SIMULTANEOUS MEASUREMENT OF VELOCITY AND EQUIVALENT DIAMETER OF PARTICLES WITH ARBITRARY SHAPE

Authors
Citation
U. Terhaag et U. Renz, SIMULTANEOUS MEASUREMENT OF VELOCITY AND EQUIVALENT DIAMETER OF PARTICLES WITH ARBITRARY SHAPE, Particle & particle systems characterization, 13(2), 1996, pp. 150-155
Citations number
14
Categorie Soggetti
Materials Science, Characterization & Testing","Engineering, Chemical
ISSN journal
09340866
Volume
13
Issue
2
Year of publication
1996
Pages
150 - 155
Database
ISI
SICI code
0934-0866(1996)13:2<150:SMOVAE>2.0.ZU;2-J
Abstract
Only a few optical techniques are available to measure simultaneously the velocity and size of coarse particles dispersed in a fluid. Since particles are randomly shaped with a rough surface and inhomogeneous w ith respect to the refractive index, phase-based sizing techniques are not reliable. The applied optical sizing technique is based on light intensity measurement of a scattering particle crossing a top-hat lase r beam. This optical set-up was first described by Grehan et al. In th e range of geometrical optics, the sampled light at the receiving syst em is proportional to the square of the equivalent particle diameter w ithin the diameter range 20-700 mu m. Velocity information is obtained by using a smaller concentric laser Doppler probe volume. Coincidence of the signals is guaranteed by the optical set-up, since the smaller probe volume diameter defines the triggering event. To demonstrate th e performance of the system, some diameter distributions measured with the top-hat beam system are compared with results for a commercial la ser diffraction system for different materials. The system is applied to obtain size-correlated velocity information of a particle-laden two -phase flow at a single-sided backward-facing step.