Study on Flow Near the Impeller Outlet of a Winnowing Fan : 3rd Report, Observations on the Static Pressure Contour Near to Impellers and the Particles Flow Near to Delivery and Suction Ports

This study aimed at clarifying unsteady flow near the delivery port of winnowing fans using CFD technology, the commercially available flow analysis software FLUENT/UNS, and the visualization software AVS. Both standard impellers and forward-inclined impellers were studied for comparison purposes. The results of this investigation demonstrate that forward-inclined impellers have better performance in terms of producing uniform flow. They develop many points where the static pressure is low, and from where large and unstable three-dimensional vortexes are produced. It was also demonstrated that a characteristic of winnowing fans is that they produce a balance between the swirling now after the suction port and that after the delivery port. This means that the flow after the impeller can be made uniform within a short distance.