Experimental investigation of dilute solid-liquid suspension in an unbaffled stirred vessels by a novel pulsed laser based image analysis technique

The availability of experimental information on solid distribution inside stirred tanks is a topic of great importance in several industrial applications. The measurement of solid particle distribution in turbulent multiphase flow is not simple and the development of suitable measurement techniques is still in progress. In this work a novel non-intrusive technique for measuring particle concentration fields in solid-liquid systems is employed. The technique makes use of a laser sheet, a high sensitivity digital camera for image acquisition and a Matlab procedure for post-processing the acquired images. Experimental data are here obtained for the case of an unbaffled stirred tank. Stable toroidal attractors for particles are observed under given circumstances. Their existence, consistency and extension depends on particle type, fluid properties, tank geometry and impeller velocity.