Sealing Performance Analysis And Test Research Of Press-Fitting Connector Of Submarine Pipeline

As the lifeline of marine oil and natural gas transportation,seabed pipelines play a very important role in the exploitation of marine oil and gas.However,the harsh working environment of the sea,such as corrosion,vibration,ocean currents and Haiti earthquake,can easily damage the submarine oil and gas pipelines,affect the transportation of seabed oil and gas resources,and pollute the marine environment,resulting in huge economic losses.Therefore,when the submarine pipeline is damaged,repairing and blocking damaged pipelines in time and effectively can reduce the loss to the maximum extent,and ensure the normal operation of the production.Underwater welding is one of the quick repair solution in subsea pipeline repair which plays an important role in the connection,but the water and the existence of the submarine high pressure,causing the welding technical difficulty,weld with high hydrogen and poor quality and cannot work continuously,so the method of quick mechanical connection is more reliable.Submarine pipeline press-fitting connector is a mechanical connector that can be used for quick repair of offshore pipelines.Its structure is simple,operation is convenient,and connection efficiency is high.It has broad application prospects in offshore oil resources exploitation.This paper first puts forward the structure scheme of the pressing-fitting connector.The mechanism of metal sealing for the press-fitting connector is studied,and the design principle of the sealing part is put forward.The finite element software ANSYS is used to simulate the initial design of the press-fitting connector.The results show that the sealing performance of the initial design press-fitting connector is poor and needs to be optimized.In order to improve the optimization efficiency,correlation analysis of the relevant structural parameters of the press-fitting connector is carried out,and the structural parameter group that has the greatest influence on the sealing performance is obtained,and the adaptive multi-objective optimization design of press-fitting connector is carried out.The numerical simulation of the 1.5 times rated internal pressure condition of the optimized press-fitting connector is carried out,and the change of its sealing performance is studied.The micro contact sealing performance of the optimized press-fitting connector is studied.Based on the fluid flow model in the microscopic seal gap,a gas leakage microscopic model of the press-fitting is built considering the micro gas sparse and the roughness of the sealing interface and the gas leakage rate equation is deduced.The microscopic contact mechanics model of the sealing surface is established,and the average surface force equation is derived.The three-dimensional model of micro rough surface is established by MATLAB and UG reverse engineering,and the surface contact process of micro rough sealing is simulated.The leakage rate of micro gas quality of the press-fitting connector is analyzed,and its sealing performance is evaluated quantitatively.Aiming at the change of sealing performance of the press-fitting connector in submarine pipeline transportation of high temperature oil and gas,the sealing performance of the pressfitting connector is analyzed in the steady temperature and pressure coupling field.The heat transfer model and finite element model of the press-fitting connector are established.Numerical simulation of the high pressure coupling field of press-fitting connector is carried out.The steady temperature field distribution and the sealing performance change of pressfitting connector are analyzed.By simulating different temperature conditions,the rule of temperature field and sealing performance of press-fitting connector is analyzed,and the range of temperature is determined.In order to verify the design of the press-fitting connector can meet the design index of the corresponding processing,1:1 press-fitting connector prototypes are test in accordance with the international standard connector test procedures,including prototype installation test and hydrostatic pressure test,air tightness test and pipe surface indentation test.The test results show that the designed press-fitting connector has good sealing performance and meets the relevant design indexes.The optimization effect of the press-fitting connector is very obvious,so it is feasible to use the adaptive multi-objective method to optimize the design.