空调器室外机轴流风机内部流动的PIV研究

采用粒子图像测速仪PIV，对具有半管道式结构特点的空调器室外机轴流风机内部流场进行了实验研究，并结合实验结果分析了叶片顶部的叶尖涡和叶片出口尾缘涡的流动特性。实验结果显示在轴流风机流道内部叶顶区域存在与叶轮旋转方向相反的叶尖涡结构。叶尖涡产生于叶片前缘叶顶近吸力面侧，在流道内部与主流发生干涉后朝向周向和出口传播并逐渐耗散。叶尖涡涡心轨迹与叶顶弦长方向的夹角为10°，在叶高方向上叶尖涡的径向位置并不固定。与普通管道内部流动不同，叶片顶部与导风罩间的间隙中未捕捉到明显的叶顶泄漏涡现象。叶片出口近尾缘处30％以上叶高明显捕捉到尾缘涡结构，叶片压力面和吸力面侧的径向速度存在明显的方向变化，切向速度在尾迹区增加。

PIV measurement of axial fan internal flows inside outdoor units of air-conditioner

Flow field inside flow passage of partly ducted axial flow fan in outdoor units were researched by particle imaging velocimetry （PIV） and flow characters of blade tip vortex and trailing edge vortex were analyzed. It is shown that blade tip vortex inside flow passage of axial flow fan can be found with rotation opposite to rotor. This blade tip vortex comes of tip suction side at blade leading edge, after interacting with main flow it develops along circumferential and downstream direction, and gradually dissipates. Trail of blade tip vortex core has an angle of 10 degree with the blade tip chord and its radial position is not constant along spanwise direction. It is different from common ducted fan that blade leakage vortex is not captured in the experiment. At downstream of rotor trailing edge, vortex can be seen over 30% spanwise of blade with apparent reverse of radial velocity from blade pressure side to suction side and high increase of tangential velocity in wake area.