Research Of The Photonic Doppler Velocimetry System For Two-dementional Velocity Measurment

Photonic Doppler Velocimetry System (PDV) is a velocimeter diagnostic tool based on optical fiber interferometer and it has been widely used in measurement field due to the advantages of compact structure, high resolution and strong anti- jamming capability. Currently, multipoint photonic doppler velocimeter for remote moving objects has already been developed. Nevertheless, PDV has an important limitation that it could only detect the velocity along the axial direction of the probe. As the deviation from the axial direction is aggravated, the measurement error increases.To this end, experimental study on this problem is carried out in this paper. First of all, we presented an overview of Laser Doppler Velocimeters (LDVs) and introduced some typical cases of LDVs as well as techniques of two-dimensional velocity measurement. Then we proposed a two-demensional velocity measurment system based on the traditional phtonic doppler velocimeter.Above all,we assembled a LD laser with good performance after fabricating the peripheral circuits. With the the self-made laser, Phtonic Doppler Velocimeters with single probe and dual probes were established, respectively. Then the completed systems were used to detect the velocity of vibration exciter in different moving directions, and the velocity was obtained by demodulating doppler shift using the fringe method. The final experimental results showed that the measured velocity detected by singal probe was the axial component of velocity and the velocity we measured using the dual probes PDV system is consistent with the actual velocity of the vibration exciter, which means that our dual probe PDV system works well.