Application Of Laser Doppler In The Measure Of Scattering By A Particle

Based on Doppler Effect of moving particle, Laser phase Doppler anemometry technique (PDA) can be used to measure particle's property information and velocity of flow. PDA has been widely employed in many fields such as hydromechanics, aerodynamics, metallurgy, chemical industry, environmental protection and so on.In this dissertation, based on Mie's scattering theory, the scattering intensity, the scattering power and the Doppler frequency have been gained. The three models, such as reference light pattern, dual-beam pattern and dual-scattering pattern, of measure circuitry for LDA and PDA have been presented. The scattering intensity and the scattering power of the fringe patterns scattered by the particle in two models of plane LDA have been studied and computed in relation with the particle's moving velocity, size, and relative retraction index simultaneously.In addition, based on GLMT's scattering theory and LDA theory, the scattering intensity, the scattering power and the Doppler bandwidth of the fringe patterns scattered by the particle from the parameters of PDA signal in PDA have been acquired. Based on the stationary phase theory of physical optics, the influence of spherical particle's shape on PDA signal's phase and the phase difference have been analyzed. And, the scattering properties of the particle with different shape parameters have been simulated respectively in the modes of reflection and refraction. Moreover, some kinds of particle have been measured and computed by PDA, such as water globelet, oil globelet, glass and three kinds of known blood corpuscle. The influence of spherical particle's moving velocity, size, and relative retraction index simultaneously on PDA signal's scattering power and phase have been analyzed. The scattering signals in PDA computed simultaneously in relation with the particle's moving velocity, size, and relative retraction index simultaneously have been approved.