LDV管道测速实验折射率问题分析

通过分析管壁壁厚、折射率和测量流体折射率对激光多普勒测速实验测量精确性的影响发现 ,圆管内测量体的位置比管壁厚趋于 0时的位置靠近轴心。管壁材料的折射率越大 ,测量体的位置与管壁厚趋时位移差也越大。在管内流体中测量体的步进距离与激光发射探头的步进距离呈线性关系。对减小折射率影响的几种措施进行了总结 ,并且提出了未采用折射率补偿时测量点坐标修正或在实验前正确布置测量点坐标的方法。该分析对实验具有指导意义

Study on techniques in LDV pipe velocity measurement

The effect of pipe thickness, refractive and the fluid refractive index on measurement accuracy in the Laser Doppler Velocimetry experiments was analyzed.It is discovered that the position of the measurement volume is nearer to the center in the pipes than that in the pipes whose thickness is zero. If the refractive index is larger, the translocation difference of the measurement volume is larger. The ratio of step distance of the measurement volume in the pipe fluid to that of the laser transmit probe is linear. Several methods to reduce the influence of the refractive index are also summed. If refractive index compensation is not adopted, the coordinate of measurement positions have to be revised, otherwise it would be lay out correctly before the measurement. The analysis is of directive value in experiments.