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在直流式低速风洞中,应用PIV系统对水平轴风力机的中心尾迹区进行测试,揭示了在不同风速及不同尖速比下,气流通过风轮时叶片中央尾迹区流场的运动规律。通过实验发现,风经过风轮后,由于动量损失和涡流诱导效应,风轮中心尾迹区内部流场速度减小,外部流场轴向速度增加,在风轮机舱处形成强速度梯度区域。随着方位角的增大,中心涡的轴向传播距离逐渐减小。随着中心尾迹的延伸,中心涡的运动轨迹逐渐扩散,即径向位移是逐渐增加的,且涡量逐渐减小。中心涡在中心尾迹区的径向影响范围大约为风轮直径的0.42倍,轴向影响范围大约为风轮直径的0.58倍。
In the DC low speed wind tunnel, the PIV system was used to test the wake region of the horizontal axis wind turbine. The flow field of the wake in the center of the blade was revealed when the airflow passed the rotor at different speeds and speeds. The experimental results show that the velocity of the flow field in the wake area of the rotor reduces and the axial velocity of the external flow field increases due to the loss of momentum and the induced effect of vortices. After the wind passes through the rotor, the velocity gradient is formed in the wind turbine nacelle. With the increase of azimuth angle, the axial propagation distance of central vortex decreases gradually. With the extension of the center trail, the motion trajectory of the central vortex is gradually diffused, that is, the radial displacement is gradually increased and the vorticity is gradually decreased. The radial extent of the central vortex in the wake region is approximately 0.42 times the diameter of the rotor and the axial influence is about 0.58 times the diameter of the rotor.