Cavitation can cause what kind of damage to hydraulic components such as impellers?

• A. Cavitation polishes impeller surfaces.
• B. Cavitation has no effect on impellers.
• C. Cavitation can cause erosion of impeller surfaces and downstream components.
• D. Cavitation only occurs in cold fluids.

Answer: (C)

Cavitation happens when local pressure drops below the liquid’s vapor pressure, causing tiny vapor bubbles to form. When those bubbles collapse in higher-pressure zones near impeller blades, they release sharp energy, creating microjets and shock waves that attack material surfaces. This leads to erosion and pitting of the blade surfaces, producing roughness and thinning, which can disrupt balance and efficiency. The damage can propagate to downstream components such as seals, bearings, and housings due to increased vibration and pressure fluctuations. So cavitation results in erosion of impeller surfaces and downstream components. It doesn’t polish surfaces, and it’s not limited to cold fluids—lower temperatures can make cavitation more likely, but it can occur over a range of operating conditions.