Impeller, centrifugal compressor, and refrigeration cycle apparatus

Abstract

An impeller according to the present disclosure includes a hub and wings. Each of the wings has a leading edge portion and a body portion. The leading edge portion is positioned on an upper surface side of the hub. The body portion is positioned on a lower surface side of the hub. A tip of the leading edge portion and a tip of the body portion extend from the upper surface side of the hub toward the lower surface side of the hub on a side opposite to a side where the wing is in contact with the hub. In a plan view of the wing seen from a radial direction perpendicular to an axis of the impeller, a profile of the tip of the leading edge portion has a linear shape and a profile of the tip of the body portion has a curved shape.

What is claimed is: 
     
         1 . An impeller for a centrifugal compressor comprising:
 a hub that has an upper surface, a lower surface, and an outer surface; and   wings that are fixed to the hub and that are arranged radially around the outer surface of the hub, wherein   a wing has a leading edge portion and a body portion, the wing being each of the wings, the leading edge portion being positioned on an upper surface side of the hub, the body portion being positioned on a lower surface side of the hub, the leading edge portion including a leading edge,   a tip of the leading edge portion and a tip of the body portion extend from the upper surface side of the hub toward the lower surface side of the hub on a side opposite to a side where the wing is fixed to the hub, and   in a plan view of the wing seen from a radial direction perpendicular to an axis of the impeller, a profile of the tip of the leading edge portion has a linear shape and a profile of the tip of the body portion has a curved shape.   
     
     
         2 . The impeller according to  claim 1 ,
 wherein each of the wings has a pressure surface and a suction surface,   in the plan view of the wing seen from the radial direction, the profile of the tip of the leading edge portion includes a first upstream portion on a pressure surface side and a second upstream portion on a suction surface side, and the first upstream portion and the second upstream portion have a linear shape, and   in the plan view of the wing seen from the radial direction, the profile of the tip of the body portion includes a first downstream portion on the pressure surface side and a second downstream portion on the suction surface side, and the first downstream portion and the second downstream portion have a curved shape.   
     
     
         3 . The impeller according to  claim 1 ,
 wherein, in a case where a total length of each of the wings in an axial direction parallel to the axis of the impeller is defined as a meridional plane length in a projection view of a meridional plane that is obtained in a manner in which the wing is rotationally projected on the meridional plane containing the axis of the impeller, the leading edge portion occupies a portion of the wing extending from the leading edge to a position 5% of the meridional plane length away from the leading edge in the axial direction in the projection view of the meridional plane.   
     
     
         4 . The impeller according to  claim 1 ,
 wherein the wings form respective main wings of the impeller,   the impeller further includes sub wings, and   each of the sub wings is disposed between the main wings that are adjacent to one another in a circumferential direction of the impeller.   
     
     
         5 . The impeller according to  claim 1 ,
 wherein a ratio of a radius of the hub to a radius of each of the wings ranges from 0.6 to 0.7 at the leading edge of the wing.   
     
     
         6 . A centrifugal compressor comprising:
 the impeller according to  claim 1 ; and   a shroud wall accommodating the impeller.   
     
     
         7 . A refrigeration cycle apparatus comprising:
 the centrifugal compressor according to  claim 6 ,   wherein a material whose saturated vapor pressure is a negative pressure at a normal temperature is used as a refrigerant.   
     
     
         8 . The refrigeration cycle apparatus according to  claim 7 ,
 wherein the material contains water.