Study On The Effect Of Seal Ring Defect On The Sealing Performance Of Underwater Connector

As the exploitation of oil and gas resources moves from land to sea,the connection and sealing between underwater equipment has become a key technology that must be mastered.Vertical claw underwater connector is one of the key connecting equipment of underwater production system.It is used to connect Christmas tree and crossover pipe.Its sealing performance directly affects the safety of underwater production system.Aiming at the sealing problem of vertical claw underwater connector,the main research contents of this thesis are as follows:(1)The mechanical model of vertical claw underwater connector is established,the calculation formulas of contact stress and contact width of conical sealing ring are deduced,and the judgment method of sealing performance of the connector under preload and working conditions is determined.(2)Based on the first-order sine wave surface assumption,the calculation formulas of leakage rate of metal flat washer and conical seal ring are deduced.(3)The three-dimensional simplified model of vertical claw underwater connector is constructed by using the finite element software ABAQUS.The effects of axial preload and internal pressure on the sealing performance of the connector are systematically analyzed,and the minimum axial preload required to meet the sealing requirements of the connector under different working conditions is determined.(4)The effects of installation deviation of conical sealing ring,manufacturing error of conical surface and pitting corrosion on sealing performance are analyzed.The results show that the greater the axial preload,the lower the internal working medium pressure,and the better the sealing performance of the connector.When the medium pressure is 0,14 MPa,20MPa,30 MPa,35MPa and 52.5MPa respectively,the minimum axial preload required to meet the sealing performance of the connector is444 k N,482 k N,526 k N,580 k N,615 k N and 778 k N respectively.When the installation deviation of the conical sealing ring is less than 1 °,the manufacturing error of the inclination angle of the first conical surface is in the range of-0.5 °-0 °,and the spot corrosion radius is less than 2mm,it has no obvious impact on the sealing performance of the connector.When the radius of pitting corrosion is larger,the position of pitting corrosion is closer to the position of the first conical surface of conical seal ring,and the number of pitting corrosion defects is more,the contact stress of conical seal ring is smaller.The research content of this paper has a certain theoretical reference value for the calculation of the leakage rate of the conical seal ring,and has a certain engineering reference significance for the judgment of the sealing performance of the connector when the seal ring has defects.