旋转控制头密封胶芯性能三维有限元分析与结构优化

Three-dimensional Finite Element Analysis and Structural Optimization of Rubber Core of Rotating Control Head

为提升带压起下钻过程中旋转控制头胶芯密封性能,基于虚功原理得到动态密封过程的有限元控制方程,并进行橡胶单轴压缩试验确立胶芯变形过程中的Yeoh本构模型;运用ABAQUS试验平台建立胶芯三维有限元模型,通过模拟起下钻过程中胶芯动态密封过程,得出密封面上受力分布规律;研究胶芯内锥角、外锥角、内径等结构参数对密封性能的影响。结果表明:胶芯主密封面的接触压力大于其他部位,其中主密封面与内锥面拐点处接触压力最大;内锥角增大时内锥面接触压力变大,外锥角增大时密封面接触压力波动,内径增大时主密封面接触压力降低。通过正交试验对结构参数进行优化,得到的最优结构参数组合为内锥角24°、外锥角64°、胶芯内径79 mm,优化方案的接触压力峰值降低了0.51 MPa,Mises应力幅值降低了57.5%。现场应用结果表明,优化方案在满足胶芯密封要求前提下,疲劳寿命显著增长,验证有限元仿真分析的准确性。

In order to improve the sealing performance of rubber core of rotating control head in the process of drilling with pressure,the finite element governing equation of dynamic sealing process was obtained based on the virtual work principle,and the Yeoh constitutive model in rubber core deformation process was established by uniaxial compression tests.The three-dimensional finite element model of rubber core was established by using ABAQUS experimental platform.By simulating the dynamic sealing process of rubber core in the process of drilling with pressure,the force distribution on the mechanical seal face was obtained.The influence of the structural parameters such as such as inner cone angle,outer cone angle and inner diameter of rubber core on the sealing performance of the drill pipe were studied.The results show that the contact pressure of the main sealing surface of the rubber core is greater than that of other parts,and the contact pressure at the inflection point between the main sealing surface and the inner conical surface is the largest.The contact pressure of inner cone surface increases when the inner cone angle increases,the contact pressure of sealing surface fluctuates when the outer cone angle increases,and the contact pressure of main sealing surface decreases when the inner diameter increases.The structural parameters are optimized by orthogonal test.It is concluded that the optimal combination of structural parameters is inner cone angle of 24°,outer cone angle of 64°and inner diameter of 79 mm of the rubber core.The peak contact pressure of the optimized scheme is reduced by 0.51 MPa and the Mises stress amplitude is decreased by 57.5%.The field application shows that the fatigue life of the rubber core is significantly increased under the premise of meeting the requirements of the rubber core seal,which verifies the accuracy of the finite element simulation analysis.