Cavitation
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Transcript of Cavitation
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Introduction Cavitation is the formation and then immediate implosion of
cavities in a liquid that are the consequence of forces acting
upon the liquid.
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The formation of cavities and the implosion phenomenon
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Major places where cavitation occurs are in pumps, on propellers,
or at restrictions in a flowing liquid.Cavitation is a significant
cause of wear in some engineering contexts.
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Cavitation
Inertial
Cavitation
Non-Inertial
Cavitation
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Inertial Cavitation
Inertial cavitation is the process where a void or bubble in a
liquid rapidly collapses, producing a shock wave.
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Inertial Cavitation takes place in :
Nature
Man-made Objects : control valves, pumps, propellers and impellers.
Mantis shrimps
Pistol shrimps
Vascular tissues of plants
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The implosion of a bubble inside, provides
mantis shrimps with enough energy to
throw their arm and catch the prey as
rapidly as possible .
Pits in a plant vessel
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Non-Inertial Cavitation
Non inertial cavitation is the process in which a bubble in a
fluid is forced to oscillate in size or shape due to some form of
energy input, such as an acoustic field.
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Cavitation due to oscillation of
the fluid
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Cavitation damage
In devices such as propellers and pumps, cavitation causes a
great deal of noise, damage to components, vibrations, and a
loss of efficiency.
Typical cavitation damage on the
blade of a mixed flow pump.
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A valve, damaged with cavitation Cavitation damage in propellers
Cavitation damage in a pump
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Some cases of cavitation occurrence
Hydrodynamic Cavitation which occurs in a flowing liquid as a
result of a decrease and subsequent increase in pressure.
Hydrodynamic cavitation development
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k Discharge Cavitation which occurs when the pump discharge
pressure is extremely high, normally occurring in a pump that is running at
less than 10% of its best efficiency point.
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k Suction Cavitation which occurs when the pump suction is under a
low-pressure/high-vacuum condition where the liquid turns into a vapour at
the eye of the pump impeller.
Suction cavitation damage will appear on the
visible side of the impeller vanes at the suction
eye of the impeller.
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Cavitation control and solutions
1. Redesigning the systems
2. Changing the materials Common Solutions
3. Eliminating the turbulence from
inlet fluid flow
4. Adding anti-pitting solutions
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Anti Cavitations Valve
They are used extensively in the power, process, oil production, chemical refining, and otherindustries. They are able to control high pressure drop liquids (up to 2600 psi) while avoiding the damaging effects of cavitations.
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If you managed to regulate something, you are
able to put it into practice of advantages . . .
Usage
Cleaning : Ultrasonic cleaning
• Non inertial
Biomechanics : Destruction of undesirable elements
• Chemical engineering applications : Purifying water due to specific use.
• Heating and vaporizing : In assist of cavitation process you don’t
need too much heat and electricity to achieve massive evaporations.
Making ultrasonic noises by high speed bubbles
picking up and carrying contaminant particles away so that theydo not reattach to the material being cleaned
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Thanks to your consideration
Shahab Mehranfar ( 1st part)
Muhamad Ali Mirtaheri (2nd part)
Ardalan Amiri ( 3rd part)