| 摘要 |
A fan arrangement has a rotatable fan, a plurality of blades formed on the fan, and a shroud. The blades extend radially and are spaced circumferentially. The blades also extend perpendicularly to the radial direction. The base angle of each blade is set at a value of 55 DEG to 75 DEG . The shroud is located on the periphery of the fan so as to cover a part of the fan in such a manner that the fan is partially exposed at its downstream part and a clearance is formed therebetween. The covering percentage of the shroud relative to the fan is set at a value of 50% to 90%. The covering percentage is defined as 100xL2/L1, where L1 is the axial width of the outer edge of each blade and L2 is the axial distance of the shroud from the downstream end thereof to a point in the same axial position as the upstream end of the outer edge of each blade.
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