Despite the fact that the complete dispersion characteristics in agitated gas-liquid contactors are operationally important, the flooding-loading transition is widely used as a design criterion, due to its experimental convenience and accuracy. Moreover, limited data are available in the literature on the interrelation of the flooding-loading and the loading-complete dispersion transitions, although several investigators have worked on these two transition stages. Thus, knowledge of the interrelation between these two stages would be of theoretical and practical importance. In this work, the dependence of the stirrer speed at complete dispersion, n CD , on the stirrer speed at flooding, n F , was experimentally studied, in coalescing and non-coalescing systems, using Rushton turbines of two different diameters. The experimental results, having an accuracy of < 5 %, are given in the form of a dimensionless correlation.
In gas-liquid agitated vessels the flooding stage is generally used as a design criterion. The flooding stage is a characteristic dispersion stage which must be avoided in order to achieve efficient dispersion characteristics, while the identification of this flooding-loading transition helps also determining the complete dispersion stage. Several methods have been applied for the determination of the floodingloading transition point. In this work, the light transmission method is used as a new technique for identification of this point in an air-water dispersion system, agitated by a single six-blade disc turbine. Using a relatively simple instrumentation, satisfactory results have been obtained. The method suggested is reliable, does not interfere with the fluid dynamics of the system, and is also applicable to nontransparent industrial reactors.
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