Effect of Acoustic Standing Wave in a Bubble Column

Abstract

Experiments using nickel magnetostrictive oscillators as transducers that generate acoustic standing waves in a bubble column were conducted in this study. The acoustic frequencies employed are 16 and 20 kHz with power up to 400 W. The column is operated at a constant room temperature, with the heat generated from acoustic excitation removed by the use of a water jacket. The study examines the fundamental behavior of initial bubble size, bubble rise velocity and movement of a swarm of mesobubbles (2−8 mm in diameter), gas−liquid mass transfer, and turbulence under the influence of the Bjerknes force in the acoustic field. The results indicate a smaller initial bubble size, a slower bubble rise velocity, and more concentrated bubble aggregates in the presence, rather than in the absence, of the acoustic field. Furthermore, the gas−liquid mass transfer rate and the liquid-phase turbulence are found to be significantly enhanced when an acoustic field is present.

In situ characterisation of a concentrated colloidal titanium dioxide settling suspension and associated bed development: Application of an acoustic backscatter system

“…Alternative approaches include those analysing the transmission-attenuation response of laser light in sample based devices such as the Lumizier (from Lum GmbH) and Turbiscan (Formulation, SA) [9][10][11]; however, these ex situ systems are only suitable for small sample analysis of slowly evolving suspensions. In situ devises include light based transmission/backscatter or fluorescence devices [12][13][14][15][16][17][18], CCD video analysis [19][20][21][22][23], gamma ray [24,25] or x-ray CATSCAN [26], and also tomographic techniques which measure electrical resistance within suspensions [27,28]. However, a number of these techniques suffer from common limitations to their use, such complicated set-ups that encompass specific vessel requirements (and hence are not suitable for deployment industrially) while many are highly intrusive, or complex and expensive in application [29].…”

Absorption of carbon dioxide in aqueous colloidal silica solution with NaOH

“…The techniques for the enhancement of heat and mass transfer performance are generally categorized into several methods: mechanical, chemical, acoustic [2] and electromagnetic treatments, and application of nanotechnology [3]. The selection of heat transfer mode such as falling film type and bubble type is a kind of mechanical treatment.…”

Absorption of carbon dioxide into aqueous colloidal silica solution with diisopropanolamine

“…The techniques for the enhancement of heat and mass transfer performance are generally categorized into several methods: the mechanical treatment, the chemical treatment, the acoustic [2] and electromagnetic [3] treatments, and the application of nanotechnology. The selection of heat transfer mode such as falling film type and bubble type is a kind of the mechanical treatment.…”