Calculation of the performance of resonant wave energy converters in real seas
Calculation of the performance of resonant wave energy converters in real seas
复制标题
真实海洋中谐振波能量转换器的性能计算
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
M. B. Widden
中科院分区：
文献类型：
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作者：
H. Yavuz;A. P. McCabe;G. Aggidis;M. B. Widden
众所周知，点吸收式波浪能转换器（WEC）的性能取决于与波浪频率的共振。事实上，谐振点吸收器WEC在规则海洋中的理想性能可以由简单的正弦曲线表示，这是众所周知的，只要所有运动都很小并且保持在线性区域中。然而，这种装置在更现实的、不规则的海洋中的性能不能如此容易地计算，所述海洋不是由简单的正弦曲线表示的。第一个困难在于模拟装置的流体动力学行为。最近的发展，在表示的流体动力衍射和辐射力，使相对简单的模拟模型，如本文中提出和使用。第二个难点在于设备本身的设计。在具有已知波浪频率的规则海洋中，动力输出系统的设置可以被限定在公知的最佳值。它示出在本文件中，即使当波的频率是不恒定的，本地波的频率可以估计，这种估计可以用来调整的动力输出系统的设置，以保持准共振，因此，接近的性能水平，在一个可比的定期海。以这种方式，对于不规则的海洋，可以在相对短的时间段内识别主波频率，并且连续地使用该频率来调节动力输出系统设置，以便适应当前的海洋条件。在某些海况下，动力输出装置可能在部分循环中提供动力，而不是吸收动力。这将增加对动力输出装置的要求，特别是当动力流方向必须可逆时，对动力输出装置的效率的要求。这种可调谐点吸收WEC的相对性能进行评估的文件。结果表明，在不规则海域转换的功率可能高达额定功率的50%，后者的估计是相当于在相应的正常海域转换的功率。
It is well known that the performance of point-absorber wave energy converters (WECs) depends upon resonance with the wave frequency. Indeed, the ideal performance of a resonating point-absorber WEC in a regular sea that can be represented by a simple sinusoid is well known, provided all motions are small and remain in the linear region. However, the performance of such a device in a more realistic, irregular sea that is not represented by a simple sinusoid cannot be so readily calculated. The first difficulty lies in modelling the hydrodynamic behaviour of the device. Recent developments in representing the hydrodynamic diffraction and radiation forces have enabled relatively simple simulation models to be developed, such as those presented and used in this paper. The second difficulty lies in the design of the device itself. In a regular sea with a known wave frequency, the settings of the power take-off system can be defined at well-known optimum values. It is shown in the present paper that, even when the wave frequency is not constant, the local wave frequency can be estimated, and this estimate can be used to adjust the power take-off system settings to maintain quasiresonance and, hence, approach the level of performance in a comparable regular sea. In this manner, for irregular seas it is possible to identify a dominant wave frequency over a relatively short time period and to use this frequency continuously to adjust the power take-off system settings, so as to adapt to the current sea conditions. This is likely, in some sea conditions, to involve the power take-off supplying power over part of the cycle, rather than absorbing it. This will increase the demands placed on the power take-off - particularly on its efficiency when the direction of power flow has to be reversible. The relative performance of such a tuneable point-absorber WEC is assessed in the paper. It is shown that the power converted in irregular seas could be as much as 50 per cent of the rated power, where the latter estimate is equivalent to the power converted in a corresponding regular sea.