波浪中漂浮式潮流能装置的水动力学问题研究

Tidal current energy is one kind of clean and contaminated marine renewable energy, which has become research focus recently and is gradually forming a new equipment industry chain. In the real sea, the floating tidal current device is a dynamic coupling system with a multi-point mooring. The turbine is hanged on the platform of this system, and the motion of the turbine under water is a composite “gyro” motion; the complicated mechanical behavior of the turbine is a hidden danger for its reliable and efficient operation. The motion of this system is coming from external excitation (result from wind, tidal current and wave) and internal excitation (result from the rotation of turbine). Therefore, the project studies on the new hydrodynamic problems on floating tidal current device when wave and current are presented. Combined potential flow theory with viscous fluid theory, an effective calculation model and method used to study the hydrodynamic performance of tidal current device (platform + turbine) is developed when wave and current are presented. The “gyro” motion, hydrodynamic phenomenon and its mechanism and changing law are revealed; and the extreme loads, coupled resonance or cavitation problem which might exist are explored. The model experiment is carried out, and the turbine is observed under effects of free surface, wave and “gyro” coupled, which supply the basement for theory method and mechanism validation. The results of this project will be significant in improving the hydrodynamic design theory of ocean engineering and tidal current turbine in complexity ocean environment, and will provide with scientific methods and techniques to enhance the efficiency of turbine and the overall performance of floating tidal current device.

潮流能作为一种清洁的海洋可再生能源，已成为国内外研究的热点，并且正逐渐形成新型装备产业链。实际海洋环境中的漂浮式潮流能装置是一个多点系泊的动力学耦合系统，该系统载体吊挂的转轮在水中呈“陀螺”复合运动形态，其复杂的力学行为成为高效可靠运行的隐患。该系统运动源于系统外部（风浪流）激励和内部（叶轮转动）激励。本项目针对浪流环境下潮流能装置的水动力学新问题开展研究。基于势流和粘流理论，发展有效的浪流作用下潮流能装置（载体+水轮机）水动力计算模型和方法；揭示其“陀螺”运动模式、水动力新现象及其发生机理和变化规律，探索可能的极端载荷、耦合共振或空化问题；开展水动力模型试验，通过观测叶轮的自由面、波浪和“陀螺”耦合效应，为理论模型算法和机理的研究和验证提供依据。本项目完成，对于丰富复杂环境海洋工程和潮流能水轮机水动力设计理论具有重要意义，为提高水轮机的获能和系统效率奠定科学方法与技术基础。

潮流能作为一种清洁的海洋可再生能源，已成为国内外研究的热点，并且正逐步向阵列化、大型化发展，形成新型装备产业链。真实海洋环境中的漂浮式潮流能装置是一个多点系泊的动力学耦合系统，该系统载体吊挂的转轮在水中呈“陀螺”复合运动形态，其复杂的力学行为成为高效可靠运行的隐患。该系统运动源于系统外部（风浪流）激励和内部（叶轮转动）激励。本项目基于N-S方程的粘性流理论，在浪流作用下，首先建立了全几何模型的潮流能水轮机水动力性能计算方法。其次建立了潮流能叶轮强迫运动的数值计算方法。最后建立了浪流作用下，漂浮式潮流能装置（水轮机+浮式载体+锚链）全耦合运动的水动力性能计算方法。研究典型的海洋环境（潮流、自由液面、波浪、水深等）作用下，浮式潮流能装置的水动力特性，揭示叶轮“陀螺”运动模式、水动力新现象及其发生机理和变化规律，探索可能的极端载荷、耦合共振或空化问题。本项目完成，对于丰富复杂环境海洋工程和潮流能水轮机水动力设计理论具有重要意义，为提高水轮机的获能和系统效率奠定科学方法与技术基础。