Compressor

Abstract

To suppress the lowering of efficiency by suppressing a leakage flow.SOLUTION: A variable stator blade comprises: a variable stator body extending in a blade height direction; and a blade rotating shaft which is connected to an end of the variable stator body in the blade height direction, and is rotatable so as to change an angle of the variable stator body with respect to a flow direction of a working fluid. The blade rotating shaft includes: a rotating shaft body extending around a rotating axis line extending in the blade height direction; and an increased diameter portion extending around the rotating axis line and connecting the rotating shaft body and the stator blade body, the increased diameter portion having a larger outside diameter as viewed from the blade height direction than an outside diameter of the rotating shaft body. The stator blade body has a front edge extending in the blade height direction, a rear edge extending in the blade height direction, and a positive pressure surface and a negative pressure surface extending in the blade height direction and connecting the front edge and the rear edge. The increased diameter portion is formed with a size such that it overlaps at least one of the front edge and the rear edge when viewed from the blade height direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to variable stator vanes and compressors. [Background technology]

[0002] Some compressors include a rotor that rotates about an axis, a casing that covers the rotor, and a plurality of stator blade rows. The rotor has a rotor body centered on the axis, and a plurality of moving blade rows attached to the rotor body. The plurality of moving blade rows are aligned in the axial direction, which is the direction in which the axis extends. Each moving blade row has a plurality of moving blades aligned in the circumferential direction, centered on the axis. The plurality of stator blade rows are attached to the casing. Each of the plurality of stator blade rows is arranged downstream of one of the plurality of moving blade rows. Each stator blade row has a plurality of stator blades aligned in the circumferential direction. Some compressors have a structure in which the stator blades are rotatable.

[0003] For example, the compressor described in Patent Document 1 has a variable stator vane that is rotatably configured to change the angle of the stator vane body with respect to the flow direction of the mainstream of the working fluid. This variable stator vane has a stator vane body connected to a rotating shaft, and a curved surface portion is provided on the blade surface adjacent to the radial end surface that protrudes outward from the rotating shaft. The radius of curvature of the curved surface portion is formed to gradually decrease with increasing distance from the rotating shaft. In the variable stator vane of Patent Document 1, this curved surface portion suppresses turbulence in the flow of the working fluid near the rotating shaft, where the pressure difference between the blade surface is large. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2019 / 116983 Summary of the Invention [Problem to be solved by the invention]

[0005] When variable stator vanes are applied to a compressor, minute gaps are formed between the stator vane body and the inner casing and outer casing that support the stator vane body via the rotating shaft. If leakage flow occurs in these gaps, the flow of the working fluid flowing around them is disturbed, generating vortices. The occurrence of leakage flow in these gaps increases pressure loss, which can reduce the efficiency of the compressor.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a variable stator vane and a compressor that can suppress leakage flow and prevent a decrease in efficiency. [Means for solving the problem]

[0007] In order to solve the above problem, a variable stator vane according to the present disclosure includes a stator vane body extending in a blade height direction intersecting a flow direction of a working fluid, and a blade rotation shaft connected to an end of the stator vane body in the blade height direction and rotatable so as to change an angle of the stator vane body with respect to the flow direction of the working fluid, wherein the blade rotation shaft has a rotation shaft body extending about a rotation axis extending in the blade height direction, and an expanded diameter portion extending about the rotation axis to connect the rotation shaft body and the stator vane body, the expanded diameter portion having an outer diameter when viewed from the blade height direction greater than that of the rotation shaft body, the stator vane body has a leading edge extending in the blade height direction, a trailing edge extending in the blade height direction, and a pressure surface and a suction surface extending in the blade height direction and connecting the leading edge and the trailing edge, and the expanded diameter portion is formed to a size such that it overlaps with at least one of the leading edge and the trailing edge when viewed from the blade height direction.

[0008] The compressor according to the present disclosure includes a rotor including the variable stator vanes as described above, a rotor body, and a plurality of rotor blades arranged in the axial and circumferential directions of the rotor body, an inner casing arranged outside the rotor, an outer casing arranged outside the inner casing, and a rotary drive unit connected to the blade rotation shaft and rotating the blade rotation shaft, and the variable stator vanes are arranged rotatably relative to the inner casing and outer casing. [Effects of the Invention]

[0009] According to the variable stator vane and compressor of the present disclosure, leakage flow can be suppressed, and a decrease in efficiency can be suppressed. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view of a main portion (upper half on the suction port side) of a compressor according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is an enlarged cross-sectional view of a main portion of the variable stator vane according to the first embodiment of the present disclosure. [Figure 3] FIG. 3 is a schematic view illustrating a variable stator vane taken along the line III-III in FIG. 2. [Figure 4] 4 is a view corresponding to FIG. 3 taken along the arrows and showing a variable stator vane according to a first modified example of the first embodiment of the present disclosure. [Figure 5] 4 is a view taken along an arrow corresponding to FIG. 3, showing a variable stator vane according to a second modified example of the first embodiment of the present disclosure. FIG. [Figure 6] FIG. 5 is an enlarged cross-sectional view of a main portion of a variable stator vane according to a second embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] (First embodiment) Hereinafter, embodiments for implementing a variable stator vane and a compressor 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] (Compressor configuration) The compressor 1 takes in and compresses a large amount of working fluid A. The compressor 1 is, for example, an axial flow compressor applied to a gas turbine. As shown in Fig. 1, the compressor 1 has a rotor 2, a casing 3, and a plurality of variable stator vane mechanisms 4.

[0013] For the sake of convenience in the following description, the direction in which the axis O of the compressor 1 extends is referred to as the axial direction Da. The axial direction Da is also the flow direction of the working fluid A in the compressor 1. The upstream side Dau in the flow direction of the working fluid A is referred to as the upstream side Dau of the axial direction Da (one side, first side). The downstream side Dad in the flow direction of the working fluid A is referred to as the downstream side Dad of the axial direction Da (the other side, second side). The radial direction of the compressor 1 based on the axis O is simply referred to as the radial direction Dr. The side of this radial direction Dr that approaches the axis O is referred to as the inner side Dri of the radial direction Dr. The side of this radial direction Dr opposite to the inner side Dri of the radial direction Dr is referred to as the outer side Dro of the radial direction Dr. The circumferential direction of the compressor 1 centered on the axis O is simply referred to as the circumferential direction Dc.

[0014] The rotor 2 has a rotor body 21 and a plurality of rotor blade rows 22. The rotor body 21 extends in an axial direction Da centered on the axis O. The rotor body 21 is a columnar member centered on the axis O. The rotor body 21 is rotatably supported relative to the casing 3 by bearings (not shown).

[0015] The plurality of moving blade rows 22 are attached to the rotor body 21. The plurality of moving blade rows 22 are arranged at intervals in the axial direction Da. Each of the plurality of moving blade rows 22 has a plurality of moving blades 25 arranged in the circumferential direction Dc. Here, of the plurality of moving blade rows 22, the moving blade row 22 furthest upstream Dau in the axial direction Da is referred to as the first moving blade row 221. The moving blade row 22 arranged downstream Dad in the axial direction Da relative to the first moving blade row 221 is referred to as the second moving blade row 222. Thus, in this embodiment, the first moving blade row 221, second moving blade row 222, third moving blade row 223, and fourth moving blade row 224 are arranged in this order from the upstream side Dau to the downstream side Dad in the axial direction Da.

[0016] A plurality of rotor blades 25 are arranged for each rotor blade row 22. The plurality of rotor blades 25 are fixed to the rotor body 21. The plurality of rotor blades 25 fixed to the rotor body 21 are arranged in the circumferential direction Dc for each rotor blade row 22. The rotor blades 25 are arranged so as to protrude from the outer peripheral surface of the rotor body 21.

[0017] The casing 3 has an inner casing 31, an outer casing 32, and struts 33. The inner casing 31 is formed in a cylindrical shape centered on the axis O, and covers a part of the rotor body 21 from the outside Dro in the radial direction Dr. A plurality of inner casings 31 are arranged spaced apart in the axial direction Da. The outer casing 32 is formed in a cylindrical shape centered on the axis O. The outer casing 32 covers the inner casing 31 and the rotor body 21 from the outside Dro in the radial direction Dr.

[0018] A cylindrical main flow path S through which the working fluid A flows is formed between the outer casing 32 and the inner casing 31. In other words, an inner circumferential surface 321 of the outer casing 32 and an outer circumferential surface 311 of the inner casing 31 form flow path forming surfaces that define a part of the main flow path S. The inner circumferential surface 321 of the outer casing 32 facing the inner side Dri in the radial direction Dr is inclined from the upstream side Dau to the downstream side Dad in the axial direction Da in a region overlapping with positions where the rotor blades 25 and variable stator vanes 5 described later are disposed, when viewed from the circumferential direction Dc. The inner circumferential surface 321 of the outer casing 32 is curved in a concave shape when viewed from the axial direction Da. The outer peripheral surface 311 of the inner casing 31 facing the outer side Dro in the radial direction Dr is inclined from the upstream side Dau to the downstream side Dad in the axial direction Da when viewed from the circumferential direction Dc in a region overlapping with the positions where the rotor blades 25 and the variable stator vanes 5 are arranged. The outer peripheral surface 311 of the inner casing 31 is curved in a convex shape when viewed from the axial direction Da.

[0019] A plurality of struts 33 are arranged in the circumferential direction Dc between the inner casing 31 and the outer casing 32. The plurality of struts 33 connect the inner casing 31 and the outer casing 32 together.

[0020] The casing 3 also has a suction port 35 and a discharge port (not shown). The suction port 35 is formed to open at an end Dau on the upstream side in the axial direction Da of the casing 3. The suction port 35 is connected to the main flow path S. The suction port 35 supplies working fluid A (e.g., outside air) into the main flow path S. The discharge port is formed to open at an end Dad on the downstream side in the axial direction Da of the casing 3. The discharge port is connected to the main flow path S. The discharge port discharges the working fluid A, which has circulated through the main flow path S and been compressed, to the outside of the casing 3.

[0021] (Configuration of variable stator vane mechanism) The multiple variable stator vane mechanisms 4 are arranged on the upstream side Dau in the axial direction Da with respect to each rotor blade row 22 so as to correspond to each rotor blade row 22. That is, in the compressor 1 of the present embodiment, the variable stator vane mechanisms 4 include a first variable stator vane mechanism 41 arranged on the upstream side Dau in the axial direction Da of the first rotor blade row 221, a second variable stator vane mechanism 42 arranged on the upstream side Dau in the axial direction Da of the second rotor blade row 222, a third variable stator vane mechanism 43 arranged on the upstream side Dau in the axial direction Da of the third rotor blade row 223, and a fourth variable stator vane mechanism 44 arranged on the upstream side Dau in the axial direction Da of the fourth rotor blade row 224.

[0022] 1 to 3, the configuration of the variable stator vane mechanism 4 will be described. As shown in Fig. 1, the variable stator vane mechanism 4 is attached to a casing 3. The variable stator vane mechanism 4 of this embodiment has a plurality of variable stator vanes 5 and a rotary drive unit 8.

[0023] (Variable stator vane configuration) The variable stator vanes 5 are arranged rotatably relative to the inner casing 31 and the outer casing 32. The multiple variable stator vanes 5 are arranged side by side in the circumferential direction Dc. The variable stator vanes 5 are arranged on the upstream side Dau of each rotor blade 25 in the axial direction Da. The variable stator vane 5 of this embodiment has a stator vane body 51 and two blade rotation shafts 6.

[0024] The stator vane body 51 is a three-dimensional blade having a blade-shaped cross section and extending in the blade height direction D1. The stator vane body 51 is disposed in a main flow path S through which a working fluid A flows. As shown in Figures 2 and 3, the stator vane body 51 has two edges, a leading edge 511 and a trailing edge 512, and a pressure surface 515 and a suction surface 516, which are blade surfaces.

[0025] The blade height direction D1 in this embodiment is a direction perpendicular to (intersects with) the axial direction Da, which is the flow direction of the working fluid A, and is the radial direction Dr in the compressor 1. A blade chord direction D2, which will be described later, is a direction perpendicular to the blade height direction D1 in this embodiment, includes the direction in which the chord connecting the leading edge 511 and the trailing edge 512 in the blade cross section extends, and is a direction parallel to an imaginary line connecting the tip end of the leading edge 511 and the rear end of the trailing edge 512 when viewed from the blade height direction D1. The blade chord direction D2 may coincide with the axial direction Da in the compressor 1. The direction perpendicular to (intersects with) the flow direction and the blade height direction D1 is the circumferential direction Dc in the compressor 1.

[0026] The leading edge 511 extends in the blade height direction D1. The leading edge 511 is the forward end in the chord direction D2 where the pressure surface 515 and the suction surface 516 are connected. The trailing edge 512 extends in the blade height direction D1. The trailing edge 512 is the rear end in the chord direction D2 where the pressure surface 515 and the suction surface 516 are connected. The pressure surface 515 is the blade surface on the pressure side when viewed from the blade height direction D1, and is formed in a concave shape. The suction surface 516 is the blade surface on the suction side when viewed from the blade height direction D1, and is formed in a convex shape. Therefore, the stator vane main body 51 has an airfoil cross section in which the pressure surface 515 and the suction surface 516 are continuous via the leading edge 511 and the trailing edge 512.

[0027] As shown in FIG. 1 , the ends 52, 53 of the stator vane body in the radial direction Dr are connected to the blade rotation shaft 6. The blade rotation shaft 6 is connected to each of the stator vane bodies 51. The end 52 of the stator vane body on the outer side Dro in the radial direction Dr is inclined so as to move away from the blade rotation shaft 6 from the leading edge 511 toward the trailing edge 512 when viewed from the circumferential direction Dc. In this embodiment, the end 52 of the stator vane body on the outer side Dro in the radial direction Dr is inclined so as to be parallel to the inner circumferential surface 321 of the outer casing 32 when viewed from the circumferential direction Dc. The end 53 of the stator vane body on the inner side Dri in the radial direction Dr is inclined so as to move away from the blade rotation shaft 6 from the leading edge 511 toward the trailing edge 512 when viewed from the circumferential direction Dc. In this embodiment, the end 53 of the stator vane body on the inner side Dri in the radial direction Dr is inclined so as to be parallel to the outer circumferential surface 311 of the inner casing 31 when viewed from the circumferential direction Dc.

[0028] The blade rotation shaft 6 is rotatable so as to change the angle of the stator vane body 51 with respect to the axial direction Da (the direction of the mainstream flow of the working fluid A). The variable stator vane 5 of this embodiment has, as the blade rotation shafts 6, an outer blade rotation shaft 61 connected to an end portion 52 of the stator vane body on the outer side Dro in the radial direction Dr, and an inner blade rotation shaft 62 connected to an end portion 53 of the stator vane body on the inner side Dri in the radial direction Dr. The inner blade rotation shaft 62 and the outer blade rotation shaft 61 extend around the same rotation axis Ar extending in the blade height direction D1. When viewed from the blade height direction D1, the rotation axis Ar is located closer to the leading edge 511 than the trailing edge 512 in the blade chord direction D2.

[0029] The outer blade rotation shaft 61 is disposed rotatably relative to the outer casing 32 around the rotation axis Ar. The outer blade rotation shaft 61 of this embodiment is formed in a shape different from that of the inner blade rotation shaft 62. The outer blade rotation shaft 61 is a cylindrical member extending in the blade height direction D1 around the rotation axis Ar. The outer blade rotation shaft 61 extends so as to penetrate the outer casing 32.

[0030] As shown in Fig. 2, the inner blade rotation shaft 62 is arranged rotatably relative to the inner casing 31 around the rotation axis Ar. The inner blade rotation shaft 62 is housed inside the inner casing 31 so as to fit into a hole recessed from the outer circumferential surface 311 of the inner casing 31. The inner blade rotation shaft 62 of this embodiment has a rotation shaft main body 71, an expanded diameter portion 72, and an outer disk portion 73. The rotation shaft main body 71 extends in the blade height direction D1 around the rotation axis Ar. The rotation shaft main body 71 has a circular cross section centered on the rotation axis Ar.

[0031] The expanded diameter portion 72 extends in the blade height direction D1 around the rotation axis Ar. The expanded diameter portion 72 connects the rotating shaft main body 71 and the stator vane main body 51. The expanded diameter portion 72 is formed integrally with the rotating shaft main body 71 and the stator vane main body 51. The expanded diameter portion 72 has a circular cross section centered on the rotation axis Ar that is larger than that of the rotating shaft main body 71. In other words, the expanded diameter portion 72 is formed so that its outer diameter, when viewed from the blade height direction D1, is larger than that of the rotating shaft main body 71. As shown in FIG. 3 , the position of the side surface of the expanded diameter portion 72 overlaps with the position of the end of the innermost part Dri in the radial direction Dr of the leading edge 511, when viewed from the blade height direction D1. The expanded diameter portion 72 also has a first surface 723 to which the stator vane main body 51 is connected. When viewed from the circumferential direction Dc, the first surface 723 is inclined from the front end portion 721 close to the leading edge 511 toward the rear end portion 722 close to the trailing edge 512 so as to move away from the rotating-shaft main body 71. More specifically, when viewed from the circumferential direction Dc, the first surface 723 is inclined so as to form a straight line from the upstream side Dau to the downstream side Dad in the axial direction Da and toward the outer side Dro in the radial direction Dr so as to be parallel to the outer circumferential surface 311 of the inner casing 31 when the stator vane main body 51 is positioned at a position (angle) when the compressor 1 is operating at a rated speed. Therefore, the first surface 723 is formed so as to form a smooth surface together with the outer circumferential surface 311 of the inner casing 31 when the stator vane main body 51 is positioned at a position (angle) when the compressor 1 is operating at a rated speed. When viewed from the axial direction Da, the outer circumferential surface 311 of the inner casing 31 is curved in a convex shape.

[0032] The outer circular plate portion 73 extends in the blade height direction D1 around the rotation axis Ar. The outer circular plate portion 73 is connected to the rotating shaft main body 71 on the opposite side of the expanded diameter portion 72 in the blade height direction D1. The outer circular plate portion 73 is formed integrally with the rotating shaft main body 71. The outer circular plate portion 73 has a circular cross section centered on the rotation axis Ar that is larger than the rotating shaft main body 71 and smaller than the expanded diameter portion 72. In other words, the outer diameter of the outer circular plate portion 73 when viewed in the blade height direction D1 is larger than the outer diameter of the rotating shaft main body 71 and smaller than the expanded diameter portion 72.

[0033] The rotation drive unit 8 rotates the blade rotation shaft 6. The rotation drive unit 8 is connected to the blade rotation shaft 6. In this embodiment, the rotation drive unit 8 is connected to multiple outer blade rotation shafts 61 in each variable stator vane mechanism 4. The rotation drive unit 8 rotates the outer blade rotation shaft 61 about the rotation axis Ar, thereby indirectly rotating the inner blade rotation shaft 62 about the rotation axis Ar as well. Furthermore, the rotation drive unit 8 rotates the multiple outer blade rotation shafts 61 at the same rotation angle. This changes the rotation angles of the multiple stator vane bodies 51 lined up in the circumferential direction Dc, and changes the flow path area between two stator vane bodies 51 adjacent to each other in the circumferential direction Dc.

[0034] (Action and effect) In the variable stator vane 5 and compressor 1 configured as described above, when the blade rotation shaft 6 is formed to a size that does not overlap the stator vane body 51 when viewed from the blade height direction D1, minute gaps of about several millimeters are formed between the ends 52, 53 of the stator vane body and the inner casing 31 or the outer casing 32 around the leading edge 511 or the trailing edge 512 of the stator vane body 51 that do not overlap with the blade rotation shaft 6. If leakage flow occurs in this gap, the flow of the working fluid A flowing around it is disturbed, and a vortex is generated.

[0035] However, due to the expanded diameter portion 72, the leading edge 511 and the inner blade rotation shaft 62 overlap when viewed from the blade height direction D1. Therefore, no gap is generated between the stator vane body 51 and the inner casing 31 around the leading edge 511. Therefore, no turbulence occurs in the flow of the working fluid A between the stator vane body 51 and the inner casing 31 around the leading edge 511 of the inner casing 31. This prevents leakage flow from occurring in the gap, thereby reducing pressure loss. As a result, it is possible to suppress a decrease in the efficiency of the compressor 1 due to pressure loss in the variable stator vanes 5.

[0036] Furthermore, in a structure in which the stator vane body 51 protrudes in the chord direction D2 relative to the blade rotation shaft 6, vibrations become large at distant positions that are not fixed to the blade rotation shaft 6, such as the leading edge 511 and the trailing edge 512. As a result, there is a possibility that the vibratory stress at the leading edge 511 and the trailing edge 512 will increase. This becomes more pronounced as the size of the compressor 1 increases and the stator vane body 51 becomes larger. However, in this embodiment, the leading edge 511 of the end portion 53 of the stator vane body is connected to the expanded diameter portion 72, thereby suppressing vibration at the leading edge 511.

[0037] Furthermore, turbulence in the flow of the working fluid A occurs in both the inner casing 31 and the outer casing 32, but is more pronounced around the leading edge 511 of the inner casing 31, where the flow rate of the working fluid A is high. Therefore, the influence of the gap becomes greater around the leading edge 511 of the inner casing 31. In this embodiment, the expanded diameter portion 72 prevents a gap from occurring between the stator vane body 51 and the inner casing 31 around the leading edge 511. Therefore, turbulence in the flow of the working fluid A does not occur around the leading edge 511 of the inner casing 31. This suppresses leakage flow in the gap around the leading edge 511, and suppresses a decrease in the efficiency of the compressor 1.

[0038] Furthermore, when viewed from the blade height direction D1, the rotation axis Ar of the inner blade rotation shaft 62 is disposed in a position closer to the leading edge 511 in the blade chord direction D2 than to the trailing edge 512. That is, in the blade chord direction D2, the inner blade rotation shaft 62 is disposed in a position closer to the leading edge 511 than to the trailing edge 512. Therefore, the expanded diameter portion 72 can intensively suppress turbulence of the flow of the working fluid A around the leading edge 511 of the inner casing 31. This makes it possible to more accurately suppress the occurrence of leakage flow in the gap around the leading edge 511 and suppress a decrease in the efficiency of the compressor 1.

[0039] (First Modification of the First Embodiment) Next, a first modified example of the first embodiment of the variable stator vane 5 according to the present disclosure will be described. In the first modified example of the first embodiment described below, components common to the first embodiment will be denoted by the same reference numerals in the drawings, and descriptions thereof will be omitted. In the first modified example of the first embodiment, the shape of the expanded diameter portion 72A of the blade rotation shaft 6A is different from that of the first embodiment.

[0040] Specifically, the expanded diameter portion 72A is not limited to a shape overlapping only with the leading edge 511 when viewed from the blade height direction D1, as in the first embodiment. The expanded diameter portion 72A only needs to overlap with at least one of the leading edge 511 and the trailing edge 512 when viewed from the blade height direction D1. Therefore, when viewed from the blade height direction D1, the expanded diameter portion 72A may overlap only with the trailing edge 512, or may overlap with both the leading edge 511 and the trailing edge 512. In the inner blade rotating shaft 62 of the first modified example of the first embodiment, as shown in FIG. 4, the expanded diameter portion 72A may overlap with both the leading edge 511 and the trailing edge 512 when viewed from the blade height direction D1. Even in this state, the expanded diameter portion 72A has a circular cross section centered on the rotation axis Ar that is larger than that of the rotating shaft main body 71.

[0041] In this way, due to the expanded diameter portion 72A, the trailing edge 512 and the inner blade rotation shaft 62 overlap when viewed from the blade height direction D1. Therefore, no gap is generated between the stator vane body 51 and the inner casing 31 around the trailing edge 512. Therefore, no turbulence occurs in the flow of the working fluid A between the stator vane body 51 and the inner casing 31 around the trailing edge 512 of the inner casing 31. This prevents leakage flow from occurring in the gap, thereby reducing pressure loss.

[0042] Furthermore, due to the expanded diameter portion 72A of the first modified example, the leading edge 511 and the entire area of ​​the leading extension overlap with the inner blade rotation axis 62 when viewed from the blade height direction D1. Therefore, no gap is generated between the stator vane body 51 and the inner casing 31 in the entire area from the leading edge 511 to the trailing edge 512. Therefore, no turbulence occurs in the flow of the working fluid A between the stator vane body 51 and the inner casing 31 in the entire area from the leading edge 511 to the trailing edge 512. This more effectively suppresses leakage flow in the gap, minimizing pressure loss. As a result, it is possible to significantly suppress a decrease in the efficiency of the compressor 1 due to pressure loss in the variable stator vanes 5.

[0043] (Second Modification of the First Embodiment) Next, a second modified example of the first embodiment of the variable stator vane 5 according to the present disclosure will be described. In the second modified example of the first embodiment described below, components common to the first embodiment will be denoted by the same reference numerals in the drawings, and descriptions thereof will be omitted. In the second modified example of the first embodiment, the shape of the expanded diameter portion 72B of the blade rotation shaft 6B is different from that of the first embodiment.

[0044] 5, in the inner blade rotation shaft 62 of the second modified example of the first embodiment, the expanded diameter portion 72B overlaps only with the leading edge 511 when viewed from the blade height direction D1, as in the first embodiment. However, the expanded diameter portion 72B is formed to a size that allows it to come into sliding contact with the expanded diameter portion 72B of another adjacent variable stator vane 5 when viewed from the blade height direction D1. In other words, the expanded diameter portion 72B is formed to the largest possible size without interfering with the expanded diameter portion 72B of another adjacent variable stator vane 5. When viewed from the blade height direction D1, the expanded diameter portion 72B expands in the blade chord direction D2 to a position beyond the leading edge 511.

[0045] In this way, due to the expanded diameter portion 72B, when viewed from the blade height direction D1, the stator vane body 51 and the inner blade rotation shaft 62 overlap over a very large area, not just at the leading edge 511. This results in a very large area where no gap occurs between the stator vane body 51 and the inner casing 31. As a result, turbulence in the flow of the working fluid A does not occur over a wide area between the stator vane body 51 and the inner casing 31. This significantly reduces the occurrence of leakage flow in the gap, and significantly reduces pressure loss.

[0046] It should be noted that the expanded diameter portions 72, 72A, and 72B are not necessarily limited to a structure in which they overlap the leading edge 511 when viewed from the blade height direction D1. The expanded diameter portion 72 only needs to be formed to a size that allows it to overlap at least one of the leading edge 511 and the trailing edge 512 when viewed from the blade height direction D1. Therefore, for example, the expanded diameter portion 72 may overlap only the trailing edge 512 when viewed from the blade height direction D1.

[0047] Second Embodiment Next, a second embodiment of the variable stator vane 5 according to the present disclosure will be described. In the second embodiment described below, components common to the first embodiment will be denoted by the same reference numerals in the drawings, and descriptions thereof will be omitted. In the second embodiment, the shape of the periphery of the expanded diameter portion 72C of the blade rotation shaft 6C is different from that of the first embodiment.

[0048] As shown in FIG. 6 , in the expanded diameter portion 72C of the second embodiment, the first surface 723C is recessed from the front end 721 to the rear end 722 of the stator vane body as viewed in the circumferential direction Dc so as to move away from the end 53 of the stator vane body. The first surface 723C is recessed from the imaginary line VL. The imaginary line VL is an imaginary line that corresponds to the position of the outer circumferential surface 311 of the inner casing 31 as viewed in the circumferential direction Dc, assuming that the outer circumferential surface 311 of the inner casing 31 is not recessed. The first surface 723C of the present embodiment is formed as a three-dimensional curved surface in which the recess amount ΔD from the imaginary line VL at the rotation axis Ar is the largest. The first surface 723C is recessed to reduce a step ΔH that occurs between the imaginary line VL and the side surface when the stator vane body 51 is rotated, for example, by approximately 15° to 25° relative to a state in which the stator vane body 51 is positioned (angle) when the compressor 1 is in rated operation. The recess amount ΔD from the imaginary line VL at the rotation axis Ar is formed to be larger than the step ΔH. Furthermore, when viewed from the circumferential direction Dc, the outer peripheral surface 311 of the inner casing 31 is also recessed from the imaginary line VL on the downstream side Dad in the axial direction Da. When viewed from the circumferential direction Dc, on the downstream side Dad in the axial direction Da with respect to the expanded diameter portion 72C, the outer peripheral surface 311 of the inner casing 31 is recessed as an extension of the first surface 723C in a state where the stator vane body 51 is positioned at a position (angle) when the compressor 1 is operating at rated speed.

[0049] Generally, when the blade rotating shaft 6 is rotated so that the vane body 51 is positioned at the opening angle (angle) required for rated operation of the compressor 1, the first surface 723, which is the top surface of the inner blade rotating shaft 62, is nearly smooth with the outer peripheral surface 311 of the inner casing 31. In other words, while the compressor 1 is operating at rated speed, the first surface 723 is almost even with respect to the outer peripheral surface 311 of the inner casing 31. On the other hand, when the compressor 1 is operating outside of rated speed, such as when starting or stopping, the opening angle (angle) is changed, and the blade rotating shaft 6 is rotated at an angle different from that required for rated speed operation. The first surface 723 has different sizes in the blade height direction D1 between the front end 721 and the rear end 722. Therefore, as the blade rotating shaft 6 rotates, the front end 721 is recessed relative to the outer peripheral surface 311 of the inner casing 31, while the rear end 722 protrudes. In particular, in this embodiment, since the diameter of the expanded diameter portion 72 is large, there is a large difference in size in the blade height direction D1 between the front end portion 721 and the rear end portion 722. In other words, there may be cases where the first surface 723 becomes significantly uneven relative to the outer peripheral surface 311 of the inner casing 31.

[0050] However, in the second embodiment, the first surface 723C of the expanded diameter portion 72C is recessed. Therefore, it is possible to reduce the unevenness of the first surface 723C relative to the outer circumferential surface 311 of the inner casing 31. This makes it possible to reduce the blade surface Mach number of the variable stator vanes 5 when operating at an opening degree different from the rated operation. As a result, it is possible to significantly improve the efficiency when the compressor 1 is operated at a low atmospheric temperature or a high flow rate.

[0051] (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.

[0052] The number of the rotor blade rows 22 and the variable stator vane mechanisms 4 is not limited to that in the embodiment. The number of the rotor blade rows 22 and the variable stator vane mechanisms 4 may be one or more. Therefore, the number of the rotor blade rows 22 and the variable stator vane mechanisms 4 may be only one, or may be four or more as in the present embodiment.

[0053] In this embodiment, the inner blade rotation shaft 62 and the outer blade rotation shaft 61 have different shapes. However, the inner blade rotation shaft 62 and the outer blade rotation shaft 61 are not limited to having different shapes and may have the same shape. However, it is preferable that at least the inner blade rotation shaft 62 has an expanded diameter portion 72.

[0054] <Additional Notes> The variable stator vanes 5 and the compressor 1 described in each embodiment can be understood, for example, as follows.

[0055] (1) A variable stator vane 5 according to a first aspect includes a stator vane body 51 extending in a blade height direction D1 intersecting the flow direction of a working fluid A, and a blade rotation shaft 6B connected to ends 52, 53 of the stator vane body in the blade height direction D1 and rotatable so as to change the angle of the stator vane body 51 relative to the flow direction of the working fluid A. The blade rotation shaft 6B includes a rotation shaft body 71 extending about a rotation axis Ar extending in the blade height direction D1, and a rotor 72 extending about the rotation axis Ar and connecting the rotation shaft body 71 and the stator vane body. and an expanded diameter portion 72 connecting the stator vane main body 51 to the rotor shaft main body 71 and having an outer diameter larger than the outer diameter of the rotor shaft main body 71 when viewed from the blade height direction D1. The stator vane main body 51 has a leading edge 511 extending in the blade height direction D1, a trailing edge 512 extending in the blade height direction D1, and a pressure surface 515 and a suction surface 516 extending in the blade height direction D1 and connecting the leading edge 511 and the trailing edge 512. The expanded diameter portion 72 is formed to have a size that overlaps with at least one of the leading edge 511 and the trailing edge 512 when viewed from the blade height direction D1.

[0056] As a result, no gap is generated between the stator vane body 51 and the casing 3 around at least one of the leading edge 511 and the trailing edge 512. Therefore, no turbulence occurs in the flow of the working fluid A between the stator vane body 51 and the inner casing 31 around at least one of the leading edge 511 and the trailing edge 512 of the casing 3. This prevents leakage flow from occurring in the gap, thereby reducing pressure loss. As a result, it is possible to suppress a decrease in the efficiency of the compressor 1 due to pressure loss in the variable stator vanes 5.

[0057] (2) A variable stator vane 5 according to a second aspect is the variable stator vane 5 of (1), in which the expanded diameter portion 72 overlaps with the leading edge 511 when viewed from the blade height direction D1.

[0058] This prevents turbulence in the flow of the working fluid A around the leading edge 511 of the casing 3. This prevents leakage flow from occurring in the gap around the leading edge 511, and suppresses a decrease in the efficiency of the compressor 1.

[0059] (3) A variable stator vane 5 according to a third aspect is the variable stator vane 5 of (1) or (2), in which the expanded diameter portion 72 overlaps with the trailing edge 512 when viewed from the blade height direction D1.

[0060] As a result, no turbulence occurs in the flow of the working fluid A between the vane body 51 and the inner casing 31 around the trailing edge 512 of the casing 3. This prevents leakage flow from occurring in the gap, thereby reducing pressure loss.

[0061] (4) A variable stator vane 5 according to a fourth aspect is any one of the variable stator vanes 5 of (1) to (3), wherein a plurality of the variable stator vanes 5 can be arranged side by side in a direction intersecting the flow direction and the blade height direction D1, and the expanded diameter portion 72 is formed to have a size that allows it to slide against the expanded diameter portion 72 of another adjacent variable stator vane 5 when viewed from the blade height direction D1.

[0062] This significantly increases the area where no gap occurs between the stator vane body 51 and the casing 3. Therefore, turbulence in the flow of the working fluid A does not occur over a wide area between the stator vane body 51 and the casing 3. This significantly reduces the occurrence of leakage flow in the gap, and significantly reduces pressure loss.

[0063] (5) A variable stator vane 5 according to a fifth aspect is any one of the variable stator vanes 5 of (1) to (4), and the rotation axis Ar is positioned closer to the leading edge 511 than the trailing edge 512 in the chord direction D2 in which the chord connecting the leading edge 511 and the trailing edge 512 extends, when viewed from the blade height direction D1.

[0064] As a result, in the blade chord direction D2, the blade rotation shaft 6B is disposed at a position closer to the leading edge 511 than to the trailing edge 512. Therefore, the expanded diameter portion 72 can intensively suppress turbulence of the flow of the working fluid A around the leading edge 511 of the inner casing 31. As a result, the occurrence of leakage flow in the gap around the leading edge 511 can be suppressed with higher accuracy, and a decrease in the efficiency of the compressor 1 can be suppressed.

[0065] (6) A variable stator vane 5 according to a sixth aspect is any one of the variable stator vanes 5 according to (1) to (5), wherein the expanded diameter portion 72 has a first surface 723 facing the stator vane body 51 in the blade height direction D1, and the ends 52, 53 of the stator vane body are inclined away from the rotating shaft body 71 from the leading edge 511 toward the trailing edge 512 when viewed from a direction intersecting the flow direction and the blade height direction D1, and the first surface 723 is recessed away from the ends 52, 53 of the stator vane body between the front end 721 close to the leading edge 511 and the rear end 722 close to the trailing edge 512 when viewed from a direction intersecting the flow direction and the blade height direction D1.

[0066] This reduces the unevenness of the first surface 723 relative to the outer peripheral surface of the casing 3. This reduces the blade surface Mach number of the variable stator vanes 5 when operating at an opening degree different from the rated operation. As a result, it is possible to significantly improve the efficiency when operating the compressor 1 at low atmospheric temperatures and high flow rates.

[0067] (7) A compressor 1 according to a seventh aspect includes a variable stator vane 5 of any one of (1) to (6), a rotor 2 including a rotor body 21 and a plurality of rotor blades 25 arranged in the axial direction Da and circumferential direction Dc of the rotor body 21, an inner casing 31 arranged on the outside Dro of the rotor 2, an outer casing 32 arranged on the outside Dro of the inner casing 31, and a rotary drive unit 8 connected to the blade rotation shaft 6B and rotating the blade rotation shaft 6B, and the variable stator vane 5 is arranged rotatably relative to the inner casing 31 and the outer casing 32. [Explanation of symbols]

[0068] 1...Compressor 2...Rotor 21...Rotor body 22...Rotating blade row 221...First rotor blade row 222...Second rotor blade row 223...Third rotor blade row 224…Fourth rotor blade row 25...moving blade 3...Casing 31...Inner casing 311...(inner casing) outer surface 32...Outer casing 321...(Outer casing) inner surface 33...Strut S…Main flow path 35...Intake port 4...Variable stator vane mechanism 41...First variable stator vane mechanism 42...Second variable stator vane mechanism 43...Third variable stator vane mechanism 44...Fourth variable stator vane mechanism 5...Variable stator vanes 51...Stator blade body 511...leading edge 512… Trailing edge 515...Pressure surface 516…Negative pressure surface 52, 53...End of the stationary blade body 6, 6A, 6B, 6C... Blade rotation shaft 61...Outer blade rotation axis 62...Inner blade rotating shaft Ar...axis of rotation 71...Rotating shaft body 72, 72A, 72B, 72C... Expanded diameter part 721...Front end 722...Rear end 723, 723C…front page 73...Outer disc part 8...Rotation drive unit A...Working fluid O…Axis line Da…Axis direction Dau…upstream side Dad…downstream Dc…Circumferential direction Dr…Radial direction Dro...outside Dri…inside D1...Wing height direction D2…Chord direction

Claims

1. A stator vane body extending in a vane height direction intersecting a flow direction of the working fluid; a blade rotation shaft connected to an end of the stator vane body in the blade height direction and rotatable so as to change an angle of the stator vane body with respect to the flow direction of the working fluid, The blade rotation shaft is a rotating shaft main body extending about a rotation axis extending in the blade height direction; an expanded diameter portion that extends about the rotation axis to connect the rotating shaft body and the stator vane body, and has an outer diameter larger than the outer diameter of the rotating shaft body when viewed in the blade height direction; The stator blade body includes: A leading edge extending in the wing height direction; A trailing edge extending in the wing height direction; a pressure surface and a suction surface extending in the blade height direction and connecting the leading edge and the trailing edge; the expanded diameter portion is a variable stator vane formed to a size such that it overlaps with the leading edge when viewed from the blade height direction; a rotor including a rotor body and a plurality of rotor blades arranged in an axial direction and a circumferential direction of the rotor body; an inner casing disposed outside the rotor; an outer casing disposed outside the inner casing; A rotation drive unit connected to the blade rotation shaft and configured to rotate the blade rotation shaft, In a compressor in which the variable stator vane is rotatably arranged with respect to the inner casing and the outer casing, The expanded diameter portion has a first surface facing the stator vane main body in the blade height direction, an end portion of the stator vane body is inclined from the leading edge toward the trailing edge so as to move away from the rotating shaft body when viewed from a direction intersecting the flow direction and the blade height direction, the first surface is recessed away from an end of the stator vane body between a front end portion close to the leading edge and a rear end portion close to the trailing edge when viewed from a direction intersecting the flow direction and the blade height direction, the outer peripheral surface of the inner casing is inclined radially outward as it progresses downstream in the flow direction, and a step is formed by extending a top surface of a recess in the first surface in an area on the trailing edge side of the stator vane body that overlaps with a position where the variable stator vane is arranged.

2. The variable stator vanes can be arranged in a plurality of rows in a direction intersecting the flow direction and the blade height direction, The compressor according to claim 1 , wherein the expanded diameter portion is formed to have a size that allows it to come into sliding contact with the expanded diameter portion of an adjacent variable stator vane when viewed from the blade height direction.

3. 3. The compressor according to claim 1, wherein the rotation axis is disposed at a position closer to the leading edge than the trailing edge in a chord direction in which a chord connecting the leading edge and the trailing edge extends when viewed from the blade height direction.

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