On hydraulic efficiency of pitched blade impellers

Hydraulic Design and Power Characterization of Closed Turbine-Type Agitator

Designs of impeller as an agitator with alteration and modification of a conventional turbine type impeller were proposed to improve the power characteristics and to provide a favorable efficiency. For development of the turbine type impeller, a concept of the alterative design was for the impeller blades to transmit fully energy. This impeller has shrouds structurally and was named “closed impeller”. For baffled vessels agitated by the closed impellers, the internal liquid flow as well as the bulk liquid flow were examined to be analyzed for energy consideration. The closed impeller being modified, its internal flow was observed to be appreciably smooth along the blade surfaces. In evaluation in terms of hydraulic and energetic efficiencies indicating the phenomenon in the impeller swept region and that in the rest, respectively, the closed impellers were demonstrated to have improved power characteristics as an increased transmission and consequent uniformized dissipation.