What is Cavitation?

Cavitation is a harmful condition that occurs in a hydraulic system component like a pump or a valve when the existing space in the working component is not filled with the system fluid. It is the formation and collapse of vapor or air bubbles in the pumped fluid as it passes through the component. Undetected intermittent pump cavitation will eventually cause significant damage to a pump.

Suction head Pressure

It is the actual pressure that the fluid experiences at the pump inlet.

Vapour Pressure

It is the minimum pressure needed to prevent liquid from turning into vapour.

Cavitation Process

Cavitation occurs when the suction head pressure falls below the fluid’s vapour pressure or the saturation pressure of the entrained air in the fluid. This fall in the pressure causes the formation of bubbles in the fluid. Soon, the bubbles collapse as the pressure on the fluid goes beyond the fluid’s vapour pressure or the saturation pressure of the entrained air upon migration to a high-pressure area. The process of formation and collapse of bubbles is nothing but cavitation.

The collapse of bubbles is a violent process. It creates an impacting action on the inside surface of the pump or any other component, causing wear and damage, vibration, and damage to bearings, wearing rings, and seals. It can be prevented by maintaining a sufficient fluid level, keeping filters in good condition, and adjusting the fluid temperature.

Cavitation can be distinguished by the loud popping noise it makes. The collapsing bubbles create certain vibration patterns, which help detect cavitation. Early detection of cavitation minimizes pump damage and reduces downtime. 

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Authored by JOJI Parambath, Founder/Director, Fluidsys Training Centre, Bangalore, email: info@fluidsys.org web: https://fluidsys.org

[Fluidsys Training Centre provides training in the field of Pneumatics, Electro-pneumatics, Hydraulics, and Electro-hydraulics]

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