Comparison of axial flow impellers using a laser Doppler anemometer

Abstract

Influence of shapes of eight axial flow impellers on flow in agitated vessels was studied using a laser Doppler anemometer. The tank diameter was 500 mm with a flat bottom and provided with four standard (width = T/10) baffles. In all cases the tank to impeller diameter ratio was 3 and the impellers were centrally located. The flow generated by different axial impellers has been compared in terms of mean velocities, turbulent kinetic energy, pumping effectiveness, and hydraulic efficiency. The measured flow data near the impeller have been presented in the form suitable for specifying the boundary conditions to the numerical model. The two-equation (k-ε) turbulence model has been shown to be adequate for predicting the bulk flow in the case of all impellers.