North Carolina Surface Water Practice Exam

Cavitation in a centrifugal pump occurs when the local pressure drops below the vapor pressure of the liquid, leading to the formation of vapor bubbles which subsequently collapse with force. A key indication of this phenomenon is the characteristic "pinging" or "cavitation" noise that results from the rapid collapse of these vapor pockets within the pump. This noise, often compared to marbles rolling around in the pump or metal knocking, serves as a clear warning sign that the pump is operating under conditions that are conducive to cavitation.

While low pressure readings, excessive vibration, and continuous flow are relevant to pump operation and may indicate other issues, the distinct pinging noise directly correlates with the condition of cavitation. Understanding this allows operators to take corrective actions, such as adjusting the flow rate or increasing suction pressure, before serious mechanical damage occurs to the pump system.