Research on the Sealing Performance and Structural Optimization of Pipe Rubber Core of the Ram Blowout Preventer Under Ultra-high Pressure
To investigate the sealing performance of the pipe rubber core of the ram blowout preventer(BOP)under 140 MPa ultra-high pressure,according to the hyperelastic large deformation theory and numerical simulation method,the con-tact relationship between the rubber core,ram and the drill pipe of ram BOP was studied.The analysis model of the rubber core sealing performance was established,and the sealing performance of the rubber core under the action of hydraulic cyl-inder driving force and 140 MPa drilling medium was analyzed.The influence of structural parameters of the rubber core such as eccentricity,the shim radius and the rubber core thickness on sealing performance was studied,and the optimized parameters for the rubber core structure were obtained.The sealing performance of different structures of the lip surface of rubber core was evaluated.The results illustrate that the weak position of rubber core seal is located at the junction of rub-ber core arc surface and end plane.Under the action of 140 MPa drilling medium,the rubber core appears"over-sealing"and stress concentration,which will lead to a sharp decrease in the service life of the rubber core.The effective contact stress of the rubber core decreases with the increase of eccentricity,shim radius,and rubber core thickness.The maximum equivalent stress increases with the increase of eccentricity,decreases with the increase of rubber core thickness,and first decreases and then increases with the increase of shim radius.Taking into account the contact stress and equivalent stress of the three types of lip surface structures,namely rectangular,circular arc,and chamfered,the chamfered lip surface rubber core is the most optimal.After optimizing the structure of the pipe core using the optimal lip structure and core parameter values,the high stress area of the rubber core is reduced,the maximum stress is reduced by 16.7％,and the effective seal-ing area is increased by 34.9％.
ram blowout preventerpipe rubber coresealing performancestructure optimizationhyperelastic large de-formation theory
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