At what threshold does cavitation initiate______________________?
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Answer: A. the pressure at any location reaches an absolute pressure equal to the saturated vapour pressure of the liquid
Explanation
Cavitation begins when local static fluid pressure drops to the saturated vapor pressure. Reaching this critical vapor threshold causes dissolved gases and liquid vapor to form bubbles. The rapid collapse of these vapor bubbles generates intense localized shockwaves and mechanical wear. Vapor pressure represents the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases. Fluid acceleration around curved boundaries often causes local static pressure to drop significantly. Thermodynamic properties of the liquid determine the exact vapor pressure at any given temperature.
Hydraulic engineers must prevent cavitation to protect high-speed turbine blades from severe pitting damage. Pump failures in municipal water supply networks often stem from unrecognized low-pressure cavitation zones. Designing efficient flow paths minimizes pressure drops and prevents damaging vapor bubble formation. Pressures higher than critical pressure suppress bubble formation rather than initiate cavitation events. Simply increasing overall flow rate without lowering local pressure does not directly cause cavitation. Increasing pressure raises the margin above vapor pressure, making cavitation much less likely.
- Subject
- Engineering
- Category
- Civil Engineering
- Topic
- —
- Difficulty
- medium
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