No abstract

Knowledge of the fluid dynamic characteristics in a stirred vessel is essential for reliable design and scale-up of a mixing system. In this paper, 3D hydrodynamics in a vessel agitated by a Rushton turbine were numerically studied (with the help of a CFD computer program (CFX 13.0)). The study was carried out covering a wide Reynolds number range: 10 4 -10 5 . Computations, based on control volume method, were made using the k-ε model. Our main purpose was to investigate the effect of vessel configuration and agitation rates on the flow structure and power consumption. Three types of vessels were used: unbaffled, baffled and a vessel with slots placed at the external perimeter of its vertical wall. The effect of slot length has been investigated. The comparison of our predicted results with available experimental data shows a satisfactory agreement.

No abstract

The energy efficiency of a deep hollow blade disk turbine in unbaffled mixing vessel is determined in this article via numerical simulations. The vessel is filled with xanthan gum solutions, which have a shear thinning behavior with yield stress (viscoplastic). The Herschel-Bulkley law is used to model the fluid behavior. Three-dimensional calculations are achieved by the computer tool CFX (version 16.0), and the computational domain is meshed using the software ICEM CFD (version 16.0). Mixing is achieved at low impeller rotational speeds which correspond to the laminar and transitional flow regimes. Our main purpose is to explore the effect of blade size (width and height), Reynolds number, and fluid properties on the mixing efficiency of deep hollow bladed impellers. A validation test of our predicted results with experimental data of a previous study was done, and it has shown a good agreement.

No abstract