What is the primary mechanism of failure in a centrifugal pump experiencing cavitation?

The primary mechanism of failure in a centrifugal pump experiencing cavitation is material erosion caused by the implosion of vapor bubbles near the impeller surface. Cavitation occurs when the absolute pressure of the liquid being pumped falls below its vapor pressure at the prevailing temperature. This typically happens at the impeller's inlet where the liquid's velocity is highest, and the pressure is lowest. When the pressure drops below the vapor pressure, vapor bubbles form in the liquid. These bubbles are carried along with the liquid flow towards the higher-pressure regions of the impeller. As the bubbles enter these regions of higher pressure, they rapidly collapse or implode. This implosion generates intense, localized shock waves and micro-jets of liquid that impinge on the impeller surface. The repeated impact of these shock waves and micro-jets causes material fatigue and erosion, gradually removing small particles of metal from the impeller. Over time, this erosion can lead to significant damage, including pitting, cracking, and eventual failure of the impeller. The noise produced by the collapsing bubbles sounds like gravel or rocks are inside the pump. While corrosion can exacerbate the effects of cavitation, the dominant mechanism of failure is the mechanical erosion caused by the imploding vapor bubbles.