Effect of Pre-Swirling Flow on Performance and Flow Fields in Semi-Opened Axial Fan

In this study, we tried to improve the performance by giving a pre-swirling flow radial inflow that occurred in semi-opened axial fan. addition, fields of rotor outlet were clarified experimentally, and effect was considered. The experiment carried out using test wind tunnel with square cross section 880 mm. Three types casings prepared, which blade tip protruded 0%, 20%, 40% meridional chord length. They called R25, R15, R05, respectively, casing bellmouth model code. Guide blades for generating installed on vertical wall surface casing. 60% upstream length as an obstacle prevent inflow. velocity measured hot-wire anemometer. From results, did not significantly affect fan performance. When there no obstacles upstream, partial increase efficiency, but difference so large. efficiency increased overall case only low rate region, conversely decreased high region. By observing when improved, it confirmed influence leakage vortex weakened.