The effect of impeller type and shear rate on the evolution of floc size and structure during shear-induced flocculation of polystyrene particles with aluminum sulfate is investigated by image analysis. One radial flow (six-blade Rushton turbine) and two axial flow (three-blade fluid foil, four-blade 45° pitch) impeller configurations are examined. The steady state average floc size is show...

The paper presents experimental evidence for the potentials of CFD methodology in revealing external flow and inner flow shear deformation rates in stirred tanks. Two basic issues are considered: could CFD produce valid solutions for shear rates in mixing vessels, and could practical shear rate differences relevant to specific impeller designs be reproduced by CFD. In a first part, the shear ra...

This study involves CFD simulation of blood flow through a non-pulsatile, axial pump consisting of a complex multisectioned impeller with rotating and stationary components, and a stationary housing. We use a particlebased method, Smoothed Particle Hydrodynamics (SPH), to investigate the effects of varying the impeller blade pitch angle and the gap size between the rotor and housing. Regions of...

Flow in baffled stirred vessels involve interactions between flow around rotating impeller blades and stationary baffles. When more than one impeller is used, which is quite common in practice, the flow complexity is greatly increased, especially when there is an interaction between the multiple impellers. The extent of interaction depends on relative distances between the impellers and clearan...

In a gas-liquid stirred reactor, gas tends to accumulate in low-pressure regions behind the impeller blades. Such gas accumulation forming so-called gas cavities, significantly alters impeller performance characteristics. We have computationally investigated gas-liquid flow generated by a Rushton turbine. Rotating Rushton turbine generates trailing vortices behind the blades, which enhance the ...

The impeller blades are very important and precise parts in turbine, but they can be worn and deformed easily. In this paper, we present a novel approach to detect the shape of the impeller blades. The proposed approach is to compare the designed 3D model of the impeller blades with the virtual 3D model of the tested part which is reconstructed by non-contact coordinate measuring machine. The n...

The object of this work was to evaluate the capability of numerical simulation to predict different features of non-Newtonian fluid mixing process. A relatively simple impeller (six bladed vane rotor) was used for the mixing of carboxymethyl cellulose. A LDA method was used to measure the tangential velocity at two points inside the mixing vessel. Using visualization, a significant vortex above...

The aim of this paper is to introduce numerical procedures to calculate the flow parameters in the bladed space of a cylindrically bladed radial-flow fan-impeller. The characteristics of the flow belonging to different duty points of the fan were determined by the numerical procedure. In this calculation, the blade effects as well as the effects of the fluid friction and the turbulence were tak...

Abstract Flotation performance is influenced by many hydrodynamic variables, such as impeller speed, airflow rate, and cell geometry. These variables’ effects interactions remain unsatisfactorily explored, especially concerning scaling-up procedures. As an innovative approach, this study considered factorial-designed experiments to explore the of factors (impeller tip speed superficial gas velo...