Introduction Cavitation is the formation and then immediate implosion of

cavities in a liquid that are the consequence of forces acting

upon the liquid.

The formation of cavities and the implosion phenomenon

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.

Cavitation

Inertial

Cavitation

Non-Inertial

Cavitation

Inertial Cavitation

Inertial cavitation is the process where a void or bubble in a

liquid rapidly collapses, producing a shock wave.

Inertial Cavitation takes place in :

Nature

Man-made Objects : control valves, pumps, propellers and impellers.

Mantis shrimps

Pistol shrimps

Vascular tissues of plants

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

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.

Cavitation due to oscillation of

the fluid

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.

A valve, damaged with cavitation Cavitation damage in propellers

Cavitation damage in a pump

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

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.

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.

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

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.

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

Thanks to your consideration

Shahab Mehranfar ( 1st part)

Muhamad Ali Mirtaheri (2nd part)

Ardalan Amiri ( 3rd part)