What is one requirement for NPSHa to prevent cavitation?

To prevent cavitation in a pumping system, the Net Positive Suction Head available (NPSHa) must be greater than the Net Positive Suction Head required (NPSHr) by the pump. Cavitation occurs when the pressure in the pump suction drops below the vapor pressure of the liquid being pumped, leading to the formation of vapor bubbles that collapse violently, causing damage to the pump.

When NPSHa exceeds NPSHr, it ensures there is adequate pressure at the pump suction to keep the liquid in a non-vapor state. This helps maintain the functionality and efficiency of the pump, as well as prolonging its lifespan by preventing cavitation-related damage. Therefore, it is crucial to always ensure that NPSHa is greater than NPSHr in order to achieve reliable and effective pump operation.