Analysis And Optimization Of Sealing Performance Of Hard Sealed Ball Valves

Ball valves are mainly used in piping systems to distribute,cut off and change the flow of media.In recent years,due to the simple structure and good sealing performance of the ball valve,when the nominal size is the same,by comparing with other valves,the ball valve occupies a small volume,light weight,minimal material loss,and low torque and high flow characteristics.development of.Seal performance is particularly important in valve performance indicators.For fixed hard-sealed ball valves,the sealing principle is that the surface of the sphere and the valve seat form a sealing surface,so that the medium in the pipeline cannot pass the sealed state of the sealing surface.The sealing effect of the sealing surface depends on the quality of the sealing surface,the width of the sealing surface,the internal and external pressure difference of the sealing surface,the specific pressure of the sealing surface,the material of the sealing surface,the properties of the fluid medium,and the presence of grease on the sealing surface.Under normal working conditions,the ball valve may deform to varying degrees due to the influence of the pressure and temperature of the medium fluid.If the location of the deformation appears on the seal surface and the deformation destroys the necessary conditions for the seal,the seal will fail.For the leakage and failure of hard-seal ball valves during use,the subject is to optimize the sealing performance of hard-seal ball valves as the main line,and select the factors that affect the sealing performance to optimize the sealing gap value of the main seal structure of the ball valve.Therefore,this topic has done the following work:1.Introduce the research background and significance of hard-sealed ball valves,elaborate the development trend of hard-sealed ball valves and the current status of research at home and abroad,and summarize the sealing principles,contact problems,finite element analysis,and research on seal leakage models.Finally,the main work content of this subject is discussed.2.Calculate the sealing force on the sealing surface by performing a force analysis on the hard-seal fixed ball valve seat,and further calculate the required specific pressure for the seal,ideal rough and smooth sealing surface.3.Taking the inlet end of an O-shaped hard-seal fixed ball valve of KCM as the research object,a three-dimensional model of the main seal structure is established according to its original parameters.The non-linear algorithm of contact problem is combined with ANSYS Workbench software to perform statics on the main seal structure of the hard-seal ball valve simulation.Analyze the deformation of the hard-sealed ball valve body and valve seat to determine whether there is a risk of leakage.4.Select the pressure angle,seal width and DMP / DJH three factors affecting the sealing performance of hard-sealed ball valves,and use a uniform test design to carry out weight-sensitive analysis of the factors affecting the sealing performance of hard-sealed ball valves.A uniform test design and Biharmonic spline interpolation a scheme for optimizing the sealing performance of hard-sealed ball valves was established by model and load analysis,in order to optimize the clearance value of the sealing surface of the main seal structure of the hard-sealed ball valve,and compared with the numerical simulation verification to select a better one.