엇회전식 축류팬의 3차원 비정상 유동에 관한 실험적 연구

Abstract

Experiments were done for the three dimensional unsteady flow in a counter-rotating axial flow fan under peak efficiency operating condition Flow fields In a counter rotating axial flow fan were measured at cross-sectional planes of the upstream and downstream of each rotor Cross sectional flow patterns were Investigated through the acquired data by the 45° inclined hot-wire Flow characteristics such as tip vortex, secondary flow and tip leakage flow were confirmed through axial, radial and tangential velocity vector plot. It has been found that the radial and tangential velocity components disappeared, while the axial Velocity component highly Increased as soon as the tip vortex was generated It has been observed that secondary flow and turbulence intensity which were Increased by the front rotor were dissipated passing through the rear rotor As the result the energy loss of the counter rotating axial flow fan decreased at the downstream of rear rotor<br/> Also, It has been verified that tip vortex pattern of the rear rotor was dampened because the tip vortex generated by front rotor was mixed with that of the rear rotor<br/>