油輪單點繫泊之柔性立管配置設計分析

DESIGN ANALYSIS OF FLEXIBLE RISER CONFIGURATION FOR SINGLE POINT BUOY MOORED TANKER

單點繫泊系統常作為海外卸油設施，其中又以懸垂式錨泊最為常見，在海外卸油通常也伴隨風險，由於海外卸油不似港口內平穩，若在風浪較大時有漏油事件發生，將對生態造成浩劫，故本研究透過數值方法，探討應用於單點繫泊系統中柔性立管之安全性。研究主要使用Orcaflex進行數值模擬，分析單點繫泊系統繫泊油輪，在不同方向風波流耦合作用下，對柔性立管的曲率以及張力影響，再由動態與靜態分析結果，進而計算動力放大因子（dynamicamplification factor，DAF），評估緩波型（lazy wave）及陡波型（steep wave）兩條不同配置之柔性立管是否適用於高雄港外海海域。從研究結果顯示，兩種配置之柔性立管在作業極限的環境條件下，張力與曲率尚在安全範圍內，惟陡波型立管配置於高雄港外海作業環境條件下可有更好的適應能力。

The single point mooring system is often used as an oil transport facility, and the most common type is catenary anchor leg mooring (CALM) system. Offshore loading or offloading liquid products is usually accompanied by risks. If oil spill happens, it will cause environmental pollution. Therefore, this study discusses the safety of the flexible riser applied in the single point mooring system. The study uses Orcaflex for numerical simulation by consideration of the effect of wind, wave, and current in different directions. Two different configurations of flexible risers were compared, including of lazy wave and steep wave. Firstly, conducting static and dynamic analysis, and then the dynamic amplification factor (DAF) was investigated from the results of static and dynamic analysis. From the obtained result, it showed that both the lazy wave and steep wave configuration the risers are safe under operating conditions. However, under the ocean environmental loadings the steep wave riser is better suited to the application in Kaohsiung harbor.