WEMU性能的數值計算與實驗之研究

Abstract

本研究主要利用計算流體力學模擬可變攻角以及可變襟翼葉片的WEMU(Wind Energy Marine Unit)在水槽中的性能表現，觀察在不同葉片幾何外型以及葉片數目下的性能差異，再針對各種不同類型的葉片所組合而成的葉輪加以分析比較。藉助於CFD計算軟體FLUENT模擬WEMU在固定入流下運轉，計算其性能表現，紊流模型採用Spalart-Allmaras之方程式，計算時在X方向設定入流，並在葉輪轉子區域利用MRF(Moving Reference Frame)法模擬葉輪旋轉，利用給定不同周速比，分別計算出不同葉片組合之葉輪所產生之扭力以及功率；為驗證數值模擬結果，在實驗部分，利用拖車將WEMU實驗裝置在水槽中拖曳，使葉輪轉子旋轉，並且使用扭力計以及轉速計量測出扭力以及轉速之平均輸出，計算與實驗之結果發現葉片數目越多，葉輪所產生的力矩以及功率越大，而葉片襟翼可變形的葉輪比固定式襟翼的葉輪所產生的扭力以及功率較差。

ABSTRACT This study discusses the performance of Wind Turbine Marine Unit (WEMU) with variable pitch angle and deformable flap, as determined by computational fluid dynamics (CFD) and water tank experiment. Different types of rotor with different geometric and blade numbers were compared and analyzed. The CFD software FLUENT was used to simulate the turbine rotating in the flow field. Numerical computation was run using the Spalart-Allmaras turbulence model. The inlet direction was set along the X-axis from negative X to positive X. The moving reference frame (MRF) method was used to simulated the rotation of rotor zone , and different tip speed ratio (TSR) were specified to calculate the torque and power generated from different types of blade rotors. To verify the CFD results, a tow carriage was used to pull the WEMU in the water tank in order to simulate water flow through the turbine. When the turbine started running, the average torque and rotation speed were measured by torque meter and tachometer respectively. The results showed that the higher the blade number set, the greater the torque and power derived. It was also found that the deformation of the flaps resulted in a decrease in torque and power, contrary to what had been expected.