Answer / gurmeet singh

In certain point in fluid.. the presuure of localized point
or area decreases below vapour pressure.. this causes the
evaporation of fuild and vapour bubbles are formed. These
bubbles rise in the fluid and at certain point, where the
preesure is above vapour pressure, the bubbles blast. If it
occurs our surface (Turbine blade or any other), it causes
the preesue to effect the surface too. And the surface
comes under stress. After that stress is relived. this
process countinues. i.e. stressing and reliving. this cause
development of fatigue load, which inturen cause the
failure of the impeller.

Answer / sriram_veluri

normally vapour bubbles are formed in an impeller due to
the phenomenon of turbine cavitation.the vapour bubbles
being low pressure points raise to the surface hitting the
impeller ,get ruptured between the high pressure fluid and
the impeller body and eventually burst damaging the
impeller body.

Answer / parani

vapour bubble is one which cause damage the pump. pump is
not a pressure developing device ,due to rotation of
impeller speed a centrifugal force is created in case of
centrifugal pump where vaccum is created at centre which
air may mix with fluid to form bubbles ,where rotation of
impeller which strikes the bubbles which the oxidation
effect damage the pumpcasing & impeller.

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