Abstract: The LDA measurement results of double correlation of the separated flow in a U bend duct rotating around a axis parallel with the bend axis is discussed.The measurement is made in the symmetry plane perpendicular to the rotating axis with Re =100,000,and Ro =0,0.2,or 0.2 respectively.The components of double correlation directly measured are u 2 x , u 2 z and u xu z ,The results show that rotation has strong influence on turbulence distrbution pattern.Among the three rotating cases.positive rotation with Ro =0.2 has lowest and negative rotation has strongest turbulence intensity.Based on the measured information the generation rate of Reynolds stress u iu j is estimated,the results show that negative rotation has higher generation rate than positive rotation.

Key words: Turbulent flow;Rotating fluid;Reynolds stress;Flow velocity measurement;Laser Doppler velocimeter

摘要： 为了深入了解旋转涡轮叶片内冷通道中的紊流特性 ,并为CFD研究提供实验数据 ,用激光多普勒测速仪 (LDA)测量了旋转U型通道中分离流的雷诺应力分量。通道的转轴与弯道的曲率轴平行 ,测量是在与转轴垂直的对称平面中进行的 ,流动状态为Re=10 0 ,0 0 0 ,Ro =0 ,0 2和 - 0 2。直接测量的分量为u2 x,u2 z和uxuz,结果表明旋转对紊流分布的形式有很强的影响。在测量的三种旋转状态中Ro =0 2的正转和Ro =0 2的负转分别具有最低和最高的紊流强度。根据测量到的信息估算了雷诺应力uiuj的产生率 ,结果显示负转的产生率比正转时高

关键词: 湍流;旋转流体;雷诺应力;流速测量;激光多普勒速度计