A comparative analysis concerning the influence of different factors on momentum transfer in mechanically agitated systems was carried out on the basis of experimental results for solid-liquid, gas-liquid and gas-solid-liquid systems. The effects of the impeller - baffles system geometry, scale of the agitated vessel, type and number of impellers and their off-bottom clearance, as well as physical properties of the multiphase systems on the critical impeller speeds needed to produce suspension or dispersion, power consumption and gas hold-up were analysed and evaluated.
The aim of the research presented in this paper was determination of power consumption and gas hold-up in mechanically agitated aerated aqueous low concentration sucrose solutions. Experimental studies were conducted in a vessel of diameter 0.634 m equipped with high-speed impellers (Rushton turbine, Smith turbine or A 315). The following operating parameters were changed: volumetric gas flow rate (expressed by superficial gas velocity), impeller speed, sucrose concentration and type of impeller. Based on the experiments results, impellers with a modified shape of blades, e.g. CD 6 or A 315, could be recommended for such gas-liquid systems. Power consumption was measured using strain gauge method. The results of gas holdup measurements have been approximated by an empirical relationship containing dimensionless numbers (Eq. (2)).