深水液压控制阀门执行机构失效分析

Failure analysis of actuator of subsea hydraulic control valve

针对南中国海某气田水下液压控制阀门执行机构的失效问题,对该执行机构的设计结构进行了优化,并采用优化后的设计参数和所使用的膨胀液,分别采用伯努利方程和CFD软件进行了理论计算和有限元分析。研究表明,液控水下阀门执行机构内的压差与操作时间成反比,也与环境温度成反比。当阀门所处环境温度较低,操作速度过快时,安全阀会打开,从而导致膨胀液泄漏到海水环境中去。由此可能导致蓄能器中无膨胀液可以流回弹簧腔,导致形成液压锁,引起阀门执行机构故障。可以通过增加水下阀门的操作时间、增大弹簧腔与蓄能器之间连接管的管径、增加蓄能器数量、选用低温下黏度较小的膨胀液等措施,以避免液控水下阀门执行机构发生失效。

Considering the actuator failure of the subsea hydraulic control valve in a gas field in the South China Sea,the design structure of the actuator is optimized.The optimized design parameters and adopted inflation fluids are used for theoretical calculation and finite element(FE)analysis by the Bernoulli equation and CFD software,respectively.The research demonstrates that the pressure difference in the actuator is inversely proportional to the operation time and the ambient temperature.When the ambient temperature of the valve is low,and the operation speed is excessive,the safety valve will open,which results in the leakage of inflation liquids into seawater.It is likely that no inflation fluid in the accumulator can flow back to the spring cavity,which leads to the formation of a hydraulic lock and thus the failure of the actuator.The failure of the actuator can be avoided,however,by increasing the operation time of the subsea valve,the diameter of the connecting pipe between the spring cavity and the accumulator,and the number of accumulators,as well as using the inflation liquid with low viscosity at low temperature.