悬停旋翼桨尖涡的试验研究

Investigation of hovering rotor tip vortex

为了详细研究悬停旋翼桨尖涡的形成与发展过程,以及旋翼状态参数与桨尖涡及其尾迹的关系,开展了桨尖涡及其尾迹的测量和研究。在研究中采用了Φ2m旋翼模型试验台、单桨叶(翼型为NACA 0015)旋翼模型和二维PIV测量系统,通过改变转速和总距角的状态组合,对桨尖周围及近尾迹局部区域进行了详细的桨尖涡流场测量。通过研究,基本掌握了用PIV测量旋翼动态流场的技术;利用PIV成功地获取了从桨尖前缘至后缘下游近流场的不同方位角截面粒子流动图像;通过后处理获得了合理有效的结果。测量结果表明,桨尖涡在桨叶表面形成的过程中,其强度逐渐增强;桨尖涡的强度与旋翼的桨尖马赫数和总距等密切相关。

The measurements of hovering blade tip vortex and rotor wake were conducted to investigate the blade tip vortex formation and evolution, and its relationship with the rotor test states. Ф2m rotor model test stand, single-bladed rotor model （airfoil NACA 0015） and 2-D PIV measurement system were applied in the investigation. Detailed flow field measurements were conducted for tip vortex around tip and within near wake local region under various combinations of rotating speed and collective pitch angle. The technique of PIV in rotor dynamic flow field measurements was mastered through the research, and particle flow images of cross sections in azimuth station from tip leading edge to near field downstream of trailing edge were obtained successfully by PIV, delivering reasonable and effective results through post-processing. It is shown from the results of measurements that the vorticity of the tip vortex increases during its formation on the surface of blade and depends tightly on the tip Mach number and collective pitch of the rotor.