A study on particle size distribution measuring method for floating particles in the upward air flow with its velocity equal to their terminal velocity

We have examined the particle size measuring method in which flour particles are floated into the airflow at a test section with its upward velocity equal to their terminal velocity. As a result, it was verified that the terminal velocity was experimentally related to the size of floating particle, and that it made possible to obtain spherically equivalent diameter of the floating particle by an elliptical approximation of the image. We further applied this floating method to measure particle size distribution as a simpler way in which the floating particles were counted in number according to the various upward velocities.