Numerical Simulation on Flow Field of Nuclear Safety Grade 2 Single-Seat Pneumatic Diaphragm Control Valve

The Computational Fluid Dynamics（CFD） method is employed to simulate numerically the steady flow and transient flow under variable openings of the nuclear safety grade 2 single-seat pneumatic diaphragm control valve,which is a sleeve valve.The steady simulations under rated condition tells that there is a large amount of vortex in the valve seat necking and around the valve cone,which leads to a much greater flow impact on the head of the valve cone and uneven pressure distribution on spool face.More consideration should be taken on the characteristics of the valve cone accordingly,when designing a valve of this kind.Then the transient flow under 100% and 40% openings is simulated numerically on the basis of steady simulations.The pulsation of the pressure magnitude at the points with large vorticity,in the valve seat necking and around the valve cone,is monitored.The main pulsation frequencies differ from the low natural frequencies of the model,which means that it is safe from leading to structural resonance.