Cavitation

What is Cavitation?

The simple explanation of cavitation is the formation of air bubbles around a pump’s impeller caused by the suction created when the impeller turns. Cavitation occurs when the pump is being starved of fluid flow. This happens most often in a car’s water pump when the radiator is partially clogged and can’t deliver coolant fast enough, or in the car’s power steering pump when the steering gear, fluid return lines or in-line filters have debris buildup.

What actually causes cavitation air bubbles?

All fluids have a boiling point where they turn from a liquid into a gas. If you lower the pressure or put the fluid under a vacuum, you also lower that fluid’s boiling point. When a pump is starved for fluid, it creates a vacuum condition inside the pump which lowers the fluid’s boiling point and causes it to turn into vapor bubbles.

As the vapor bubbles move from the suction side of the pump to the outlet side, the bubbles explode, creating a shock wave that hits the impeller and pump case.

What does cavitation do to pumps?

The exploding bubbles create not only noise, but the bubbles also destroy the impeller and case. They create noise that is often mistaken for a “bad” pump when it’s actually a restriction in fluid flow.

Water pump cavitation

©, 2019 Rick Muscoplat