What causes cavitation in a pump suction line?

Cavitation in a pump suction line is primarily caused by insufficient inlet pressure, which leads to the vaporization of the liquid. When the pressure of the liquid drops to its vapour pressure, vapour bubbles form within the fluid.12

These bubbles are then carried into the pump, where they encounter regions of higher pressure and collapse suddenly. This process is detrimental to engineering systems for several reasons:21

• Mechanical Damage: The rapid collapse of these cavities generates extreme pressures that cause erosion and pitting on metal surfaces, such as rotating blades.21
• Operational Issues: Cavitation creates excessive noise and vibrations, often described as knocking.21
• Efficiency Loss: The formation of these vapour spaces distorts the flow pattern, leading to a significant reduction in pump efficiency.2

To ensure optimal performance, it is essential to maintain adequate inlet pressure to prevent the liquid from vaporizing before it enters the pump.1