Sealing Design And Mechanical Analysis Of Union Connection Of High-pressure Manifold

The high-pressure union is a kind of connection head for connecting pipes.It will be affected by external factors such as working pressure,vibration,erosion,corrosion,etc.in the work,and it is easy to leak fluid media,resulting in the problem of safety accidents in which the seal is invalid.At present,domestic oil resources tend to be in deeper strata and the actual conditions of more severe environments.Therefore,unions of manifolds need to be connected to meet complex working conditions.At present,the proportion of FIG1502 high-pressure unions used in domestic oilfields has reached more than 60%,so it is necessary to study the sealing performance of this type union to prevent seal failure.Through the research on the sealing performance of union,it can not only solve the sealing problem for the structural improvement and optimization of union,but also improve the economic benefits of oilfield exploitation and provide reference value for oil development.Through the research and analysis of the structure type,sealing method,sealing material,rubber material model,and principle of union sealing of FIG1502high-pressure union at home and abroad,seals with different fillet radii and different fillet groove radii were designed.The union of the union is sealed with a rubber ring,hydrogenated nitrile rubber is selected as the sealing material,and the Mooney-Rivlin two-parameter model of the rubber material is selected,considering the friction,compression(displacement load),and rubber hardness,the radius of the fillet of the seal,and the radius of the groove of the union affect the sealing performance of this type of high-pressure union.Using the finite element software ANSYS Workbench to simulate and analyze the effect of union sealing performance,the law between the stress(working pressure 105MPa)and sealing parameters of this type of union sealing is obtained,which provides a reference for optimizing union sealing.The conclusions obtained by studying the sealing performance of high-pressure unions are as follows:(1)Study the effects of different rubber hardness,different compression(displacement load),different seal fillet radius,and different friction coefficient between metal and rubber on the performance of the union seal,and obtain the male and female joint stress of the union.When the pressure is constant,the stress of the union will tend to be a fixed value,and the stress value is less than the yield strength of the metal material(650MPa);When the fillet radius of groove of female union joint is less than1.8mm,the contact stress of the male and female union joints shows an upward trend,and when the radius of corner is greater than 1.8mm,the contact stress begins to decrease and finally tends to a stable value,And less than the yield strength of metallic materials.(2)Under the influence of different rubber hardness and different friction coefficients between the metal and rubber contact surfaces,the stress of the unionsurface of the union of male and female unions is in a relatively stable state;analysis of different compression amounts(displacement loads)gives the union of male union The stress on the contact surface of the joint decreases first and then rises.When the amount of compression reaches about 1.35 mm,it decreases.When the radius of the groove of the female union is less than 1.8mm,the stress on the contact surface of the male and female joints of the union is on the upward trend,and when it is greater than 1.8mm,it begins to decline and eventually tends to be stable;the rubber seals are under different corner radius.The contact surface stress of the union of male union and female union is increasing,but the overall rise is slow,indicating that the radius of the rubber seal fillet is insensitive to the stress of the joint surface of the union of male and female unions;The stress on the contact surface of the female joint is relatively large,due to the effect of stress concentration,but the stress is less than the yield strength of the material.(3)By changing the hardness of the rubber,it is found that the sealing pressure of the seal increases as the hardness increases,but the growth trend is relatively slow;as the radius of the groove of the female joint groove of the union increases,the sealing pressure of the seal is on the upward trend,When the fillet radius exceeds 1.9mm,the sealing pressure of the seal drops,while the fillet radius exceeds 2.0mm,the seal pressure of the seal tends to a stable state;as the radius of the seal fillet increases,the seal pressure of the rubber seal first rises The trend is that when the fillet radius of the seal is greater than 1.6mm,the seal pressure of the seal decreases,while the seal pressure of the seal with a radius of more than 1.7mm is increasing;the sealing performance gradually increases with the increase of the amount of compression(displacement load)of the rubber,When the compression amount is less than 1.35 mm,the sealing pressure of the seal is less than the working pressure and cannot play the role of sealing,and when the compression amount is greater than 1.35 mm,the sealing pressure of the seal exceeds the working pressure to meet the requirements of sealing;change between rubber and metal The coefficient of friction found that when the coefficient increases,the stress of the seal increases,and when the stress exceeds 0.5,the stress of the rubber seal basically tends to a fixed value.(4)When the union of female union groove radius changes,the union sealing law is as follows: when the radius of the seal groove is less than 1.8mm,the stress of the seal groove is in an upward trend,when the fillet is greater than 1.8mm,the seal The stress of the groove is reduced and tends to a stable state,and the stress of the sealed groove is less than the yield limit of the material(650MPa).