基于等效数值模型的漂浮式OWC共享系泊阵列性能研究

    Performance of Floating OWC Shared- Mooring Arrays Based on Equivalent Numerical Model

    • 摘要: 为降低漂浮式振荡水柱(Oscillating Water Column, OWC)波浪能装置阵列的系泊系统成本,并兼顾阵列获能性能与极端海况安全性,本文以漂浮式圆筒形OWC装置为研究对象,开展三装置共享系泊阵列综合性能研究。首先,基于AQWA建立频域水动力模型,采用Fluent识别PTO阻尼和黏性阻尼,并将修正结果引入OrcaFlex等效OWC模型;随后,通过对比物理模型试验与数值模拟的结果,验证修正后的等效模型描述漂浮式OWC动力响应与获能特性的准确性。在此基础上,构建独立系泊阵列和3种共享系泊阵列,比较其运动响应、系泊张力、获能特性和经济性。结果表明,工作海况下,中心节点式共享阵列Array-3C平均输出功率( P_\textarr )为95.86 kW,较独立系泊阵列Array-3A的P_\textarr (88.16 kW)提高8.73%;其锚点数量由Array-3A的9个减少至6个,系泊缆总长度由909 m减少至567 m。同时,Array-3C阵列年发电量( E_\textarr )为839 733 kWh,高于Array-3A阵列的 E_\textarr (772 306 kWh)。综合阵列运动稳定性、获能性能、经济性和极端海况安全性,Array-3C表现出较优的综合性能,表明合理设计共享系泊构型有助于提升漂浮式OWC阵列的工程应用潜力。

       

      Abstract: To reduce the cost of the mooring system for the floating Oscillating Water Column (OWC) wave energy converter arrays and meanwhile to give considerations to the energy capture performance and the safety under extreme sea conditions, the comprehensive performance of a three-device shared mooring array is investigated by taking a floating cylindrical OWC device as the object. Firstly, a frequency-domain hydrodynamic model is established using AQWA and Fluent is used to identify the PTO damping and the viscous damping, and then the corrected damping parameters are introduced into the OrcaFlex equivalent OWC model. Subsequently, the results from the physical model tests are compared with those from the numerical simulations in order to verify the accuracy of the corrected equivalent model in describing the motion response and energy-capture performance of the floating OWC devices. On the basis of these, an independent mooring array and a three-device shared mooring array are constructed and compared in terms of motion response, mooring tension, energy-capture performance and economical efficiency. The results show that under the operating sea conditions, the average output power P_\textarr of the center-node shared mooring array (Array-3C) reaches to 95.86 kW, whereas that of the independent mooring array (Array-3A) is 88.16 kW, with the former being 8.73% higher than the later. The number of anchor points reduces from 9 in Array 3A to 6 in Array 3C and the total length of the mooring line reduces from 909 m down to 567 m. In addition, the annual energy production E_\textarr of Array-3C reaches 839733 kWh, being higher than that of Array-3A (772306 kWh). From the aspects of motion stability, energy capture performance, economical efficiency and the safety under extreme sea conditions, it can be seen that the Array-3C demonstrates superior over-all properties, indicating that rational design of shared mooring configurations can help enhancing the engineering application potential of floating OWC arrays.

       

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