CPC F04D 29/284 (2013.01) [F04D 17/10 (2013.01); F04D 29/30 (2013.01); F01D 5/048 (2013.01); F01D 5/141 (2013.01); F05D 2240/303 (2013.01); F05D 2240/304 (2013.01); F05D 2250/70 (2013.01)] | 6 Claims |
1. An impeller, comprising:
a disk-shaped hub centered on an axis; and
a plurality of blades arranged in a circumferential direction and protruding from a surface of the hub facing one side in a direction of the axis,
wherein, in a cross-sectional view including a blade height direction which is a direction away from the hub toward a tip of each blade, the blade has a recessed surface curved convexly toward a rear side in a rotational direction,
wherein, in the cross-sectional view, when a distance between an imaginary line connecting a tip-side edge and a hub-side edge of the blade and a midspan of the blade along a direction perpendicular to the imaginary line is defined as a recess amount,
the blade has a portion where the recess amount increases from a leading edge side to a trailing edge side, and
wherein, in a position of the trailing edge of the blade, a blade angle at the midspan is smaller than a blade angle on the hub side and a blade angle on the tip side.
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