Define the types of NPSH. What are the differences between them?

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Types of NPSH and their differences

Net Positive Suction Head (NPSH) is the difference between the absolute pressure at the pump suction and the vapor pressure of the liquid being pumped.
Types of NPSH are available NPSH (NPSHa) and required NPSH (NPSHr).
NPSHa is the amount of NPSH available at the pump suction, while NPSHr is the amount of NPSH required by the pump.
The difference between NPSHa and NPSHr determines whether the pump will operate properly or experience cavitation.
Cavitation occurs when the pressure at the pump suction drops below the vapor pressure of the liquid, causing the formation of vapor bubbles that collapse and damage the impeller.
To avoid cavitation, the NPSHa should be greater than the NPSHr.

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