应用LDV研究二元管道内分离流动

APPLICATION OF LDV IN INVESTIGATION ON SEPARATING FLOW IN A 2-D CHANNEL

关键词:  湍流  分离流  附面层  激光测速仪  扩压器

Key words:  Turbulent flow  Separating flow  Boundary layer  Laser Doppler velocimeter  Diffuser

摘要:

应用二维激光多普勒仪测量了二元曲壁非对称扩张通道内的湍流附面层分离流动。得到了时均速度、雷诺应力、平均流动方向角及正反向间歇流动因子的分布。文中给出了所测结果的不确定度,并在激光测速的近壁测量上做了尝试。实验结果分析表明:间歇瞬时分离点对应于附面层内垂直压强梯度的最大值;Schofield的速度尺度和长度尺度可用于形成新的速度相似型;正反向间歇流动因子γpuo与平均流动方向角存在着简单的线性关系。

Abstract:

The separating flow in a turbulent boundary layer was surveyed in a 2-D curved-wall diffuser by employing 2-D laser Doppler vel-ometer. Mean velocities, Reynolds stresses, mean flow angles and upstr-eam-downstream intermittencies were obtained. The error analysis of experimental results was also made and the uncertainty are presented, experimental results showed that, the intermittent instantameous detachment occurs at the point with the maximum of the normal pressure gradient in the boundary layer. Schofields velocity scale and length scale are adapted to form a new velocity similarity. Mean flow angles are linearly related to the up-stream-downstream intermittencies.