周向弯曲方向对弯掠叶片气动-声学性能影响的实验

Experimental study on aerodynamic and aero-acoustic performance of low pressure axial flow fan with circumferential skewed blades

以具有相同几何参数的常规径向叶片、周向前弯和周向后弯叶片为研究对象,对旋转动叶片周向弯曲后叶轮的气动和声学性能进行了对比试验研究。同时采用五孔探针半对向测量方法研究了周向弯曲后出口气流参数沿叶高的分布规律。结果表明,与原型径向叶轮相比,在保持叶片几何参数不变,仅引入周向弯曲后,无论周向前弯还是后弯,均导致叶轮的效率和压升降低。叶片周向前弯可以有效地降低气动噪声,大幅度地增加风扇的喘振裕度。在相同的周向弯曲角度下,采用周向前弯技术明显优于周向后弯。此外,研究表明弯掠叶片径向力对于气流参数沿叶高的分布具有较大的影响。周向前弯叶轮改善了叶顶附近的流动状况,但中部叶高区域的损失增加。对于周向后弯叶轮,虽然叶片中部损失减小,但两端部损失增加明显。

Low pressure axial flow fan with circumferential skewed rotors was studied. The rotors include the traditional radial rotor, the forward-skewed rotor and the backward-skewed rotor. In present study,aerodynamic and aeroacoustic performance of these three type rotors was measured and analyzed. The results show that the forward-skewed rotor may reduce noise effectively and extend the range of steady operation compared to the radial rotor. With the same skew angle, both the aerodynamic and aeroacoustic performance of forward-skewed rotor is better than that of the backward-skewed one. The performance difference comes from the direction of blade radial force. The tip flow condition of forward-skewed rotor is better, but the mid-span losses are increased.