Abstract: A centrifugal compressor comprises: an impeller; an inlet pipe portion forming an intake passage to introduce air to the impeller; and a throttle mechanism capable of reducing a flow passage area of the intake passage upstream of the impeller. The throttle mechanism includes an annular portion configured to move between a first position and a second position upstream of the first position in an axial direction of the impeller. In a cross-section along a rotational axis of the impeller, an outer peripheral surface of the annular portion is formed to smoothly connect a leading edge and a trailing edge of the annular portion.

Abstract: A scroll structure of a centrifugal compressor according to an embodiment is a scroll structure of a centrifugal compressor having a scroll passage formed in spiral shape, comprising: a tongue portion separating the scroll passage from an outlet passage connected to the downstream side of the scroll passage at the most downstream position of the scroll passage in a passage connecting portion where a winding start portion and a winding end portion of the scroll passage intersect; and a ridge portion protruding from an inner peripheral surface of the scroll passage on the axially downstream side of the centrifugal compressor toward the axially upstream side of the centrifugal compressor, with a protruding height toward the axially upstream side gradually increasing toward the tongue portion from a starting position that is located upstream from the tongue portion in the scroll passage.

Abstract: In a centrifugal compressor, when the position of the tongue of the scroll section in the circumferential direction of the impeller is defined as 60° and the downstream direction in the rotation direction of the impeller is defined as the positive direction of the position in the circumferential direction, a diffuser section outer diameter distribution indicating a relationship between the position in the circumferential direction and outer diameter R of the diffuser section includes an outer diameter increasing portion where the outer diameter R increases going toward the positive direction, and in the diffuser section outer diameter distribution, the position of a start point of the outer diameter increasing portion is 150° or less, and the position of an end point of the outer diameter increasing portion is 270° or more.

Abstract: A compressor housing includes: when an intake side in an axial direction of the centrifugal compressor is defined as a front side, and a side opposite to the intake side in the axial direction is defined as a rear side, a shroud surface including a surface facing a tip of an impeller blade of the impeller with a predetermined gap; a front-side inner peripheral surface formed on the front side of the shroud surface in the axial direction and positioned on an outer side in a radial direction than a front end of the shroud surface; and plurality of grooves formed in the front-side inner peripheral surface at intervals in a circumferential direction wherein each of the plurality of grooves includes: an inclined portion whose depth gradually increases toward a rotation direction of the impeller; and a stepped portion formed at a downstream end of the inclined portion in the rotation direction.

Abstract: A compressor includes: a shroud surface; a front-side inner peripheral surface formed on a front side of the shroud surface in the axial direction and disposed outward of a front end of the shroud surface in the radial direction; and at least one projection protruding from the front-side inner peripheral surface inward in the radial direction. A rear end of the at least one projection is configured to be connected to the front end of the shroud surface. The at least one projection is formed in a plate shape, and in a cross-sectional view along an axis of the impeller, has an inclined front edge extending obliquely to the axis of the impeller from a front end of the projection toward a rear side.

Abstract: An impeller of a centrifugal compressor includes: a hub; and at least one blade disposed on a hub surface of the hub. A hub-side end of a trailing edge of the at least one blade is located radially outward of an outer peripheral portion of the hub, and is located on either of a first line extending radially outward from the hub surface of the hub or a second line extending radially outward from a back surface of the hub.

Abstract: A centrifugal compressor includes: an impeller; an inlet pipe portion forming an intake passage to introduce air to the impeller; and a throttle mechanism capable of reducing a flow passage area of the intake passage upstream of the impeller. The throttle mechanism includes an annular portion configured to move between a first position and a second position upstream of the first position in an axial direction of the impeller, and a strut supporting the annular portion. The strut extends toward at least one of an outer side in a radial direction of the impeller or a downstream side in the axial direction of the impeller with an increase in distance from the annular portion.

Abstract: An impeller of a centrifugal compressor according to the present disclosure includes: a hub; a plurality of full blades disposed on a peripheral surface of the hub at intervals in a circumferential direction; and a plurality of splitter blades each of which is disposed between adjacent full blades of the plurality of full blades on the peripheral surface of the hub. When a blade height ratio which is a ratio of a blade height (Hf) of each full blade to a blade height (Hs) of each splitter blade on a meridional plane of the impeller is defined as Hs/Hf, the blade height ratio satisfies Hs/Hf<1 at least at a leading edge of each splitter blade.

Abstract: A compressor housing internally forms: an inlet passage with an inflow port formed in a shroud surface; an outlet passage with an outflow port formed in an introduction surface formed on a front side of a shroud surface; and a recirculation passage connecting the inlet passage and the outlet passage. An intake air introduction portion of the compressor housing has: a front-side surface defining a front side in the outlet passage; a rear-side surface defining a rear side in the outlet passage; and a front-side introduction surface formed on the front side relative to the outflow port on the introduction surface. Each of the front-side surface, the rear-side surface, and the front-side introduction surface is inclined to the rear side from an outer side toward an inner side in a radial direction, the rear-side surface includes a convex curved portion, and the front-side introduction surface includes an introduction surface-side convex curved portion.

Abstract: A scroll casing for a centrifugal compressor satisfies a relationship of Tb/Ta?1.0 in a range of an angular position around a scroll center of the scroll passage from 180 degrees to 360 degrees, where Ta is a passage width of the diffuser passage along an axial direction of the centrifugal compressor, Tb is a shortest distance from a start position which is a connection position with a hub-side passage surface of the diffuser passage on an inner peripheral surface of a scroll portion forming the scroll passage to a virtual arc that touches an end position which is a position opposite to the start position on the inner peripheral surface, and the angular position is defined so that the angle gradually increases from a merging position between a scroll start and a scroll end of the scroll passage of 60 degrees to the downstream side of the scroll passage.

Abstract: A compressor wheel device comprises a compressor wheel attached to a rotary shaft and a thrust collar attached to the rotary shaft at a back surface of the compressor wheel. The compressor wheel includes: a wheel body part with a hub and at least one blade provided on an outer peripheral surface of the hub; and a sleeve part having a cylindrical shape projecting along an axis direction from a back surface of the hub and having an outer peripheral surface on which a sealing groove extending along a peripheral direction is formed. The thrust collar has a circular plate-like shape including: one surface including an abutting surface abutting on an end surface of the sleeve part and extending along a radial direction; and the other surface including a slidably-contacting surface slidably contacting a thrust bearing supporting the rotary shaft in a thrust direction and extending along the radial direction.

Abstract: A scroll casing of a centrifugal compressor includes a scroll part forming a scroll passage of the centrifugal compressor. The scroll part has a near-circular scroll cross-section which includes a first arc portion extending from a connection position with a hub-side passage surface of a diffuser passage of the centrifugal compressor (first position) to a one-direction side (side toward fourth position), a second arc portion formed on the one-direction side of the first arc portion so as to include at least a part of a region between an outermost end in the radial direction (second position) and an innermost end in the radial direction (fourth position), and a third arc portion formed on the one-direction side of the second arc portion so as to include an end position of the scroll part on the one-direction side (fifth position) and satisfies a relationship of R2>R3, where R2 is a curvature radius of the second arc portion, and R3 is a curvature radius of the third arc portion.

Abstract: An impeller for a centrifugal turbomachine includes: a hub having a small-diameter portion positioned at a first end portion in an axial direction and a large-diameter portion positioned at a second end portion in the axial direction, the large-diameter portion having a greater diameter than the small-diameter portion; and a blade having a first edge positioned at an axial-directional position of the small-diameter portion and a second edge positioned at an axial-directional position of the large-diameter portion, the blade being disposed on an outer peripheral surface of the hub. The impeller is configured such that, when a first radial-directional cross section is a cross section of the impeller at an axial-directional position passing a tip of the first edge, at least a part of the first radial-directional cross section in a blade-height range of 50% or more is inclined downstream in a rotational direction of the impeller with respect to a radial direction.

Abstract: A bend pipe for supplying a fluid to a fluid machine or discharging the fluid from the fluid machine, wherein, provided that: a line including a pipe axial center line of an inlet pipe portion and an extension line thereof is defined as a line L; a line including a pipe axial line of an outlet pipe portion and an extension line thereof is defined as a line M; and a direction parallel to an intersection line formed by a plane orthogonal to the line M and a plane orthogonal to the line M is defined as a direction I, and when, as seen from the direction I, a side of the line M on which the inlet pipe portion exists is defined as a front side and a side of the line M on which the inlet pipe portion does not exist is defined as a back side, a side surface on an outer side with respect to a bend direction of a bend pipe portion includes an outer inclined surface on the back side of the line M, the outer inclined surface being inclined so that a distance from the line M decreases toward a downstream side.

Abstract: A rotor includes: a hub; and a plurality of blades disposed on the hub. Each of the plurality of blades has a suction surface, a pressure surface, a leading edge, a trailing edge, a tip-side edge, and a hub-side edge. The suction surface has a first curved surface portion curved convexly toward the trailing edge such that the trailing edge is inclined to a pressure surface side in a first region which is a partial region, in a blade height direction of the blade, of a region connected to the trailing edge.

Abstract: A scroll structure of a centrifugal compressor according to an embodiment is a scroll structure of a centrifugal compressor having a scroll passage formed in spiral shape, comprising: a tongue portion separating the scroll passage from an outlet passage connected to the downstream side of the scroll passage at the most downstream position of the scroll passage in a passage connecting portion where a winding start portion and a winding end portion of the scroll passage intersect; and a ridge portion protruding from an inner peripheral surface of the scroll passage on the axially downstream side of the centrifugal compressor toward the axially upstream side of the centrifugal compressor, with a protruding height toward the axially upstream side gradually increasing toward the tongue portion from a starting position that is located upstream from the tongue portion in the scroll passage.

Abstract: A scroll structure of a centrifugal compressor includes, of a flow passage connection section where a scroll start portion and a scroll end portion of a scroll flow passage intersect, a connection region where a first inner circumferential surface of the scroll end portion in the centrifugal compressor and a second inner circumferential surface of the scroll start portion in the centrifugal compressor are connected. The connection region includes a turning start point where a direction starts to change from the first inner circumferential surface toward the second inner circumferential surface, and a turning end point where the change in direction from the first inner circumferential surface toward the second inner circumferential surface comes to an end.

Abstract: A centrifugal compressor includes an impeller, a plurality of diffuser vanes arranged in a circumferential direction on a radially outer side of the impeller, and a housing which includes a scroll portion forming a scroll flow passage positioned on a radially outer side of the plurality of diffuser vanes. The plurality of diffuser vanes include at least one first diffuser vane positioned in an angular range between a tongue section of the scroll portion and a scroll end of the scroll portion in the circumferential direction, and a second diffuser vane positioned outside the angular range. A vane outlet angle formed by a tangent line at a trailing edge to a pressure surface of each of the plurality of diffuser vanes satisfies ?1<?2, where ?1 is the vane outlet angle of the first diffuser vane, and ?2 is the vane outlet angle of the second diffuser vane.

Abstract: A centrifugal compressor includes: an impeller; a compressor inlet tube configured to guide air to the impeller; a scroll flow passage disposed on a radially outer side of the impeller; a bypass flow passage branching from the scroll flow passage via a branch port, the bypass flow passage connecting to the compressor inlet tube not via the impeller; and a bypass valve capable of opening and closing a valve port disposed in the bypass flow passage. The branch port has a non-circular shape when viewed along a normal N1 of the branch port passing through a center of the branch port.

Abstract: A centrifugal compressor includes an impeller, a compressor inlet pipe for guiding air to the impeller, a scroll passage disposed on an outer peripheral side of the impeller, and a bypass passage connecting the compressor inlet pipe and the scroll passage and bypassing the impeller. In a cross-section perpendicular to an axis of the compressor inlet pipe, when A1 is a connection portion on a downstream side in a rotational direction of the impeller of connection portions between an inner wall surface of the compressor inlet pipe and an inner wall surface of the bypass passage, C is a virtual circle constituting the inner wall surface of the compressor inlet pipe, and L1 is a tangent line of the virtual circle C at the connection portion A1, the inner wall surface of the bypass passage is formed from the connection portion A1 along the tangent line L1.