Aiming at solving the problem of control valve cavitation damage in main feed system of ultra-supercritical thermal power units

this paper carried out numerical simulation on internal flow field of the control valve

by combining with multistage throttle theory and multiphase flow technology

and using the computational fluid dynamic software CFX.The influence of shroud stage and ring hole on the control valve's cavitation flow field was studied.The results show that

due to the multistage shroud structure

the minimum pressure inside the control valve rises from 3.55 MPa to 6.58 MPa and is higher than the cavitation pressure

and the maximum vapor fraction reduces from 0.96 to almost zero.The velocity of the whole flow field reduces obviously

so the damage of the control valve caused by cavitation can be effectively prevented.Moreover

on the premise of satisfying the operating conditions of the control valve

increasing the throttle hole number will leading to opposite effects on the pressure reduction and velocity control.