| 摘要 |
<p>PURPOSE: To prevent separation of an air flow, and restrict turbulence in a confluent flow in the condition of high air way resistance wherein speed increase of an axially discharged air flow from a pressure surface side trailing edge of a blade generates a large circulation vortex at a suction side leading part of the blade, separates an air flow along a negative pressure surface by a suction, turbulent air flow, enlarge turbulence when the pressure surface side air flow is confluent with the negative pressure surface side one at the trailing edge, deteriorate blowing performance of an impeller, and increase generated turbulence sound. CONSTITUTION: A recessed part (air flow direction changing means) 8b extended to be close to the trailing edge of the blade 8 at one end is provided on the side of a pressure surface 5 of the blade 8, and a protruded part 8a (air flow adhering means) is provided at a trailing edge part of the blade 8. An air flow of a large radial speed component passing the impeller 9 is converted into an axial direction by the recessed part 8b to increase air flow speed in the axial direction, and separation of the negative surface side air flow is restricted by the protruded part 8a. Turbulence when the air flow on the negative surface side is confluent with the air flow on the pressure surface side can thus be restricted, thereby deterioration of blowing performance of the impeller and increase of blowing noise can be restricted.</p> |
