what is cavitation in pump.....?

Question

tell me in details............you can suggest any site or source also.............thanx

Answer 1

Cavitation is when the pump generates so much suction, that bubbles form in the liquid. If you have seen the experiment where room temperature water is placed in a vacuum chamber and the pressure is lowered until the water begins to "boil"? This is because the pressure in the chamber has reached the vapor pressure of the water and the water is forced to convert to a gas. This can happen on a microscopic scale inside a pump or on the blades of a propeller on a boat and generate a lot of bubbles. Pumps made to move liquids don't like to be filled with a gas and can become vapor locked. Similarly, some boats, like submarines, don't like to generate bubbles on their propellers because it is too noisy and they can be heard and their location pinpointed.

Answer 2

That happens when the liquid feeding the pump stops and the pump just spins in the air

Cavitation is a general term used to describe the behaviour of voids or bubbles in a liquid. Cavitation is usually divided into two classes of behaviour: inertial (or transient) cavitation and non-inertial cavitation. Inertial cavitation is the process where a void or bubble in a liquid rapidly collapses, producing a shock wave. Such cavitation often occurs in pumps, propellers, impellers, and in the vascular tissues of plants. Non-inertial cavitation is the process where 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. Such cavitation is often employed in ultrasonic cleaning baths, and will also be observed in pumps, propellers etc.

Answer 3

An over simplification of cavitation is loss of suction due to the liquid which is being pumped flashing in to vapor.

Cavitation may ocurr for several reasons.

1.) Sudded loss of booster pressure in a suction line
2.) pumping volital liquids with a low vapor pressure (like gasoline)
3.) pumping excessively hot liquids (overheated liquids) like water near the boiling point or oil from a heater
4.) restriction in the suction line
5.) excessive pump impeller (propeller) speed



The flashing of liquid into vapor causes the formation of bubbles in the liquid. A small amount of bubbles will cause the pump to make noise, a larger formation can cause loss of suction.