Correct option is C
Net Positive Suction Head (NPSH) is a critical parameter for pumps to prevent cavitation.
NPSH available (NPSHa) is the absolute pressure at the pump suction minus the vapor pressure of the fluid.
NPSH required (NPSHr) is the minimum pressure required at the suction to avoid cavitation, as specified by the pump manufacturer.
If NPSHa < NPSHr, the pump's suction pressure is insufficient, leading to:
Cavitation: The fluid vaporizes locally, forming bubbles that collapse violently when entering high-pressure regions. This causes:
· Damage to impeller and surfaces (pitting),
· Noise and vibration,
· Reduced efficiency and head,
· Possible loss of flow.
