越頂式波能發電系統水槽試驗研究

Experimental Study of an Overtopping Wave Energy Converter

盧志朋(Chih-Peng Lu)

指導教授 ： 蔡進發

國立臺灣大學/工學院/工程科學及海洋工程學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201701483

摘要

本研究主要進行越頂式波浪發電機的性能評估實驗，配合中山科學研究院提供的原形製作1/25縮尺模型以滿足幾何相似定律、運動相似定律及動力相似定律，於台大船模水槽進行實驗，並參考統計1998-2005年台灣東北海域龍洞浮標資料，由實際浪況作為進行實驗的波浪條件，藉以推估越頂式波浪發電機於實海域時的性能及運動狀態，由實驗結果發現無因次上浪水量流率與Kofoed 提出的越頂水流量經驗公式有所差異，因此本論文採用更多波浪試驗條件求得適用於本論文之越頂波能發電系統的越頂水流量經驗公式。

本研究亦針對越頂式波能發電機之縱搖、起伏量量測求得系統集水平台有無裝水之起伏及縱搖之反應振幅運算子(Response Amplitude Operator RAO)，實驗結果顯示於入射波頻率0.74Hz時為縱搖運動的共振頻率，該頻率之波長為2.85公尺，接近試驗模型之波向長度3公尺。在無上浪時，集水平台有裝水會減低起伏與縱搖運動的反應振幅運算子，但是在有上浪情況時，且入射波頻率大於0.74Hz時起伏與縱搖運動的反應振幅運算子都有增加的趨勢。

針對繫泊力的分析，本研究直接採用試驗期間之最大受力，並採用Chen提出之越頂波浪衝擊力之無因次方法，試驗結果顯示影響繫泊力主要參數為入射波浪波高、週期與上浪斜坡的乾舷。

關鍵字

波能發電 ； 越頂 ； 反應振幅運算子 ； 繫泊力

並列摘要

The purpose of this study is to evaluate the performance of an overtopping wave energy converter by model test. A 1/25 overtopping wave energy model, which was designed by the National Chung-Shan Institute of Science & Technology, was made to conduct the performance test. A series of tests, based on the similarity laws which include geometry, kinematic and dynamic similarity law, were conducted in the towing tank of National Taiwan University. The tested wave conditions were determined from the statistical data of Long-Dong buoy which is located in northeastern Taiwan during 1998 and 2005. The motions and efficiency of the overtopping wave energy converter were evaluated by the selected wave conditions. The test results show that the non-dimensional overtopping flow rate is different from empirical formula developed by Kofoed. More wave conditions were conducted to find the empirical formula for the overtopping wave energy converter.

The motions of the overtopping wave energy converter were studied in this study to get the response amplitude operator(RAO) of pitch and heave of the overtopping wave energy converter. The pitching and heaving of the overtopping wave energy converter with full and empty reservoir were also measured. The measured results show that the resonance frequency of the pitch RAO is about 0.74 Hz. The corresponding wave length is about 2.85 m which is near the length of the wave overtopping energy converter model. The water accumulated in the reservoir reduces the pitch and heave RAO when there is non-overtopping. The overtopping water increase the pitch and heave RAOs when the wave frequency is greater than the resonance frequency 0.74 Hz.

The maximum value of the measured mooring force in the duration of a test was chosen for the analysis of the mooring force. The scheme of the wave impact loading on buildings and structures, which was developed by Chen. was utilized to analyze the mooring force of the system. The results show the mooring force majorly determined by the incident wave height, wave period and the freeboard of the system.

並列關鍵字

Wave energy converter ； Overtopping ； Response Amplitude Operator (RAO) ； Mooring force

參考文獻

[2] X. Chen, "Hydrodynamic loads on buildings caused by overtopping waves," 2011.

[3] A. Muetze and J. Vining, "Ocean wave energy conversion-a survey," in Industry Applications Conference, 2006. 41st IAS Annual Meeting. Conference Record of the 2006 IEEE, 2006, pp. 1410-1417.

[4] A. Nielsen and J. P. Kofoed, "The Wave Dragon: evaluation of a wave energy converter," 1997.

[5] D. Vicinanza, L. Margheritini, J. P. Kofoed, and M. Buccino, "The SSG wave energy converter: Performance, status and recent developments," Energies, vol. 5, pp. 193-226, 2012.

[13] J. Van der Meer, "Technical report wave run-up and wave overtopping at dikes," Rijkswaterstaat, DWW2002.