An Experimental Study on Flow Structures near the Impeller Blades in a Mixing Vessel

Abstract

Turbulent flow fields around two impellers, a standard four flat paddle-type impeller and the same type impeller with a hole at each blade, were investigated using by LDV. Mixing Reynolds number was 1.2×(10)^5. Power number was also measured with torque meter. Mixing vessel used was a closed cylindrical tank of 490mm diameter with a flat bottom and four vertical baffles. It can be found from the results that power number of the modified impeller was 8% lower than standard impeller, but total discharge flow rates were almost the same.