Estimation of Bubble Fusion Requirements during High-Pressure, High- Temperature Cavitation

Yoshimura, Toshihiko; Yoshiya, Hiroyuki; Tanaka, Kumiko; Ijiri, Masataka

doi:10.4172/0976-4860.1000206

Cited by 9 publications

(10 citation statements)

References 24 publications

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“…Using the Keller-Miksis formulation, the changes in bubble radius and internal pressure and temperature in acetone were calculated for an initial bubble size of 10 μm, a sound pressure of 1 atm and a bubble contraction to 0.1 μm. As previously reported Yoshimura et al (2018c), the shrinkage pressure associated with MFC equipped with a large 0.8 mm nozzle was 7.51 × 10 7 MPa, while that during UTPC using a small 0.1 mm nozzle was determined to be 1.10 × 10 5 MPa. In addition, the temperature at the time of shrinkage was 1.68 × 10 12 K for the large-scale equipment [Yoshimura et al (2018c)] and 3.07 × 1012 K for the smaller apparatus, due to the higher expansion coefficient of the bubbles (3.75 = 37.5/10).…”

Section: Bubble Fusion Theory 31 Bubble Pressure and Temperaturesupporting

confidence: 72%

“…As previously reported Yoshimura et al (2018c), the shrinkage pressure associated with MFC equipped with a large 0.8 mm nozzle was 7.51 × 10 7 MPa, while that during UTPC using a small 0.1 mm nozzle was determined to be 1.10 × 10 5 MPa. In addition, the temperature at the time of shrinkage was 1.68 × 10 12 K for the large-scale equipment [Yoshimura et al (2018c)] and 3.07 × 1012 K for the smaller apparatus, due to the higher expansion coefficient of the bubbles (3.75 = 37.5/10). In previous work Zoghi-Foumani and Sadighi-Bonabi (2014) with an initial bubble radius of 5.10 μm, the bubble internal temperatures were determined to be in the range of 10 6 K < T < 10 7 K. In reality, as the temperature inside the bubbles increases, the upper limit is determined by thermal decomposition of the deuterated acetone vapor, chemical reactions and thermal conductivity.…”

Section: Bubble Fusion Theory 31 Bubble Pressure and Temperaturesupporting

confidence: 72%

“…Previous work has demonstrated that MFC processing in which water jet cavitation (WJC) is combined with ultrasonication in deuterated acetone could potentially result in bubble fusion Yoshimura et al (2018c). However, it is unlikely that the pressures that are generated during bubble shrinkage will exceed the threshold pressure required for bubble fusion or that the energy density of the atoms in the bubbles during bubble shrinkage will exceed the fusion threshold.…”

Section: Introductionmentioning

confidence: 99%

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Estimation of Nuclear Fusion Requirements in Bubbles During Ultra-High-Pressure, Ultra-High-Temperature Cavitation Promoted by Magnetic Field

Yoshimura

Ijiri

Sato

2022

Int. J. Eng. Sci. Tech

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In the present work, a strong magnetic field was applied near the outlet of the water jet nozzle to promote the generation of multifunction cavitation bubbles. Because these bubbles contained charged species, the bubbles experienced a Lorentz force due to the magnetic field and collided with greater force. As such, the internal bubble pressure exceeded the threshold value required for fusion to occur. The expansion of these charged bubbles in response to ultrasonic irradiation affected adjacent charged bubbles so that the energy density of the atoms in the bubbles was greater than the fusion threshold. The results of this work strongly suggest that the formation of bubbles via the UTPC process in conjunction with a strong magnetic field may result in bubble fusion.

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Section: Bubble Fusion Theory 31 Bubble Pressure and Temperaturesupporting

confidence: 72%

Section: Bubble Fusion Theory 31 Bubble Pressure and Temperaturesupporting

confidence: 72%

Section: Introductionmentioning

confidence: 99%

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Estimation of Nuclear Fusion Requirements in Bubbles During Ultra-High-Pressure, Ultra-High-Temperature Cavitation Promoted by Magnetic Field

Yoshimura

Ijiri

Sato

2022

Int. J. Eng. Sci. Tech

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“…WJP and MFC were performed in the same way as in the previous study [ 3 ]. In addition to the aforementioned processing techniques, a swirl flow nozzle (SFN) [ 19 , 20 ] was installed to increase the number and size of cavitation bubbles at the tip of the WJ nozzle. Attaching an SFN has been demonstrated to enable suppression of erosion traces formed in the central part when an Al surface is processed [ 19 , 21 ].…”

Section: Experimental Methodsmentioning

confidence: 99%

High-temperature corrosion behavior of high-temperature and high-pressure cavitation processed Cr–Mo steel surface

Ijiri

Ogi

Yoshimura

2020

Heliyon

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In this paper, long-term high-temperature corrosion at 500 °C and high-temperature corrosion at the melting temperature of a corrosive ash mixture were examined because the use of high-temperature equipment such as boilers and gas turbines increases year over year. To investigate the optimum cavitation processing conditions for the specimens used in high-temperature corrosion tests, the surface properties of each processed specimen were examined. In specimens processed using multifunction cavitation (MFC), the compressive residual stress was high when the processing time was 10 min and the Cr content on the surface was greater than on the surface of an unprocessed specimen. On the other hands, in specimens subjected to water-jet peening (WJP), the compressive residual stress was high when the processing time was 10 min. In the present study, the processing time was selected to be 10 min and all high-temperature corrosion tests were conducted by the coating method. In the case of long-term high-temperature corrosion at 500 °C, the corrosion loss of the MFC-processed and WJP-processed specimens was small, whereas the corrosion loss of the unprocessed specimen was large.

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“…Previously, we developed a new method for the nanoscale processing of TiO 2 particles as well as a new technique for adding a Pt co-catalyst to TiO 2 particles [5]. Furthermore, TiO 2 particles were processed by multifunction cavitation [6][7][8][9][10][11] in order to modify the surface morphology and electrochemical surface condition. It was determined that multifunction cavitation is effective at improving the photocatalytic properties of TiO 2 under visible light irradiation.…”

Section: Introductionmentioning

confidence: 99%

Nanolevel Surface Processing of Fine Particles by Waterjet Cavitation and Multifunction Cavitation to Improve the Photocatalytic Properties of Titanium Oxide

Yoshimura¹,

Tanaka²,

Ijiri³

2018

Cavitation - Selected Issues

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Titanium oxide particles were treated by water jet cavitation (WJC) generated and multifunction cavitation (MFC) using an ejector nozzle. Generation, growth, and collapse of cavitation are repeated with the particles of titanium oxide and platinum. Because the cavitation has an extremely high collapse pressure, the surface of the titanium oxide particles is processed by the microjets of cavitation in a reactor comprising the ejector nozzle. In the multifunction cavitation, ultrasonic irradiation of a waterjet during floating cavitation was used to generate microjets with hot spots. Hot working can be performed at the nanoscale on a material surface using this MFC process, resulting in morphological changes and variations in the surface electrochemical characteristics. The fundamental characteristics of multifunction cavitation were investigated theoretically and experimentally. Furthermore, the additional nozzle was put on the ejector nozzle in order to increase the temperature and pressure of bubble and the mechanism was clarified. The quantities of hydrogen and oxygen generated from titanium dioxide particles treated by multifunction cavitation in response to UV and visible light irradiation were remarkably increased compared to the amounts produced by particles treated by WJC processing. In this chapter, the methods and their results of processing particles by cavitation are introduced.

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Estimation of Bubble Fusion Requirements during High-Pressure, High- Temperature Cavitation

Cited by 9 publications

References 24 publications

Estimation of Nuclear Fusion Requirements in Bubbles During Ultra-High-Pressure, Ultra-High-Temperature Cavitation Promoted by Magnetic Field

Estimation of Nuclear Fusion Requirements in Bubbles During Ultra-High-Pressure, Ultra-High-Temperature Cavitation Promoted by Magnetic Field

High-temperature corrosion behavior of high-temperature and high-pressure cavitation processed Cr–Mo steel surface

Nanolevel Surface Processing of Fine Particles by Waterjet Cavitation and Multifunction Cavitation to Improve the Photocatalytic Properties of Titanium Oxide

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