Which situation can lead to cavitation in a pump?

• A. Low ambient pressure
• B. Too high viscosity
• C. Low vapor pressure due to cold temperature
• D. An increase in vapor pressure caused by high temperature or high flow

Answer: (D)

Cavitation happens when the pressure inside the pump drops below the liquid’s vapor pressure, causing vapor bubbles to form and then collapse as they move to higher pressure regions. When the liquid’s temperature is high, its vapor pressure increases, so the same pressure drop inside the pump can exceed this higher vapor pressure, initiating cavitation. High flow can also create lower pressures on the suction side, further enabling the liquid to reach its vapor pressure and form bubbles. So an increase in vapor pressure caused by high temperature or high flow directly sets up the condition for cavitation to occur.

Low ambient pressure can contribute by reducing available suction margin, but it’s the rise in vapor pressure from temperature (and the pressure drop from high flow) that more directly triggers cavitation. Cold temperatures lower vapor pressure, making cavitation less likely, and high viscosity doesn’t promote cavitation.