风力机尾流场及相互作用的实验研究

Experimental Study on the Wake Field and Interaction of Wind Turbines

运用压差式精密风速仪对风力机尾流场及相互作用进行测量研究。对于单台风力机,测量其后不同距离处的尾流场轴向速度;对于两台风力机,测量下游风力机(第二台风力机)后不同距离处的尾流场轴向速度,由于下游风力机置于上游风力机(第一台风力机)尾流场中,尾流在向下扩展的过程中相互叠加影响,使得下游风力机尾流场变化更复杂。试验结果表明:由于风轮旋转和来流衰减,使得单台风力机后尾迹区存在速度亏损,尾迹区速度亏损随着风轮下游轴向距离的增加逐渐减弱,且轴向速度和轴向诱导速度在水平方向上表现出较强的对称性。由于风轮旋转时叶尖涡脱落,在距测量中心较远处出现高速度区域。当下游风力机置于上游风力机尾流场时,下游风力机的尾迹区内速度亏损更严重,由于上游风力机尾流的不稳定延伸,尾流叠加,轴向速度和轴向诱导速度出现明显的波动现象,且随着两风力机距离及下游风力机后轴向距离的增加,上游风力机对下游风力机的影响逐渐减弱。

The wake field and interaction of wind turbines are measured by pressure gradient precision anemometer in this paper. For a single wind turbine,the axial velocity of the wake at different distance is measured; for two wind turbines,the axial velocity of wake at different distance after downstream wind turbine( the second wind turbine) is measured. Due to the situation that the downstream wind turbine is located in the wake field of upstream wind turbine( the first wind turbine),the trailing is superimposed in the process of wake downward expansion,and the changes of downstream wind turbine wake field are more complex. The experiment results show that the single wind turbine wake region has speed loss due to the wind wheel rotation and flow attenuation,and the speed loss of wake is decreased gradually with the axial distance increasing of downstream wind turbine. The axial velocity and axial induced velocity show a strong symmetry in the horizontal direction,and there are high velocity regions further away from the center of the measurement because of the shedding of tip vortex when wind turbine blade rotating. The velocity loss in the wake of the downstream wind turbine is more serious when the downstream turbine located in the wake field of upstream wind turbine. Due to the instability extension of upstream wind turbine wake,wake superposition,and the fluctuation phenomenon of axial velocity and axial induced velocity is obvious. Also,the influence of upstream wind turbine on the downstream wind turbine is gradually weakened with the increase of distance between two wind turbines and axial distance of the downstream wind turbine.