Optical investigations of cavitation

by Yonghua Jin

Written in English
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Edition Notes

Thesis (Ph.D.) - Loughborough University of Technology.

Statementby Jonghua Jin.
ID Numbers
Open LibraryOL21516430M

User Tools. Cart. Sign In.   In the research reported here an attempt has been made to discover by experiment what physical assumptions and approximations are appropriate in the theory of cavitation microstreaming, especially for cavitation bubbles located near solid boundaries. A systematic investigation of the phenomenon has been made and its dependence on certain parameters (e.g., amplitude of sound) . Sample Medium. At first, de-ionized water was used as a sample medium for the transparent tissue of the crystalline lens or the cornea. Various publications have shown that the optical and thermodynamic properties of water also determine the LIOB process and cavitation bubble occurrence in highly hydrated tissues like e.g. cornea –,, –.However, the rheological properties of tissue as an. Kadivar, E, & el Moctar, O. "Investigation of Cloud Cavitation Passive Control Method Using Cavitating-Bubble Generators (CGs)." Proceedings of the 10th International Symposium on Cavitation (CAV). Ed. Katz, J. ASME Press,

In the present study, Large Eddy Simulations (LES) have been performed with a 3D model of a step nozzle injector, using n-pentane as the injected fluid, a representative of the high-volatility components in influence of fuel temperature and injection pressure were investigated in conditions that shed light on engine cold-start, a phenomenon prevalent in a number of combustion.   1. Introduction. Object trapping [1,2], material ablation, and cavitation bubbles generation [] are standard applications of strongly focused laser -beam traps using continuous irradiation have been realized to guide and confine a broad range of objects, from cold atom clouds [] to cells [], polystyrene particles [], and even stabilized gas bubbles []. Fast liquid jets, called micro-jets, are produced within cavitation bubbles experiencing an aspherical collapse. Here we review micro-jets of different origins, scales and appearances, and propose a unified framework to describe their dynamics by using an anisotropy parameter $\unicode[STIX]{x1D}\geqslant 0$, representing a dimensionless measure of the liquid . The present study refers to a cavitating Venturi type section geometry characterized by a convergent angle of 18° and a divergent angle of about 8° where the sheet cavity presents typical self-oscillation behavior with quasi-periodic vapor clouds shedding. This work is an extension of previous works concerning void ratio measurements and velocity fields using double optical probe and.

22 May Experimental investigations and numerical modeling of shock wave emission and cavitation bubble generation by picosecond and nanosecond optical breakdown. Alfred Vogel, Ulrich Parlitz, Stefan Busch. Author Affiliations +. Haixia Liu's 30 research works with 86 citations and 2, reads, including: Experimental Study of the Influence of Test Chamber Dimensions on Aggressive Intensity of the Cavitating Jet. INTRODUCTION. Residual cavitation bubble nuclei produced by the collapse of primary acoustic cavitation can limit the efficacy of ultrasound therapies such as shock wave lithotripsy (SWL) [1–6] and histotripsy [].The collapse of a single primary bubble can generate dozens of microscopic . The cavitating flow characteristics inside multi-hole injectors for large Diesel engines have been investigated. Flow imaging obtained inside transparent nozzle replicas using simultaneously two high speed cameras and various illumination light sources has shown that cavitation is formed not only at the hole entrance due to the local pressure drop induced by nozzle inlet geometry, but also.

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Vol Issue 3, AprilPages Optical investigation of cavitation erosion by laser-induced bubble collapse. Author links open overlay panel X. Chen R.Q. Xu Z.H. Shen J. Lu X.W. Abstract. By means of a new Cited by: Optical and Acoustic Investigations of the Dynamics of Laser-Produced Cavitation Bubbles Near a Solid Boundary September Journal of Fluid Mechanics (-1) - Optical investigations of cavitation Author: Jin, Yong-Hua ISNI: This doctoral thesis describes the investigation carried out by the author in Optical investigations of cavitation book of a better understanding of the mechanism of cavitation.

To create cavitation bubbles under laboratory conditions, an intense Q-switched Nd:YAG laser was used and the Author: Yong-Hua Jin. This book provides a comprehensive treatment of the cavitation erosion phenomenon and state-of-the-art research in the field.

It is divided into two parts. Part 1 consists of seven chapters, offering a wide range of computational and experimental approaches to cavitation erosion. It includes a general introduction to cavitation and cavitation.

Optical investigations of cavitation book waves and cavitation bubbleswere investigated in regular and retrograde liquids. Interactions of the shock waves with the wall and another shockwaves were observed. Distilled water, isooctane, glycerine and water with additives were investigated to show an influence of liquid properties.

Initial laser pulses were produced by Nd:YAG and Tm:YAG lasers. The group of the authors has reported in, for the first time averaged images of cavitation developing in a real-size 6-hole transparent tip nozzle for single and pilot-main split injections up to.

Data from these investigations are further reported here and utilized for validation of the newly developed model. By means of a new force sensor based on optical beam deflection (OBD), the mechanical effects of laser-matter interaction underwater at different incident laser energy are investigated in detail.

The experimental results show that a target underwater is impacted in turn by laser-plasma ablation force and high-speed liquid-jet impulse induced by bubbles collapse in the vicinity of a solid boundary.

Numerical and experimental investigations on cavitation erosion View the table of contents for this issue, or go to the journal homepage for more IOP Conf. Ser.: Earth Environ. Experimental investigation of the collapse of laser-generated cavitation bubbles near a solid boundary 1.

Introduction. Cavitation is a dynamic phenomenon occurred in flowing liquids, where the local pressure is lower than 2. Experimental setup. The. Gorkh, S. Schmidt, and N. Adams, “ Numerical investigation of cavitation-regimes in a converging–diverging nozzle,” in Proceedings of the 10th International Symposium on Cavitation (CAV18), Baltimore, This book is intended as a combination of a reference book for those who work with cavitation or bubble dynamics and as a monograph for advanced students interested in some of the basic problems associated with this category of multiphase flows.

A book like this has many roots. It began many years ago when, as a young postdoctoral fellow at the. Investigation Of Very Short Cavitation Shock Waves By Coherent Optical Methods Hinsch, Klaus; Brinkmeyer, Ernst During the cavitation bubbles in fluids very short and intense shock waves During the collapse of cavitation bubbles in fluids very short and intense shock waves are radiated.

Their study is of interest since they. 1. Blake and D. Gibson, “ Cavitation bubbles near boundaries,” Annu. Rev. Fluid Mech. 19, 99 (). Lord Rayleigh, “ On the pressure developed in a liquid during the collapse of a spherical cavity,” Philos. Mag. 34, 3. Plesset, “ Bubbles dynamics and cavitation,” Annu.

Rev. Optical and acoustic investigations of the dynamics of laser-produced cavitation bubbles near a solid boundary. Optical and acoustic investigations of the dynamics of laser-produced cavitation bubbles near a solid boundary - Volume - A.

Vogel, W. Lauterborn, R. Timm. The optical imaging data show evidence of cavitation inception in the valve-group swirler-channels-caused by the rapid flow acceleration-and multiple cavitations within the conical nozzle region. Towards Real-Time Optical Measurement of Microbubble Content in Hydrodynamic Test Facilities Proceedings of the 10th International Symposium on Cavitation (CAV) Wall Shear Rates Induced by a Single Cavitation Bubble Collapse.

where p e is the ambient pressure, p V is the vapor pressure ( kPa in water at 20 °C), σ = × 10 −2 Pa m is the liquid/vapor surface tension, ρ L is the liquid density, and ν L is the liquid kinematic viscosity.

For water at room temperature and ambient pressure, p e = MPa, the surface tension is entirely negligible for millimeter bubbles. Typically, the effect of. Two different patterns of string cavitation defined as “needle” and “hole connecting” string cavitation were obtained in the optical experiments.

Then the transient flow characteristics inside a five-hole injector nozzle were studied under needle lift and off-axis motion using the validated models.

An optical investigation of cavitation phenomena in true-scale high-pressure diesel fuel injector nozzles Author: Reid, Benjamin A.

Awarding Body: Loughborough University Current Institution: Loughborough University Date of Award:   The resulting pressure wave can cause cavitation in and around the optical absorber. Cavitation induced by this mechanism is through the photomechanical process, which causes the tissue to fracture as opposed to causing a phase change (Paltauf and Dyer ).

Cavitation is known to be an essential physical phenomenon to induce the fuel primary breakup process, which further influences subsequent secondary atomization and combustion in diesel engines.

This paper reports on noninertial cavitation that occurs beyond the zone close to the horn tip to which the inertial cavitation is confined.

The noninertial cavitation is characterized by collating the data from a range of measurements of bubbles trapped on a solid surface in this noninertial zone. Specifically, the electrochemical measurement of mass transfer to an electrode is compared.

Vogel, W. Lauterborn, and R. Timm, “ Optical and acoustic investigations of the dynamics of laser-produced cavitation bubbles near a solid boundary,” J.

Fluid Mech. (). Furthermore, the size and dynamics of the cavitation clouds have been assessed by optical detection. The fluctuations of the cloud sizes showed a maximum value for those cavitation numbers related to maximum erosive aggressiveness.

The finding suggests the suitability of a model approach which relates the erosion process to cavitation cloud. Vogel, W. Lauterborn, and R. Timm, “ Optical and acoustic investigations of the dynamics of laser-produced cavitation bubbles near a solid boundary,” J. Fluid Mech. ().

Google Scholar Crossref Title:Nano-level Material Processing by Multifunction Cavitation VOLUME: 8 ISSUE: 1 Author(s):Toshihiko Yoshimura*, Kumiko Tanaka and Naoto Yoshinaga Affiliation:Department of Mechanical Engineering, Tokyo University of Science, Yamaguchi, Daigakudori, Sanyo-Onoda, YamaguchiDepartment of Mechanical Engineering, Tokyo University of Science.

Individual travelling cavitation bubbles generated on two axisymmetric headforms were detected using a surface electrode probe. The growth and collapse of the bubbles were studied photographically, and these observations are related to the pressure fields and viscous flow.

Megasonic cleaning has been a traditional approach for the cleaning of photomasks. Its feasibility as a damage free approach to sub 50 nm particulate removal is under investigation for the cleaning of optical and EUV photomasks.

Two major mechanisms are active in a megasonic system, namely, acoustic streaming and acoustic cavitation. The present chapter is about the Flash and Splash project, which is dedicated to the study of bubble dynamics in microgravity.

The story of this project started in with a simple curiosity on how a cavitation bubble may behave within a water drop and evolved into an outstanding, internationally renowned science project as well as a wonderful human adventure.

So far, we have participated in. Optical Verification of Ultrasound Measurements. The ultrasound method was first verified by comparing ultrasound and optical measurements obtained from nine microbubbles generated using a pulse energy of mJ.

Each cavitation bubble was produced in gel and measured both optically and ultrasonically at equilibrium. The bubble dynamics are investigated experimentally by means of a fiber‐optic force sensor based on optical beam deflection (OBD).

This sensor is applied to detect the laser‐induced plasma ablation force and liquid‐jet impact during the cavitation bubble collapse.Optical and acoustic investigations of the dynamics of laser-produced cavitation bubbles near a solid boundary A.

Vogel, W. Lauterborn, R. Timm Journal of Fluid Mechanics.