Cavitation

Cavitation 4 dummies

1. Cavitation

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 Man-made Objects : control valves, pumps, propellers and impellers. Mantis shrimps Pistol shrimps Vascular tissues of plants

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. 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.

15. 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.

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 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 they do not reattach to the material being cleaned

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