JP2023113428A - Impeller and rotary machine - Google Patents

Abstract

To provide an impeller and a rotary machine that restrain occurrence of pressure pulsation by reducing pressure fluctuation in an outflow port.SOLUTION: An impeller comprises a hub having a disk shape around an axis, a shroud arranged opposite to the hub in the direction of an axis, and a plurality of blades arranged at intervals in a circumferential direction between the hub and the shroud, and has different meridian plane shapes in the circumferential direction.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to impellers and rotating machines.

As a rotating machine, there is a centrifugal compressor that houses an impeller inside. A centrifugal compressor imparts pressure and velocity energy to a fluid by rotating an impeller. As an impeller applied to a centrifugal compressor, there is a closed impeller having a plurality of blades arranged between a hub and a shroud. Examples of closed impellers include those described in the following patent documents.

Japanese Patent No. 3299638

A typical closed impeller is provided with a helical flow path from an inlet at the center to an outlet at the outer periphery. Since the flow paths are provided radially, the flow path area rapidly expands toward the outer periphery, and the fluid tends to separate and loss easily occurs. Therefore, it is conceivable to suppress the rapid expansion of the passage area by gradually increasing the thickness of the blade from the inlet to the outlet. However, when the thickness of the blade is gradually increased from the inlet to the outlet, a plurality of outlets are interrupted in the circumferential direction by the thickness of the blade. Then, there is a problem that the pressure of the fluid discharged from each outflow port of the outer peripheral portion fluctuates in the circumferential direction, and pressure pulsation occurs.

An object of the present disclosure is to solve the above-described problems, and to provide an impeller and a rotary machine that suppress pressure pulsation by reducing pressure fluctuations at the outlet.

The impeller of the present disclosure for achieving the above object comprises a disk-shaped hub centered on an axis, a shroud arranged opposite to the hub in the direction of the axis, the hub and the shroud. and a plurality of blades circumferentially spaced between and having different meridional shapes in the circumferential direction.

A rotary machine of the present disclosure also includes the impeller.

According to the impeller and the rotary machine of the present disclosure, it is possible to suppress the occurrence of pressure pulsation by reducing pressure fluctuations at the outlet.

FIG. 1 is a cross-sectional view showing a main part of a rotary machine to which the impeller of this embodiment is applied. FIG. 2 is a front view showing the impeller. FIG. 3 is a cross-sectional view taken along arrow III in FIG. 2 showing the meridional shape of the upper half of the impeller of this embodiment. FIG. 4 is a cross-sectional view taken along arrow IV in FIG. 2 showing the meridional shape of the upper half of the impeller of this embodiment. FIG. 5 is a cross-sectional view taken along the arrow V in FIG. 2 showing the meridional shape of the upper half of the impeller of this embodiment. FIG. 6 is a cross-sectional view taken along arrow VI in FIG. 2 showing the meridional shape of the upper half of the impeller of this embodiment. FIG. 7 is a side view of the essential part of the impeller showing the outflow port of the impeller of this embodiment. FIG. 8 is a schematic diagram showing the shape of the blades on the hub side of the impeller. FIG. 9 is a schematic diagram showing the shape of blades in an intermediate portion between the hub and shroud of the impeller. FIG. 10 is a schematic diagram showing the blade shape on the shroud side of the impeller. FIG. 11 is a side view of the main part of the impeller showing the outflow port of the impeller of the first modified example. FIG. 12 is a side view of the main part of the impeller showing the outflow port of the impeller of the second modification. FIG. 13 is a side view of the essential part of the impeller showing the outflow port of the impeller of the third modification.

Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. It should be noted that the present disclosure is not limited by this embodiment, and when there are a plurality of embodiments, the present disclosure also includes a combination of each embodiment. In addition, components in the embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range.

[Embodiment]
<Centrifugal Compressor>
FIG. 1 is a cross-sectional view showing the meridional shape of the upper half of an impeller applied to a rotating machine. In this embodiment, a centrifugal compressor will be applied as a rotating machine.

As shown in FIG. 1, the centrifugal compressor 10 includes a casing 11, a rotating shaft 12, and an impeller 13. The centrifugal compressor 10 rotates the impeller 13 to give pressure energy and velocity energy to the working fluid (liquid or gas, etc.).

The casing 11 accommodates a portion of the rotating shaft 12 and the impeller 13 . The casing 11 has a cylindrical shape elongated in the direction in which the axis O of the rotating shaft 12 extends (hereinafter referred to as the axial direction Da). The casing 11 includes a first space portion 21 having a cylindrical shape along the axial direction Da and a second space portion 22 having a disk shape extending in a direction orthogonal to the axial direction Da (hereinafter referred to as a radial direction Dr). is provided. A plurality of second space portions 22 are arranged at intervals in the axial direction Da of the first space portion 21 . The first space 21 and the plurality of second spaces 22 communicate with each other. The rotating shaft 12 is housed in the first space 21 , and the impeller 13 is housed in each of the plurality of second spaces 22 .

The casing 11 is provided with an inflow passage 23 for introducing the working fluid G into the impeller 13 on one side (left side in FIG. 1) in the axial direction Da. Further, the casing 11 is provided with a discharge passage 24 for discharging the working fluid G from the impeller 13 on one side (upper side in FIG. 1) in the radial direction Dr. The discharge passage 24 bends toward the axis O so that the downstream side forms a U shape, and then bends along the other side in the axial direction Da (right side in FIG. 1) so as to form an L shape. That is, although not shown, the discharge passage 24 is provided with a diffuser portion, a return bend portion, and a return passage on the downstream side. The discharge passage 24 communicates with the inflow passage 23 of the impeller 13 whose return passage is adjacent in the axial direction Da.

The rotary shaft 12 is rotatably supported around the axis O with respect to the casing 11 . The rotary shaft 12 is rotatably supported on the casing 11 by bearings (not shown) at both ends in the axial direction Da. Impeller 13 is fixed to rotating shaft 12 . The impeller 13 rotates together with the rotating shaft 12 . The impeller 13 compresses the working fluid G using centrifugal force.

<Basic configuration of the impeller>
FIG. 2 is a front view showing the impeller.

As shown in FIGS. 1 and 2, impeller 13 is a closed impeller comprising hub 31 , shroud 32 and multiple blades 33 . The impeller 13 is configured by arranging a plurality of blades 33 between a hub 31 and a shroud 32 at intervals (preferably at equal intervals) in the circumferential direction Dc. One of the plurality of blades 33 in the axial direction Da is fixed to the hub 31 and the other is fixed to the shroud 32 . The impeller 13 is provided with a plurality of impeller flow passages 34 surrounded by a hub 31 , a shroud 32 and a plurality of blades 33 . The impeller flow path 34 is arranged to form a spiral shape centered on the axis O while bending approximately 90 degrees from the axis C side to the outer peripheral portion side.

The hub 31 has a disc shape centered on the axis O. As shown in FIG. The hub 31 gradually expands outward in the radial direction Dr from one side to the other side in the axial direction Da. The hub 31 is formed with a circular through hole 41 penetrating in the axial direction Da at the position of the axis O, which is the central portion. The hub 31 is integrally fixed to the rotating shaft 12 with the inner peripheral surface of the through hole 41 fitted into the outer peripheral surface of the rotating shaft 12 .

The hub 31 has a main surface 42 formed on one side in the axial direction Da. The main surface 42 spreads outward in the radial direction Dr from one side to the other side in the axial direction Da. A portion on one side in the axial direction Da of the main surface 42 faces outward in the radial direction Dr, and a portion on the other side in the axial direction Da faces one side in the axial direction Da. That is, the main surface 42 forms a concave curved surface shape by curving so as to face one side in the axial direction Da as it goes from one side to the other side in the axial direction Da.

The shroud 32 is arranged on the other side in the axial direction Da with a predetermined distance from the hub 31 . The shroud 32 gradually expands outward in the radial direction Dr from one side in the axial direction Da to the other side. The shroud 32 has a facing surface 43 formed on the other side Dad in the axial direction Da. The facing surface 43 extends outward in the radial direction Dr from one side in the axial direction Da toward the other side. A portion of the facing surface 43 on one side in the axial direction Da faces outward in the radial direction Dr, and a portion on the other side in the axial direction Da faces the other side in the axial direction Da. That is, the facing surface 43 forms a convex surface shape by curving toward the other side in the axial direction Da from one side to the other side in the axial direction Da.

Blades 33 connect hub 31 and shroud 32 . The blade 33 is fixed to the main surface 42 of the hub 31 at one end in the axial direction Da, and fixed to the opposing surface 43 of the shroud 32 at the other end in the axial direction Da. The blade 33 extends from one side in the axial direction Da so as to bend outward in the radial direction Dr. A plurality of blades 33 are arranged at intervals in the circumferential direction Dc around the axis O. As shown in FIG. The plurality of blades 33 are arranged radially outward in the radial direction Dr with the axis O as the center. The blades 33 curve rearward in the rotational direction of the impeller 40 as they move from the inner side in the radial direction Dr to the outer side in the radial direction Dr.

A plurality of impeller passages 34 are formed between the hub 31 and the shroud 32 and partitioned in the circumferential direction Dc by the plurality of blades 33 . The impeller flow path 34 extends while curving from the inside to the outside in the radial direction Dr as it goes from one side to the other side in the axial direction Da. The impeller flow path 34 has an inlet 44 that opens inside in the radial direction Dr and on one side in the axial direction Da. Further, the impeller flow path 34 has an outflow port 45 that opens outside in the radial direction Dr and on the other side in the axial direction Da. The inflow port 44 communicates with the inflow passage 23 , and the outflow port 45 communicates with the discharge passage 24 .

<Impeller meridional shape>
3 is a cross-sectional view at the position of arrow III in FIG. 2 showing the meridional shape of the upper half of the impeller of this embodiment, and FIG. 4 shows the meridional shape of the upper half of the impeller of this embodiment. FIG. 5 is a cross-sectional view at the position of arrow IV in FIG. 2, and FIG. 5 is a cross-sectional view at the position of arrow V in FIG. FIG. 3 is a cross-sectional view at the position of arrow VI in FIG. 2 showing the meridional shape of the upper half of the impeller of the present embodiment;

The impeller 13 is a closed impeller that includes a hub 31 , a shroud 32 and a plurality of blades 33 , and a plurality of impeller flow paths 34 are formed by the hub 31 , the shroud 32 and the plurality of blades 33 . The impeller 13 has different meridional shapes in the circumferential direction Dc.

That is, in the impeller 13, the plurality of impeller passages 34 partitioned by the hub 31, the shroud 32, and the plurality of blades 33 are arranged such that the positions of the outflow ports 45 on the outer peripheral side are different in the circumferential direction Dc in the axial direction. It shifts to Da.

3 to 6 are cross-sectional views showing the meridional shape of the upper half of the impeller 13 at different positions in the circumferential direction Dc. As shown in FIG. 3, in the meridional shape of the impeller 13 at the first position, the impeller flow path 34-1 is closest to the hub in the axial direction Da on the outflow port 45 side with respect to the reference impeller flow path 34-0. Located on the 31st side. At this time, the height H1 of the outflow port 45 in the axial direction Da is shorter than the height H of the reference impeller flow path 34-0. As shown in FIG. 4, in the meridional shape of the impeller 13 at the second position, the impeller flow path 34-2 is located on the hub 31 side in the axial direction Da with respect to the reference impeller flow path 34-0. and the middle position of the shroud 32, and located slightly on the hub 31 side. At this time, the height H2 of the outflow port 45 in the axial direction Da is shorter than the height H of the reference impeller flow path 34-0.

As shown in FIG. 5, in the meridional shape of the impeller 13 at the third position, the impeller flow path 34-3 is located on the hub 31 side in the axial direction Da with respect to the reference impeller flow path 34-0. and the middle position of the shroud 32, and is located slightly on the shroud 32 side. At this time, the height H3 of the outflow port 45 in the axial direction Da is shorter than the height H of the reference impeller flow path 34-0.
As shown in FIG. 6, in the meridional shape of the impeller 13 at the fourth position, the impeller flow path 34-4 is shrouded most in the axial direction Da on the outflow port 45 side with respect to the reference impeller flow path 34-0. 32 side. At this time, the height H4 of the outflow port 45 in the axial direction Da is shorter than the height H of the reference impeller flow path 34-0.

In addition, in the meridional shape of the impeller 13 at each position, the heights H1, H2, H3, and H4 of the impeller flow path 34 (outflow port 45) in the axial direction Da may be the same or different. There may be.

FIG. 7 is a side view of the essential part of the impeller showing the outflow port of the impeller of this embodiment.

As shown in FIG. 7, the impeller 13 shifts in the axial direction Da at different positions in the circumferential direction Dc of the outflow port 45 in the impeller flow path 34 . Therefore, the shape of the outflow port 45 when the impeller 13 is viewed in the radial direction Dr from the outer peripheral side is arranged along the inclined line L2 having a predetermined inclination angle θ with respect to the reference line L1 along the circumferential direction Dc. . At this time, the outflow port 45 has a passage shape of a square (parallelogram).

The blade 33 has a body portion 33a and two extension portions 33b and 33c. The body portion 33 a is fixed to the hub 31 at one end in the axial direction Da and fixed to the shroud 32 at the other end. The extending portion 33 b extends taperingly along the shroud 32 in one circumferential direction Dc from the main body portion 33 a and is fixed to the shroud 32 . The extending portion 33 c extends taperingly along the hub 31 in the other circumferential direction Dc from the main body portion 33 a and is fixed to the hub 31 . The impeller flow path 34 (outflow port 45) includes a surface 34a of the main body portion 33a of the blade 33, a surface 34b of the extension portion 33b, a surface 34c of the main body portion 33a of the adjacent blade 33, and a surface of the extension portion 33c. 34d to form a square (parallelogram). Since the impeller 13 rotates in the other side (the left side in FIG. 7) in the circumferential direction Dc, the surface 34d of the blade 33 is a pressure surface and the surface 34b is a suction surface.

In this case, the impeller flow path 34 (outflow port 45) is such that the shapes of the impeller flow paths 34-1, 34-2, 34-3, and 34-4 at each position in FIGS. By continuously changing in the longitudinal direction, surfaces 34b and 34d are formed, and the outflow port 45 has a square shape (parallelogram shape). The impeller flow path 34 (outflow port 45) is such that the shape of the impeller flow paths 34-1, 34-2, 34-3, and 34-4 at each position in FIGS. The direction may be changed stepwise.

FIG. 8 is a schematic diagram showing the blade shape on the hub side of the impeller, FIG. 9 is a schematic diagram showing the blade shape on the intermediate portion between the hub and the shroud in the impeller, and FIG. 10 is a blade shape on the shroud side of the impeller It is the schematic showing a shape.

As described above, the impeller 13 has the hexagonal shape of the outflow port 45 along the inclined line L2, so the blades 33 have different thicknesses at different positions in the axial direction Da. 8 shows the blade shape on the hub 31 side, FIG. 9 shows the blade shape on the intermediate portion between the hub 31 and the shroud 32, and FIG. 10 shows the blade shape on the shroud 32 side. As shown in FIGS. 8 to 10, the thickness of the blade 33 on the outer peripheral side (outlet 45) at the intermediate portion between the hub 31 and the shroud 32 is greater than the thickness on the outer peripheral side (outlet 45) at the hub 31 side. It is thinner than the thickness on the shroud 32 side and the thickness on the outer peripheral side (outflow port 45).

That is, as shown in FIG. 7, the blade 33 has a thickness C1 on the outer peripheral side (outflow port 45 side) on the hub 31 side and a thickness C3 on the outer peripheral side (outflow port 45 side) on the shroud 32 side. , are the same. The thickness C2 of the blade 33 on the outer peripheral side (on the outflow port 45 side) at the intermediate portion between the hub 31 and the shroud 32 is thinner than the thickness C1 on the hub 31 side and the thicknesses C1 and C3 on the shroud 32 side. set.

As shown in FIGS. 8 to 10 , the thickness of the blades 33 on the hub 31 side and the thickness on the shroud 32 side gradually increase from the axis O side toward the outer peripheral side of the impeller 13 . Therefore, the width of the impeller passage 34 on the side of the hub 31 and the width on the side of the shroud 32 are substantially the same. there is Therefore, the impeller 13 suppresses rapid expansion of the passage area in the impeller flow path 34, thereby suppressing separation of the working fluid from the inner surface of the impeller flow path 34 and reducing loss.

On the other hand, the thickness of the blades 33 at the intermediate portion between the hub 31 and the shroud 32 is substantially constant from the axis O side toward the outer peripheral portion side of the impeller 13 . The impeller 13 compresses the working fluid more efficiently in the intermediate region between the hub 31 and the shroud 32 than in the region on the hub 31 side and the shroud 32 side in the impeller passage 34 . Therefore, by securing a sufficient volume of this region, it is possible to efficiently secure the lift (pressure) and improve the efficiency.

The thickness of the blade 33 on the outflow port 45 side in the intermediate portion between the hub 31 and the shroud 32 is thinner than the thickness on the hub 31 side and the shroud 32 side on the outflow port 45 side. Then, the plurality of outflow ports 45 provided in the outer peripheral portion of the impeller 13 are substantially continuous in the circumferential direction Dc. That is, the plurality of outflow ports 45 are interrupted only by the thickness of the main body portion 33 a of the blade 33 . Therefore, the discharge of the working fluid from each outlet 45 is less likely to be interrupted, pressure fluctuations are reduced, and the occurrence of pressure pulsation can be suppressed.

The impeller 13 of this embodiment is manufactured by cutting, but the manufacturing method is not limited. For example, it may be manufactured by a three-dimensional layered manufacturing method such as AM (Additive Manufacturing).

[Modification]
FIG. 11 is a side view of essential parts of the impeller showing the outlet of the impeller of the first modification, FIG. 12 is a side view of the essential parts of the impeller showing the outlet of the impeller of the second modification, and FIG. It is a principal part side view of the impeller showing the outflow port of the impeller of a modification.

In the first modified example, as shown in FIG. 11, the impeller 13A includes a hub 31, a shroud 32, and a plurality of blades 33A. is a closed impeller in which is formed. The impeller 13A has different meridional shapes in the circumferential direction Dc. That is, in the impeller 13A, the plurality of impeller passages 34A partitioned by the hub 31, the shroud 32, and the plurality of blades 33A are arranged so that the outflow ports 45 on the outer peripheral side are located at different positions in the circumferential direction Dc. It shifts to Da.

The impeller 13A has different meridional shapes at different positions in the circumferential direction Dc, as shown in FIGS. That is, the impeller 13A changes its meridional shape in the order of FIGS. 3, 4, 5, and 6 from the upstream side in the rotational direction. A change in the meridional shape of the impeller 13A is the same as in the above-described embodiment. The shape of the outflow port 45 when the impeller 13A is viewed in the radial direction Dr from the outer peripheral side is arranged along an inclined line L3 having a predetermined inclination angle θ with respect to the reference line L1 along the circumferential direction Dc. . At this time, the outflow port 45 has a hexagonal passage shape.

The blade 33A has a body portion 33a and two extension portions 33b and 33c. The body portion 33 a is fixed to the hub 31 at one end in the axial direction Da and fixed to the shroud 32 at the other end. The extending portion 33 b extends taperingly along the shroud 32 in one circumferential direction Dc from the main body portion 33 a and is fixed to the shroud 32 . The extending portion 33 c extends taperingly along the hub 31 in the other circumferential direction Dc from the main body portion 33 a and is fixed to the hub 31 . The impeller flow path 34A (outflow port 45) includes a surface 34a of the main body portion 33a of the blade 33A, a surface 34b of the extension portion 33b, a surface 34c of the shroud 32, and a surface 34d of the main body portion 33a of the adjacent blade 33A. , and a surface 34e of the extension 33c and a surface 34f of the hub 31, forming a hexagonal shape.

In the second modified example, as shown in FIG. 12, the impeller 13B includes a hub 31, a shroud 32, and a plurality of blades 33B. is a closed impeller in which is formed. The impeller 13B has different meridional shapes in the circumferential direction Dc. That is, in the impeller 13B, the plurality of impeller passages 34B partitioned by the hub 31, the shroud 32, and the plurality of blades 33B are configured so that the outflow ports 45 on the outer peripheral side are located at different positions in the circumferential direction Dc in the axial direction. It shifts to Da.

The impeller 13B has different meridional shapes at different positions in the circumferential direction Dc, as shown in FIGS. That is, the impeller 13A changes its meridional shape in the order of FIGS. 6, 5, 4, and 3 from the upstream side in the rotational direction. The change in the meridional shape of the impeller 13B is opposite to that of the first modification described above. When the impeller 13B is viewed from the outer peripheral side in the radial direction Dr, the shape of the outflow port 45 is arranged along an inclined line L4 inclined with respect to the reference line L1 along the circumferential direction Dc. At this time, the outflow port 45 has a parallelepipedal shape. That is, in the meridional shape of the impeller 13B at different positions in the circumferential direction Dc, the height of the outflow port 45 along the axial direction Da is the same height.

In the third modification, as shown in FIG. 13, the impeller 13C includes a hub 31, a shroud 32, and a plurality of blades 33C and 33D. It is a closed impeller in which impeller flow paths 34A and 34B are formed. The impeller 13C has different meridional shapes in the circumferential direction Dc. That is, in the impeller 13C, the plurality of impeller passages 34A, 34B partitioned by the hub 31, the shroud 32, and the plurality of blades 33C, 33D have outlets 45 on the outer peripheral side that are positioned differently in the circumferential direction Dc. It shifts in the axial direction Da at the position.

That is, the impeller 13C is a combination of the first embodiment (FIG. 7) and the second modification (FIG. 12), and by alternately arranging blades 33C and 33D of different shapes in the circumferential direction Dc, The impeller flow paths 34A, 34B are arranged alternately in the circumferential direction Dc.

[Action and effect of the present embodiment]
The impeller according to the first aspect includes a disk-shaped hub 31 centered on the axis O, a shroud 32 arranged opposite to the hub 31 in the axial direction Da, and between the hub 31 and the shroud 32 A plurality of blades 33, 33A, 33B, 33C, and 33D are arranged at intervals in the circumferential direction Dc, and the shape of the meridional surface differs in the circumferential direction Dc.

According to the impeller according to the first aspect, the impellers 13, 13A, 13B, and 13C have different meridional shapes in the circumferential direction Dc. By being shifted and biased, the plurality of outflow ports 45 are substantially continuous in the circumferential direction Dc. That is, the plurality of outflow ports 45 are interrupted only by the thickness of the main body portion 33a of the blades 33, 33A, 33B, 33C, and 33D, and the discharge of the working fluid from each outflow port 45 is hardly interrupted, and the pressure fluctuation is reduced. By reducing the pressure fluctuation in the circumferential direction at the outflow port 45, the occurrence of pressure pulsation can be suppressed.

In the impeller according to the second aspect, the impeller flow passages 34, 34A, 34B partitioned by the hub 31, the shroud 32, and the pair of blades 33, 33A, 33B, 33C, 33D are the outflow ports 45 on the outer peripheral side. The positions are shifted in the axial direction Da at different positions in the circumferential direction Dc. As a result, the plurality of outlets 45 can be brought as close to each other as possible in the circumferential direction Dc, pressure fluctuations at the outlets 45 can be reduced, and pressure pulsation can be suppressed.

In the impeller according to the third aspect, the outflow port 45 is arranged along inclined lines L2, L3, and L4 having a predetermined inclination angle θ with respect to the reference line L1 along the circumferential direction Dc. Thereby, it is possible to bring the plurality of outflow ports 45 as close as possible in the circumferential direction Dc.

In the impeller according to the fourth aspect, the outflow port 45 has a square passage shape. As a result, the area in which the blades 33 block the outflow port 45 can be reduced in the circumferential direction Dc, pressure pulsation in the circumferential direction Dc can be effectively suppressed, and performance can be improved.

In the impeller according to the fifth aspect, the outflow port 45 has a hexagonal passage shape. As a result, the area in which the blades 33 block the outflow port 45 can be reduced in the circumferential direction Dc, pressure pulsation in the circumferential direction Dc can be effectively suppressed, and performance can be improved.

In the impeller according to the sixth aspect, the blades 33, 33A, 33B, 33C, and 33D have a thickness C2 on the outer peripheral side at the intermediate portion between the hub 31 and the shroud 32, which is the thickness on the outer peripheral side at the hub 31 side. It is thinner than the thickness C3 on the outer peripheral side on the C1 and shroud 32 side. As a result, the thicknesses of the blades 33, 33A, 33B, 33C, and 33D on the hub 31 side and the shroud 32 side gradually increase toward the outer peripheral portion side, thereby increasing the passage area of the impeller flow passages 34, 34A, and 34B. Rapid expansion is restrained. Therefore, separation of the working fluid from the inner surface of the impeller flow path 34 is suppressed, and loss can be reduced. On the other hand, since the thicknesses of the blades 33, 33A, 33B, 33C, and 33D in the intermediate portion between the hub 31 and the shroud 32 are substantially constant toward the outer peripheral portion, it is necessary to secure a sufficient volume in this region. Therefore, the head (pressure) can be efficiently secured, and the efficiency can be improved.

The impeller according to the seventh aspect is a closed impeller in which one of the plurality of blades 33, 33A, 33B, 33C, 33D is fixed to the hub 31 and the other is fixed to the shroud 32. As a result, pressure fluctuations at the outlets 45 of the impellers 13, 13A, 13B, and 13C can be reduced, and the occurrence of pressure pulsations can be suppressed.

A rotary machine according to an eighth aspect has impellers 13, 13A, 13B, and 13C. This reduces pressure fluctuations at the outlets 45 of the impellers 13, 13A, 13B, and 13C, suppresses the occurrence of pressure pulsations, and as a result improves the efficiency of the rotary machine.

In the above-described embodiment, the meridional shape of the impellers 13, 13A, 13B, and 13C is changed in the circumferential direction Dc in the order of FIGS. is hexagonal or quadrangular, but is not limited to this shape. Any shape may be used as long as the meridional shape of the impeller is different at different positions in the circumferential direction Dc.

In the above-described embodiment, the impellers 13, 13A, 13B, and 13C are closed impellers, but they may be open impellers in which the hub and blades rotate relative to the shroud.

Further, in the above-described embodiments, the rotating machine is explained as a centrifugal compressor, but it may be another rotating machine.

10 centrifugal compressor (rotating machine)
Reference Signs List 11 casing 12 rotating shaft 13, 13A, 13B, 13C impeller 21 first space 22 second space 23 inflow passage 24 discharge passage 31 hub 32 shroud 33, 33A, 33B, 33C, 33D blades 34, 34A, 34B impeller flow Channel 41 Through hole 42 Principal surface 43 Opposite surface 44 Inlet 45 Outlet

Claims (8)

a disk-shaped hub centered on the axis;
a shroud arranged to face the hub in the direction of the axis;
a plurality of blades circumferentially spaced between the hub and the shroud;
with
The meridional shape is different in the circumferential direction,
impeller. In the channel defined by the hub, the shroud, and the pair of blades, the position of the outflow port on the outer peripheral side is shifted in the direction of the axis at different positions in the circumferential direction.
Impeller according to claim 1. The outflow port is arranged along an inclined line having a predetermined inclination angle with respect to a reference line along the circumferential direction.
Impeller according to claim 2. The outflow port has a square passage shape,
Impeller according to claim 3. The outflow port has a hexagonal passage shape,
Impeller according to claim 3. In the blade, the thickness on the outer peripheral side at the intermediate portion between the hub and the shroud is thinner than the thickness on the outer peripheral side on the hub side and the thickness on the outer peripheral side on the shroud side,
Impeller according to any one of claims 1 to 5. A closed impeller in which one of a plurality of blades is fixed to the hub and the other is fixed to the shroud,
Impeller according to any one of claims 1 to 6. A rotating machine comprising an impeller according to any one of claims 1 to 7.

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