襟翼对垂直轴风力机性能影响的数值模拟

Influence of Various Flaps on Performance of Vertical Axis Wind Turbines

采用能够模拟风力机转子与定子间相互作用的滑移网格技术对NACA0015三叶片直翼式垂直轴风力机进行了二维非定常数值模拟,在此基础上对翼型上、下表面分别加装高度为2%翼型弦长的不同形式襟翼,对4种襟翼改型进行了转矩系数和功率系数的研究并与原型进行了对比.结果表明:NACA0015三叶片直翼式垂直轴风力机在尖速比为3.5时达到最大输出功率;内侧格尼襟翼比原型的输出功率最大可提高约4%;流线型襟翼对降低风力机的运行阻力起到一定作用;当尖速比提高到4以后,由于风力机的运行阻力大幅度增加,叶片加装襟翼反而会降低垂直风力机的功率.

Taking the NACA0015 airfoil as an object of study, numerical simulation has been carried out on 2D unsteady flow of three-straight-blade vertical axis wind turbine based on moving meshes capable of sim- ulating the interaction between rotor and stator. On this basis, various flaps were added respectively to the upper and lower surface of the airfoil, with a flap height being 2 % chord length of the blade. Four modi- fied airfoils with newly added flaps were studied and compared with the original NACA0015 one on torque and power coefficient. Results show that for the original NACA0015 three-straight-blade vertical axis wind turbine, the maximum power output appears at a tip-speed ratio of 3.5~ the power output of airfoil with inside flap （Gurney flap） can be increased by 4~ at the maximum compared to the prototype. Streamlined flap plays a role in reducing flow resistance of wind turbine. However, the power output of wind turbine with flaps may reduce once the tip-speed ratio gets up to 4 due to great increase of operation resistance.