【作者】 李振宇；

【导师】 王立权；

【作者基本信息】 哈尔滨工程大学 ， 机械工程， 2023， 博士

【摘要】 海底管道卡压式连接器属于一种较为新颖的海管连接器,它利用径向金属静密封原理实现海底管道的连接与密封。针对该连接形式的基本力学原理及密封性能的相关研究尚未成熟,因此,对海管卡压式连接器相关的基础理论研究具有重要意义和实际应用价值。本文围绕海管卡压式连接器在预紧及轴向过载条件下的力学原理与密封性能进行了深入的基础理论研究。本文针对卡压式连接器存在的密封压力受管道材料限制、轴向承载力不足等问题,提出了一种卡压式连接器的改进结构方案。论文针对卡压式连接器力学原理基础研究中的不足,基于海管卡压式连接器的预紧及轴向过载过程,提出了连接器的预紧状态力学模型及轴向承载力模型。基于卡压式连接器的径向密封原理,提出了连接器环向泄漏率的半解析模型。针对连接器内部密封面变形无法准确验证的问题,提出了一种针对径向密封的剪切试验方法,并开展了压力及轴向过载等方面的试验研究,验证了不同结构方案卡压式连接器的力学及密封性能。针对海管卡压式连接器的基本结构存在的不足,提出了一种连接器改进结构方案。针对海管卡压式连接器力学理论研究的不足,开展连接器在预紧状态下的应力及变形问题研究,针对基本结构及改进结构的连接器分别提出了的预紧状态力学模型,得到了连接器各部分径向变形量与密封接触压力的关系;针对可能出现的管道轴向过载问题,提出了轴向承载力模型,分析了关键设计参数对不同结构方案连接器轴向承载力的影响。分别通过承载力模型与有限元模型,分析了出现塑性变形前后,相同参数对不同结构方案连接器力学性能的影响。针对海管卡压式连接器内部径向金属静密封结构的密封性能问题,开展连接器在预紧及轴向过载条件下的密封性能研究。分析了连接器径向金属静密封表面的形貌特征,提出了密封表面形貌的表征方程,建立密封面有限元接触模型,得到了密封交界面的泄漏通道横截面变形规律。基于Abbott-Firestone曲线及粘性流动的雷诺方程,建立了连接器泄漏率的半解析模型,得到了基体径向变形量、密封面轴向相对位移与环向泄漏率的关系。本研究将预紧过程中密封交界面的变形过程分解为“同步”“嵌入”和“完成”三个阶段,提出了以基体的挠度分量wb2作为各阶段的划分依据;将轴向过载过程中密封交界面的变形过程分解为“跟随”“分离”和“滑移”三个阶段,提出了以密封面之间的轴向相对位移变化率x’r作为各阶段的划分依据。此外,分析了管道密封面附近材料的移动和堆积现象对提高连接器密封性能的辅助作用。针对卡压式连接器内部径向金属密封面的试验问题,提出了一种密封面的剪切试验方法,通过该方法实现了在预紧和轴向过载过程中,对具有内圆车削形貌密封表面的变形情况的模拟,并通过该试验验证了密封有限元模型与仿真结果的正确性。此外,对基本结构和改进结构的连接器分别进行了工作压力、极限压力和轴向过载试验,揭示了真实泄漏率与理论泄漏率的区别。本研究的理论分析及样机试验结果表明,即使在超过了最大轴向承载力、出现了密封面滑动的严重失效情况下,具有内圆车削形貌密封面的海管卡压式连接器仍能保持密封状态,这说明其具有较高的密封性能及抗轴向过载失效能力,这是海管卡压式连接形式区别于其他连接形式的最显著的特点。本文所提出的各理论模型、改进结构方案及密封面试验方法,可为海底管道卡压式连接器的研究提供新的研究思路和方向。更多还原

【Abstract】 The compression type connector belongs to a new type of subsea pipeline connector,which uses radial metal static seal to achieve connection and sealing.At present,the research work on the basic mechanical principle of connection and performance of the radial metal seal is still insufficient,so it is of great significance and practical value to the relevant theoretical research on subsea pipeline connectors.In this study,the mechanical principle and sealing performance of the connector during connection and axial overload are deeply studied.A modified construction of the connector is proposed to solve problems such as limited sealing pressure and insufficient axial bearing capacity.Based on the process of preload and axial overload,the study presents analytical models of the preloaded state and axial bearing capacity of the connector.Based on the radial sealing principle,a semi-analytical model of the leakage ratio is presented.Aiming at the problem that the deformation of the inner sealing surface of the connector cannot be accurately verified,a shear test method for the radial seal is proposed,and experimental research on pressure and axial overload is carried out to verify the mechanical and sealing properties of different constructions of the connector.In view of the shortcomings of the basic construction of the connector,a modified construction is proposed.In view of the lack of mechanical theory of the compression type connector,the stress and deformation of the connector in the preload state are studied.The mechanical analysis models of the preload state are proposed for both the basic and modified constructions,and the relationship between the deflection of each part of the connector and the seal contact pressure is obtained.In view of the problem of axial overload of the pipeline,analytical models of axial bearing capacity are proposed,and the influence of key design parameters on axial bearing capacity of connectors with different constructions is analyzed.The influence of the same parameters on the mechanical properties of connectors with different constructions before and after plastic deformation is analyzed by analytical model and finite element model respectively.Aiming at the sealing performance of the radial metal static seal inside the connector,the sealing performance of the connector under the condition of preload and axial overload is studied.The surface topography characteristics of the radial metal static seal are analyzed,the surface morphology characterization of the seal is proposed,the finite element contact model of the sealing surface is established,and the cross section deformation law of the leakage channel at the sealing interface is obtained.Based on the Abbots-Firestone curve and Reynolds equation of viscous flow,a semi-analytical model of the leakage ratio is established,and the relationship between the deflections of the base,axial displacement of the sealing surface and circumferential leakage ratio is obtained.In the study,the deformation process of the sealing interface in the preload process is divided into three stages:"synchronization","embedding"and "completion",and the deflection component of the base is proposed as the division of each stage.The deformation process of the sealing interface in the axial overload process is divided into three stages:"following","separating" and "sliding",and the change rate of axial relative displacement between sealing surfaces is proposed as the division of each stage.In addition,the positive effect of material movement and accumulation near the sealing surface on improving the sealing performance is analyzed.Aiming at the test problem of the radial metal sealing surface inside the connector,a shear test method of the sealing surface is proposed.By this method,the deformation of the sealing surface with internal turning topography is simulated during preload and axial overload.The correctness of the finite element sealing model and simulation results are verified.In addition,tests of working pressure,ultimate pressure and axial overload are carried out on the connectors of the basic and modified construction respectively,and the difference between the actual and theoretical leakage ratios is revealed.The theoretical analysis and prototype test results show that even if the maximum axial bearing capacity is exceeded and the sealing surface is severely slid,the compression connector with an internal turning topography can still maintain the sealing state,indicating that it has high sealing performance and axial overload resistance.This is the most important feature of the subsea compression connection different from other connection forms.The theoretical model,modified construction and sealing surface test method proposed in this study can provide new idea and direction for the research of subsea pipeline compression connectors.更多还原