深井极端工况下机械密封磨损过程的多尺度模拟仿真与预测

Aimed at the abrasion problem of equipment under deep well environment, this project propose a multi-scale simulation and prediction approach to deal with the abrasion process of mechanical seal within high temperature, high pressure and heavy corrosive environment. A molecular dynamic (MD) method is utilized to simulate the dynamic behavior of polymer materials swelling and metal corrosion. Thus find out the corrosion mechanism and abrasion of mechanical seal in the typical deep well environment. Combined the meso-scale quasi-continuum simulation and finite element analysis method, a partial multi-scale contact model of seal face is bulid. This model can simulate the complex wear behavior caused by contact friction, fluid flow, abrasion wear etc. Therefore, the dynamic evolutionary modification process of seal face micrographs can be simulated. Multiple linear regression method is employed to map and extend the change law of rough surface fractal features of partial abrasion result, after an abrasion simulation loop by meso-scale contact model, to global seal surface. The seal characteristic factors like frictional coefficient and leakage rate are calculated according to the simulation result. Repeating a number of simulation loops, the change tendency of seal characteristic factors can be calculated. This information can be used to predict the life of mechanical seal. By offering the basis and reference of relevant parameters quantitative control technique, this research provide an assistant tool for long lifecycle, high reliability mechanical seal of deep well drilling or testing equipment.

针对深井极端工况下的设备密封问题，开展高温高压腐蚀环境下机械密封磨损失效过程的多尺度模拟仿真与寿命预测研究。建立分子动力学模型对高分子材料密封件的溶胀和金属密封端面溶解腐蚀磨损行为进行微观模拟仿真，揭示典型深井环境下密封端面的腐蚀机理和腐蚀磨损规律。综合运用准连续介质模拟和有限元分析方法，建立密封端面的局部接触多尺度流固耦合分析模型，模拟接触摩擦、流体流动、腐蚀等复杂物理化学综合作用下的密封端面磨损行为，实现密封端面形貌演化过程的动态求解与模拟仿真。采用多元线性回归方法，根据一个仿真循环内进行的多个局部细观接触模型的磨损行为模拟仿真结果，将局部表面形貌分形特征的改变规律映射到全局宏观层面上，并求解密封性能的参数摩擦系数和泄露率。经过多次仿真循环得到密封性能的变化趋势，预测密封寿命。为开发深井钻探装备用机械密封长周期、高可靠运行相关参数定量控制技术提供依据。

本项目研究深井极端工况下机械密封磨损过程的多尺度模拟仿真与预测方法。提出了高温高压环境下静密封元件泄漏预测模型，基于分形理论和有限元计算方法模拟了流体泄漏路径，给出了高温高压环境下静密封元件的泄漏预测方法。提出了动密封元件的多尺度磨损模型，宏观尺度下基于分形理论建立了密封件与被密封件间的接触模型，微观尺度下对密封件磨损过程中的材料去除进行了模拟，建立了基于离散元方法的微观接触模型。提出了高温高压环境下往复直线运动密封元件在全膜润滑状态下的泄漏预测模型，基于弹性流体动力学理论和有限元计算方法给出了高温高压环境下全膜润滑动密封元件泄漏预测方法。基于Archard磨损理论和有限元方法，提出了混合润滑状态下动密封元件磨损仿真方法。建立了高温高压环境下混合润滑动密封元件泄漏预测模型，提出了基于混合润滑状态下动密封元件磨损仿真方法，给出了高温高压状态下混合润滑动密封元件的泄漏预测方法。