| 摘要 |
PROBLEM TO BE SOLVED: To improve fan performance and reduce noise in a centrifugal multiblade fan having multiple blades disposed around a rotary shaft. SOLUTION: The centrifugal multiblade fan has the multiple blades 13 disposed around the rotary shaft 12, sucks air into radial inside from an axial one end side of the rotary shaft 12, and blows off the air to radial outside. A front edge 22 of the blades 13 takes the form of an acute angle with a curvature radius of 0.2 mm or less. Thereby, air flow can be surely peeled off at the front edge 22, and a peeling point and a readhesion point can be prevented from changing, so that the flow between the blades 13 can be prevented from becoming unstable. Compared with a case where the front end is smoothly curved, the peeling point and the readhesion point can be positioned in air flow upstream, the distance capable of straightening the flow between the blades 13 of a rear end 25 side increases, so that air flow blown from between the blade 13 can be prevented from becoming unstable. As a result, the fan efficiencyηcan be improved, and noise can be reduced. COPYRIGHT: (C)2008,JPO&INPIT
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