Objectives  In order to solve the problems of pipeline corrosion and vibration caused by cavitation in large flow and high-pressure differential feedwater recirculation pipelines of marine steam power system, a design scheme for multi-stage throttle orifice plates is proposed.

  Methods  According to the design rule of the decreasing geometric series of multi-stage throttle orifice plates, the selection of orifice series, calculation of orifice diameter and verification of orifice thickness are carried out. Taking the feedwater recirculation pipeline of a ship as the design object, the numerical simulation of a Mixture multiphase flow model is carried out under the severe working conditions of a real ship.

  Results  The simulation results show that when two or one throttle orifice plates are used, cavitation occurs to varying degrees in the feed water recirculation pipeline, but when three throttle orifice plates are used, cavitation will not occur.

  Conclusions  The results of this study can provide references for the rectification of pipeline cavitation damage behind throttle orifice plates in the feedwater recirculation pipelines of real ships.