Towards energy efficient nanobubble generation with fluidic oscillation

Zimmerman, William B.; Tesař, Václav; Bandulasena, Hemaka C.H.

doi:10.1016/j.cocis.2011.01.010

Cited by 190 publications

(99 citation statements)

References 31 publications

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“…This is due to the laminar pattern of the microbubble through the liquid which gently detached from the pores of the diffuser [8,[11][12][13]. This advantage gives the preference for evaporation to dominate over the sensible heat transfer during the bubble rising through liquid until the maximum concentration is achieved.…”

Section: Resultsmentioning

confidence: 99%

Microbubble Distillation for Ethanol-Water Separation

Al-Yaqoobi

Hogg²,

Zimmerman

2016

International Journal of Chemical Engineering

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In the current study, a novel approach for separating ethanol-water mixture by microbubble distillation technology was investigated. Traditional distillation processes require large amounts of energy to raise the liquid to its boiling point to effect removal of volatile components. The concept of microbubble distillation by comparison is to heat the gas phase rather than the liquid phase to achieve separation. The removal of ethanol from the thermally sensitive fermentation broths was taken as a case of study. Consequently the results were then compared with those which could be obtained under equilibrium conditions expected in an "ideal" distillation unit. Microbubble distillation has achieved vapour compositions higher than that which could be obtained under traditional equilibrium conditions. The separation was achieved at liquid temperature significantly less than the boiling point of the mixture. In addition, it was observed that the separation efficiency of the microbubble distillation could be increased by raising the injected air temperature, while the temperature of the liquid mixture increased only moderately. The separation efficiency of microbubble distillation was compared with that of pervaporation for the recovery of bioethanol from the thermally sensitive fermentation broths. The technology could be controlled to give high separation and energy efficiency. This could contribute to improving commercial viability of biofuel production and other coproducts of biorefinery processing.

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Section: Resultsmentioning

confidence: 99%

Microbubble Distillation for Ethanol-Water Separation

Al-Yaqoobi

Hogg²,

Zimmerman

2016

International Journal of Chemical Engineering

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“…Therefore, design of a CO 2 dosing system with a relatively high gas mass transfer and low energy cost tends to be a major consideration for cost-competitive microalgae culture. Since an energy efficient microbubble dosing system has been developed [8] and proved to have a relatively higher mass transfer coefficient than normal bubble dosing [9,10], the same level of dissolved CO 2 concentration can be achieved at relatively lower dosing flow rate, consequently, considerable energy saving along with higher productivity will be made. To further study the impact of microbubbles produced by fluidic oscillation, a range of ALB bench cultures of D. salina were set up to discover 1) the contrast between aerated ALB cultures and non-aerated flask…”

Section: Introductionmentioning

confidence: 99%

Growth Enhancement of Dunaliella salina by Microbubble Induced Airlift Loop Bioreactor (ALB)—The Relation between Mass Transfer and Growth Rate

Ying¹,

Gilmour²,

Shi³

et al. 2013

JBNB

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The efficiency of a novel microalgal culture system (an airlift loop bioreactor [ALB] engaged with a fluidic oscillator to produce microbubbles) is compared with both a conventional ALB (producing fine bubbles without the fluidic oscillator) and non-aerated flask culture. The impact of CO 2 mass transfer on Dunaliella salina growth is assessed, through varying the gas (5% CO 2 , 95% N 2 ) dosing flow rate. The results showed that approximately 6 -8 times higher chlorophyll content was achieved in the aerated ALB cultures than in the non-aerated flasks, and there was a 20% -40% increase in specific growth rate of D. salina in the novel ALB with microbubbles when compared with the conventional ALB cultures. The increase in chlorophyll content was found to be proportional to the total amount of CO 2 mass transfer. For the same dosing time and flow rate, higher CO 2 mass transfer rate (microbubble dosing) resulted in a greater growth rate.

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“…No electric current is needed (an advantage in the harsh environment in, e.g., waste water processing). The hopes associated with this new idea have even led to the promise of generating the so far somewhat enigmatic and elusive nanobubbles [3,4]. In some respects, the microbubbles generated by fluidics can even exhibit behaviour qualitatively different from that of coarse bubbles -an example is the direct contact evaporation where it was demonstrated [5] that microbubbles make possible delivering heat into the requested vaporisation without wasting energy on heat transfer into liquid.…”

Section: Introductionmentioning

confidence: 99%

Unexpected behaviour of microbubbles immediately at the aerator exit

Tesař¹

2013

Computational Methods in Multiphase Flow VII

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Microbubbles (of diameter less than 1 mm) are desirable for many engineering applications. Until quite recently, generating them efficiently was a problem. A solution was found in excitation of gas supply by inexpensive and reliable nomoving-part fluidic oscillators. Strangely, generated microbubbles are larger than expected. The author studied their formation using a high-speed camera with a long distance macro-lens. The images revealed the cause being a conjunction of bubbles, mostly taking place within the very proximity of the aerator exit. Small bubbles move slowly and do not vacate fast enough from the position in which they were generated. They thus get into contact with the next generated bubble. Another cause of slow departure is the increased drag caused by shape oscillation driven by energy released in the conjunction. The conjunctions may also occur due to lateral bubble motion if the Reynolds number exceeds the vortex shedding threshold.

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Towards energy efficient nanobubble generation with fluidic oscillation

Cited by 190 publications

References 31 publications

Microbubble Distillation for Ethanol-Water Separation

Microbubble Distillation for Ethanol-Water Separation

Growth Enhancement of Dunaliella salina by Microbubble Induced Airlift Loop Bioreactor (ALB)—The Relation between Mass Transfer and Growth Rate

Unexpected behaviour of microbubbles immediately at the aerator exit

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