Study on Aerodynamic Performance Characteristics of Horizontal Axis Wind Turbine under Combined Inflow Condition

本研究旨在通过数值方法研究包括极端风速、阵风等极端风况和普通风况（湍流特性、风切变等）在内的组合入流条件对水平轴风力机（HAWT）转子气动性能特性的影响。由此建立了一套从气动角度估算风力发电系统发电功率和寿命的方法。针对入流条件的建模及其对温度的影响，在此期间进行了以下工作。-利用统计方法，从气象桅杆上多个点的风速测量时间序列中提取出阵风的时空形态，并与一些理论模型进行比较。-采用上述理论模型和基于加速度势法的载荷计算模型，数值研究了阵风对HAWT转子的气动影响。本文对HAWT动叶的流固耦合振动进行了数值研究。-在计算中，涡轮叶片采用多体动力学模型表示，并在NREL的风洞实验模型中考察了入流偏航不对中对耦合振动的影响。通过与实验的比较，该计算模型可以准确地估计出叶片扑翼振荡的第一和第二共振频率。-对于动叶的扑翼振荡，发现由于叶片振荡对叶片的相对风速的波动，存在气动阻尼力效应。此外，还对风力发电机的气动噪声特性和发电特性进行了实验研究。

This study aims at examining the effects of combined inflow condition that includes extreme wind condition such as extreme wind speed and wind gust, and ordinary wind condition (turbulent characteristics, wind shear, etc.) on the aerodynamic performance characteristics of the horizontal axis wind turbine (HAWT) rotors, by using numerical methods, which leads to establish a procedure to estimate the generating power of WTGS (Wind Turbine Generator System) and its life time from the aerodynamic point of view.Concerning about the modeling of the inflow condition and their effects on the HAWTs, following works has been done during the period.- By using statistical method, temporal and spatial gust shapes were extracted from the time series of measured wind speed at multiple points on the meteorological masts and are compared with some theoretical models.- The aerodynamic effects of the wind gust on the HAWT rotors are examined numerically by using the preceding theoretical models and the load calculation model based on acceleration potential method.Some numerical studies on fluid-construction coupled vibration of the HAWT rotor blades have been done as follows.- In the calculation, the turbine blade is represented by a multi-body dynamic model, and the effects of the inflow yaw misalignment on the coupled vibration have been examined for the wind tunnel experimental model at NREL. From comparison with the experiments, the first and second resonant frequencies for the flapwise oscillation of the blades can be estimated correctly by the present calculation model.- For the flapwise oscillation of the rotor blades, an aerodynamic damping force effects have been found to exist due to the fluctuation of the relative wind speed to the blade by the blade oscillation.Moreover, studies on aerodynamic noise characteristics and power generation for field wind turbines have been performed experimentally.