Two multiorifice in serie that produce cavitation in a water coolant system of a nuclear plant. The DP is aproximately 3 kg/cm2 (Outlet pressure is atmosferic).
Do you know special valve to change my passive design and that reduce or eliminate the cavitation?. This valve must be ASME III.
One way to define severe service is to calculate the percent of pressure drop across the valve. If it is over 50%, it will be severe service.  Assuming your delta P across your ball valve is 3 bar, or 45 psid, while valve outlet pressure is atmospheric.  Then [P1 - P2]/P1 is almost
[60 - 15]/60 or 0.75, i.e. 75% (>50%).  You need a serve service valve.
You need a valve with a K-factor (or lost coefficient) large enough to absorb the fluid energy at all flows. Once you specify the flows, the effective flow areas for each brand/model of control valves can be calculated if trim geomtry is not too geometries, along with its trim exit velocity and trim exit Kinetic Energy.  In marine engineering, at water fluid velocity of 100 feet/sec., pitting starts to occur at the tips of the propellers.  100 feet/sec is equivalent to 70 psi for water. Therefore you need to consider a control valve that will not give you a trim exit fluid Kinetic Energy larger than 70 psi. 

MORE NEWS