Centrifugal Pump: Cavitation Detection Based on Corrected NPSHr (Net-Positive Suction Head Required)

In the context of centrifugal pumps, the term cavitation implies a dynamic process involving the formation of bubbles inside the liquid, their growth and their subsequent collapse as the liquid flows through the pump. Generally, the bubbles that form inside the liquid are one of two types: vapor bubbles or gas bubbles. Cavitation usually occurs in pumping systems, where it aggressively damages the pump if it is not detected correctly and at the right moment. Its impact results from a lack of pressure at the suction line of the pump, which forms air bubbles that implode inside the core of the pump. Cavitation causes an alteration of pump characteristics, mechanical damage, noises, and vibrations that can lead to complete pump destruction. Moreover, if the pump is not destroyed, cavitation reduces its life expectancy and increases maintenance costs. In this chapter, we will present the causes and consequences of cavitation and the solution to detect cavitation, and we will develop our proposed solution on the basis of correcting the net-positive suction head required for the change in pump characteristics resulting from mechanical wear.