What is the primary cause of cavitation in pumps?

Cavitation in pumps primarily occurs due to low pressure conditions at the inlet of the pump, which can cause the fluid to vaporize. When the pressure in the pump drops below the vapor pressure of the liquid being transported, small vapor bubbles form. These bubbles can collapse violently when they move into higher pressure regions within the pump, leading to damage and reduced efficiency.

In practical terms, maintaining sufficient pressure at the pump inlet is crucial in preventing cavitation. This is why ensuring proper NPSH (Net Positive Suction Head) is essential in pump design and operation. Low pressure allows for vapor formation and subsequent cavitation, making it the central factor in this phenomenon.