A low-voltage spark-discharge method for generation of consistent oscillating bubbles

Goh, Bing Hui Terence; Oh, Yu-Na; Klaseboer, Evert; Ohl, Siew-Wan; Khoo, Boo Cheong

doi:10.1063/1.4776187

Cited by 33 publications

(19 citation statements)

References 10 publications

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“…Among our spark-induced bubbles, the minimum of the volume ratios is 0.008, as shown in Figure 9b. This is small compared with other spark-induced cavitation bubbles [18,29,32], but still larger than those induced by laser.…”

Section: Statistical Propertiesmentioning

confidence: 67%

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Improved Instruments and Methods for the Photographic Study of Spark-Induced Cavitation Bubbles

Zhang

Zhai

2018

Water

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An underwater spark is able to induce a cavitation bubble, and this principle has been utilized to make cavitation bubble generators for several decades. In this paper, an improved instrument for generating spark-induced cavitation bubbles is described in detail. The voltage time history inside the instrument is measured to show the working process and principle. Cavitation bubbles are generated by the instrument and recorded by a high-speed camera. The radius time history of the bubble is obtained using an image processing algorithm. The ratio of its minimum radius to its maximum radius reaches ~0.2, which indicates that there is little undissolved gas in the bubble. With the radius time history, the velocity fields around the bubbles were calculated by the 1D continuity flow equation, and the pressure fields were calculated by the 1D Euler equation. One cavitation bubble is chosen and discussed in detail. The velocity and pressure on the bubble interface achieve their maximums (~25 m/s and ~1.2 MPa, respectively) at the same time, when the radius is at its minimum (~1 mm). Some statistical results are also presented to show the effect of the instrument.

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Section: Statistical Propertiesmentioning

confidence: 67%

“…A low-voltage device was introduced by Goh et al [32]. This device is able to accurately generate cavitation bubbles with various radii by adjusting the length of its electrodes.…”

Section: Introductionmentioning

confidence: 99%

Improved Instruments and Methods for the Photographic Study of Spark-Induced Cavitation Bubbles

Zhang

Zhai

2018

Water

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“…In case of spark discharge method, typically two electrodes are separated by a small gap and a very high (2-20 kV) voltage is passed. However, in this work, low voltage (typically less than 100 V) is applied to create the spark through electrodes which are in contact with each other [13][14]. This method, besides being safer to handle, employs smaller electrode sizes (100-300 m) in comparison to that ( 1 mm) in high voltage method.…”

Section: Experimental Methodologymentioning

confidence: 99%

“…The disadvantage of this method is the need to replace electrodes after each spark. Figure 2(a) shows the circuit used for the production of low (at 60 V) voltage spark based on the descriptions given in prior work [13][14]. Figure 2(b) shows the backlight LED lamp used to capture high speed images at 40,000 fps using Photron SA-4 camera.…”

Section: Experimental Methodologymentioning

confidence: 99%

Towards Development of Surface Coating for Improved Cavitation Resistance

Kamble¹,

Sureka²,

Syamsundar³

et al. 2018

Proceedings of the 10th International Symposium on Cavitation (CAV2018)

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Hydrodynamic cavitation is known to have many harmful effects and of these effects, cavitationinduced erosion and surface pitting are detrimental to the life of hydraulic machines. One approach to reduce material damage could be through development of new materials and coatings with improved cavitation resistance. Though a large body of work exists on surface treatment methods, especially those involving surface hardening processes, use of non-metallic materials such as polymers as coatings on steel substrate has not received adequate attention. Present study addresses this gap through systematic study of different coatings involving vibratory cavitation (ASTM G-32 protocol) as well as studying the dynamics of single bubble near a material surface with appropriate coatings. Mass loss for different coatings under vibratory cavitation as well as the scanning electron microscopy study of these specimens has been reported. Pressure measurement as well as high speed imaging of single bubble collapse near the coated surface is also highlighted to bring out the efficacy of this system.

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“…These thin naked copper wires are used as electrodes, that are connected to the spark generator device that discharges a large capacitor in a very short time (∼400 µs). The spark generator reproduces the discharge circuit described in Willert et al Willert et al (2010) but replacing the LED by the electrodes, as suggested by Goh et al Goh et al (2013). A capacitor (2200 µF) is charged through a power supply (30-35 V) and is discharged thought a fast MOSFET power transistor when it receives a TTL trigger signal.…”

Section: Setup Of the Experimentsmentioning

confidence: 99%

Drop Tower Setup to Study the Diffusion-driven Growth of a Foam Ball in Supersaturated Liquids in Microgravity Conditions

Vega-Martínez

Rodríguez-Rodríguez

Meer

et al. 2017

Microgravity Sci. Technol.

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The diffusion-driven growth of a foam ball is a phenomenon that appears in many manufacturing process as well as in a variety of geological phenomena. Usually these processes are greatly affected by gravity, as foam is much lighter than the surrounding liquid. However, the growth of the foam free of gravity effects is still very relevant, as it is connected to manufacturing in space and to the formation of rocks in meteorites and other small celestial bodies. The aim of this research is to investigate experimentally the growth of a bubble cloud growing in a gas-supersaturated liquid in microgravity conditions. Here, we describe the experiments carried out in the drop tower of the Center of Applied Space Technology and Microgravity (ZARM). In few words, a foam seed is formed with spark-induced cavitation in carbonated water, whose time evolution is recorded with two high-speed cameras. Our preliminary results shed some light on how the size of the foam ball scales with time, in particular at times much longer than what could be studied in normal conditions, i.e. on the surface of the Earth, where the dynamics of the foam is already dominated by gravity after several milliseconds.

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A low-voltage spark-discharge method for generation of consistent oscillating bubbles

Cited by 33 publications

References 10 publications

Improved Instruments and Methods for the Photographic Study of Spark-Induced Cavitation Bubbles

Improved Instruments and Methods for the Photographic Study of Spark-Induced Cavitation Bubbles

Towards Development of Surface Coating for Improved Cavitation Resistance

Drop Tower Setup to Study the Diffusion-driven Growth of a Foam Ball in Supersaturated Liquids in Microgravity Conditions

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