Impeller wheel and centrifugal compressor having impeller wheel
An impeller wheel according to an embodiment includes a hub, a plurality of long blades disposed on a circumferential surface of the hub, the plurality of long blades extending from an inlet portion to an outlet portion of fluid and a plurality of short blades each disposed on the circumferential surface of the hub, the plurality of short blades extending from a downstream side of leading edges of the plurality of the long blades to the outlet portion in a flow passage formed between adjacent long blades of the plurality of long blades. In the impeller wheel, an expression β 2s,full <β 2s,spl is satisfied, where β 2s,full and β 2s,spl are respectively blade angles on tip side edges of the plurality of long blades and the plurality of short blades at the outlet portion.
1. An impeller wheel comprising:
a hub;
a plurality of long blades disposed on a circumferential surface of the hub, the plurality of long blades extending from an inlet portion to an outlet portion of fluid; and
a plurality of short blades each disposed on the circumferential surface of the hub, the plurality of short blades extending from a downstream side of leading edges of the plurality of the long blades to the outlet portion in a flow passage formed between adjacent long blades of the plurality of long blades,
wherein an expression β 2s,full <β 2s,spl is satisfied, where β 2s,full and β 2s,spl are respectively blade angles on tip side edges of each long blade and each short blade at the outlet portion.
2. The impeller wheel according to claim 1 ,
wherein an expression β 2s,spl −β 2s,full ≥5° is satisfied.
3. The impeller wheel according to claim 1 ,
wherein an expression β s,full <β s,spl is satisfied over an entire length of each short blade,
where β s,full and β s,spl are respectively blade angles on the tip side edges of each long blade and the short blade at the same position when the impeller wheel is viewed from a meridian plane direction.
4. The impeller wheel according to claim 1 , wherein an expression β 2h,spl −β 2h,full ≥5° is satisfied where β 2h,full and β 2h,spl are respectively blade angles on hub side edges of each long blade and each short blade at the outlet portion.
5. The impeller wheel according to claim 4 ,
wherein an expression β s,spl,m=mLE −β s,full,m=mLE ≥5° is satisfied, where β s,full,m=mLE and β s,spl,m=mLE are respectively blade angles on the tip side edges of each long blade and each short blade at a position of a leading edge of the short blade when the impeller wheel is viewed from a meridian plane direction.
6. The impeller wheel according to claim 5 ,
wherein the leading edge of each short blade includes a first portion and a second portion positioned radially outward from the first portion, and
wherein an expression θ 1 >θ 2 is satisfied, where θ 1 is an acute angle between a direction in which the first portion extends and a rotational axis of the impeller wheel when viewed from a meridian plane, and θ 2 is an acute angle between a direction in which the second portion extends and the rotational axis of the impeller wheel when viewed from the meridian plane.
7. The impeller wheel according to claim 4 ,
wherein an expression β h,full,m=mLE >β h,spl,m=mLE is satisfied, where β h,full,m=mLE and β h,spl,m=mLE are respectively blade angles on the hub side edges of each long blade and each short blade at a position of a leading edge of the short blade when the impeller wheel is viewed from a meridian plane direction.
8. A centrifugal compressor comprising:
the impeller wheel according to claim 1 .