Morphing-Blades: New-Concept Turbine Blades for Unsteady Load Mitigation

该项目旨在以模型规模展示一种新技术，以减少潮汐涡轮机的不稳定负荷，提高弹性和可靠性，并降低能源的平准化成本。潮汐能是一种很有前途的可再生能源，可以为英国提供能源安全。第一组和第二组潮汐涡轮机现已在苏格兰部署，确认了英国在这一新兴能源领域的世界领先地位。从潮汐中收集能量的主要技术挑战之一是叶片承受的巨大负载波动。这可能导致叶片的疲劳失效，以及发电机的功率波动，必须在向电网供电之前进行平滑处理。该项目的目的是开发一种技术，从源头上消除非定常负荷，同时将涡轮机的复杂性降到最低，以确保整个系统的高弹性和可靠性。目前用于减轻空气负荷波动的技术，例如风力涡轮机和飞行器所采用的技术，由于恶劣的海洋环境和高流体动力载荷，不能直接转移到潮汐涡轮机上。例如，复杂的系统需要铰链与轴承将受到污染，并将降低叶片的可靠性。为了解决这个问题，我们将考虑引入不影响叶片关键结构元件的局部灵活性，其位移可以减轻负载波动。叶片的负荷最低的部分是后缘，这也是最小的形状变形可以导致最大的总负荷变化的地方。我们可以制造一种与传统刚性叶片（玻璃纤维）相同材料的叶片，但其结构设计允许后缘弯曲以应对流量变化。为了保证系统的高可靠性，我们可以利用无传感器和执行器的被动变形。叶片弯曲部分的小惯性可以对气流波动作出迅速反应。我们的初步研究表明，具有柔性后缘的叶片理论上可以在不影响平均输出功率的情况下减轻90%以上的负载波动。该项目旨在通过测试模型尺寸的原型来验证这些初步结果。我们的目标是设计和制造两套0.6 m和1.2 m的叶片，分别进行模型尺寸涡轮机的流体力学试验和疲劳试验。这些试验将证明变形叶片的有效性、稳健性、弹性和可靠性。该项目包括主要的潮汐能和风能技术公司：SIMEC Atlantis energy、Orbital Marine Power、Nautricity、Nova Innovation、Schottel Hydro、ACT Blades和Wood Group。与这些工业合作伙伴一起，我们的目标是研究变形叶片在不同潮汐技术中的适用性，从70千瓦到2兆瓦，从4米到20米直径，以及海底安装和浮动的单转子和多转子涡轮机。如果证明对潮汐涡轮机有效，我们还将与我们的风能合作伙伴（ACT Blades和Wood Group）探讨这项技术是否适合补充或取代风力涡轮机目前采用的一些现有的非定常负荷缓解技术。变形叶片有助于减少疲劳负荷，提高可靠性和寿命产量，从而降低能源成本。根据设想，这种技术可能比陆上风力涡轮机更适合海上风力涡轮机，因为组件可靠性的相对重要性更高。总体而言，本项目旨在研究变形叶片减轻潮汐涡轮机非定常负荷的适用性，旨在降低叶片成本，提高能量产量，从而降低潮汐能的总体成本。

This project aims to demonstrate at model-scale a novel technology to reduce unsteady-loading for tidal turbines, improving resilience and reliability, and decreasing the levelised cost of energy.Tidal energy is a promising renewable energy source that can contribute to providing energy security to the UK. The first and second array of tidal turbines has now been deployed in Scotland, confirming the UK as a world leader in this emerging energy sector. One of the main technical challenges of harvesting energy from tidal currents is the large load fluctuations experienced by the blades. These can result in fatigue failures of the blades and in power fluctuations at the generator that must be smoothed before power can be provided to the grid. The aim of this project is to develop a technology that cancels the unsteady loading at its source, while adding minimal complexity to the turbine to ensure high resilience and reliability of the overall system. The technology currently adopted to mitigate load fluctuations in air, such as that one employed by wind turbines and aerial vehicles, is not directly transferable to tidal turbines because of the harsh marine environment and the high hydrodynamic loads. For example, complex systems requiring hinges with bearings would be subjected to fouling and would reduce the blade reliability. To address this issue, we would consider introducing local flexibility that does not affect the key structural elements of the blade, and whose displacement can mitigate load fluctuations. The lowest loaded part of the blade is the trailing edge, and this is also where the smallest shape morphing can lead to the largest changes in the overall load. We could manufacture a blade made of the same material as a conventional rigid blade (fibreglass) but with a structural design that allows the trailing edge to bend to react to flow changes. To ensure high reliability of the system, we could exploit passive deformation without sensors and actuators. The small inertia of the part of the blade that bends would enable a prompt reaction to flow fluctuations. Our preliminary studies showed that a blade with a flexible trailing edge can theoretically mitigate more than 90% of the load fluctuations without affecting the mean power output. This project aims to verify these initial results by testing model-scale prototypes. We aim to design and manufacture two sets of 0.6 m and 1.2 m span blades to undertake fluid dynamics tests on a model-scale turbine and fatigue tests, respectively. These tests will demonstrate the efficacy, robustness, resiliency and reliability of morphing blades. The project includes key tidal and wind energy technology companies: SIMEC Atlantis Energy, Orbital Marine Power, Nautricity, Nova Innovation, Schottel Hydro, ACT Blades and Wood Group. Together with these industrial partners we aim to investigate the applicability of morphing blades to different tidal technologies, from 70 kW to 2 MW, from 4 m to 20 m diameter, and both seabed mounted and floating turbines with single and multi rotors. If proven effective for tidal turbines, we would also explore with our wind energy partners (ACT Blades and Wood Group) whether this technology is suitable to complement or replace some of the existing unsteady load mitigation technology currently adopted by wind turbines. Morphing blades could contribute to reduce fatigue loads, to increase reliability and lifetime yield, and hence to reduce the levelised cost of energy. It is envisaged that this technology could be more suitable for offshore wind turbines than onshore wind turbines because of the higher relative importance of component reliability. Overall this project aims to investigate the suitability of morphing blades to mitigate unsteady loads on tidal turbines, aiming at decreasing costs of blades and increase the energy yields, and thus decrease the overall cost of tidal energy.