Cavitation occurs when cavities form in liquid due to pressure changes and then rapidly collapse, producing shockwaves. There are two types: inertial cavitation involves rapid bubble collapse producing shockwaves, while non-inertial cavitation involves bubble oscillation due to acoustic energy. Cavitation commonly occurs in pumps, propellers, and where liquids experience pressure changes, and can cause damage through noise, vibrations and material erosion. Solutions involve redesigning systems, changing materials, reducing turbulence, and adding anti-cavitation agents.

2. Introduction
 Cavitation is the formation and then immediate implosion of
cavities in a liquid that are the consequence of forces acting
upon the liquid.

3. The formation of cavities and the implosion phenomenon

4. 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.

5. Cavitation
Inertial
Cavitation
Non-Inertial
Cavitation

6. Inertial Cavitation
 Inertial cavitation is the process where a void or bubble in a
liquid rapidly collapses, producing a shock wave.

7. Inertial Cavitation takes place in :
 Nature
Mantis shrimps
Pistol shrimps
Vascular tissues of plants
 Man-made Objects : control valves, pumps, propellers and impellers.

8. 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

9. 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.

10. Cavitation due to oscillation of
the fluid

11. 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.

12. A valve, damaged with cavitation Cavitation damage in propellers
Cavitation damage in a pump

13. 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

14.  Discharge Cavitation which occurs when the pump discharge
k
pressure is extremely high, normally occurring in a pump that is running at
less than 10% of its best efficiency point.

15.  Suction Cavitation which occurs when the pump suction is under a
k
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.

16. 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

17. Anti Cavitations Valve
They are used extensively in the power, process, oil production,
chemical refining, and other
industries. They are able to control high pressure drop liquids
(up to 2600 psi) while avoiding the damaging effects of cavitations.

18. If you managed to regulate something, you are
able to put it into practice of advantages . . .
Usage
picking up and carrying contaminant
particles away so that they
do not reattach to the material being cleaned
Cleaning : Ultrasonic cleaning
• Non inertial
Making ultrasonic
noises by high
speed bubbles
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.

19. Thanks to your consideration
Shahab Mehranfar ( 1st part)
Muhamad Ali Mirtaheri (2nd part)
Ardalan Amiri ( 3rd part)