Volume of Cavity Formed behind Blade of Turbine Impeller in Aerated Agitated Vessel with Highly Viscous Newtonian Liquid

Abstract

An experimental study has been carried out on the volume of the cavities formed behind pitched-blades of turbine impeller in an aerated agitated vessel with highly viscous Newtonian liquid. Some kinds of pitched-blade turbines with different diameters and inclination-angles are used to examine the effects of impeller configuration and operating conditions on the total volume of the stable cavities remaining behind the blades even after stopping aeration. The experimental results are provided for each type of impeller and discussed with the consideration on the forces acting on the cavity. A balance equation is proposed for the forces, such as buoyant force, inertia force caused by axial flow, and force arising from dynamic pressure. The balance equation results in the correlation equations for each stable cavity volume in the laminar or turbulent flow region, respectively.