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What is cavitation in pumps and control valves?

asked Mar 25, 2014 in Process by wangroc (3,280 points) | edited Jan 30, 2015 by wangroc

1 Answer

+2 votes
answered Jan 30, 2015 by gagonza (3,020 points) | selected Apr 13, 2015 by odadmin
 
Best answer
Cavitation occurs when the bubbles in the liquid move down stream, the cross sectional flow area opens up in the body of the pumps/valves, the velocity goes down and pressure builds up. Those conditions create bubbles with an internal pressure equal to the vapor pressure surrounded by a higher pressure. The bubbles collapse in on themselves. This combination of bubble formation and the resulting choked flow, along with the collapse of the bubbles downstream is called Cavitation.

Cavitation causes serious wear and tear and can damange a part in the pumps or valves eventually. The primary causes for their formation include vaporization at low pressure, air ingestion, flow turbulence, and internal re-circulation.

General industry usually uses very hard materials to give some improvement, but the improved performance is typically not enough to justify the high cost of the material.

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