| 摘要 |
PROBLEM TO BE SOLVED: To greatly damp roaring or draining noises of a fan blade of a heat radiation fan device for a home electric fan, an industrial blower or electric equipment or a propeller of an oceanographic research vessel and a submarine. SOLUTION: The best angle of advance or sweepback of the fan blade or the propeller near its end in the rotating direction is set to be 45°to a normal line, which is a nonconventional great angle of advance or sweepback. The angle of advance or sweepback of the blade at its front and rear edges is gradually changed in a range of 45-90°to greatly damp the roaring or draining noises. COPYRIGHT: (C)2004,JPO&NCIPI
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