dimensionless parameter of the thermodynamic effect Σ* is discussed. While the influence of dissolved gas content on cavitation inception [56], on lift/drag characteristics of a hydrofoil in the cavitating flow [57], and on cavitation damage [58] have been widely investigated, its effect on unsteady cavitation behavior at different degrees of thermodynamic effect still remains unclear. For the present study, a blow-down type tunnel was designed to operate with a constant content of dissolved gases (measured by dissolved oxygen, DO) and a constant temperature during each blow-down experiment.…”

Section: Please Cite This Article As Doi:101063/15116156mentioning

confidence: 99%

Thermodynamic effects on Venturi cavitation characteristics

Zhang

Zuo

Mørch³

et al. 2019

Physics of Fluids

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In this paper the thermodynamic effect is systematically studied by Venturi cavitation in a blow-down type tunnel for the first time, using water at temperatures up to relatively high levels, and at controlled dissolved gas contents in the supply reservoir (measured by dissolved oxygen, DO). The mean attached cavity length cav L   is chosen to reveal the thermodynamic effect, and the cavitation characteristics are analyzed from the experiments. With an increase of the thermodynamic parameter *  , a decrease of cav L   vs. the pressure recovery number κ is observed, which is consistent with suppression of cavitation by the thermodynamic effect, but the decrease is related not only to this effect. Based on the experimental results, a model is presented of the attached cavity cloud that develops from the Venturi throat. It is found that either the length of this cloud oscillates stably around a mean value, or the cloud breaks regularly at some upstream position, allowing that a detached cavity cloud is shed, flows downstream and collapses, while the remaining attached cloud regenerates. Applying this model to experimental results obtained first with cold water, then with hot water, we find that when the mean length of the attached cavity cloud oscillates stably, temperature increase causes reduction of the mean cavitation length. This is interpreted to be a consequence of the thermodynamic effect. When detachment of large cavity clouds occurs, the mean length is increased at temperature increase. This is a consequence of cloud configuration changes being superposed on changes due to the thermodynamic effect. These observations explain conflicting results reported for attached cavity clouds in relation to the thermodynamic effect. The gas content in the water is found to be without significance within the range of dissolved oxygen tested.

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The Effect of Nuclei on the Inception of Bubble and Sheet Cavitation on Axisymmetric Bodies

Cited by 18 publications

References 0 publications

Multiscale tow-phase flow modeling of sheet and cloud cavitation

Multiscale tow-phase flow modeling of sheet and cloud cavitation

Modelling of cavitation in diesel injector nozzles

Thermodynamic effects on Venturi cavitation characteristics

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