频率调制多普勒全场测速实验系统测试

频率调制多普勒全场测速技术是一种基于分子滤波和多普勒频移现象的流场速度测量方法,在高速、超高速及大尺度风洞流场测量方面潜力巨大.我们设计开发了采用CCD相机作为接收探头的FM-DGV实验系统,该系统主要包括激光器、片光光学系统、碘分子滤波器、图像采集相机、频率监测单元等.基于该系统进行了谐波幅值比和转盘线速度测试实验.实验结果表明,该实验系统工作正常,速度测量误差最大值小于2m/s.

Test on a frequency modulation Doppler global velocimetry system

Frequency modulation Doppler global velocimetry(DGV),which was based on molecular/atomic filter principle and laser Doppler shift phenomenon,had great potential use in the cases of high supersonic speed and large scale wind tunnels.We developed an FM-DGV system,of which a CCD camera was used as the detector to receive the scattering light.The system was made up of a narrow band laser,a light-sheet-forming optics,an iodine cell,an image acquisition CCD camera,and a frequency monitor unit.Based on this system,measurement was carried out on the ratio of amplitudes of the first and second harmonics,and on the velocity distribution of a rotating wheel.The results showed that the system is stable with the maximum velocity measurement error less than 2 m/s.