Formation of Cavitation

Question

Explain the reason behind formation of the Cavitation in the Centrifugal Pump and not in the Displacement Pump?

Answer 1

Formation of the cavities or the bubbles is invoked by the flow separation, or non-uniform flow velocities, inside the pump casing. In the centrifugal pumps, eye of pump impeller is smaller in comparison to the flow area of pipe. This decrease in the flow area of pump causes the increase in flow rate. So the pressure drops occurred between pump suction and vanes of the impeller. Air bubbles or the cavities are formed due to the liquid vapour because of the increase in the temperature in impeller. This air bubbles are transmitted to the pump that forms the cavitation.