20kW級浮游式黑潮發電渦輪機流體動力分析

Abstract

為開發黑潮發電以擷取可觀之海洋再生能源，如何將水下浮游式海流渦輪機組錨繫於深水海底而能穩定浮游並發電，並能有效控制其位置以供維修或避險，將成為這項技術最大的挑戰之一。為能控制浮游式海流渦輪機於設定水深，並於必要時能浮出水面或深潛，其系統外觀將如一般水下載具，包含壓艙水控制功能之翼形浮體(Foil Float)、直柱(Vertical Support)、橫樑(Cross Beam)、內藏直驅式永磁發電機的機艙(Nacelle)、平軸左右對轉轉子葉片(Rotor Blades)等元件組成；此外藉由纜與錨所構成的錨繫系統將之固定於海底。本研究在於探討浮游式海流渦輪機在不同流速及相對應轉速下所受之升阻力，再搭配繫纜程式模擬海流渦輪機在水下的位置，而海流渦輪機之流體動力計算是應用CFD軟體ANSYS-FLUENT進行。本研究以海流流速0.25m/s~2.0m/s時，以額定輸出20kW為目標之機組系統為例進行探討，且一機組是由左右配置而對轉的葉片所組成，由此機組去探討在不同流速及轉速下所受之升阻力及繫纜張力。

In responds to the growing needs of energy and the drive to develop renewable power nowadays, we are dedicating to develop the Floating Kuroshio Turbine (FKT), which is a device used to extract energy from Kuroshio Current. In order to apply this technique to practical application, how to anchor the floating marine current turbine and run steadily under the deep water seabed, and how to efficiently control its position for maintenance and risk avoidance are going to be the biggest challenges. The system appearance is similar to a regular underwater vehicle which composed of a Foil Float that has ballasting water control, Vertical Supports, Cross Beams, Nacelles that each has a direct-drive permanent magnet generator inside, and Rotor Blades. In the present study, we take a turbine set composed of counter rotating twin rotors that has rated power output of 20kW as an example to discuss. The ocean current speed is between 0.25m/s and 2.0m/s. We mainly discuss the corresponding lift and drag when the floating marine current turbine encounter different current speed and blades rpm; plus, collocating with mooring cable program to simulate the underwater position of the turbine. The CFD software, ANSYS-FLUENT, is adopted to deal with the hydrodynamic calculation of the turbine.