Control Valve Liquid Cv & Cavitation Calculator
Size industrial control valves for liquid flow per IEC 60534 and ISA-75.01 with cavitation index, choked pressure drop, and travel percentage estimation.
Liquid Operating Conditions
Valve Trim & Geometry
Sizing & Cavitation Analysis
Recommended Tools & Equipment
Tested hardware and components for high reliability
Frequently Asked Questions
What is the liquid pressure recovery factor FL in IEC 60534?
FL is the liquid pressure recovery factor of a control valve orifice. It defines the valve’s ability to convert vena contracta kinetic energy back into static pressure downstream. High-recovery valves like ball and butterfly valves have low FL (0.55 - 0.70) and choke at modest pressure drops, whereas globe valves have high FL (0.85 - 0.92) and resist cavitation much better.
What is the difference between cavitation and flashing in control valves?
Cavitation occurs when vena contracta pressure drops below liquid vapor pressure Pv, creating vapor bubbles, but downstream pressure P2 recovers above Pv, causing the bubbles to violently implode and pit valve metal. Flashing occurs when downstream pressure P2 remains below Pv, so the liquid stays vaporized and exits as high-velocity erosive two-phase mist.
Why should normal operating valve travel remain between 20% and 85%?
Below 20% travel, high-velocity jetting between plug and seat creates severe wire-drawing erosion and poor throttling resolution. Above 85% travel, the valve loses control headroom and cannot respond dynamically to transient process flow surges.