Flow Analysis And Structure Optimization On Control Valve

The study on the control valve is very important, because its wide use in both energyindustry and industrial field. The control valve is the centrol part of the control system ofsteam turbine, and its regulating capacity will influence the security and stability of thesystem directly. The flow filed inside the control valve of steam turbine is not onlycomplicated but also randomness and tridimensional.Experiment has been the main methodof this research, and it can get the performance of the control valve. But researchers have todevise and develop it with expirical formula and similar design for the restriction of the costand the test period. As a result of it, accurate related parameters of the fluid flow inside thecontrol valve cannot be received in some complicated conditions. This study calculated andanalyzed the flow filed inside the control valve with numercial simulation.According to the viscous flow, turbulent flow and rotating eddy flow in the flow filed ofcontrol valve, combining the basic theory and methods of fluid dynamics, establish3D flowfiled model of control valve, select typical conditions and conduct the numerical simulation offlow filed of control valve by Fluent, and thus acquire the inside fluids flow parameters likepressure distribution, velocity distribution and Mach distribution.Based on the numerical calculation results in typical conditions, ascertain therelationship between control valve flow and opening, and the influences of valve channelstructure and geometric parameters on its pressure loss. The results suggest that the structureand type inside the valve is the main reason of steam flow in small opening compared withother openings. Meanwhile, analyze the unstable phenomena initiated by the inside specialchannel structure, for example: impinging jet, vortex flow, shock wave effect and so on insmall opening, and determine the reasons that lead to flow losses.Finally, based on the relationship between the control valve main structure parametersand the flow loss, improves the design of the structure parameters like the diffusing angle ofvalve seat, spool contour and eccentric angle, ascertain the control valve structure when theflow loss is smallest.