Investigation of impeller design and flow structures in mechanical stirring of molten aluminum.

This study investigated the flow characteristics of aluminum melt agitated by differently shaped impellers. A typical impeller used in the aluminum industry has twisted blades. The present study examined the effect of twisting angle on the flow pattern through PIV experiments and numerical simulation using water model. The results revealed that the twisting angle affects the strength and direction of discharge flow. The strength of discharge flow became weaker with increasing the twisting angle while the flow direction was influenced by both the front blade surface of impeller and space interval between the adjacent blades. The structure of trailing vortices was found to be also varied depending on the impeller twisting angle. [ABSTRACT FROM AUTHOR]