What causes cavitation in pumps?

Cavitation in pumps occurs primarily due to the formation of vapor bubbles in the liquid being pumped. This phenomenon typically arises when the pressure in the pump falls below the vapor pressure of the liquid. Once the pressure is reduced sufficiently, small vapor bubbles form in areas where the liquid experiences low pressure. As these bubbles travel to higher pressure regions within the pump, they collapse or implode violently, creating shockwaves that can damage the pump components, leading to reduced efficiency, excessive wear, or even catastrophic failure.

Understanding the underlying mechanics of cavitation highlights the importance of maintaining appropriate operating conditions in a pumping system, including ensuring sufficient inlet pressure and avoiding situations where the liquid could boil or vaporize due to low pressure. This understanding also clarifies why merely excessive pressure or improper mechanical alignment does not directly induce cavitation; rather, those factors can influence the general functioning of the pump but do not lead to the characteristic bubble formation central to cavitation.