| 摘要 |
PURPOSE: An axial flow fan is provided to reduce vortex generated at an end of a blade by reducing resistance at the end of the blade, while reducing noise and loss of efficiency by reducing the vortex generated from the pressure surface toward the negative pressure surface. CONSTITUTION: An axial flow fan comprises a hub(10), and blades radially arranged around the outer peripheral surface of the hub. Each of blades has a blade tip(230) forming an outer periphery of the blade; a leading edge(210) connecting an end of the blade tip and the hub; a trailing edge(220) connecting the other end of the blade tip and the hub; and a streamlined protrusion(250) having a thickness formed linearly, in radial and axial directions, from the intermediate portion of the blade tip toward a front end(240) of the blade. The length(l) of the outer periphery of the streamlined protrusion from the front end toward the intermediate portion of the blade tip, is shorter than 50 percent of the chord(c) of the blade. The front end of the blade is extended and protruded from the leading edge of the blade, in such a manner that the front end of the blade does not contact the trailing edge of the blade. The length of the extension is shorter than 30 percent of the total length of the outer periphery of the streamlined protrusion.
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