A Consideration on the Measurement of Particle Sizes by a Non-Contacting Optical Fiber Probe

Abstract

The characteristics of a non-contacting optical fiber probe for measurement of local velocity and size of a moving particle were studied.
A two-dimensional response model was developed in which both the surface reflection light and the secondary one of a spherical particle were accounted for. Then the diffuse line light source model was employed to simulate the projected light.
Basic steric factors were introduced to represent typical particle motions against the probe. As the reflected light intensity was significantly varied due to the steric factors, the standard state for those factors was defined such that the reflected light intensity became the maximum.
The model could well simulate experimental results and gave a correlation to transform the characteristic length into the size of the particle in the standard state.
Bubble sizes were measured by applying this correlation to the responses detected by the probe in the bubble swarm. These results were in good agreement with those obtained by photography.