Effect of Ultrasound on Concentration Boundary Layer Formed by Anodic Reaction

Yamakado, Yuki; Yamada, Takashi; Iwai, Kazuo

doi:10.2355/tetsutohagane.tetsu-2015-090

Cited by 2 publications

(1 citation statement)

References 12 publications

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“…Recently, Yamakado et al 8) investigated the effect of the ultrasound on the boundary layer formed in an aqueous solution by anodic reaction of a copper electrode. They pointed out that the ultrasound irradiation reduces the concentration boundary layer thickness.…”

Section: Introductionmentioning

confidence: 99%

Model Experiment for Acceleration of Lime Dissolution into Slag under Ultrasound Irradiation Conditions

Okumura

2017

ISIJ International

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In the metal manufacturing process, it is considered that ultrasound technology can be applied in the promotion of solid dissolution such as lime dissolution to molten slag and solid metal addition to molten alloy. Generally, in the high-temperature reaction process, mass transfer has a large effect on the rate of reaction in isothermal conditions. In order to facilitate mass transfer, it is necessary to strengthen the agitation of the bath. However, it is impossible to avoid the erosion of the stirrer and container. Enhancement of stirring promotes mass transfer. This corresponds to thinning of the boundary layer thickness in the boundary layer theory. To further accelerate mass transfer, a new method of thinning the boundary layer of the solid surface without using mechanical stirring is needed.In this study, the effect of ultrasound on the dissolution phenomena of solid in liquid was investigated by using a sucrose-water system. Applying ultrasound to a liquid induces ultrasonic radiation pressure, acoustic streaming and various nonlinear phenomena of cavitation. Especially, when the cavitation bubble collapses, a micro jet is generated and a strong flow occurs locally. It was thought that this micro jet collided with the solid sample and the surface became uneven. If the cavitation phenomena occur at the solid surface, it is possible to disturb the boundary layer and increase the mass transfer rate by thinning the boundary layer. It was found that the cavitation in the vicinity of the solid surface at the low ultrasound frequency caused a disturbance of the boundary layer of the solid surface and promoted dissolution rate of the solid.

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Section: Introductionmentioning

confidence: 99%

Model Experiment for Acceleration of Lime Dissolution into Slag under Ultrasound Irradiation Conditions

Okumura

2017

ISIJ International

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Liquid Motion in a Solid-liquid Mixed Region under Imposition of Ultrasound

Iwai

Mano

2019

Tetsu-to-Hagane

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Flowexcitationinasolid-liquidmixedregionsurroundedbyasolidlayerisnoteasybecauseofdifficultyofdirectexertionofforceonthe liquidandlargeapparentviscosity.Ultrasoundisexpectedasaflowexcitationtoolinthesolid-liquidmixedregionbecauseitcantransmit force from the outside of the surrounding solid layer. Thus, investigation on the liquid motion under the ultrasound imposition on the solid-liquid mixed region has been done in this study. Because of the large difference of acoustic impedance between an alumina and a polyacetal,theywerechosenasthesolidparticlesinthesolid-liquidmixedregionwhilewaterwaschosenastheliquid.Thesuperficialvelocity in the solid-liquid mixed region increased as its length became shorter under the condition that the voltage on the ultrasound vibrator was constant. Apparent porosity under the imposition of the ultrasound was larger than the real porosity evaluated without the ultrasound when the water-alumina system was used, and the former increased as the solid-liquid mixed region length became shorter. On the other hand, the apparent porosity under the ultrasound imposition was only slightly larger than the real porosity without the ultrasound imposition in the case of the water-polyacetal system. The difference between these systems might be caused by the acoustic impedance difference between the alumina and the polyacetal.

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Effect of Ultrasound on Concentration Boundary Layer Formed by Anodic Reaction

Cited by 2 publications

References 12 publications

Model Experiment for Acceleration of Lime Dissolution into Slag under Ultrasound Irradiation Conditions

Model Experiment for Acceleration of Lime Dissolution into Slag under Ultrasound Irradiation Conditions

Liquid Motion in a Solid-liquid Mixed Region under Imposition of Ultrasound

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