الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Annular reactors are by far the most common and are considered the most appropriate for industrial wastewater treatment. Despite their potential success and applications, mass - transfer limitations could be an issue in these reactors depending on the kinetics, operating conditions, and the geometrical properties of the system. Hence, when modeling these reactors, an accurate prediction of fluid flow and thus, local mass transfer is needed. Nowadays Computational fluid dynamics, as a simulation technique finds extensive usage in basic and applied research, and in design of engineering equipment. This research has focused on applying CFD for modeling single - phase liquid fluid flow and mass transfer phenomena in annular reactors. CFD allows for an in - depth analysis of the fluid mechanics, and local mass transfer, thereby offering the possibility of achieving an improved performance, a better reliability, and a more confident scale - up of the equipment.
The aim of this work was to carry out a comprehensive CFD study in which simulation results were evaluated with available measurements of external mass transfer in annular reactors reported in the literature. Also the current study provides a better understanding of the design factors that affects the rate of mass transfer in annular reactors.
The CFD predicted mass transfer data obtained from this work were performed under various hydrodynamic conditions using the laminar flow model, the standard k - £ model and the low Reynolds number k - £ turbulence models, and they showed good agreement with those from other reported investigations where similar annular configurations were used. The simulations performed revealed the following results:
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The surface mass transfer taking place near the entrance region of the reactor is much higher than that happening in the rest of the reactor volume. Therefore inlet sections of annular reactors play an important role in the reactor hydrodynamics and consequently on its mass transfer performance. For that reason, these sections should be included in the annular reactor model.
The annulus diameter ratio was proved to have an important impact on the performance of the annular reactor. It is proved that when the difference between the annulus inlet and outlet diameters decreases, the surface area - to -volume ratio increase, which has a significant influence on the external mass transfer and increases the efficiency of the annular reactor.
As the inlet spacing between the inlet port of the reactor and the inner tube rounded front decreases, the mass transfer coefficient increases.