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采用PIV测量方法,对不同雷诺数下球形颗粒的尾流特性进行了研究.实验中颗粒是10mm的不锈钢球,距壁面高度G/D=0、0.25、0.5和1.0,Rep=900、2500和5000,气相示踪粒子为峰值粒径2.5μm的雾化液滴.通过对实验得到的瞬态速度场进行分析,得到时均流线图和速度场.结果表明,G/D=0时,整体涡脱落强度明显减小,颗粒下部的漩涡脱落完全被抑制,在颗粒尾部形成一个顺时针回流区,大小约为颗粒尺寸的1.5倍.0.25≤G/D≤0.5时,壁面的存在使得颗粒尾流结构出现了不对称,呈一定的角度向上倾斜.随着颗粒与壁面距离的增加,壁面对颗粒尾流的影响减弱,在颗粒后缘会出现一对回流区,上方呈顺时针旋转,而下方呈逆时针,且回流区的长度先减小后增大.“,”The characteristics of sphere particle wake in a horizontal channel flow was experimentally investigated under different Reynolds numbers, using particle image velocimetry (PIV). A steel ball of size with 10mm in diameter was used as particle and atomized droplets with peak at about 2.5μm were used as ghost particle. Experiments were performed at Rep=900, 2500, 5000. Time-averaged velocity vectors, patterns of streamlines and vorticity were examined from the point of flow physics for different sphere locations in the range of 0≤G/D≤1.0 where G was the space between the bottom point of the sphere and wall. It was found that for the case of the sphere touching the wall atG/D=0, a large circulation region formed and covered whole the wake flow region, which size was about 1.5 times of particle diameter. At the gap ratios ofG/D=0.25 and 0.5, there is a tendency of the wake to move upward and the two recirculation regions become asymmetric about the sphere centerline. As the gap increased to a value of G/D=1.0, the effect of the wall become weaker dramatically and the asymmetry of streamline decreased. With increasing the gap ratio, the length of the recirculation zone decreased firstly, and then increased.