Abstract: A centrifugal compressor includes: an upstream side squeeze portion having a flow passage cross-sectional area that decreases as the upstream side squeeze portion extends closer to a compressor impeller; a partition wall facing the inner circumferential surface of the upstream side squeeze portion and arranged with a gap from the inner circumferential surface of the upstream side squeeze portion; and a protrusion protruding from at least one of the inner circumferential surface of the upstream side squeeze portion or the outer circumferential surface of the partition wall.

Abstract: A centrifugal compressor includes: an upstream side squeeze portion having a flow passage cross-sectional area that decreases as the upstream side squeeze portion extends closer to a compressor impeller; a partition wall facing the inner circumferential surface of the upstream side squeeze portion and arranged with a gap from the inner circumferential surface of the upstream side squeeze portion; and a protrusion protruding from at least one of the inner circumferential surface of the upstream side squeeze portion or the outer circumferential surface of the partition wall.

Abstract: A centrifugal compressor includes a flow changing groove that is formed on an inner wall of the suction passage and extends in a rotation direction of the compressor wheel. A boundary part of a groove wall of the flow changing groove and the inner wall of the suction passage includes an upstream boundary part positioned on an upstream side in the circulation direction of the gas, and a downstream boundary part positioned on a downstream side in the circulation direction. The upstream boundary part is positioned on the inner side in a radial direction of the compressor wheel than the downstream boundary part, and the flow changing groove is positioned on the upstream side of the wheel in the circulation direction.

Abstract: An annular diffuser is formed on an outlet side of a wheel in a housing. A spiral scroll is formed on an outlet side of the diffuser in the housing. An annular concave part is formed to be depressed to an inside in a radial direction in a boundary between a shroud-side wall surface of the diffuser and a wall surface of the scroll.

Abstract: An annular diffuser is formed on an outlet side of a wheel in a housing. A shroud-side wall surface and a hub-side wall surface of the diffuser are parallel to a radial direction, respectively. A plurality of annular steps is formed on the shroud-side wall surface of the diffuser. Each step is formed so as to expand a flow passage width of the diffuser along a flow direction of a main flow.

Abstract: A centrifugal compressor includes a flow changing groove that is formed on an inner wall of the suction passage and extends in a rotation direction of the compressor wheel. A boundary part of a groove wall of the flow changing groove and the inner wall of the suction passage includes an upstream boundary part positioned on an upstream side in the circulation direction of the gas, and a downstream boundary part positioned on a downstream side in the circulation direction. The upstream boundary part is positioned on the inner side in a radial direction of the compressor wheel than the downstream boundary part, and the flow changing groove is positioned on the upstream side of the wheel in the circulation direction.

Abstract: An annular diffuser is formed on an outlet side of a wheel in a housing. A spiral scroll is formed on an outlet side of the diffuser in the housing. An annular concave part is formed to be depressed to an inside in a radial direction in a boundary between a shroud-side wall surface of the diffuser and a wall surface of the scroll.

Abstract: An annular diffuser is formed on an outlet side of a wheel in a housing. A shroud-side wall surface and a hub-side wall surface of the diffuser are parallel to a radial direction, respectively. A plurality of annular steps is formed on the shroud-side wall surface of the diffuser. Each step is formed so as to expand a flow passage width of the diffuser along a flow direction of a main flow.