Which term describes the phenomenon that occurs when pressure drops below the vapor pressure of oil, causing bubbles that damage the system?

• A. Hydraulic line
• B. Hydraulic cavitation
• C. Hydraulic reservoir
• D. Heat exchange

Answer: (B)

Cavitation in hydraulic systems occurs when the local pressure drops below the oil’s vapor pressure, causing tiny vapor bubbles to form in the fluid. As flow continues and pressure rises again, those bubbles collapse violently, producing shock waves and high-velocity jets that can erode surfaces, damage components like pumps and valves, and create noise and vibration. Oil’s vapor pressure increases with temperature, so hotter oil makes cavitation more likely. This phenomenon is about the formation and violent collapse of vapor pockets, not about a specific line, a reservoir, or a heat-exchanging device. Preventing it involves maintaining adequate suction head and avoiding sharp pressure drops, while controlling temperature and flow conditions. In short, the phenomenon described is hydraulic cavitation.