At WCPT3 (1998), we proposed a new centrifugal classification that employs an almost rigidly rotating through-flow produced as a perfectly laminar flow within a highly rotating double-walled classifier. The flow consists of Stewartson and Ekman layers well known in geophysics. The classifier can accurately classify not only micron but also submicron feed-particles, suspended in water at a low mass-concentration, into coarse and fine products by the difference in the centrifugal force and fluid drag exerting each particle due to the difference in particle size because the classifier can increase the centrifugal force arbitrarily without turbulent mixture and well manage the force and drag (WCPT4 2002). At WCCE7 (2005), we extended the classification to that with high throughput (five times) by replacing water, added at an inlet, with the feed suspension and by changing methods for collecting products classified. In the present study, we have proposed new accurate and multiple-product classifiers, and have verified by numerically simulating the flow (using Navier-Stokes and continuity equations) and the particle trajectory (Basset-Bousinesq-Oseen equation) that the new classifiers work well by devising water supply to prevent fine particles from entering a coarse product and by providing multiple collection regions without making classification performance so worse.

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