PIV measurement of a contraction flow using micro-bubble tracer

Ishikawa, Masaaki; Irabu, Kunio; Teruya, Isao; Nitta, Munehiro

doi:10.1088/1742-6596/147/1/012010

Cited by 13 publications

(10 citation statements)

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“…The increment of air-water ratio is expected increasing bubble coalesance rate. Collision rate is comparable with turbulence speed fluctuation and is expected having higher Reynolds number as explained by Gordiychuk et al [5].…”

Section: Distribution Of Bubble Sizesupporting

confidence: 62%

“…This research was conducted to know bubble distribution processed by image processing, power consumption, and dissolved oxygen. Other researchers are Ishikawa et al [5] who developed ventury microbubble generator and Tabei et al [6] who conducted experiment on swirl jet microbubble generator. The experiment was conducted by varying nozzle diameter, gas pressure, and gas debit.…”

Section: Introductionmentioning

confidence: 99%

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Performance of Porous-Venturi Microbubble Generator for Aeration Process

Afisna

Juwana

Indarto

et al. 2017

JEMMME

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Qualified and preserved water is declining due to metal, waste, and hazardous chemicals contamination. Demand on fresh water raises and leads to the efforts on processing waste water with effective and efficient technology. Microbubble generator technology developed lately to result dissolved oxygen for raising microorganisms to decompose waste in waste water. This research used porous-ventury microbubble generator with 30° inlet angle and 20° outlet angle, placed in the center of 280 cm x 60 cm x 40 cm aquarium for experiment. This research aimed to find out bubble distribution and microbubble generator (MBG) performance. Measurement on bubble distribution conducted using Phantom Control Camera. Obtained data analyzed using MATLAB R2016a, while MBG performance measured using pressure transducer. Analysis conducted on variations of gas debit (0,1 lpm; 0,4 lpm., and 1 lpm) and water debit (30- 80 lpm) effects toward performance parameters, such as hydraulic power (Lw) and bubble generating efficiency (ηB). Results show that the greatest microbubbles’ diameter is 150- 500 μm, hydraulic power (Lw) increases with the inclining water debit (QL), effect of gas debit variation exert low effect towards Lw, and declining number of bubble generating efficiency (ηB) parameter with the inclining number of the water debit (QL).

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Section: Distribution Of Bubble Sizesupporting

confidence: 62%

Section: Introductionmentioning

confidence: 99%

Performance of Porous-Venturi Microbubble Generator for Aeration Process

Afisna

Juwana

Indarto

et al. 2017

JEMMME

View full text Add to dashboard Cite

show abstract

“…Measuring the velocity of bubbles is also an important factor to optimize the bubble generation process. The particle image velocimetry (PIV) technique was used to provide the velocity field of air bubbles [11,[13][14][15][16]. It is an optical method and a nonintrusive measurement.…”

Section: Introductionmentioning

confidence: 99%

Measurement of the air bubble size and velocity from micro air bubble generation (MBG) in diesel using optical methods

et al. 2020

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In this paper, we determine the bubble size and velocity from air bubble generation (MBG) in a diesel using optical methods. A KTM Series Pump was used to generate micro air bubbles in diesel. The air bubble radius and velocity measurements can be useful parameters to optimize the bubble generation process. Two optical systems were used for measurement air bubble sizes and their velocities in diesel. First, the optical system without an objective lens was used to determine the velocity of air bubbles in diesel. Another optical system with a 10× objective lens was used to obtain the size distribution of air bubbles generated in diesel. An available optical system with a 10× objective lens can detect a bubble diameter greater than 3.3 µm that air bubble images were processed using the ImageJ program. We measured the size distribution of air bubbles generated using the ImageJ program. The micro air bubble radius measured in diesel was found to be 6.26 µm in the sample after a month from air bubble generation. In addition, the particle image velocimetry (PIV) technique was used to measure the velocity field. Then, we used the OpenPIV program for PIV image processing. The highest velocity distribution was determined to be 90 mm/s for diesel without air bubbles and 20 mm/s for diesel with air bubbles after a month of the bubble generation.

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“…Finally, some prototypes consist of a tube with an inner orifice [18] or a sphere [15] to produce a decrease in the internal static pressure to produce air suction from a near porous wall, fundamental for production of microbubbles. The present research focus converged on Venturi MBGs as they have the simplest and most energy-efficient design [19,20]. A Venturi tube consists of a convergent section followed by a divergent section, where the compressible air-water mixture is injected and accelerated up to supersonic Mach speed [8,9].…”

Section: Introductionmentioning

confidence: 99%

Initial Results from the Experimental and Computational Study of Microbubble Generation

Basso¹,

Hamad²,

Ganesan³

2019

Proceedings of the 4th World Congress on Momentum, Heat and Mass Transfer

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A novel design of microbubble aeration is proposed to increase dissolved oxygen (DO) levels in water, by reducing the mean bubble diameter distribution down to the 20 -50 µm range. Microbubble generators (MBGs) find application in aquaculture farms, where water oxygenation is crucial for sea lives and for disinfection through free radicals. A Venturi MBG is taken as baseline design for comparison with previous literature, to understand the pressure-recovery mechanism responsible for bubble breakup. Based on Venturi performance, a helicoidal body -at three different pitch angles -is added ahead of the throat to create sufficient swirling motion, with the aim of intensifying turbulent pressure fluctuations. Results from a validated Computational Fluid Dynamics (CFD) setup and flow visualisation are compared to assess the accuracy of present experimental results, in terms of MBG performance at different volumetric qualities. Backlight imaging and binary processing are implemented to estimate microbubble distributions. Probability distribution and mean diameter plots show an initial disagreement of experimental data from the literature and present predictions. This is presumably attributed to a possible improvement to be done, in terms of light illumination and the use of a microscopic lens, which can better spot small microbubbles. Furthermore, results from CFD show a reduction in the mean diameter when using a helicoid pitch angle of 20 degrees. Of particular interest is a mean diameter near 25μm at very low volumetric quality. By contrast, the configuration at pitch angle of 30 degrees gives a distribution with mean diameter near 70μm, for same volumetric quality. Although this paper only focuses on the bubble diameter aspect, DO measurements coupled with the analysis of microbubble distributions will reinforce authors assumption that small microbubbles represent the optimal condition to maximise water aeration and to enhance treatment of organic particles.

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PIV measurement of a contraction flow using micro-bubble tracer

Cited by 13 publications

References 0 publications

Performance of Porous-Venturi Microbubble Generator for Aeration Process

Performance of Porous-Venturi Microbubble Generator for Aeration Process

Measurement of the air bubble size and velocity from micro air bubble generation (MBG) in diesel using optical methods

Initial Results from the Experimental and Computational Study of Microbubble Generation

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