| 摘要 |
PROBLEM TO BE SOLVED: To achieve uniform pressure distribution in a circumferential direction by disposing a diffuser defined by a pair of opposite wall faces on an outer peripheral side of an impeller, and forming a projection or recess in order to change a passage area of the diffuser on at least one of the wall faces. SOLUTION: In a centrifugal compressor, a diffuser 1 encloses an impeller 2 from the outside in a radial direction, and is defined by a pair of opposite wall faces 5, 6 formed of a compressor housing 3 and a back plate 4. The wall faces 5, 6 are parallel to each other, have a predetermined length along the radial direction, and forms a ring-like passage continued in a circumferential direction. A projection 17 is formed at the wall face 5 (shroud side wall face) forward in an axial direction from a positionθ1 slightly upstream of a positionθ0 of a tongue 13 to a positionθ2 downstream at a predetermined angle of the positionθ0 of the tongue 13, thereby reducing a passage area of the diffuser 1. Consequently, the air can uniformly flow in the circumferential direction, thus enhancing compressing efficiency.
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