The capability of the WITT wave energy converter to generate megawatts of offshore power at a competitive LCOE

从海浪中利用大量清洁可再生能源的潜力是巨大的。英国政府和其他国家为应对气候变化做出的承诺要求扩大可再生能源技术的开发和部署，人们普遍认为，海浪能源将在实现减少碳排放的未来目标方面发挥重要作用。虽然在过去的35年里，在开发旨在生产强大且经济可行的波浪能转换器（WECs）的新想法方面取得了重大进展，但对于WECs的未来设计和运行方向仍然没有明确的共识。除了支持现有的概念外，重要的是继续探索有前途的波浪能转换新想法。人们普遍认为，成功的WEC设计有两个关键要素。首先，设计应该由波浪能量吸收的基本理论原理驱动，因为这些最终决定了能量转换的能力。其次，前瞻性设计必须考虑到在恶劣的海洋环境中运行时出现的重大工程挑战。克劳利、波特和埃文斯在《流体力学杂志》2013年第716期发表了一篇题为《水下圆柱体波浪能量转换器》的论文（以下简称《CPE》），提出了一种旨在解决这两种需求的WEC设计。特别是，该设计假定使用一个内部动力输出系统，该系统由一个在水平轴上旋转的钟摆组成，该钟摆的振动被阻尼以产生动力。这种设计的优点是与海洋环境隔离，机械坚固，依靠很少的运动部件，并且没有与设备过度激励相关的端停问题。理论和数值结果的结合表明，CPE装置在较宽的能量密集波周期范围内提取了显著的功率。事实上，预测的平均捕获因子是其类型的任何现有WEC的两倍以上。由WITT有限公司开发的WITT与CPE工作中设想的设备密切相关，该公司是TSB拨款的牵头方。witt不是一个在长圆柱体内封闭的浪涌/俯仰运动模式下工作的线性装置，而是一个设计用于浮标的装置。它不仅转换功率在浪涌和音调模式，但也在摇摆和滚动。WITT已由齿轮传动系统专家开发，并已被证明具有高效率的动能转换为电能。它具有可扩展性和健壮性。该项目由威特公司领导，包括专门从事系泊系统和海上部署、动力输出设计和制造以及包括波浪箱测试在内的实验方法的合作伙伴。在布里斯托尔，该项目将开发一个理论模型，用于WITTWEC设备作为一个漂浮或水下的球形浮标的操作，包括系泊线的影响，设备及其与模型海态和内部动力起飞系统的相互作用。该工作将基于cpe的早期工作，并根据修改的转换器几何形状、系泊线配置和动力输出系统进行更改。在验证测试完成后，将应用优化方法来确定在一系列物理尺度上WITT WEC器件的最佳功率转换参数。这项工作将与项目的其他合作伙伴共同开展，特别是在开发最佳系泊系统方面，并通过在南安普顿进行的实验工作验证理论预测。该项目的成功完成将为WEC设计提供一系列经过实验验证的理论结果，并有可能进行更大规模的开发，最终实现全面商业化。

The potential for harnessing significant amounts of clean renewable energy from ocean waves is vast. Commitments madeby the UK government and others to tackle climate change require an expansion in development and deployment ofrenewable technologies and it is widely recognised that ocean wave energy will play an important role in meeting futuretargets for the reduction of carbon emissions. Whilst significant advances have been made over the last 35 years indeveloping new ideas aimed towards producing robust and economically viable wave energy converters (WECs) thereremains no clear consensus on future direction of design and operation of WECs. In addition to supporting existingconcepts, it is important that promising new ideas for wave energy conversion continue to be explored. It is widelyaccepted that there are two key elements to a successful WEC design.First, the design should be driven by fundamental theoretical principles of wave energy absorption as these ultimatelydetermine the capacity for power conversion. Second, prospective designs must take account of the significantengineering challenges that arise when operating in harsh marine environments.In a recent paper "A submerged cylinder wave energy converter" Crowley, Porter & Evans, Journal of Fluid Mechanics,2013, vol 716, (hereafter CPE) advocated a WEC design which sought to address these two demands. In particular, thedesign was assumed to use an internal power take-off system consisting of a pendulum rotating on a horizontal axis whoserotation was damped to produce power.Such a design benefits by its isolation from the marine environment, mechanically robust by relying on few moving partsand free from end-stop problems associated with over-excitation of the device. A combination of theoretical and numericalresults demonstrated that the device of CPE extracts significant power over a broad range of energy-dense wave periods.Indeed, a mean capture factor more than double any existing WEC of its type was predicted.The WITT developed by WITT Limited under whom this TSB grant is being led is closely related to the device conceived inthe work of CPE. Instead of a linear device working in surge/pitch modes of motion enclosed within a long cylinder, theWITT is a device designed for use in buoys. It not only converts power in surge and pitch modes but also in sway and roll.The WITT has been developed by specialists in gear transmission systems and has been shown to have high efficiency inconversion of kinetic to electric power. It is scalable and robust. The project being led by WITT includes partnersspecialising in mooring systems and marine deployment, power take-off design and manufacture and experimentalmethods including wave tank testing. In Bristol, the project will develop a theoretical model for the operation of the WITTWEC device as a spherical buoy either floating or submerged, to include effect of the mooring lines, the device and itsinteraction with a model sea state and the internal power take-off system. The work will be based on the earlier work ofCPE, with changes implemented to account for the revised converter geometry, mooring line configuration and power take-off system.After verification tests have been completed, an optimisation method will be applied to determine parameters for optimalpower conversion for WITT WEC devices over a range of physical scales. The work will develop in tandem with otherpartners on the project, in particular in developing the optimal mooring system and through the validation of theoreticalpredictions by the experimental work performed in Southampton. The successful completion of this project will result in aset of experimentally-validated theoretical results for a WEC design with the potential to be developed a larger scale andeventually to full scale commercialisation.