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
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.