直线翼垂直轴风力机静态流场数值模拟与可视化试验

Numerical simulation and visualization of static flow field of straight blade vertical axis wind turbine

为研究翼型对直线翼垂直轴风力机启动特性的影响,选取了厚度相似的正装非对称翼型S809与通用对称翼型NACA0018进行两叶片垂直轴风力机的对比研究.首先,运用数值模拟的手段得到采用2种翼型风力机的周期静态力矩曲线,取得二者力矩差异较大的特定方位角,并且进一步获得特定方位角下的涡量图和矢量图.然后通过可视化试验得到叶片周围流场矢量图,并将其用来验证模拟结果的准确性.继而结合涡量图和矢量图,对2种风力机叶片周围的旋涡和流动变化情况进行分析.计算结果表明:2种翼型的力矩曲线随方位角变化规律一致,NACA0018翼型的启动性要好于正装S809翼型;叶片尾流的旋涡使流场变得不稳定,造成能量损失;2种翼型叶片尾流均有不同程度的旋涡产生,使流场变得不稳定,相比NACA0018翼型,正装S809翼型叶片后部的剪切流动更强,产生的旋涡更近,对叶片启动性的影响也更大.

For studying the influence of airfoils on the start-up characteristics of vertical axis wind turbines,a asymmetric airfoil named S809 and a symmetrical airfoil named NACA0018 were chosen as blades.Firstly,the static torque was obtained by numerical simulation,and the azimuth angle with obvious difference was obtained,and the vorticity and vector diagram were obtained.visualization experiment was used to verify simulation results.Combining with them,the flow field were analyzed.The results show that NACA0018 airfoil has better start-up performance than obverse-installed S809 airfoil.The vortex of blade wake flow makes the flow field unstable and causes energy loss.The wake flow of both airfoils generates vortices with varying degrees,making the flow be complex.Compared with NACA0018 airfoil,the shear flow at the back of the obverse-installed S809 airfoil is stronger,and the vortices are closer,thus influence is more significant.