Definition
Cavitation is the formation of vapor bubbles in a liquid where local pressure drops below the liquid's vapor pressure (typically at a pump impeller inlet) followed by the violent collapse of those bubbles as pressure recovers, which erodes surfaces and produces a characteristic crackling or gravel-like noise.
Key facts
- A specific fluid-dynamic phenomenon: bubble formation from local pressure drop below vapor pressure, followed by violent collapse.
- Most common at pump impeller inlets and in valves or piping restrictions with high flow velocity.
- Produces distinctive audible noise (often described as crackling or gravel-like) and characteristic pitted erosion damage.
- Distinct from general contamination or corrosion: cavitation damage has a specific pitted, localized erosion pattern from bubble collapse.
What does Cavitation reveal about failures?
Cavitation occurs when local liquid pressure drops below the vapor pressure at that temperature, forming vapor bubbles that then collapse violently as they move into a higher-pressure region: the collapse generates localized shock that erodes nearby surfaces over time.
How do teams use Cavitation in failure analysis?
Cavitation is typically recognized by a distinctive crackling or gravel-like noise from the affected component, reduced pump performance despite normal-seeming operating conditions, and, on inspection, a characteristic pitted or eroded surface pattern near the impeller inlet or restriction point, distinct from the smoother material loss typical of general erosion or corrosion.
FAQ
Frequently asked questions
What flow phenomenon does cavitation refer to?
It refers to the formation of vapor bubbles in a liquid where pressure drops below vapor pressure, followed by their violent collapse as pressure recovers, producing characteristic noise and pitted erosion damage, typically at a pump impeller inlet.
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