极端海况下软钢臂系泊浮式核电平台水动力特性研究

The floating nuclear power plant is the combination of the platform and nuclear power plant. Its designing recurence interval is 10000 year. Through experimental study, it's observed that the peak value of mooring force has appeared in the case that the wind, wave and current exerting on the platform in the same direction. That's different from the phenomenon observed from ordinary FPSOs moored by Soft Yoke whose peak mooring force occurs as there are certain angles among the wind, wave and current. Meanwhile, the peak value of mooring force in the case that the wind, wave and current in the same direction is smaller than that in the case that only waves exerting on the platform obviously, which is oppsite to the result calculated by commercial software. The reason to the former phenomenon is not clear. So that in present project the hydrodynamic characteristics of the floating nuclear power platform mooring by Soft Yoke will be studied. The numerical simulation is employed as the main researching method. By considering the nonlinear boundary condition and developing the real-time remeshing technique, the time-domain nonlinear numerical model will be established. By considering the dynamic characteristics of Soft Yoke, the mooring system multibody time-varying numerical model will also be built. Through developing numerical model considering Soft Yoke and the platform interaction and the experiment, the hydrodynamic characteristics of floating nuclear power platform mooring by Soft Yoke can be analyzed, and the mechanism and influencing factors will be revealed. The present study will become a necessary analyzing tool for designing the floating nuclear power platform. The research results of this topic could provide reference and theoretical basis for floating nuclear power plant applied to practical engineering.

海上浮动核电站是海洋平台与核电站的有机结合。核电平台的设计重现期标准达到万年一遇。实验研究发现：极端海况下，在风浪流同向作用时，平台系泊力出现峰值最为危险，有别于传统软刚臂系泊FPSO情况（在风浪流成一定角度时出现峰值）；同时，在风浪流同向工况的系泊力极值明显小于波浪单独作用时的系泊力极值，且与商用软件计算结果完全相反。前述现象的发生机理尚不明确，不利于平台实际应用。因此，本项目将针对软刚臂系泊核电平台的水动力特性进行研究。本研究以数值模拟为主要手段，考虑非线性边界条件，开发网格实时剖分技术，建立平台运动的时域非线性数值模型；考虑软刚臂动力特性，建立系泊系统的多体时变数值模型；开发软刚臂与平台流固耦合作用模型，结合风浪流模型试验，分析极端海况下软刚臂系泊平台水动力特性，揭示核电平台特有现象的产生机理和影响因素。本研究将为海上核电平台设计提供必要分析工具，为海洋核电站应用提供参考和理论依据。

海上浮动核电站是海洋平台与核电站的有机结合。核电平台的设计重现期标准达到万年一遇。本项目针对软刚臂系泊核电平台的水动力特性进行研究。本研究以数值模拟为主要手段，考虑系泊系统与浮体的耦合作用，开发软刚臂与平台流固耦合作用模型，结合风浪流模型试验，分析极端海况下软刚臂系泊平台水动力特性，揭示核电平台特有现象的产生机理和影响因素。在本项目的研究过程中，改进了已有的三维边界元时域数值模型，建立一个自由水面条件完全非线性、物面条件实时满足的时域非线性数值模型；研究了非线性波浪的作用机制，揭示大幅运动的产生机理和影响因素，研究了各环境要素对结构物受力和运动响应的影响机理，确定了不同分析理论的适用范围和应用条件；推导了软刚臂系泊机构的多刚体机构静态受力分析方程，建立了软刚臂的简化几何模型；根据结构动力分析方法，建立了系泊系统的时域受力及运动响应数值计算模型；验证系泊系统时变刚度数值计算模型；通过参数化分析，研究影响系泊系统刚度各因素的作用规律，建立了系泊系统目标参数优化方法；开展了极端海况作用下软刚臂系泊浮体运动问题的模型实验，分析了环境要素对结构物波浪力、运动响应和系泊力的影响，研究了海洋核电平台特有现象的形成机理和影响因素；开发了系泊系统和浮体响应的耦合计算程序；将风载荷和流载荷换算为风压力和流压力直接加到平台上部干网格和下部湿网格处，并实时更新，进行极端海况下软刚臂与系泊平台耦合作用的数值模拟；通过模型实验与计算结果比较，分析了海洋核电平台特有现象的形成机理和影响因素；并进一步对浮式平台与液舱的耦合作用进行了数值模拟和实验研究。通过频域和时域数值模拟及相关模型实验，研究了液舱晃荡频率和浮式平台自有运动频率之间的关系，分析了波浪作用下带液舱平台的运动规律。本研究可为海上核电平台设计提供必要分析工具，并为海洋核电站应用提供参考和理论依据。