Reducing risks and costs of in-stream tidal energy using multi-scale computational fluid dynamic simulation

以潮汐、波浪和近海风能为形式的海洋可再生能源是最丰富但相对未开发的可再生能源之一。特别是潮汐能，最近的兴趣集中在流中潮汐能转换器的开发上，这种转换器可以将快速流动的潮汐蒸汽的动能转换为电能。在加拿大，已确定190个潜在地点的电力足以满足3060万加拿大家庭的年电力需求。具体来说，位于芬迪湾的米纳斯航道被认为是世界上最好的潮汐能源地点之一，据估计，这个地点可以为140万加拿大家庭提供足够的电力。有了这样的潜力，令人惊讶的是，全世界只有有限数量的潮汐涡轮机在运行，而且目前只有一台涡轮机部署在米纳斯航道。诚然，该行业的进展慢于预期，但现在徘徊在商业化的边缘。2017年全球海洋可再生能源装机容量翻了一番，溪流潮汐能装机容量增至17兆瓦。*行业进展缓慢在很大程度上是由于项目成本和风险较高，因为涡轮机必须在具有特定场地湍流的恶劣能量环境中运行。这会在潮汐涡轮机叶片和支撑结构上产生波动的力，降低涡轮机的性能并缩短其使用寿命。美国能源部表示，发展对湍流的透彻了解是设计耐用设备和加快技术开发步伐的关键一步，从而大幅降低能源成本，类似于风能行业所取得的成就。另一个挑战是评估这些装置对当地环境的影响，特别是对鱼类和海洋哺乳动物种群以及沉积物运输的影响。这导致了社会对加拿大潮汐能行业的缓慢接受。*本研究的目的是开发一种多尺度高保真计算流体动力学工具，在真实的海洋环境中模拟团队中的潮汐涡轮机。然后，该软件将用于量化环境湍流对涡轮机的影响以及涡轮机对湍流环境的影响。重点将放在确定环境湍流如何影响涡轮机的性能和耐久性，同时也将量化涡轮机的存在如何改变湍流特性、环境噪声水平和局部泥沙输送。这将通过为开发商提供降低项目风险和成本所需的知识，同时确定芬迪湾社会可接受和环境兼容的适当潮汐能规模，从而促进加拿大的溪流中潮汐能产业。********

Ocean renewable energy in the form of tides, waves and offshore wind is one of the most abundant, but relatively untapped, renewable energy sources available. Specifically for tidal energy, recent interest has focused on the development of in-stream tidal energy converters that transform kinetic energy from fast flowing tidal steams to electricity. In Canada, 190 potential sites have been identified with sufficient power to meet the annual electricity needs of 30.6 million Canadian households. Specifically, Minas Passage, located in the Bay of Fundy, is considered one of the world's best tidal energy sites and it has been estimated that this single site could provide sufficient electricity to power 1.4 million Canadian households. With such potential, it is surprising there are only a limited number of tidal turbines operating worldwide and only one turbine currently deployed in Minas Passage. The industry has admittedly progressed slower than anticipated, but now hovers at the edge of commercialization. Global installed ocean renewable energy doubled in 2017 and installed in-stream tidal energy increased to 17 MW. ******Slow industry progress has been largely due to high project costs and risks because turbines must operate in harsh energetic environments with site-specific turbulence. This creates fluctuating forces on tidal turbine blades and support structures, degrading turbine performance and shortening its lifespan. The US Department of Energy has stated that developing a thorough understanding of turbulence is a critical step to designing durable devices and accelerating the pace of technology development, leading to a significantly lowered cost of energy, similar to what was achieved in the wind industry. An additional challenge has been assessing the impact of these devices on the local environment, in particular, the effects on fish and marine mammal populations and sediment transport. This has resulted in slow social acceptance of the tidal energy industry in Canada.******The object of this research is to develop a multi-scale high-fidelity computational fluid dynamic tool that simulates in-team tidal turbines in a realistic ocean environment. This software will then be used to quantify the impact of environmental turbulence on the turbine and the impact of the turbine on the turbulent environment. Emphasis will be place on identifying how environmental turbulence affects turbine performance and durability, while also quantifying how the presence of the turbine alters the turbulent flow characteristics, ambient noise levels, and local sediment transport. This will facilitate the in-stream tidal energy industry in Canada by providing developers with the knowledge required to reduce project risks and costs, while simultaneously determining the appropriate scale of tidal energy in the Bay of Fundy that is socially acceptable and environmentally compatible. ********