How do you design for flashing service in control valves?

Flashing occurs when downstream pressure is below liquid vapor pressure, causing permanent vaporization (unlike cavitation where bubbles collapse). Effects: erosion of downstream trim and body, noise, vibration, and capacity reduction. Design considerations: use angle-style body (directs flow away from body wall), hardened trim materials (Stellite), increased outlet size (accommodate two-phase flow), erosion-resistant body (hard-faced or ceramic-lined), and relocate valve (shorter downstream run). Valve sizing must account for two-phase flow capacity. Cannot eliminate flashing if downstream pressure is too low - must accommodate it.