The Research Of Laser Doppler Liquid Flow Rate Measurement

Liquid flow rate measurement in the industry has a lot of practical applications. Among various flow rate measurement methods, Laser Doppler Velocimetry is the most important one.Flow rate measurement system consists of optics and electronics. The optical system often uses dual beam-dual scattering configuration. Electronics system includes a preamplifier, an active high-pass filter, a signal sampling unit and a narrowband digital filtering and signal processing units.This thesis introduces the background and current status of Laser Doppler Velocimetry technology, and also describes its advantages and prospects. Then the basic principles of flow rate measurement and system configuration are introduced. A liquid flow rate measurement system is then designed. Liquid(water) flow rate was measured in a home-made system in the lab. In order to get the final velocity, the Fast Fourier Transform method was used to calculate the Doppler shift. Finally, a visualization interface for data processing tasks was designed by using MATLAB.