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MICROBUBBLE TECHNOLOGYMICROBUBBLE TECHNOLOGY

Presented byPresented by

PRASANTH CPRASANTH C

NO: 39NO: 39

S 7 MECHANICALS 7 MECHANICAL

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IntroductionIntroduction

Two types of DragTwo types of Drag Friction andFriction and

Pressure DragPressure DragFriction Drag due to frictionFriction Drag due to friction

Pressure Drag due to Eddying motionsPressure Drag due to Eddying motions

Stream line bodyStream line body Viscous DragViscous DragBluff bodyBluff body Pressure DragPressure Drag

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hy Microbubbleshy Microbubbles

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MechanismsMechanisms

Local void ratioLocal void ratio

Injection pointInjection point

Boundary layerBoundary layer

thicknessthickness

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Methods for bubble generationMethods for bubble generation

Venturi tube typeVenturi tube type

Tangential water jetTangential water jet

Foaming of dissolved airFoaming of dissolved air

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Pros and ConsPros and Cons

large reduction in skin friction up to 80%large reduction in skin friction up to 80%

No pollutionsNo pollutions

Can apply any surface orientationCan apply any surface orientation

Affected less by roll and pitchAffected less by roll and pitch

large amount of air (order of 1000cubic metre perlarge amount of air (order of 1000cubic metre permin)min)

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ApplicationsApplications

Power saving in VLCCPower saving in VLCC

PipelinesPipelines

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ConclusionConclusion

small bubbles possibly decrease thesmall bubbles possibly decrease the

overall efficiency of the microbubble dragoverall efficiency of t

he microbubble dragreduction through dispersionreduction through dispersion

The understanding of t

he mec

hanism ofT

he understanding of t

he mec

hanism ofturbulence intensity reduction byturbulence intensity reduction by

microbubbles is the key for breakmicrobubbles is the key for break--through.through.