使用半潛式臺大浮台之15 MW浮式風機系統於新竹外海場址正常運轉性能研究

Abstract

本研究預測在新竹外海海氣象條件下，使用半潛式臺大浮台、IEA 15-MW離岸風機以及3×2型式繫纜系統的浮式風機系統之正常運轉性能。本研究以Ansys Aqwa及STAR-CCM+預測水動力特性，以OrcaFlex預測浮式風機系統的繫纜受力及風機氣動力並求解運動方程式以獲得運動響應及風機功率。假設波向與風向相同，本研究考慮七個風向及四個流向的組合，預測在新竹外海一般及高波兩種波況下，浮式風機系統運動響應、風機功率和繫纜受力的平均值及標準差，並討論非黏性流和黏性流模擬方法對預測浮式風機系統性能的影響。模擬結果顯示，在起伏、橫搖及縱搖運動中，黏性對於水動力特性的影響較大。本研究結果顯示，當風機系統主纜繩與臺灣海峽最常見的東北風向夾角為0°時，在一般及高波波況下平均功率約為14 MW及15 MW，最大平均纜繩受力為1.643 MN及1.254 MN，此時風機系統之正常運轉性能相對較佳。

This study predicts the normal operating performance of a 15 MW floating wind turbine system equipped with a semi-submersible TaidaFloat platform, an IEA 15-MW offshore wind turbine and a 3×2 mooring design under the metocean conditions of the Hsinchu offshore area in the Taiwan Strait. The potential component of hydrodynamic properties is calculated by Ansys Aqwa, and the viscous component of hydrodynamic properties is obtained with the help of STAR-CCM+. The motion equations are solved by OrcaFlex to obtain the motion response and generator power, as well as the dynamic response of the mooring system and the aerodynamic loading of the wind turbine. Assuming that the wave has the same direction as the wind, this study compares the mean value and standard deviation of the motion response, generator power and mooring line tension between potential and viscous flow approaches by considering the combinations of seven wind directions and four current directions under the common wave and high wave condition in the Hsinchu offshore area. The numerical prediction shows that the viscous effect has a large impact on the hydrodynamic properties in the heave, roll and pitch motions. The angle between the leading mooring line of the system and the dominant wind direction in the Taiwan Strait, which is coming from the northeast, is recommended to be 0°, with the largest mean generator power of around 14 MW and 15 MW, and the maximum mean mooring line tension of 1.643 MN and 1.254 MN under the CW and HW condition, respectively, in order to deliver a relatively favorable performance of the system.