Flow Visualization

Asanuma, Tsuyoshi; Bajura, R.A.

doi:10.1115/1.3240676

Cited by 2 publications

(3 citation statements)

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“…7 (d) d < 0.1 mm, flow with the fluid stream and leave the rotating pipe section from the stationary outlet pipe, indicating that these smaller bubbles, which show the same particle path between the stream line of the fluid motion, can be treated as the tracer particle when further decreasing of their size is affected. As a reference to flow visualization with micro-bubbles, although they are often hydrogen bubbles (10), (11) , the maximum size of bubbles (air-bubbles in the present study), which flow along the stream line within ±1 per cent of deviation, would be approximately d max = 0.05 mm for either cases of channel geometries in the present calculation.…”

Section: Dynamic Behavior Of Micro-bubblesmentioning

confidence: 93%

Micro-Bubbly Flows in Rotating Pipe Sections with Abrupt Expansion and Contraction

Yamaguchi

Kuwahara

Ueno

2004

JSME international journal. Ser. B, Fluids and thermal engineer

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An investigation was carried out for swirling flow in a rotating pipe with highly viscous fluid containing micro-bubbles experimentally and numerically. In the numerical analysis, bubble trajectory of each bubble was calculated using resultant numerical flow field solutions. From experimental results, with an aid of the numerical simulation, data were obtained for the location of a stagnation point, which moves towards the inlet region as swirl ratio being increased. It was found that the position of the stagnation point had a particular convergence value in relation with Reynolds number and types of the rotating channel. In the bubble behavior, big bubbles fall into the stagnation point, and that the parabolic surface is formed by some smaller bubbles. Critical diameter of bubble, which was to be caught at the stagnation point, was also obtained numerically for the model rotating channels.

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Section: Dynamic Behavior Of Micro-bubblesmentioning

confidence: 93%

Micro-Bubbly Flows in Rotating Pipe Sections with Abrupt Expansion and Contraction

Yamaguchi

Kuwahara

Ueno

2004

JSME international journal. Ser. B, Fluids and thermal engineer

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“…In this experiment, linearly-aligned electrodes were employed, because the active electrode area increased towards the streamwise direction, which enabled us to visualize the spark lines extensively in comparison with the needle-typed electrodes used in sections 4.1−4.3. A previous study (29) has reported that the use of the linearly-aligned electrodes induces a velocity Vol. 8, No.…”

Section: Application Of Velocity Correction Technique To Mixing Air Jmentioning

confidence: 99%

“…[ii] When applying to a flow with a large velocity gradient, the spark line passes through a pathway that is smaller than the curvature of the actual velocity distribution due to short circuiting, and it is expected that the obtained velocities would be underestimated (29) . This is caused by the diffusion of the ionized air, and the spark line generally goes through the pathway with the minimum electric resistance that is different from the pathway of the theoretical equation.…”

Section: Journal Of Thermal Science and Technologymentioning

confidence: 99%

Velocity Measurement of Sub-Millimeter-Scale Gas Flow by Spark Tracing Method

Ichiyanagi

Koyama

Sato

et al. 2013

JTST

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A molecular tagging technique using the spark tracing method has been applied to measure velocity distributions in sub-millimeter-scale gas flows, formed as air jet flows through a sub-millimeter channel. Spark lines are generated by air ionization when applying high voltage due to the electrical discharge phenomena. The velocities measured using the displacement of spark lines were 10−30% smaller than those using the theoretical equation in a rectangular channel. In order to identify the cause of the measurement error, the relationship between the ionized air regions and the gas flow velocities was investigated by numerical simulation. The simulation revealed that a spark line goes through the pathway with the minimum electric resistance, and that the velocities from the theoretical equation agreed with the spark line velocities when the spark line width is assumed to be zero. Using this result, we propose a new velocity correction technique using the relationship between the spark line width and the measured velocity. The velocities from the experiments with the suggested correction agreed well with those from the theoretical equation. Furthermore, the corrected spark tracing method was applied to a mixing air jet flow field with different temperatures through two channels.

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Flow Visualization

Cited by 2 publications

References 0 publications

Micro-Bubbly Flows in Rotating Pipe Sections with Abrupt Expansion and Contraction

Micro-Bubbly Flows in Rotating Pipe Sections with Abrupt Expansion and Contraction

Velocity Measurement of Sub-Millimeter-Scale Gas Flow by Spark Tracing Method

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