Wettability Effect on Bubble Formation at Nozzles in Liquid Aluminum

Gnyloskurenko, Svyatoslav; Nakamura, Takashi

doi:10.2320/matertrans.44.2298

Cited by 22 publications

(18 citation statements)

References 19 publications

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“…In addition, the inlet flow rate affected size of bubble. This result agreed with findings in bubbling column [29][30][31]. The instability of inlet flow rate and high Reynolds number creates large bubbles.…”

Section: Relationship Of Carbonation and Bubblingsupporting

confidence: 92%

Effect of membrane on carbonation and carbon dioxide uptake ofChlorellasp.

Suali¹,

Sarbatly²,

Anisuzzaman³

et al. 2017

MATEC Web Conf.

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Recent studies showed that as low as 5% CO2 increased microalgae growth. However, common bioreactor operation resulted in low carbonation due to poor CO2 mass transfer and this inhibited CO2 uptake of microalgae. Although bubbling increases mass transfer of CO2-O2 exchange, preserving high dissolved CO2 remains the most challenging of microalgae cultivation in bioreactor. In order to increase high dissolved CO2 and CO2-O2 exchange, this study employed two types of membrane; hollow-fibre membrane for carbonation and hydrophobic membrane for deoxygenation. It was found that membrane increased carbonation from 20 % to 75 % when operated at control CO2 concentration. The hollow-fibre membrane capable of creating as small as 2 mm bubble which effective for high carbonation. At the same time, it increased CO2 uptake up to 85% in bioreactor. The hydrophobic membrane removed 43% O2 from the bioreactor. Both membranes increased mass transfer of CO2-O2 exchange in bioreactor which stimulated microalgae growth.

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Section: Relationship Of Carbonation and Bubblingsupporting

confidence: 92%

Effect of membrane on carbonation and carbon dioxide uptake ofChlorellasp.

Suali¹,

Sarbatly²,

Anisuzzaman³

et al. 2017

MATEC Web Conf.

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“…This effect causes early detachment of the bubble in LBE. However, Irons and Guthrie, 13 Bai and Thomas, 14 and Gnyloskurenko and Nakamura 77 found that the average bubble sizes in liquid metal are larger than those of air bubbles in water. This may be due to the lower Bond numbers used in liquid metals compared with those in water.…”

Section: Grid Independence Test and Validationmentioning

confidence: 99%

“…This may be due to the lower Bond numbers used in liquid metals compared with those in water. It was also reported 13,14,77 that the dynamics of the bubble formation process in a liquid metal were also influenced by the presence of nonwetting or hydrophobic materials with u s > 90 0 (referred to as poor wettability). This influences the bubble base diameter along the surface material and the final detached bubble volume.…”

Section: Grid Independence Test and Validationmentioning

confidence: 99%

“…It is observed that the volume of bubbles is larger in liquid aluminum than in water, which can be attributed to the differences in buoyancy forces in water and liquid aluminum metal systems. Gnyloskurenko et al 28 and Gnyloskurenko and Nakamura 77 found that the volume of a detached bubble is independent of u s in the range 0 u s < 68 0 . Therefore, the present results are valid for the wetting or hydrophilic materials with 0 u s < 68 0 .…”

Section: Grid Independence Test and Validationmentioning

confidence: 99%

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Bubble formation and dynamics in a quiescent high‐density liquid

et al. 2015

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Gas bubble formation from a submerged orifice under constant-flow conditions in a quiescent high-density liquid metal, lead-bismuth eutectic (LBE), at high Reynolds numbers was investigated numerically. The numerical simulation was carried out using a coupled level-set and volume-of-fluid method governed by axisymmetric Navier-Stokes equations. The ratio of liquid density to gas density for the system of interest was about 15,261. The bubble formation regimes varied from quasi-static to inertia-dominated and the different bubbling regimes such as period-1 and period-2 with pairing and coalescence were described. The volume of the detached bubble was evaluated for various Weber numbers, We, at a given Bond number, Bo, with Reynolds number Re ) 1. It was found that at high values of the Weber number, the computed detached bubble volumes approached a 3/5 power law. The different bubbling regimes were identified quantitatively from the time evolution of the growing bubble volume at the orifice. It was shown that the growing volume of two consecutive bubbles in the period-2 bubbling regime was not the same whereas it was the same for the period-1 bubbling regime. The influence of grid resolution on the transition from period-1 to period-2 with pairing and coalescence bubbling regimes was investigated. It was observed that the transition is extremely sensitive to the grid size. The transition of period-1 and period-2 with pairing and coalescence is shown on a Weber-Bond numbers map. The critical value of Weber number signalling the transition from period-1 to period-2 with pairing and coalescence decreases with Bond number as We $ Bo 21 , which is shown to be consistent with the scaling arguments. Furthermore, comparisons of the dynamics of bubble formation and bubble coalescence in LBE and water systems are discussed. It was found that in a high Reynolds number bubble formation regime, a difference exists in the transition from period-1 to period-2 with pairing and coalescence between the bubbles formed in water and the bubbles formed in LBE. V C 2015 American Institute of Chemical Engineers AIChE J, 61: 3996-4012, 2015

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“…The effect of the degassing technique on the quality of the aluminum alloys includes not only controlling the hydrogen content but also the resultant quality of the melt and its cleanliness. Gnyloskurenko and Nakamura 3) took advantage of in-situ observations at the melt. They found that the gas bubble volume increased as the wettability of the melt worsened, such as after using alumina nozzle.…”

Section: Introductionmentioning

confidence: 99%

Effects of Degassing and Fluxing on the Quality of Al-7%Si and A356.2 Alloys

Shih

Wen

2005

Mater. Trans.

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A covering flux is commonly used to prevent an aluminum melt from reacting with the surrounding atmosphere or from re-oxidizing. In this study, melts were degassed with and without a covering flux using a porous bar diffuser. After degassing and holding, the melts were then poured to obtain chilled samples, reduced pressure samples and permanent mold castings. The chilled samples were polished and treated by ultrasonic vibration to reveal any foggy marks and the area of the foggy marks and the pore count were measured. The densities of the chilled samples and the reduced pressure sample were also measured to compute the relative porosities. The factors influencing the relative porosities of the aluminum alloy castings were then discussed. Rotational bending fatigue tests were also conducted to assess the effect of the pore count and the relative porosity on the fatigue life cycles of the A356 alloy castings.

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Wettability Effect on Bubble Formation at Nozzles in Liquid Aluminum

Cited by 22 publications

References 19 publications

Effect of membrane on carbonation and carbon dioxide uptake ofChlorellasp.

Effect of membrane on carbonation and carbon dioxide uptake ofChlorellasp.

Bubble formation and dynamics in a quiescent high‐density liquid

Effects of Degassing and Fluxing on the Quality of Al-7%Si and A356.2 Alloys

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