CAVITATION ITS EFFECTS AND PRECAUTION

CAVITATION ITS EFFECTS AND PRECAUTION

Cavitation:

Cavitation is defined the phenomenon of formation of vapour bubbles of a flowing liquid in a region where the pressure of the liquid falls below its vapour pressure and sudden collapsing of these vapour bubbles in a region of higher pressure . When the vapour bubbles collapse, a very high pressure is created. The metallic surfaces, above which these vapour bubbles collapse, is subjected to these high pressures, which cause pitting action on the surface. Thus cavities are formed on the metallic surface and also considerable noise and vibrations are produced.

Effects:-

1. The metallic surfaces are damaged and cavities are formed on the surfaces.

2. Due to sudden collapse of vapour bubble, considerable noise and vibrations are produced.

3. The efficiency of a turbine decreases due to cavitation.

Precaution:-

1. The pressure of the flowing liquid in any part of the hydraulic system should not be allowed to fall below its vapour pressure. If the flowing liquid is water, then the absolute pressure head should not be below 2.5m of water.

2. The special materials or coatings such as aluminium-bronze and stainless steel, which are cavitation resistant materials, should be used.

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