考虑波流耦合作用的对转式潮流能水轮机流动机理研究

As a novel unit, the counter-rotating type horizontal axis tidal stream turbine plays an important role in expanding the exploitation approach and application of renewable ocean energy. However, the unique counter-rotating type blades and the complex working environment in the ocean, result in a variety of interference effects between the front and rear rotors, as well as between the turbine wakes and the wave-current induced loads. In order to fully understand the hydrodynamic characteristics and flow mechanism of counter-rotating type horizontal axis tidal stream turbines under the conditions of combined wave-current loads, a RANS-BEM model that can simulate the non-uniform shear inflow and wave loads will be developed to analyze and optimize the hydrodynamic characteristics and internal flow characteristics of the counter-rotating blades. Based on the theoretical analysis and simulations, the mechanism of energy recovery and wake flow improvement of the counter-rotating blades, as well as the interference mechanism between the turbine wakes and the wave-current induced loads will be revealed. An optimal matching model of the critical blade geometric parameters and a prediction model of the wave-current induced losses will be established for the counter-rotating blades. Simultaneously, the hydrodynamic characteristic curve and the wake flow field of the model turbine under typical wave-current conditions will be obtained by experimental tests carried out in a wave tank. And then the above-mentioned RANS-BEM model will be validated and modified by a series of experimental data. This study is contributed to improve the design theory and calculation method of counter-rotating type horizontal axis tidal stream turbines, and to provide an effective theoretical basis for the operation in the real ocean conditions.

对转式水平轴潮流能水轮机作为一种新颖机型，对于拓展可再生海洋能源开发途径和用途扮演着重要作用。但是其独特的对转叶片型式和复杂的海洋工作环境，导致前后转子之间以及水轮机尾迹流场和波流载荷之间存在着各种干涉效应。为了充分认识对转式水平轴潮流能水轮机在波流载荷耦合作用下的水动力特性和流动机理，本项目将发展可以实现非均匀剪切来流和波浪载荷模拟的RANS-BEM模型，分析并优化对转叶片水动力特性和内部流场特征，揭示对转叶片的能量回收机制和尾迹流改善机理，以及尾迹流场与波流载荷的干涉机理，建立对转叶片关键几何参数的优化匹配模型和波流载荷损失预测模型。同时，运用波浪水池实验测试手段，获取典型波流载荷工况下模型机组的水动力特性曲线和尾迹流场信息，通过一系列实验数据验证并修正上述建立的RANS-BEM模型。本研究有助于完善对转式水平轴潮流能水轮机设计理论和计算方法，同时为其在真实海况运行提供有效的理论依据。

潮流能是一种新型可再生海洋清洁能源，蕴藏量丰富，对于缓解能源危机和环境污染、促进社会经济可持续发展具有重要意义。我国潮流能发展起步较晚，在核心技术叶轮水动力设计方面缺乏完善的理论体系指导。本项目针对传统单叶轮机组和对转桨机组在复杂海洋环境波流载荷耦合作用下的水动力特性和流动机理开展研究，建立BEM-CFD全参数叶轮优化模型，实现了潮流能水轮机叶片水动力性能自动优化，相关成果在300kW并网机组上取得了良好效果，机组运行高效、稳定。开展了波浪参数对叶片非定常水动力特性的影响研究，定量分析了叶片在不同叶尖淹没深度、波高、波频等参数下的响应机制，以及对转叶轮的梢涡干涉效应，为高效对转桨水平轴潮流能水轮机设计提供理论指导。