A simple method has been developed to track the three-dimensional motion of a small particle convected in a stirred tank for about 1 h. Different flow patterns induced by a Rushton or a pitched blade turbine have been studied. The results have been compared with known results obtained by conventional techniques. Several tools which have been proposed for this purpose give rise to new insights and interpretation of transport and mixing processes in stirred tanks for engineering applications.On a mis au point une mCthode simple pour suivre le dtplacement tridimensionnel d'une petite particule dans un rCservoir agitC pendant environ 1 heure. DiffCrents profils d'tcoulement induits par une turbine Rushton ou h pales inclinkes sont CtudiCs. Les rksultats sont comparCs avec des rtsultats connus obtenus par des techniques traditionnelles. Plusieurs outils proposCs h cette fin permettent de mieux comprendre et interprtter les procCdts de transport et de mClange dans les rCservoirs agitCs pour des applications d'ingenierie. The RTD approach is easy to handle in open systems and allows to detect hydrodynamic problems such as short-cut flows or dead flow zones. The information provided by the RTD is however not sufficient because the technique considers the vessel as a black-box system and does not provide a description of the internal flows. It is not adapted to provide understanding and characterization of the interactions of multi-feed and multi-outlet flows and this is a strong limitation of the method. Furthermore, RTD may suggest different flow-models which can represent the same RTD but whose structures can be very different. 'Author to whom correspondence may be addressed. E-mail address: falh@en~ic.u-nancy.frThe first of these two approaches supplies a great amount of data which is, however, not easily applied and the second approach provides information which is condensed in a tractable -but not always adequate -way. The idea of trajectography, which consists of following the long-trajectory of a fluid particle tracer, is to provide an intermediate technique which can describe internal flows in a vessel together with giving condensed and tractable information on macromixing processes for engineers who have to make the link between hydrodynamics and mixing or chemical reactor performance. The concept is not totally new as several authors have characterized internal flow performance by trajectography. Rubinovitch and Mann (1983) studied the flow in inter-connected volumes, representing the movement of particles by a Markow chain. Information on the probability of visiting a volume and total residence time in the specific volumes could be given. The approach developed by Rubinovitch and Mann was, however very conceptual and has not been applied to real systems such as stirred vessels.Several tracking techniques, often 2 dimensional, have been developed to characterize hydrodynamics (Pervez and Solomon, 1994). PIV is a widely used technique for the measurement of velocity and vorticity fields in fine scale resolution,...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.