【摘要】 为获取激光多普勒流速仪光电倍增管电压、脉冲信号阈值和信噪比等级等系统参数对测量结果的影响,在自循环环形水槽中,采用对比实验,测量了相关系统参数对采样数据率、时均流速和脉动流速的影响程度。实验结果表明:光电倍增管电压在570～630V时脉动流速测量结果相对稳定;较低的脉冲信号阈值能提高采样数据率,实验时应根据采样数据率进行调节;信噪比等级对时均流速和脉动流速无影响,等级为Very Low时能满足水流实验需要。优化激光多普勒流速仪系统参数设置,将提高采样数据率和测量精度。更多还原

【Abstract】 The photomultiplier tubes voltage(PMT),Burst Threshold(BST) and SNR level(SNR) are system parameters of Laser Doppler Velocimetry,which are directly related to the measurement results.In circulating water flume,authors did a lot of comparative experiments,and measured the influence of system parameters to data rate,time average velocity and fluctuating velocity.The experimental results showed: higher and lower PMT will make fluctuating velocity measurement results unstable,it is best to set PMT among 570V to 630V;BST value can be set at a relatively low range,which can improve the data rate,adjusting the BST value could accord to the transformation of the data rate;SNR level can be set to Very Low,which will not affect time average velocity and fluctuating velocity,but can get higher data rate.Optimization of the parameters of Laser Doppler Velocimetry can improve the sampling data rate and accuracy.更多还原