Aiming at the leakage problem on the top of gate valve, the finite element method is used to analyze the gate valves seal face and body, as well as the distributing laws of the stress, deformation and seal pressure are obtained. The shutter is simplified as the circular plate simply supported on the whole circle, and the gate valve is optimized according to the relevant formula to meet sealing requirement. The results show that: the combination of the numerical simulation and theoretical calculation, not only the more accurate theoretical basis for the optimization of the large diameter gate valve can be provided, but also the time of the development and design can be shorten greatly.

In order to promote the localization of critical valve in ultra-supercritical thermal power generating unit, a two-stage superheated electrical steam trap was designed and developed. Its structure and operation principle was introduced. Three-dimensional numerical simulation of the internal turbulent fluid field was performed by using Fluent of computational fluid dynamics software. The results show that the superposed design of associated reaction with multiaperture equalizer and guide sleeve was adopted in the two-stage superheated steam trap. The internal flow field become more uniform, local maximum velocity reached 37.2m/s. The brush erosion of valve seat is reduced and the service life is increased. Success rate of the first sample's trial-manufacture is greatly improved by using CFD simulation experiment in the process of design. Development cycle is shortened and the cost is reduced, which can provide a reference for two-stage superheated steam trap design.

Temperature and thermo-mechanical coupling stress distributions of the electrical three-way valve body in a high pressure heater are investigated by using finite element method analysis. Maximum stress at the outer wall region of the valve body has exceed the allowable stress of the material is obtained. The weak place is improved by increasing the wall thickness and the stress meet the requirement of the allowable stress of the material after FEM analysis. And the thermo-mechanical coupling stress are classified and evaluated in the most dangerous section. The evaluation results show that the various types of stress all meet intensity requirements, which provide a guideline for the design and optimization of the high temperature and high pressure valve in the future.

In view of the transient dynamic analysis in opening swing check valve, the motion model of valve clack is built, two-dimensional dynamic numerical simulation of the internal unsteady flow is performed by using dynamic mesh and UDF in opening two kinds of swing check valve at the same working condition, the visualized results are obtained. The results show that internal flow field of the modified model become more stable, the noise, impact and the local energy loss are decreased, the service life is improved obviously; an important reference for swing check valve design and analysis of dynamic characteristics are provided by the research results.