Inlet guide vane and rotating machine

Abstract

To restrain the occurrence of a Karman vortex caused by fluid passed through an inlet guide vane.SOLUTION: An inlet guide vane comprises a plurality of movable vanes arranged at intervals in a circumferential direction of a rotating shaft, and each capable of rotating around a central axis extending in a radial direction of the rotating shaft. The movable vanes each comprise: a first vane surface and a second vane surface extending in a direction in which a front edge and a rear edge are connected; and an inclined surface formed in a rear end including the rear edge, and extending obliquely with respect to the second vane surface from the first vane surface when viewed from the radial direction. The inclined surface is a flat surface inclined so as to be connected to the second vane surface at an acute angle in the rear edge in a cross-sectional shape viewed from the radial direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an inlet guide vane and a rotary machine. [Background technology]

[0002] A centrifugal compressor circulates a working fluid inside a rotating impeller and compresses the gaseous working fluid by utilizing the centrifugal force generated when the impeller rotates. As disclosed in Patent Document 1, some centrifugal compressors have a structure equipped with inlet guide vanes to adjust the flow rate of the working fluid introduced from the outside.

[0003] Patent Document 1 describes an inlet guide vane having a plate-shaped plate portion with movable blades arranged in a flow path. This plate portion has a bent portion at the tip on the upstream side of the flow path that is inclined relative to the rest of the flow path in a cross section perpendicular to the rotation axis. This allows for efficient air inflow with a simple shape. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-200119 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in such inlet guide vanes, Karman vortices may occur downstream of the movable blades. The occurrence of Karman vortices disrupts the flow of fluid passing through the inlet guide vanes, which not only causes pressure loss but also has the potential to have adverse effects such as noise and vibration. For this reason, it is desirable to suppress the occurrence of Karman vortices by the fluid passing through the inlet guide vanes.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide an inlet guide vane and a rotary machine that are capable of suppressing the generation of Karman vortices by fluid that has passed through the inlet guide vane. [Means for solving the problem]

[0007] In order to solve the above problems, an inlet guide vane according to the present disclosure has a plurality of movable blades arranged at intervals circumferentially of a rotating shaft and rotatable around a central axis extending radially of the rotating shaft, the movable blades having first and second blade surfaces extending in a direction connecting a leading edge and a trailing edge, and an inclined surface formed at a rear end including the trailing edge and extending obliquely from the first blade surface to the second blade surface when viewed from the radial direction, the inclined surface being a plane whose cross-sectional shape when viewed from the radial direction is inclined so that it connects at an acute angle with the second blade surface at the trailing edge.

[0008] In addition, the rotary machine according to the present disclosure comprises a rotor including a rotating shaft extending in an axial direction along which an axis extends and centered on the axis, and an impeller fixed to the rotating shaft, a casing that covers the rotor and has an intake port through which a working fluid flows into the interior, and the inlet guide vane arranged inside the casing on a first side in the axial direction relative to the impeller. [Effects of the Invention]

[0009] According to the inlet guide vane and rotary machine of the present disclosure, it is possible to suppress the generation of Karman vortices by fluid that has passed through the inlet guide vane. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating a schematic configuration of a rotary machine according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view showing the configuration of the rotary machine in a state where movable blades of an inlet guide vane are fully opened. [Figure 3] FIG. 2 is a schematic diagram showing an inlet guide vane as viewed from the radial direction. [Figure 4] FIG. 10 is a schematic diagram showing an inlet guide vane according to a modified example as viewed from the radial direction. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments for implementing an inlet guide vane and a rotary machine according to the present disclosure will be described with reference to the accompanying drawings. However, the present disclosure is not limited to these embodiments.

[0012] <Embodiment> (Configuration of geared compressor) As shown in Figures 1 and 2, a geared compressor (centrifugal compressor) 1 as a rotary machine according to this embodiment mainly includes a rotor 3, a casing 2 (see Figure 2), an inlet guide vane 6 (see Figure 2), a radial bearing 12, and a thrust bearing 17.

[0013] (Rotor configuration) The rotor 3 is rotatable about an axis O relative to the casing 2. The rotor 3 includes a rotary shaft 30, an impeller 40, and an impeller cap .

[0014] The rotating shaft 30 extends in an axial direction Da along which the axis O extends, with the axis O as its center. As shown in FIG. 1 , the rotating shaft 30 is supported by a pair of radial bearings 12 so as to be rotatable about the axis O. The pair of radial bearings 12 are arranged at a distance from each other in the axial direction Da. Movement of the rotating shaft 30 in the axial direction Da is restricted by a pair of thrust bearings 17. The pair of thrust bearings 17 are arranged between the pair of radial bearings 12 at positions spaced apart on both sides of a pinion gear 15, which will be described later, in the axial direction Da.

[0015] The rotating shaft 30 is connected to an external driving source (not shown) such as a motor via the speed-increasing transmission unit 11. The speed-increasing transmission unit 11 includes a pinion gear 15 and a large-diameter gear 16. The pinion gear 15 is fixed to the rotating shaft 30 between a pair of radial bearings 12. The large-diameter gear 16 meshes with the pinion gear 15. The large-diameter gear 16 is driven to rotate by the driving source. The large-diameter gear 16 has an outer diameter dimension set larger than that of the pinion gear 15. Therefore, the rotation speed of the rotating shaft 30 to which the pinion gear 15 is fixed is higher than the rotation speed of the large-diameter gear 16. In other words, the speed-increasing transmission unit 11 increases the rotation speed of the large-diameter gear 16, which is driven by the external driving source, via the pinion gear 15, and transmits the rotation to the rotating shaft 30.

[0016] The impellers 40 are disposed on both ends of the rotary shaft 30 in the axial direction Da. As shown in Fig. 2, in this embodiment, each impeller 40 is a so-called closed impeller that includes a disk 41, blades 42, and a cover 43. Note that the impeller 40 may also be an open impeller that does not have the cover 43.

[0017] The disk 41 is disk-shaped and fixed to the rotary shaft 30. The disk 41 has a first surface 41a facing the cover 43 in the axial direction Da and a second surface 41b facing the opposite side from the first surface 41a in the axial direction Da. The second surface 41b is the back surface of the impeller 40. Here, as shown in FIG. 1 , in this embodiment, the geared compressor 1 includes an impeller 40 at each end of the rotary shaft 30 in the axial direction Da. Each impeller 40 is disposed such that the second surface 41b of the disk 41, which is the back surface, faces the pinion gear 15 in the axial direction Da, and the first surface 41a faces the end of the rotary shaft 30 opposite the pinion gear 15. In other words, the disks 41 of the first-stage impeller 40A provided at the first end of the rotary shaft 30 and the second-stage impeller 40B provided at the second end of the rotary shaft 30 are oriented in opposite directions in the axial direction Da so that their back surfaces face each other.

[0018] In the following description, in each impeller 40, the first surface 41a side of the disk 41 is referred to as the first side Da1 in the axial direction Da, and the second surface 41b side is referred to as the second side Da2 in the axial direction Da. That is, in the first stage impeller 40A and the second stage impeller 40B, the first side Da1 in the axial direction Da and the second side Da2 in the axial direction Da face opposite each other.

[0019] 2, the blades 42 extend from the first surface 41a of the disk 41 to the cover 43. The blades 42 are arranged at intervals in the circumferential direction Dc of the rotation shaft 30 around the axis O.

[0020] The cover 43 is disposed on a first side Da1 in the axial direction Da with respect to the disk 41 and the plurality of blades 42. The cover 43 is disk-shaped and formed to cover the plurality of blades 42.

[0021] A working fluid (e.g., air) flows through the impeller 40 from a first side Da1 in the axial direction Da to a second side Da2 in the axial direction Da. Each impeller 40 has an impeller flow path 45 formed between the disk 41 and the cover 43. The impeller flow path 45 has an inlet 45i and an outlet 45o. The inlet 45i opens toward the first side Da1 in the axial direction Da on the inner side Dri in the radial direction Dr of the impeller 40. Here, the radial direction Dr is the radial direction Dr of the rotation shaft 30 centered on the axis O. The outlet 45o opens toward the outer side Dro of the impeller 40 in the radial direction Dr.

[0022] A shaft end 30s, which is the end of the rotating shaft 30 in the axial direction Da, protrudes toward a first side Da1 in the axial direction Da relative to the impeller 40. An impeller cap 38 is fixed to the shaft end 30s. The impeller cap 38 rotates together with the rotating shaft 30. The impeller cap 38 forms a rotor end 3e, which is the end of the rotor 3 in the axial direction Da. The impeller cap 38 restricts movement of the impeller 40 in the axial direction Da. In other words, the impeller cap 38 restrains the position of the impeller 40 in the axial direction Da so that it does not fall off the rotating shaft 30.

[0023] (Casing configuration) As shown in Fig. 2, the casing 2 is formed to cover the rotor 3. The casing 2 is made of metal and forms an outer shell of the geared compressor 1. The casing 2 has a shaft insertion hole 21, through which the rotating shaft 30 is inserted, on the second side Da2 in the axial direction Da relative to the position where the impeller 40 is disposed. The casing 2 has an intake nozzle 22 and an exhaust flow path 23 around each impeller 40.

[0024] The intake nozzle 22 introduces working fluid into the interior of the casing 2. The intake nozzle 22 is formed in a cylindrical shape extending in the axial direction Da. An intake port 22a is formed inside the intake nozzle 22 and is centered on the axis O. Through the intake port 22a, the intake nozzle 22 communicates with the outside of the casing 2 and an inlet 45i of the impeller flow path 45 that opens to the inside Dri of the impeller 40 in the radial direction Dr. As the impeller 40 rotates in the circumferential direction Dc around the axis O, the working fluid is sucked from the outside of the casing 2 into the inside through the intake port 22a.

[0025] The exhaust passage 23 allows the working fluid inside the casing 2 to flow out of the casing 2. The exhaust passage 23 is formed on the outer side Dro in the radial direction Dr of the outlet 45o of the impeller passage 45. The exhaust passage 23 has a spiral shape that continues in the circumferential direction Dc.

[0026] (Inlet guide vane configuration) The inlet guide vane 6 controls the flow rate of the working fluid passing through the suction port 22a. The inlet guide vane 6 is arranged on the inside Dri of the suction nozzle 22 of the casing 2. In other words, the inlet guide vane 6 is arranged on the first side Da1 in the axial direction Da with respect to the impeller 40 within the casing 2. The inlet guide vane 6 has a plurality of movable blades 60. The plurality of movable blades 60 are arranged to protrude into the suction port 22a, which has a circular cross section when viewed from the axial direction Da. The plurality of movable blades 60 are arranged at equal intervals in the circumferential direction Dc about the axis O along the inner circumferential surface of the suction nozzle 22.

[0027] The movable blades 60 are rotatable around a central axis Ar extending in the radial direction Dr. As shown in Fig. 3, the multiple movable blades 60 increase their opening by rotating in the opposite direction to the rotation direction R of the rotating shaft 30. Here, the rotation direction R is the direction in which the rotating shaft 30 moves from rear to front in the circumferential direction Dc.

[0028] Here, the state in which the movable vanes 60 are arranged so that the blade chord direction D2 is parallel to the flow direction F (axial direction Da) of the working fluid is considered to be the fully open state of the movable vanes 60. In other words, the fully open state is a state in which the movable vanes 60 (blade main body 61) have rotated so that they are at their thickest in a cross-sectional view parallel to the axis O. When the movable vanes 60 are in the fully open state, the flow rate of the working fluid passing through the suction port 22a becomes 100%. Note that when viewed from the radial direction Dr, the movable vanes 60 further rotate from the fully open state toward the same direction as the rotation direction R of the rotating shaft 30, and the flow rate of the working fluid passing through the suction port 22a becomes 120%. The state in which the movable vanes 60 are arranged in this manner is considered to be the over-open state of the movable vanes 60. In contrast, when viewed from the radial direction Dr, if the movable vane 60 is rotated around the central axis Ar from the fully open state toward the opposite side of the rotation direction R of the rotary shaft 30, and the blade chord direction D2 intersects with the flow direction F (axial direction Da) of the working fluid, the suction port 22a is gradually blocked by the blade main body 61. As a result, the flow rate of the working fluid flowing into the impeller 40 from the suction port 22a through the inlet guide vanes 6, 6A decreases. The state in which the blade chord direction D2 is perpendicular to the flow direction F (axial direction Da) of the working fluid is considered to be the fully closed state of the movable vane 60. In other words, the fully closed state is a state in which the movable vane 60 (blade main body 61) has rotated to be thinnest in a cross section parallel to the axis O. Also, as shown in FIGS. 2 and 3 , in this embodiment, each movable vane 60 has a blade main body 61 and a shaft portion 62.

[0029] Each blade body 61 extends in a blade height direction D1, which is the direction in which the central axis Ar extends (radial direction Dr), so as to protrude from the inner circumferential surface of the intake nozzle 22. Here, the direction connecting the leading edge 61f and the trailing edge 61r of the blade body 61 having a blade cross-sectional shape and perpendicular to the blade height direction D1 (radial direction Dr) is referred to as the blade chord direction D2. The blade body 61 has a first blade surface 611, a second blade surface 612, and an inclined surface 613.

[0030] The first blade surface 611 and the second blade surface 612 extend in the blade chord direction D2. The first blade surface 611 and the second blade surface 612 are formed as planes whose cross-sectional shapes, when viewed from the radial direction Dr, are linear in the blade chord direction D2. In other words, the first blade surface 611 and the second blade surface 612 do not have any irregularities or curved surfaces when viewed from the radial direction Dr. As a result, the cross-sectional shape of the blade main body 61, when viewed from the radial direction Dr, is a flat plate extending in the blade chord direction D2. The first blade surface 611 and the second blade surface 612 are parallel to each other. In the blade chord direction D2, the second blade surface 612 is formed longer than the first blade surface 611. The first blade surface 611 is located forward of the second blade surface 612 in the rotation direction R of the rotation shaft 30.

[0031] The inclined surface 613 is formed at the rear end including the trailing edge 61r. The inclined surface 613 extends obliquely from the first blade surface 611 to the second blade surface 612. The inclined surface 613 is a plane inclined so that its cross-sectional shape, as viewed from the radial direction Dr, connects to the second blade surface 612 at an acute angle at the trailing edge 61r. Therefore, the inclined surface 613 is inclined to face the first side Da1 in the axial direction Da so as to face the suction port 22a when the movable blade 60 is in a fully closed state. The inclined surface 613 is formed as a linear plane without any irregularities or curves when viewed from the radial direction Dr. The inclined surface 613 has a constant angle with respect to the first surface 41a and the second surface 41b in the blade height direction D1. When viewed from the radial direction Dr, the inclined surface 613 is inclined at an angle of 15° to 45° with respect to the second blade surface 612. Preferably, the inclined surface 613 is inclined at an angle of 25° or more and 35° or less with respect to the second blade surface 612 when viewed from the radial direction Dr. Furthermore, the trailing end where the inclined surface 613 is formed is a partial region including the trailing edge 61r away from the central axis Ar when the movable blade 60 is viewed from the radial direction Dr. The trailing end is a region that is 1 / 3 or less of the total length of the movable blade 60 in the blade chord direction D2, and in this embodiment, is a region that is 1 / 4 or less.

[0032] As shown in FIG. 2, the shaft portion 62 is formed to protrude from the blade main body 61 to the outer side Dro in the radial direction Dr. The shaft portion 62 is formed integrally with the blade main body 61. The shaft portion 62 is inserted into a shaft support hole 22h formed in the intake nozzle 22. While inserted into the shaft support hole 22h, the shaft portion 62 is rotatable about the central axis Ar by a blade drive device (not shown). This allows the blade main body 61 to rotate integrally with the shaft portion 62 about the central axis Ar. By rotating each movable blade 60 about the central axis Ar, the angle of the blade main body 61 with respect to the flow direction F (axial direction Da) of the working fluid flowing through the suction port 22a is adjusted. By rotating each of the multiple movable blades 60 about the central axis Ar, the inlet guide vane 6 is opened and closed.

[0033] In this geared compressor 1, the impeller 40 rotates integrally with the rotary shaft 30, and the working fluid is sucked into the intake nozzle 22 of the casing 2 through the intake port 22a. Within the intake port 22a, the flow rate of the working fluid is adjusted by the opening of the inlet guide vane 6 as it passes through the inlet guide vane 6. The working fluid that has passed through the inlet guide vane 6 is taken into the impeller flow path 45 from the intake nozzle 22 through the inlet 45i. The working fluid flows from the inlet 45i toward the outlet 45o due to centrifugal force generated by the impeller 40, which rotates integrally with the rotary shaft 30. The working fluid is compressed as it flows from the inlet 45i toward the outlet 45o. The compressed working fluid flows out from the outlet 45o to the outer side Dro in the radial direction Dr and is sent to the exhaust flow path 23 on the outer side Dro in the radial direction Dr. The working fluid is further compressed while swirling around the axis O along the exhaust flow path 23.

[0034] (Action and effect) According to the inlet guide vane 6 and geared compressor 1 described above, an inclined surface 613 is formed at the rear end of the movable vane 60, extending obliquely from the first blade surface 611 to the second blade surface 612 and connecting to the second blade surface 612 at an acute angle at the trailing edge 61r. In other words, when viewed from the radial direction Dr, the inclined surface 613 gives the rear end of the movable vane 60 an asymmetric shape. As a result, the generation of Karman vortices by the fluid that has passed through the inlet guide vane 6 can be suppressed.

[0035] The first blade surface 611 and the second blade surface 612 are parallel to each other and have a cross-sectional shape, as viewed from the radial direction Dr, that is, a plane that is linear in the blade chord direction D2. That is, the movable blades 60 have a linear shape. Therefore, when the inlet guide vanes 6 are brought close to a fully closed state, the gap between adjacent movable blades 60 can be reduced. This reduces the amount of leakage of working fluid flowing through this gap. This improves the opening characteristics even when the inlet guide vanes 6 are in a low opening state.

[0036] Furthermore, by forming the inclined surface 613 as a flat surface, the workability of the inclined surface 613 can be improved. As a result, a shape that suppresses the generation of Karman vortices can be easily formed at the trailing end of the movable blade 60. Furthermore, by forming not only the inclined surface 613 but also the first blade surface 611 and the second blade surface 612 as flat surfaces, the workability of the entire movable blade 60 can be improved. As a result, not only the inclined surface 613 but also the movable blade 60 itself can be easily formed.

[0037] Moreover, when viewed from the radial direction Dr, the inclined surface 613 is inclined at an angle of 15° or more and 45° or less with respect to the second blade surface 612. By inclining the inclined surface 613 at an angle of 15° or more with respect to the second blade surface 612, it is possible to suppress the generation of Karman vortices with a high probability. Furthermore, by inclining the inclined surface 613 at an angle of 45° or less with respect to the second blade surface 612, it is possible to suppress separation of the working fluid flowing along the inclined surface 613.

[0038] Furthermore, the multiple movable vanes 60 rotate in the opposite direction to the rotation direction R of the rotary shaft 30, thereby widening the opening degree. The first blade surface 611 is located forward of the second blade surface 612 in the rotation direction R. As a result, when the opening degree of the movable vanes 60 is widened, the inclined surface 613 widens the flow path between adjacent movable vanes 60 at their rear ends. This makes it possible to further raise the head of the compressor when the opening degree of the movable vanes 60 is widened. This therefore makes it possible to further improve the performance of the movable vanes 60 when they are in an over-open state.

[0039] <Modification> Next, an inlet guide vane 6A according to a modified example of the present disclosure will be described. In the modified example described below, components common to the above embodiment are denoted by the same reference numerals in the drawings, and their description will be omitted. In the modified example, the rotation direction R of the rotary shaft 30 differs from that of the above embodiment.

[0040] As shown in Figure 4, the rotation direction R of the rotary shaft 30 is reversed. That is, the direction in which the rotary shaft 30 moves from rear to front in the circumferential direction Dc is reversed from that of the embodiment. The multiple movable vanes 60A rotate in the opposite direction to the rotation direction R of the rotary shaft 30, thereby widening the opening. Therefore, in the inlet guide vane 6A of the modified example, the rotation direction of the multiple movable vanes 60A is different from that of the embodiment.

[0041] In the inlet guide vane 6A of this modified example, as in the embodiment, the movable blade 60A has an asymmetric shape at the rear end due to the inclined surface 613 when viewed from the radial direction Dr. As a result, it is possible to suppress the generation of Karman vortices by the fluid that has passed through the inlet guide vane 6A. In other words, regardless of the rotation direction R of the rotating shaft 30, it is possible to suppress the generation of Karman vortices by the inclined surface 613.

[0042] (Other embodiments) The above describes in detail the embodiments of the present disclosure with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present disclosure.

[0043] In the above embodiment, a so-called single-shaft, two-stage configuration has been described as an example of the geared compressor 1. However, the configuration of the geared compressor 1 is not limited to this, and the geared compressor 1 may have two shafts, four stages, or more shafts or stages depending on the design and specifications.

[0044] Furthermore, the rotary machine of the present invention is not limited to a geared compressor, but may be a single-shaft multi-stage centrifugal compressor in which the rotary shaft 30 is directly rotated by an external drive source, a gas turbine, a steam turbine, or the like.

[0045] Furthermore, the first blade surface 611 is not limited to being located forward of the second blade surface 612 in the rotation direction R. For example, contrary to the embodiments and modified examples, the first blade surface 611 may be located rearward of the second blade surface 612 in the rotation direction R. When the first blade surface 611 and the second blade surface 612 are arranged in this manner, the inclined surface 613 is inclined to face the second side Da2 in the axial direction Da so as to face the impeller 40 when the movable blades 60 are in a fully closed state.

[0046] <Additional Notes> The inlet guide vanes 6, 6A and the rotary machine 1 described in the embodiment can be understood, for example, as follows.

[0047] (1) The inlet guide vane 6, 6A according to the first embodiment has a plurality of movable blades 60, 60A arranged at intervals in the circumferential direction Dc of the rotating shaft 30 and rotatable around a central axis extending in the radial direction Dr of the rotating shaft 30, and the movable blades 60, 60A have a first blade surface 611 and a second blade surface 612 extending in a direction connecting a leading edge 61f and a trailing edge 61r, and an inclined surface 613 formed at the rear end including the trailing edge 61r and extending obliquely from the first blade surface 611 to the second blade surface 612 when viewed from the radial direction Dr, and the inclined surface 613 is a plane whose cross-sectional shape as viewed from the radial direction Dr is inclined so that it connects at an acute angle with the second blade surface 612 at the trailing edge 61r.

[0048] As a result, when viewed from the radial direction Dr, the movable blades 60, 60A have asymmetric shapes at their rear ends due to the inclined surfaces 613. As a result, it is possible to suppress the generation of Karman vortices by the fluid that has passed through the inlet guide vanes 6, 6A.

[0049] (2) The inlet guide vane 6, 6A according to the second aspect is the inlet guide vane 6, 6A of (1), in which the first blade surface 611 and the second blade surface 612 are formed by planes whose cross-sectional shapes, as viewed from the radial direction Dr, are linear in the direction connecting the leading edge 61f and the trailing edge 61r and are parallel to each other.

[0050] This gives the moving blades a linear shape. Therefore, when the inlet guide vanes 6, 6A are brought close to a fully closed state, the gap between adjacent moving blades 60, 60A can be made small. This reduces the amount of leakage of working fluid flowing through this gap. This improves the opening characteristics even when the inlet guide vanes 6, 6A are in a low opening state.

[0051] (3) The inlet guide vane 6, 6A according to the third aspect is the inlet guide vane 6, 6A of (1) or (2), wherein the inclined surface 613 is inclined at an angle of 15° or more and 45° or less with respect to the second blade surface 612 when viewed from the radial direction Dr.

[0052] By inclining the inclined surface 613 at an angle of 15° or more with respect to the second blade surface 612, it is possible to suppress the generation of Karman vortices with a high probability. Furthermore, by inclining the inclined surface 613 at an angle of 45° or less with respect to the second blade surface 612, it is possible to suppress separation of the working fluid flowing along the inclined surface 613.

[0053] (4) The inlet guide vane 6, 6A according to the fourth aspect is any one of the inlet guide vanes 6, 6A of (1) to (3), in which the plurality of movable blades 60, 60A increase the opening angle by rotating in the opposite direction to the rotation direction R of the rotating shaft 30, and the first blade surface 611 is positioned forward of the second blade surface 612 in the rotation direction R.

[0054] As a result, when the opening of the movable vanes 60, 60A is increased, the inclined surfaces 613 widen the flow paths between the adjacent movable vanes 60, 60A at their rear ends. This allows the compressor head to be further raised when the opening of the movable vanes 60, 60A is increased. This further improves the performance of the movable vanes 60, 60A when the opening is excessive.

[0055] (5) A rotary machine 1 according to a fifth aspect includes a rotor 3 having a rotating shaft 30 extending in an axial direction Da along which an axis O extends, the rotating shaft 30 being centered on the axis O, and an impeller 40 fixed to the rotating shaft 30; a casing 2 covering the rotor 3 and having an intake port 22a through which a working fluid flows into the rotor 3; and an inlet guide vane 6, 6A selected from any one of (1) to (4) arranged inside the casing 2 on a first side Da1 in the direction of the axis O relative to the impeller 40. [Explanation of symbols]

[0056] 1...Geared compressor (rotary machine) 2...Casing 3...Rotor 3e...Rotor end 6, 6A...Inlet guide vane 11...Speed-up transmission section 12...Radial bearing 15...Pinion gear 16...Large diameter gear 17...Thrust bearing 21...Shaft insertion hole 22...Intake nozzle 22a...suction port 22h…Shaft support hole 23...Exhaust flow path 30...Rotation axis 30s…shaft end 38...Impeller cap 38s…Tip 40...Impeller 40A...First stage impeller 40B...Second stage impeller 41...Disc 41a...front page 41b…Second side 42...Blade 43...Cover 45...Impeller passage 45i…Inlet 45o…outlet 60, 60A…Movable wing 61...Wing body 61f…leading edge 61r… Trailing edge 611...First wing surface 612…Second wing surface 613…Slope surface 62...Shaft Ar…center axis line D1...Wing height direction D2: Wing chord direction Da...Axial direction Da1…first side Da2…Second side Dc…Circumferential direction Dr…Radial direction Dri…inside Dro...outside O…Axis line R...Rotation direction F...flow direction

Claims

1. a plurality of movable blades arranged at intervals in the circumferential direction of the rotary shaft and rotatable around a central axis extending in the radial direction of the rotary shaft; The movable wing includes a first wing surface and a second wing surface extending in a direction connecting a leading edge and a trailing edge, an inclined surface formed at a rear end including a trailing edge and extending obliquely from the first blade surface to the second blade surface when viewed from the radial direction; the inclined surface is a plane whose cross-sectional shape as viewed from the radial direction is inclined so as to be connected to the second blade surface at an acute angle at the trailing edge, The inlet guide vane, wherein the inclined surface is inclined at an angle of 15° to 45° with respect to the second blade surface when viewed from the radial direction.

2. 2. The inlet guide vane according to claim 1, wherein the first blade surface and the second blade surface have cross-sectional shapes, as viewed from the radial direction, that are formed by planes that are linear in a direction connecting the leading edge and the trailing edge and are parallel to each other.

3. the plurality of movable blades rotate in the opposite direction to the rotation direction of the rotary shaft to widen the opening degree; The inlet guide vane according to claim 1 or 2, wherein the first blade surface is located forward of the second blade surface in the rotation direction.

4. a rotor including a rotation shaft extending in an axial direction around the axis line, and an impeller fixed to the rotation shaft; a casing that covers the rotor and has a suction port through which the working fluid flows; The inlet guide vane according to claim 1 or 2, which is disposed inside the casing on the first side in the axial direction with respect to the impeller.

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