In a control valve handling a pure liquid, cavitation may occur if the static pressure of the flowing liquid decreases to a value less than the fluid vapor pressure. At this point, continuity of flow is broken by the formation of vapor bubbles.
Since all control valves exhibit some pressure recovery, the final downstream pressure is generally higher than the orifice throat static pressure. When downstream pressure is higher than vapor pressure of the fluid, the vapor bubbles revert back to liquid. This two-stage transformation is defined as cavitation. |
