Research On Fluid Laser Doppler Velocimeter

Laser Doppler velocimetry(LDV) occupies an important position in the laser field. As a new technology, in terms of measuring the velocity of the fluid and solid, it has many advan tages.In this paper, by building a laser Doppler tachymeter, three different semiconductor lasers are designed as light source, and a dual-beam laser Doppler velocimetry for fluid is developed. Firstly, this paper describes the laser Doppler velocimetry technique and introduces the dual-beam Doppler technology and fringes models. Then, this paper compares Prism's spectroscopic property with grating's and use gratings to split light. Photo detector and amplifier circuit matching with the system are selected. Besides that, the optical system is designed. By analyzing Doppler signals, interference fringes and different methods of Doppler signals processing, this paper use fast fourier transform(FFT) by MATLAB to process the Doppler signals.Finally, laser Doppler velocimetry system is proved feasible to measure fluid particle ve locity,which is prepared for further research.