Thermodynamic Analysis And Experimental Study Of Underwater Clamp Connector

Deepwater pipe connector is one of the indispensable equipment in the submarine pipeline engineering. The working environment of the deepwater pipe connector is very harsh,which includs the external load,vibration and temperature load. How to ensure the operational reliability in the complex environment becomes the primary task of the research work. By structural mechanics and thermodynamics analysis of underwater clamp connector and study on the temperature field and stress field distribution of the clamp connector under high temperature and high pressure, find out the main factors affecting the sealing and structure strength, have an important theoretical significance and research value.This paper take the 6 inch deepwater vertical clamp connector as the research object, from the stress characteristics , temperature field and the coupling stress distribution characteristics, connector performance three aspects to discuss.According to the characteristics of the mechanical structure, sealing structure and working condition of the clamp type connector, the axial pretightening force was determined.Through the finite element analysis, the relationship between the pretightening force and the sealing contact stress was obtained, and the stress characteristics of the key parts were analyzed to lay the foundation for the thermal structure coupling analysis.Based on the basic theory of thermodynamics, the heat transfer model of seawater layer between the flange and clamp plate ,flange joint surface and the outer surface were builded.According to the structural characteristics of clamp connections the equivalent thermal conductivity coefficient and equivalent heat transfer coefficient were introduced to simplified the heat conduction mode. Combined with the elastic thermal stress theory and the Lam formula, the comprehensive stress expression of high-temperature vessel under high temperature high pressure was deduced. Based on the Fu Liye's law the transient thermal stress was derived, and the characteristics of the stress distribution was analyzed.According to the working conditions of the connector, the heat transfer finite element model was established,and the parameters of the structure were introduced.The characteristics of clamp connector temperature field distribution was obtained though simulation. By use of thermal structure coupling analysis method, the heat load be put in the structure stress analysis as the structure load, the stress distribution and sealing status under high temperature, pressure and external load have been get. Finally, according to the criteria of ASME VII-2 the the strength reliability of high neck flange has be verified.The hydrostatic pressure test,temperature pressure test has been carried by using the special test equipment. The good sealing performance be verified by the hydrostatic pressure test. The influence of temperature and pressure on the performance of the connector was discussed in the temperature pressure test. And the test results were compared with the calculation and simulation results, the correctness of the theoretical analysis results were verified. The success of the undersea test verified its maneuverability and adaptability ,shows that the deepwater clamp type connector has the ability of engineering application.