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Proceedings Paper

Particle Size And Velocity Measurement On Flows Of Transparent Or Non Transparent Spherical Particles By Laser-Doppler-Anemometry; Problems Of Practical Application
Author(s): K. Bauckhage; U. Fritsching; J. Heuermann; G. Schulte
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Paper Abstract

In many applications of fluid atomization there is a high demand for point or overall measured data of size and flux of the liquid or solidified drops. For a few years the phase-Doppler-method (LDVS) besides of the Visibility/Intensity-method has proofed out as a very useful instrument for the analysis of such spray situations. In spite of the well known velocity measurement of particles by laser-Doppler-anemometry the particle sizing by this method is more complex and asks for both a more sophisticated electronic signal processing and above all a knowledge of the optical character of the particles under observation. The paper shows the influence of the light scattering character of different spherical particles on the necessary evaluation of Phase-Doppler data. After a brief description of the Phase-Doppler-method including the basic physical principles it will be shown the Phase difference dependency of doppler bursts on different photodetector positions on one hand and on the refraction index and particle size on the other. For both transparent and non transparent particles there will be compared the results of the complex Mie light scattering calculations with simplified geometrical based calculations and experiments to find out detection angles which give unambiguous particle size informations and in addition allow an experimental arrangement as simple as possible. The results show that in many cases where particles are not totally transparent a back-scatter-arrangement of the photodetectors should be possible. Although the requirement of particle's sphericity may restrict the applicability of the phase-Doppler-laser-anemometry we should confirm that very often in multiphase flow systems the dispersed particles are drops or bubbles or if solid have a spherical shape. In the latter case we only need a sufficient smoothness of particle surface. The experimental results presented here are obtained from very different fluids ranging from water to molten metal.

Paper Details

Date Published: 16 January 1988
Proc. SPIE 0952, Laser Technologies in Industry, (16 January 1988); doi: 10.1117/12.968875
Show Author Affiliations
K. Bauckhage, University of Bremen (Germany)
U. Fritsching, University of Bremen (Germany)
J. Heuermann, University of Bremen (Germany)
G. Schulte, University of Bremen (Germany)

Published in SPIE Proceedings Vol. 0952:
Laser Technologies in Industry
Silverio P. Almeida; Luis Miguel Bernardo; Oliverio D.D. Soares, Editor(s)

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