升阻混合风轮的性能规律

Performance of lift-drag combined wind turbine rotor

为了研究由升力型与阻力型风轮构成升阻混合立轴风轮的部分性能规律,建立了旋转直径900 mm、高度900 mm的混合风轮数理模型,应用SST k-ω湍流模型模拟分析两种风轮的半径比、高度比对混合风轮性能的影响规律,并比较了混合风轮和纯升力风轮的性能.结果证明:阻力型风轮增大了混合风轮的力矩,对下游0°转角附近的升力叶片产生了负面影响,且当阻力风轮与升力型风轮半径比为0.3、高度比为0.5时,混合风轮的性能达最佳为0.32;在低转速范围内,组合风轮具有更高的风能利用系数;在高转速范围内,阻力风轮产生的阻尼作用效果逐渐增强,混合风轮与纯升力风轮的性能相近甚至不及.建立相同尺寸的塑料物模进行了风洞试验,采用力矩仪对模型力矩和转速进行了测试,试验结果与模拟结果的对比显示,试验测量最高效率低于模拟值0.02,误差属于允许范围之内,证明SST k-ω湍流模型对混合风轮流场计算值具有适用性.

In order to get partial performance of lift-drag combined wind turbine,such a turbine rotor with 900 mm height and 900 mm diameter was simulated using the SST k-ω turbulence model.Effects of the diameter and height ratios on the performance of the lift-and drag-type rotors were analyzed,and the power coefficients were compared between the combined rotor and the pure lift-type one.The results showed that the drag rotor increases the torque of the combined rotor but decreases the torque of the lift rotor at 0° rotation angle downstream.When the diameter ratio is 0.3 and the height ratio is 0.5,the combined rotor gets a maximum power coefficient of 0.32.In lower speed the performance of combined rotor is obviously better than that of pure lift rotor,while in high speed the former is same as or even worse than the latter.In order to verify the precise of model data,a plastic wind rotor with same scales as the simulation model was tested in a wind tunnel and the torque and speed were measured by a torque dectetor. The results showed the predicted efficiency is higher than the experimental data by 2% only.The error is so small that the SST k-ω model can be used to analyze the flow field of a combined wind turbine.