This paper investigates the effects of co-flow jet on the aerodynamic performance of some symmetric blade sections of wind turbines. The Reynolds number of 1.3 × 105, angles of attack between 0° and 18° and momentum coefficients of 0.03, 0.05, and 0.08 are considered for four airfoils of NACA 0012, 0015, 0018, and 0021 as the blade sections. To numerically simulate the fluid flow, the Navier-Stokes equations are solved with a transitional turbulence model. The aerodynamic coefficients along with the lift to drag ratio are calculated and the results are compared with together for the baseline and co-flow jet geometries. The results of the baseline airfoils show that the NACA 0012 and NACA 0015 airfoils generate a larger lift at small angles of attack where the NACA 0018 and NACA 0021 airfoils produce a higher lift at larger angles of attack. Furthermore, the obtained results reveal that applying the co-flow jet has a positive effect on delaying the stall angle and increasing the lift coefficient. The aerodynamic coefficients are also more improved by increasing the thickness once the appropriate momentum coefficient is applied. The results also indicate that the momentum coefficient of 0.05 is sufficient for most of the cases.

中文翻译：

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CFJ流量控制对对称NACA翼型气动性能的影响

本文研究了协流射流对风力涡轮机部分对称叶片截面气动性能的影响。NACA 0012、0015、0018和0021的四个翼型作为叶片截面考虑雷诺数为1.3×105，攻角在0°和18°之间，动量系数为0.03、0.05和0.08。为了对流体流动进行数值模拟，使用过渡湍流模型求解 Navier-Stokes 方程。计算空气动力学系数以及升阻比，并将结果与​​基线和协流射流几何形状一起进行比较。基线翼型的结果表明，NACA 0012 和 NACA 0015 翼型在小攻角时产生较大的升力，而 NACA 0018 和 NACA 0021 翼型在较大攻角时产生较高的升力。此外，获得的结果表明，应用协流射流对延迟失速角和增加升力系数具有积极影响。一旦应用了适当的动量系数，通过增加厚度也可以进一步提高空气动力学系数。结果还表明，对于大多数情况，0.05 的动量系数就足够了。