Search results for "Chicane"
showing 3 items of 3 documents
Numerical simulations of the dependency of flow pattern on impeller clearance in stirred vessels
2001
The flow and turbulence fields in a fully baffled vessel stirred by a Rushton turbine have been simulated by means of computational fluid dynamics (CFD) techniques. The simulation techniques adopted (the "Sliding-grid" and "Inner-outer" methods) are fully predictive and require no experimental data as boundary or initial conditions. The effect of clearance (C) on the flow patterns in stirred vessels was simulated as the flow field transition observed can be considered a particularly stringent benchmark for the testing of CFD techniques. The results are compared with previously obtained LDA data and show that the double- to single-loop transition experimentally observed when impeller clearan…
Particle suspension in top-covered unbaffled tanks
2010
Abstract Unbaffled stirred tanks are seldom employed in the process industry as they are considered poorer mixers than baffled vessels. However, they may be expected to provide significant advantages in a wide range of applications (e.g. crystallization, food and pharmaceutical processes, etc.), where the presence of baffles is often undesirable. In the present work solid–liquid suspension in an unbaffled stirred tank is investigated. The tank was equipped with a top-cover in order to avoid vortex formation. A novel experimental method (the “steady cone radius method”, SCRM) is proposed to determine experimentally the minimum impeller speed at which solids are completely suspended. Experime…
An experimental study of double-to-single-loop transition in stirred vessels
1999
The velocity characteristics of the flows in a fully baffled vessel of diameter T = 290 mm stirred by a Rushton impeller of diameter D = T/3 were investigated by means of laser-Doppler anemometry measurements. The effects of clearance and rotational speed on the flow patterns in the vessel were studied. It was found that at impeller clearances from the bottom of the vessel (C) around 0.2 T the characteristic double-loop flow pattern undergoes a transition to a single-loop one with the impeller stream direction becoming partly axial and being inclined at around 25 to 30° to the horizontal. The impeller stream inclination varied with radial distance from the impeller, as well as with angular …