热力耦合作用下水下井口连接器密封特性

Sealing Characteristics of Underwater Wellhead Connector under Thermodynamic Coupling

为研究海底高温高压复杂工况下金属密封圈在井口连接器中的密封性能,根据传热学理论建立传热学和热力耦合数学模型,运用ANSYS建立井口连接器温度场有限元模型;在温度场数值模拟的基础上,进行稳态和瞬态热结构耦合数值模拟分析,得到油气介质压力及温度对水下井口连接器密封性能的影响。结果表明:油气介质温度越高,密封圈内部的温度梯度越大,在温度冲击影响下,连接器各零部件和密封圈之间的温差波动要大于匀速变温及瞬间变温下产生的温差波动。稳态热-结构耦合分析表明,金属密封圈会因温度升高而产生膨胀变形,并且该变形大于不施加温度载荷时的变形,说明温度载荷在特定条件下将直接影响连接器的密封特性;瞬态热-结构耦合分析表明,油气介质温度的快速变化,导致密封圈中接触面受热产生的线膨胀比外圈的线膨胀大,从而导致密封圈内部的不协调变形,因此在实际工作环境中应避免温度升高速度过快的现象发生。

In order to study the sealing performance of the sealing gasket in the wellhead connector under the complex conditions of high temperature and high pressure on the seabed,the heat transfer model and thermodynamic coupling mathematical model were established according to the heat transfer theory,and the temperature field finite element model of the wellhead connector was established by using ANSYS software.Based on the numerical simulation of temperature field,the steady state and transient thermal structure coupling numerical simulation analysis was carried out to obtain the influence of oil and gas medium pressure and temperature on the sealing performance of wellhead connector.The results show that the higher the temperature of oil and gas medium,the greater the temperature gradient inside the sealing gasket.The temperature difference fluctuation between the parts of the connector and the sealing gasket under the influence of temperature impact is greater than that under constant and instantaneous temperature change.Through the steady-state thermal-structural coupling analysis,it is found that the metal sealing gasket has expansion deformation due to the temperature change,and the deformation is larger than that when no temperature load is applied,which indicates that the temperature load will directly affect the sealing performances of the connector in certain conditions.Through the transient thermal-structure coupling analysis,it is found that the rapid change of temperature in oil and gas medium leads to a larger linear expansion of the contact surface in the sealing gasket than that of the outer gasket,which leads to the discordant deformation inside the sealing gasket.Therefore,excessive temperature rise should be avoided in the actual working environment.