1709 Internal Flow Patterns of an Axial Flow Fan Having Improved Stalling Characteristics Achieved by an Air Separator
Details
An air separator employing radial scooping vanes applied on an axial flow fan has demonstrated a significant stall improvement effect in the former report. Changes in the internal flow patterns in the fan in the presence of the air separator device were experimentally investigated. The air separator-applied condition tended to create tip-peaky distributions of axial velocity distributions, compared with those for the solid-wall conditions. It suggests a resulting inclination of meridional streamlines through the rotor blades toward the blade tip region. The change in the behavior was continuous and consistent over the whole flow range. The effects have been achieved only by a very small amount of recirculation flow, as small as 0.4 % of the main flow, within the air separator passage for the practically important working flow range of the fan including the zone originally stalled for the solid wall condition.
