The flow field in air-water vertical bubbling jets in a cylindrical vessel.

Iguchi, Manabu; Takeuchi, Hiroaki; Morita, Zen-ichirô

doi:10.2355/isijinternational.31.246

Cited by 27 publications

(19 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This was to be expected indeed, but a detailed description of the exact role of the gas phase in producing anisotropy of turbulence -and its proportions -was not given. Iguchi, Takeuchi & Morita (1991) found that the velocity fluctuations may be of the same order of magnitude as the mean velocities (100 % turbulence intensities), and follow a Gaussian distribution. In the experiments of Johansen et al (1988), measured turbulent intensities were weaker axially than in the experiment of Iguchi et al (1991), i.e.…”

Section: Introductionmentioning

confidence: 99%

“…Iguchi, Takeuchi & Morita (1991) found that the velocity fluctuations may be of the same order of magnitude as the mean velocities (100 % turbulence intensities), and follow a Gaussian distribution. In the experiments of Johansen et al (1988), measured turbulent intensities were weaker axially than in the experiment of Iguchi et al (1991), i.e. about 50 %, but still substantially stronger in the radial direction (>100 %) except near the free surface.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Turbulent transport mechanisms in oscillating bubble plumes

et al. 2009

View full text Add to dashboard Cite

The detailed investigation of an unstable meandering bubble plume created in a 2-m-diameter vessel with a water depth of 1.5 m is reported for void fractions up to 4% and bubble size of the order of 2.5 mm. Simultaneous particle image velocity (PIV) measurements of bubble and liquid velocities and video recordings of the projection of the plume on two vertical perpendicular planes were produced in order to characterize the state of the plume by the location of its centreline and its equivalent diameter. The data were conditionally ensemble averaged using only PIV sets corresponding to plume states in a range as narrow as possible, separating the small-scale fluctuations of the flow from the large-scale motions, namely plume meandering and instantaneous cross-sectional area fluctuations. Meandering produces an apparent spreading of the average plume velocity and void fraction profiles that were shown to remain self-similar in the instantaneous plume cross-section. Differences between the true local time-average relative velocities and the difference of the averaged phase velocities were measured; the complex variation of the relative velocity was explained by the effects of passing vortices and by the fact that the bubbles do not reach an equilibrium velocity as they migrate radially, producing momentum exchanges between high- and low-velocity regions. Local entrainment effects decrease with larger plume diameters, contradicting the classical dependence of entrainment on the time-averaged plume diameter. Small plume diameters tend to trigger ‘entrainment eddies’ that promote the inward-flow motion. The global turbulent kinetic energy was found to be dominated by the vertical stresses. Conditional averages according to the plume diameter showed that the large-scale motions did not affect the instantaneous turbulent kinetic energy distribution in the plume, suggesting that large scales and small scales are not correlated. With conditional averaging, meandering was a minor effect on the global kinetic energy and the Reynolds stresses. In contrast, plume diameter fluctuations produce a substantial effect on these quantities.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Turbulent transport mechanisms in oscillating bubble plumes

et al. 2009

View full text Add to dashboard Cite

show abstract

“…The bubble motions characterized by bubble frequency, f B , gas holdup, a, mean bubble rising velocity, ū B , and mean bubble diameter, d¯B, were measured with a two-needle electroresistivity probe. 21,22) The number of bubbles passing through the needle tip in 1 s is defined as the bubble frequency. The gas holdup is calculated from:…”

Section: Introductionmentioning

confidence: 99%

The Coanda Effect on Bubbling Jet behind a Horizontally Placed Circular Cylinder.

et al. 2002

Self Cite

View full text Add to dashboard Cite

The motions of bubbles and liquid behind a circular cylinder placed horizontally in a vertical water-air bubbling jet were experimentally investigated. Bubbles approaching the cylinder were separated by the cylinder in the two ways along the side wall of the cylinder, and they gathered together again at a certain distance from the cylinder due to the Coanda effect. This situation was confirmed from the measurements of gas holdup and mean water velocity components. The mean bubble diameter behind the cylinder became small because disintegration of bubbles took place around the cylinder. The mean bubble rising velocity also became very low behind the cylinder. The horizontal spreading of the bubbling jet was significantly suppressed by the cylinder.

show abstract

“…(7). The previous study 15) revealed that the sub-boundary (3) By referring to the discussion on the sub-boundary (4) in a bath agitated by bottom liquid injection, 12) the following first two methods will be proposed for a bath agitated by bottom gas injection.…”

Section: Sub-boundary (3)mentioning

confidence: 99%

“…According to the previous paper 12) for a bath agitated by (7) where k 1 Ј and k 12 are constants, Q Ls is the liquid flow rate at the bath surface, 12,[14][15][16][17] u L, cl is the centerline velocity of liquid flow, b u is the half-value radius of the axial velocity distribution of the liquid flow, and H L is the bath depth. The bubble dispersion region in the bath is called the bubbling jet.…”

Section: Prediction Of Four Sub-boundariesmentioning

confidence: 99%

Occurrence Condition for a Swirl Motion of a Bath Agitated by Bottom Gas Injection

Iguchi

Sasaki

et al. 2004

ISIJ International

Self Cite

View full text Add to dashboard Cite

A swirl motion of a cylindrical bath appears under a certain condition when the bath is agitated by bottom gas injection. The swirl motion can be classified into two types. One is called the shallow-water wave type, and the other is called the deep-water wave type. The condition for the occurrence of a swirl motion of the deep-water wave type was experimentally investigated based on water model experiments. Empirical equations were proposed for predicting the condition as functions of the gas flow rate, vessel diameter, inner diameter of the nozzle, and the physical properties of fluids.KEY WORDS: steelmaking; refining; swirl motion; wastewater treatment; bubbling jet; injection. Fig. 1. Classification of swirl motions of a bath agitated by bottom gas injection.

show abstract

The flow field in air-water vertical bubbling jets in a cylindrical vessel.

Abstract: Also, the flow rate, momentum and kinetic energy of rising waterwere determined, being necessary to refine previous theoretical models predicting the fluid behavior induced by bubbles.

Cited by 27 publications

References 0 publications

Turbulent transport mechanisms in oscillating bubble plumes

Turbulent transport mechanisms in oscillating bubble plumes

The Coanda Effect on Bubbling Jet behind a Horizontally Placed Circular Cylinder.

Occurrence Condition for a Swirl Motion of a Bath Agitated by Bottom Gas Injection

Contact Info

Product

Resources

About