Control Valve Cavitation Damage | Mechanism & Complete Avoidance Solutions

Cavitation is the most destructive and harmful failure mode of liquid medium control valves, widely existing in chemical processing, water treatment, power plant and process pipeline systems. Long-term throttling operation under large pressure difference will cause severe cavitation erosion on control valves, bringing about core pitting corrosion, metal surface peeling, violent pipeline vibration and excessive operating noise. Without timely treatment, it will lead to permanent valve failure and affect process stability. The cavitation damage mechanism is derived from fluid dynamic changes during valve throttling. When liquid medium flows through the narrow throttling section of the control valve, the fluid velocity rises sharply, and the local pressure drops rapidly below the saturated vapor pressure of the liquid medium. The liquid will vaporize instantly to generate a large number of tiny vacuum bubbles inside the valve cavity. After the fluid flows out of the valve throttling area, the pipeline pressure recovers rapidly in a short time. Massive vacuum bubbles burst violently within microseconds, producing high-energy micro jet impact force. The continuous high-frequency impact bombards the valve core, valve seat and internal flow passage wall, causing fatigue pitting, erosion peeling and continuous metal material loss. Field operation verifies that long-term small-opening operation and large pressure difference matching are the main working condition inducements of severe cavitation damage. Sustained cavitation will completely destroy the valve sealing structure, trigger pipeline vibration and process parameter fluctuation, and result in frequent valve maintenance and replacement. Combined with industrial mature application experience, a complete set of anti-cavitation solutions is summarized. Adopt multi-stage pressure reduction structure to disperse single-point pressure difference; equip anti-cavitation cage trim to optimize internal flow field; select high-hardness anti-cavitation alloy materials to improve erosion resistance. Meanwhile, optimize pipeline pressure difference configuration to avoid excessive pressure drop, and prohibit long-term small-opening throttling operation. Reasonable structural upgrading and scientific working condition matching can fundamentally solve the cavitation damage problem of liquid medium control valves.