PIV Measurement and CFD Simulation of Turbulent Flow Fields Stirred by Novel Combined Inner-Outer Agitator

The PIV and CFD technique were adopted to investigate the turbulent flow fields in stirred vessels with novel combined inner-outer agitator.The velocity fields and turbulent kinetic energy stirred by the combined inner-outer agitator with different rotating speed ratios were analyzed.Results show that,in the turbulent flow regime,the introduction of outer agitator leads to the slight change of the velocity fields.The combined inner-outer agitator could enhance the turbulent level in stirred vessels,especially in the regions near the vessel wall and bottom,and the region located at mid-height of the two pitched paddles.The lower speed ratio could be beneficial to the rapid mixing of fluids.