Compressors, gas turbines

Abstract

To provide a compressor that further reduces losses by suppressing a leakage flow.SOLUTION: A compressor 1 includes a rotor that has plural stages of discs, a shaft portion connected to a downstream side of the discs, and plural stages of moving blades fixed to the plural stages of discs, a stator that has a compressor casing, and plural stages of stationary blades respectively disposed between the plural stages of the moving blades, an outlet guiding blade that has blade bodies disposed at intervals in a circumferential on the axial direction downstream side of the disc in the last stage, and an inner side shroud connecting the blade bodies on the radial direction inner side in a circumferential direction, and an inner casing disposed on the axial direction downstream side of the disc in the last stage with a gap from the disc. The inner casing has an outer peripheral wall surface that has a recessed portion storing the inner side shroud and forms a diffuser with an inner peripheral surface of the compressor casing on the downstream side of the recessed portion, and an inner peripheral wall surface forming an extraction cavity. An extraction hole is formed at a part on the downstream side in the recessed portion.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a compressor, a gas turbine. [Background technology]

[0002] A gas turbine compressor includes a rotor having a plurality of disks stacked in the axial direction and rotor blade stages provided on the outer peripheral surfaces of the disks, a casing that covers the rotor from the outer peripheral side and has stator blade stages provided on the inner peripheral surface, and a cylindrical diffuser provided downstream of the casing (see Patent Document 1 below). The diffuser is defined by the inner peripheral surface of the casing and a cylindrical inner casing that is spaced apart from the inner peripheral surface of the casing. The diffuser is configured so that the flow path cross-sectional area increases downstream. This reduces the flow velocity of high-pressure fluid that flows into the diffuser, and restores static pressure.

[0003] Generally, outlet guide vanes (OGVs) are provided in the flow path of the diffuser. To provide OGVs, a vane body extending radially from the axis is cantilevered on the inner circumferential surface of the casing, or a shroud is provided on the inner circumferential side of multiple vane bodies. In the latter case, a recess for accommodating the shroud is formed on the outer circumferential surface of the inner casing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-62767 Summary of the Invention [Problem to be solved by the invention]

[0005] However, as mentioned above, static pressure recovery of the fluid occurs inside the diffuser, and the fluid pressure increases toward the downstream side. This can cause leakage flow from the downstream side to the upstream side through the recess. When this leakage flow joins the mainstream, it causes loss.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a compressor and a gas turbine in which losses are further reduced by suppressing leakage flow. [Means for solving the problem]

[0007] In order to solve the above problems, a compressor according to the present disclosure includes a rotor having a plurality of stages of disks stacked in an axial direction, a shaft portion connected to the disks on the downstream side in the axial direction, and a plurality of stages of moving blade stages fixed to the plurality of stages of disks, a compressor casing surrounding the rotor from the outer periphery side, a stator having a plurality of stages of stationary vane stages fixed to the compressor casing and respectively arranged between the moving blade stages, and blade bodies arranged at intervals in the circumferential direction so as to protrude from the compressor casing on the downstream side in the axial direction of the disk of a final stage, and an inner casing arranged downstream in the axial direction of the disk of the final stage with a gap between the disk and the outlet guide vane, the outlet guide vanes being arranged in a plurality of rows at intervals in the axial direction, the inner casing having a plurality of recesses provided corresponding to the outlet guide vanes to accommodate the inner shrouds of the outlet guide vanes in a plurality of rows, and in an outer circumferential wall surface that forms a diffuser together with an inner circumferential surface of the compressor casing downstream in the axial direction of a recess located on the most downstream side; and an inner circumferential wall surface that forms a bleed cavity into which a fluid is introduced via the gap between the outer circumferential surface of the shaft portion and the outer circumferential wall surface of the shaft portion, inAn air bleed hole that passes through the inner casing in the radial direction is formed in the axially downstream portion of the recess located on the most downstream side.

[0008] A compressor according to the present disclosure comprises: a rotor having multiple stages of disks stacked in the axial direction, a shaft portion connected to downstream sides of the disks in the axial direction, and multiple stages of rotor blade stages fixed to the multiple stages of disks; a compressor casing surrounding the rotor from an outer periphery, and a stator having multiple stages of stationary vane stages fixed to the compressor casing and respectively arranged between the rotor blade stages; an outlet guide vane having blade bodies arranged at intervals in the circumferential direction so as to protrude from the compressor casing on the downstream side of the disk of a final stage in the axial direction, and an inner shroud circumferentially connecting these blade bodies on the radially inner side; a rotor extension portion provided on the downstream side of the disk of the final stage in the axial direction, and having a recess for accommodating the inner shroud of the outlet guide vane; and an inner casing arranged on the downstream side of the rotor extension portion in the axial direction with a gap interposed between the rotor extension portion and the rotor extension portion, and extending cylindrically in the axial direction, The outlet guide vanes are arranged in a plurality at intervals in the axial direction, a plurality of the recesses are provided corresponding to the outlet guide vanes to accommodate the inner shrouds of the plurality of rows of outlet guide vanes, respectively; The aforementioned The inner casing is The final end of the plurality of recesses is located on the most downstream side in the axial direction. an outer peripheral wall surface that forms a diffuser together with the inner peripheral surface of the compressor casing on the axial downstream side of the recess; 、 an inner peripheral wall surface that forms a bleed cavity between itself and the outer peripheral surface of the shaft portion, The final end The portion of the recess on the downstream side in the axial direction is open toward the downstream side, The final end A communication portion communicating with the bleed cavity is formed between the recess and the inner casing. are . [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a compressor and a gas turbine in which leakage flow is suppressed and thereby losses are further reduced. [Brief explanation of the drawings]

[0010] [Figure 1]FIG. 1 is a schematic diagram showing a configuration of a gas turbine according to a first embodiment of the present disclosure. [Figure 2] FIG. 1 is a cross-sectional view showing a configuration of a compressor according to a first embodiment of the present disclosure. [Figure 3] FIG. 3 is an enlarged cross-sectional view of a main part of FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view showing the configuration of a compressor according to a second embodiment of the present disclosure. [Figure 5] FIG. 5 is an enlarged cross-sectional view of a main part of FIG. 4. DETAILED DESCRIPTION OF THE INVENTION

[0011] First Embodiment (Gas turbine configuration) A gas turbine 100 and a compressor 1 according to a first embodiment of the present disclosure will be described below with reference to FIGS. 1 to 3. In the following description, the term "same" means that the dimensions and shapes are substantially the same, and design tolerances and manufacturing errors are allowed. As shown in FIG. 1, the gas turbine 100 includes a compressor 1, a combustor 2, a turbine 3, and a rotor 4. The compressor 1 compresses air taken in from the outside to generate high-pressure air. The combustor 2 burns a mixture of this high-pressure air and fuel to generate high-temperature, high-pressure combustion gas. The turbine 3 is driven by this combustion gas. The compressor 1 and the turbine 3 are coaxially connected by the rotor 4. Therefore, the rotational driving force of the turbine 3 is transmitted to the compressor 1 via the rotor 4, thereby driving the compressor 1.

[0012] (Compressor configuration) Next, the configuration of the compressor 1 will be described with reference to Fig. 2 or 3. The compressor 1 has the above-mentioned rotor 4, a stator 7, outlet guide vanes 8, and an inner casing 9. The rotor 4 has a cylindrical shape extending along the axis Ax. The rotor 4 has a plurality of discs 4D stacked in the direction of the axis Ax, a shaft portion 4S, and an inducer 42.

[0013] The disks 4D are disk-shaped and centered on the axis Ax. Each disk 4D is provided with a rotor blade stage 5. The rotor blade stage 5 has a plurality of rotor blades extending radially outward from the outer circumferential surface of the disk 4D (disk outer circumferential surface Ds). These plurality of rotor blades are arranged in the circumferential direction with respect to the axis Ax.

[0014] The shaft portion 4S protrudes further downstream from the downstream end face of the disk 4D that is located furthest downstream in the direction of the axis Ax (air flow direction) among the multiple disks 4D. The diameter of the shaft portion 4S is smaller than the diameter of the disk 4D.

[0015] The inducer 42 is an intake mechanism provided on the outer peripheral surface of the shaft portion 4S (the outer peripheral surface 41 of the shaft portion). Although not shown in detail, the inducer 42 draws in air near the outer peripheral surface 41 of the shaft portion 4S (the rotor 4) as the shaft portion 4S (the rotor 4) rotates. The drawn-in air is used, for example, to cool high-temperature components of the turbine 3.

[0016] The stator 7 has a compressor casing 1C and stator vane stages 6. The compressor casing 1C is cylindrical and centered on the axis Ax. The compressor casing 1C covers the rotor 4 from the outer periphery. A plurality of stator vane stages 6 are provided on a portion of the inner circumferential surface of the compressor casing 1C facing the disk 4D (the casing inner circumferential surface 11). Note that only one stator vane stage 6 is shown in the example of FIG. 2. The stator vane stage 6 has a plurality of stator vanes extending radially inward from the casing inner circumferential surface 11. These plurality of stator vanes are arranged in the circumferential direction about the axis Ax. The stator vane stages 6 and the rotor blade stages 5 are arranged alternately along the axis Ax. The space between the casing inner circumferential surface 11 and the disk outer circumferential surface Ds (i.e., the space in which the rotor blade stages 5 and the stator vane stages 6 are provided) forms a compression flow path Fc through which high-pressure air flows.

[0017] Of the inner peripheral surface of the compressor casing 1C, a portion downstream of the casing inner peripheral surface 11 is made into a diameter expansion surface 12. The diameter expansion surface 12 extends radially outward as it moves downstream in the direction of the axis Ax.

[0018] A plurality of outlet guide vanes 8 are provided downstream of the final (most downstream) rotor blade stage 5 on the casing inner circumferential surface 11. The outlet guide vanes 8 are provided to rectify (reduce swirling components of) the flow of high-pressure air that has passed through the final rotor blade stage 5 and flowed downstream. A plurality of outlet guide vanes 8 are arranged in the direction of the axis Ax downstream of the final-stage disk 4D. In this embodiment, as an example, three rows of outlet guide vanes 8 are provided. Each outlet guide vane 8 has a plurality of blade bodies 81 that protrude radially inward from the casing inner circumferential surface 11 and are spaced apart in the circumferential direction, and an inner shroud 82 that connects these blade bodies 81 in the circumferential direction. The radially inner end of the blade body 81 is located at the same radial position as the disk outer circumferential surface Ds. The inner shroud 82 is provided at the radially inner end of the blade body 81. The inner shroud 82 has an annular shape centered on the axis Ax. The dimension of the inner shroud 82 in the direction of the axis Ax is larger than the dimension of the blade main body 81 in the direction of the axis Ax.

[0019] An inner casing 9 is provided downstream of the final-stage disc 4D, with a gap G extending in the direction of the axis Ax interposed therebetween. The inner casing 9 has a cylindrical shape extending in the direction of the axis Ax. The inner casing 9 has an inner casing upstream section 9U located relatively upstream in the direction of the axis Ax, and an inner casing downstream section 9D located downstream.

[0020] The inner casing upstream portion 9U is a portion of the inner casing 9 that corresponds to the outlet guide vane 8 in the direction of the axis Ax. The outer peripheral surface (first outer peripheral surface 91A) of the inner casing upstream portion 9U has the same outer diameter as the outer diameter of the disc 4D. The first outer peripheral surface 91A has the same outer diameter over the entire area in the direction of the axis Ax. Similarly, the inner peripheral surface (first inner peripheral surface 92A) of the inner casing upstream portion 9U also has the same inner diameter over the entire area in the direction of the axis Ax.

[0021] A plurality of recesses R that accommodate the inner shroud 82 are formed on the first outer peripheral surface 91A. Each recess R is recessed radially inward from the first outer peripheral surface 91A. Each recess R has an annular shape centered on the axis Ax, and is rectangular in a cross section including the axis Ax. A small gap is formed between the recess R and the inner shroud 82. In other words, the volume of the recess R is slightly larger than the volume of the inner shroud 82. The outer peripheral surface of the inner shroud 82 is located at the same position as the first outer peripheral surface 91A in the radial direction.

[0022] The inner casing downstream portion 9D is provided integrally with the inner casing upstream portion 9U on the downstream side thereof. An outer peripheral surface (second outer peripheral surface 91B) of the inner casing downstream portion 9D extends radially inward as it moves downstream in the direction of the axis Ax. The second outer peripheral surface 91B faces the expanded diameter surface 12 of the compressor casing 1C described above. An inner peripheral surface (second inner circumferential surface 92B) of the inner casing downstream portion 9D also extends radially inward as it moves downstream in the direction of the axis Ax.

[0023] The first outer peripheral surface 91A and the second outer peripheral surface 91B described above form an outer peripheral wall surface 91 of the inner casing 9. This outer peripheral wall surface 91 and the inner peripheral surface of the compressor casing 1C form a diffuser space D (diffuser). The diffuser space D is provided to recover static pressure by reducing the flow velocity of the high-pressure air that has flowed downstream through the compression flow path Fc.

[0024] The first inner circumferential surface 92A and the second inner circumferential surface 92B form an inner circumferential wall surface 92 of the inner casing 9. A space serving as an air bleed cavity Cs is formed between this inner circumferential wall surface 92 and the outer circumferential surface of the shaft portion 4S (the shaft portion outer circumferential surface 41). This air bleed cavity Cs communicates with the diffuser space D via a gap G formed between the inner casing 9 and the final-stage disk 4D. The air in the air bleed cavity Cs is bled by the inducer 42 described above. That is, in the air bleed cavity Cs, an air flow is formed from the gap G toward the inducer 42.

[0025] Furthermore, of the multiple recesses R, the recess Rd located furthest downstream is formed with an air bleed hole H. This air bleed hole H extends radially inward from the bottom surface (inner peripheral surface) of the recess Rd, thereby penetrating the inner casing 9 in the radial direction. In other words, this air bleed hole H connects the diffuser space D with the bleed cavity Cs. As a result, in the bleed cavity Cs, in addition to the air flow toward the inducer 42 from the gap G, another air flow toward the inducer 42 from the air bleed hole H is formed. Note that, as shown enlarged in FIG. 3, the air bleed hole H is formed in a portion of the recess Rd that is biased toward the downstream side. In other words, the downstream end face of the air bleed hole H is in contact with the downstream end face of the recess Rd.

[0026] (Action and effect) Next, the operation of the gas turbine 100 and compressor 1 according to this embodiment will be described. To operate the gas turbine 100, first, an external drive source (such as an electric motor) rotates the rotor 4. As the rotor 4 rotates, the compressor 1 takes in external air and compresses it to generate high-pressure air. The combustor 2 mixes fuel with this high-pressure air to generate an air-fuel mixture, and burns the mixture to generate high-temperature, high-pressure combustion gas. The combustion gas is supplied to the turbine 3, which drives the turbine 3 (applying rotational force to the rotor 4). The rotational force of the rotor 4 is transmitted to the compressor 1. The gas turbine 100 is operated by continuously repeating this cycle.

[0027] In the compressor 1, high-pressure air is supplied to the diffuser space D via the compression flow path Fc. Static pressure recovery of the air flow occurs within the diffuser space D, increasing the pressure downstream. Therefore, for example, if the above-described bleed hole H is not formed, leakage flow from downstream to upstream may occur through the gap between the recessed portion R and the inner shroud 82. Such leakage flow merges with the mainstream, resulting in loss. Therefore, in the compressor 1 according to this embodiment, the most downstream recessed portion Rd is formed with the bleed hole H, which connects the bleed cavity Cs to the diffuser space D. This allows the leakage flow that has flowed into the most downstream recessed portion Rd to be guided to the bleed cavity Cs through the bleed hole H. As a result, leakage flow upstream of the recessed portion Rd can be reduced. This reduces loss within the compressor 1.

[0028] Furthermore, according to the above configuration, by providing a plurality of outlet guide vanes 8, it is possible to further reduce the swirling component (the flow component swirling in the rotation direction of the rotor 4) contained in the flow of the fluid flowing into the diffuser space D. As a result, the flow component in the direction of the axis Ax becomes larger, and the performance of the compressor 1 can be further improved.

[0029] Furthermore, with the above configuration, the provision of the bleed holes H can reduce leakage flow and simultaneously suppress the development of a boundary layer in the diffuser space D. Therefore, as described above, it is possible to reduce the diameter of the second outer peripheral surface 91B, which is the portion of the inner casing 9 downstream of the outlet guide vane 8, toward the downstream side. This makes it possible to further increase the flow path cross-sectional area of the diffuser space D. As a result, it is possible to further promote the recovery of static pressure of the fluid by the diffuser space D.

[0030] Second Embodiment Next, a second embodiment of the present disclosure will be described with reference to Figures 4 and 5. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. In a compressor 1B according to this embodiment, the main differences from the first embodiment are the configurations of a rotor 4b and an inner casing 9b.

[0031] The rotor 4b further includes a rotor extension 4E formed integrally with the most downstream disk 4D on the downstream side. The rotor extension 4E is cylindrical and centered on the axis Ax, tightly covering the shaft portion 4S from the outer periphery. The outer periphery of the rotor extension 4E is a first outer periphery 91A' having the same diameter as the outer diameter of the disk outer periphery Ds. This first outer periphery 91A' is formed with a plurality of recesses Rb that accommodate the inner shrouds 82 of the outlet guide vanes 8. In this embodiment, the inner periphery of the inner shroud 82 is provided with a seal portion S that seals the flow of fluid between the recesses Rb and the inner shroud 82. Specifically, the seal portion S is a plurality of seal fins that protrude radially inward from the inner periphery of the inner shroud 82. Note that instead of seal fins, other configurations such as a labyrinth seal may be used as the seal portion S.

[0032] Of the multiple recesses Rb, the recess Rd' located most downstream has a different shape from the other recesses Rb located upstream. Specifically, the downstream portion of the recess Rd' opens toward the downstream side. In other words, the recess Rd' is defined only by the upstream end face and bottom surface.

[0033] An inner casing 9b is provided downstream of this recess Rd' with a gap (communication portion Hc) in the direction of the axis Ax. The inner casing 9b has a cylindrical shape that extends radially inward with respect to the axis Ax as it approaches the downstream side. An outer peripheral surface (second outer peripheral surface 91B) of the inner casing 9b, together with the first outer peripheral surface 91A', forms an outer peripheral wall surface 91. As in the first embodiment described above, the outer peripheral wall surface 91 defines a diffuser space D together with the inner peripheral surface of the compressor casing 1C.

[0034] The inner circumferential surface of the inner casing 9b is an inner circumferential wall surface 92. An bleed cavity Cs' is formed between the inner circumferential wall surface 92 and the shaft outer circumferential surface 41. Furthermore, the upstream end face (upstream end face 9T) of the inner casing 9b faces the recess Rd' and the downstream end face (extension end face Et) of the rotor extension 4E via the communication portion Hc.

[0035] Here, since static pressure recovery of the fluid occurs in the diffuser space D, the fluid pressure increases toward the downstream side. This can lead to leakage flow from the downstream side to the upstream side through the recess Rb. Such leakage flow merges with the mainstream, resulting in loss. However, in the above configuration, the downstream portion of the recess Rd' opens toward the downstream side. Furthermore, a gap serving as a communication hole Hc is formed between the recess Rd' and the inner casing 9b. This allows the leakage flow that has flowed into the recess Rd' to be guided to the bleed cavity Cs' through the communication hole Hc. As a result, the leakage flow toward the upstream side of the recess Rd' can be reduced. This further improves the performance of the compressor 1B.

[0036] Furthermore, according to the above configuration, by providing a plurality of outlet guide vanes 8, it is possible to further reduce the swirling component (the flow component swirling in the rotation direction of the rotor 4) of the air flow that flows into the diffuser space D downstream thereof. As a result, the flow component directed in the direction of the axis Ax increases, and the performance of the compressor 1B can be further improved.

[0037] Furthermore, with the above configuration, the provision of the communication portion Hc not only reduces leakage flow but also suppresses the development of a boundary layer in the diffuser space D. Therefore, by reducing the diameter of the inner casing 9b downstream as described above, the flow path cross-sectional area of the diffuser can be increased, thereby further facilitating the recovery of static pressure of the fluid in the diffuser space D.

[0038] In addition, according to the above configuration, the seal portion S can further reduce leakage flow toward the upstream side through the recessed portion Rd'.

[0039] (Other embodiments) The embodiments of the present disclosure have been described above in detail 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. The seal portion S described in the second embodiment can also be applied to the first embodiment. The number of outlet guide vanes 8 and the corresponding recesses R are not limited to those in the above-described embodiments and drawings, and can be changed as appropriate depending on the design and specifications.

[0040] <Additional Notes> The compressor 1 and the gas turbine 100 described in each embodiment can be understood, for example, as follows.

[0041] (1) A compressor 1 according to a first aspect includes a rotor 4 having a plurality of stages of disks 4D stacked in the direction of the axis Ax, a shaft portion 4S connected to the disks 4D on downstream sides in the direction of the axis Ax, and a plurality of stages of moving blade stages 5 fixed to the plurality of stages of disks 4D, a compressor casing 1C surrounding the rotor 4 from an outer circumferential side, a stator 7 having a plurality of stages of stationary vane stages 6 fixed to the compressor casing 1C and respectively arranged between the moving blade stages 5, an outlet guide 81 having blade bodies 81 arranged at intervals in the circumferential direction so as to protrude from the compressor casing 1C on the downstream side of the disk 4D of a final stage in the direction of the axis Ax, and an inner shroud 82 connecting the blade bodies 81 in the circumferential direction on the radially inner side. and an inner casing 9 that extends cylindrically in the direction of the axis Ax and is disposed downstream of the disk 4D of a final stage in the direction of the axis Ax with a gap G interposed between the disk 4D and the outlet guide vane 8. The inner casing 9 has a recess R that houses an inner shroud 82 of the outlet guide vane 8, and an outer peripheral wall surface 91 that forms a diffuser D together with the inner peripheral surface of the compressor casing 1C downstream of the recess R in the direction of the axis Ax, and an inner peripheral wall surface 92 that forms a bleed cavity Cs into which a fluid is introduced via the gap G between the inner peripheral wall surface 91 and the outer peripheral surface of the shaft portion 4S, and an air bleed hole H that radially penetrates the inner casing 9 is formed in a portion of the recess R that is downstream in the direction of the axis Ax.

[0042] Here, because static pressure recovery of the fluid occurs within the diffuser D, the fluid pressure increases toward the downstream side. This can cause leakage flow from the downstream side to the upstream side through the recessed portion R. This leakage flow merges with the mainstream, causing loss. However, in the above configuration, bleed holes H are formed downstream of the recessed portion R. This allows the leakage flow that has flowed into the recessed portion R to be guided to the bleed cavity Cs through the bleed holes H. As a result, the leakage flow toward the upstream side of the recessed portion R can be reduced.

[0043] (2) In the compressor 1 according to the second aspect, the outlet guide vanes 8 are arranged at intervals in the direction of the axis Ax, and the recesses R are provided for each of the outlet guide vanes 8.

[0044] According to the above configuration, the provision of a plurality of outlet guide vanes 8 can further reduce the swirling component (the flow component swirling in the rotation direction of the rotor) contained in the flow of the fluid flowing into the diffuser D downstream thereof. As a result, the flow component directed in the direction of the axis Ax increases, and the performance of the compressor 1 can be further improved.

[0045] (3) In the compressor 1 according to the third aspect, the bleed hole H is formed in the recess Rd on the most downstream side of the plurality of recesses R.

[0046] According to the above configuration, the bleed hole H is formed in the recessed portion Rd on the most downstream side, so that it is possible to reduce the possibility that the leakage flow will reach the upstream side of the recessed portion Rd on the most downstream side.

[0047] (4) In the compressor 1 according to the fourth aspect, the portion of the inner casing 9 downstream of the outlet guide vane 8 extends radially inward toward the downstream side.

[0048] According to the above configuration, the provision of the bleed holes H can reduce leakage flow and simultaneously suppress the development of a boundary layer in the diffuser D. Therefore, as described above, it is possible to reduce the diameter of the portion of the inner casing 9 downstream of the outlet guide vane 8 toward the downstream side. This allows the flow path cross-sectional area of the diffuser D to be enlarged. As a result, the static pressure recovery of the fluid by the diffuser D can be further promoted.

[0049] (5) A compressor 1B according to a fifth aspect includes: a rotor 4 having a plurality of stages of disks 4D stacked in the direction of the axis Ax, a shaft portion 4S connected to the disks 4D on downstream sides in the direction of the axis Ax, and a plurality of stages of moving blade stages 5 fixed to the plurality of stages of disks 4D; a compressor casing 1C surrounding the rotor 4 from an outer circumferential side; a stator 7 having a plurality of stages of stationary vane stages 6 fixed to the compressor casing 1C and respectively arranged between the moving blade stages 5; outlet guide vanes 8 having blade bodies 81 arranged at intervals in the circumferential direction so as to protrude from the compressor casing 1C on the downstream side of a final stage of disks 4D in the direction of the axis Ax, and inner shrouds 82 connecting the blade bodies 81 in the circumferential direction on the radially inner side; and an outlet guide vane 8 provided downstream of the final stage of disks 4D, The compressor compressor includes a rotor extension 4E having a recess Rb that houses an inner shroud 82 of the outlet guide vane 8, and an inner casing 9b that is arranged downstream of the rotor extension 4E in the direction of the axis Ax with a gap between it and the rotor extension 4E and that extends cylindrically in the direction of the axis Ax, the inner casing 9b having an outer peripheral wall surface 91 that forms a diffuser D together with an inner peripheral surface of the compressor casing 1C downstream of the recess Rb in the direction of the axis Ax, and an inner circumferential wall surface 92 that forms an bleed cavity Cs′ between itself and the outer peripheral surface of the shaft portion 4S, the portion of the recess Rb that is downstream in the direction of the axis Ax opening toward the downstream side, and a communication portion Hc that communicates with the bleed cavity Cs′ is formed between the recess Rb and the inner casing 9b.

[0050] Here, because static pressure recovery of the fluid occurs within the diffuser D, the fluid pressure increases toward the downstream side. This can lead to leakage flow from the downstream side toward the upstream side through the recess Rb. Such leakage flow merges with the mainstream, resulting in loss. However, in the above-described configuration, the downstream portion of the recess Rb opens toward the downstream side. Furthermore, a gap serving as a communication hole Hc is formed between the recess Rb and the inner casing 9b. This allows the leakage flow that has flowed into the recess Rb to be guided to the bleed cavity Cs' through the communication portion Hc. As a result, the leakage flow toward the upstream side of the recess Rb can be reduced.

[0051] (6) In the compressor 1B according to the sixth aspect, the outlet guide vanes 8 are arranged at intervals in the direction of the axis Ax, and the recesses Rb are provided for each of the outlet guide vanes 8.

[0052] According to the above configuration, the provision of a plurality of outlet guide vanes 8 can further reduce the swirling component (the flow component swirling in the rotation direction of the rotor) contained in the flow of the fluid flowing into the diffuser D downstream thereof. As a result, the flow component directed in the direction of the axis Ax increases, and the performance of the compressor 1B can be further improved.

[0053] (7) In the compressor 1B according to the seventh aspect, of the plurality of recesses Rb, the recessed portion Rd' located most downstream in the direction of the axis Ax communicates with the communication portion Hc.

[0054] According to the above configuration, the recessed portion Rd' on the most downstream side is in communication with the communication portion Hc, and therefore, the possibility that the leakage flow will reach the upstream side of the recessed portion Rd' on the most downstream side can be reduced.

[0055] (8) In the compressor 1B according to the eighth aspect, the inner casing 9b extends radially inward toward the downstream side.

[0056] According to the above configuration, the provision of the communication portion Hc reduces leakage flow and simultaneously suppresses the development of a boundary layer in the diffuser D. Therefore, as described above, it is possible to reduce the diameter of the inner casing 9b downstream. This allows the flow path cross-sectional area of the diffuser D to be enlarged. As a result, the static pressure recovery of the fluid by the diffuser D can be further promoted.

[0057] (9) The compressor 1B according to the ninth aspect further includes a seal portion S that is provided on the inner circumferential surface of the inner shroud 82 and seals the flow of fluid between the inner circumferential surface and the recess Rb.

[0058] According to the above configuration, the seal portion S can further reduce leakage flow toward the upstream side through the recessed portion Rb.

[0059] (10) A gas turbine 100 according to a tenth aspect includes a compressor 1, 1B according to any one of the above aspects, a combustor 2 that generates combustion gas by burning a mixture of high-pressure fluid and fuel generated by the compressor 1, 1B, and a turbine 3 that is driven by the combustion gas.

[0060] According to the above configuration, the leakage flow of the compressors 1, 1B is reduced, thereby reducing the loss of the compressors 1, 1B. As a result, the efficiency of the gas turbine 100 can be further improved. [Explanation of symbols]

[0061] 100 Gas Turbine 1,1B compressor 1C Compressor casing 11 Casing inner surface 12 Expanded diameter surface 2. Combustor 3 Turbine 4,4b rotor 41 Shaft outer surface 42 Inducer 4D disc 4E Rotor extension 4S shaft part 5 rotor stage 6 stator vane stages 7 Stator 8 Exit guide vanes 81 Wing body 82 Inner shroud 9,9b Inner casing 9D Inner casing downstream 9U Inner casing upstream section 9T Upstream end face 91 Outer wall 92 Inner wall surface 91A,91A´ First outer peripheral surface 91B Second outer peripheral surface 92A First inner surface 92B Second inner circumferential surface Ax axis Cs, Cs´ Bleed cavity D Diffuser space Ds outer surface of disc Et Extension end face Fc compression channel H Bleed hole Hc communication part R, Rb, Rd, Rd´ recess

Claims

1. a rotor including a plurality of stages of disks stacked in an axial direction, a shaft portion connected to the disks on the downstream side in the axial direction, and a plurality of stages of rotor blades fixed to the plurality of stages of disks; a compressor casing surrounding the rotor from an outer periphery side, and a stator fixed to the compressor casing and having a plurality of stationary vane stages respectively disposed between the rotor blade stages; an outlet guide vane including blade bodies arranged at intervals in a circumferential direction so as to protrude from the compressor casing downstream in the axial direction of the disk of a final stage, and an inner shroud connecting the blade bodies in a circumferential direction on a radially inner side thereof; an inner casing that is disposed downstream of the final stage disk in the axial direction with a gap between the disk and the final stage disk, and that extends cylindrically in the axial direction; Equipped with a plurality of outlet guide vanes are arranged at intervals in the axial direction, The inner casing includes: an outer circumferential wall surface having a plurality of recesses provided corresponding to the plurality of rows of outlet guide vanes to accommodate inner shrouds of the outlet guide vanes, respectively, and forming a diffuser together with an inner circumferential surface of the compressor casing downstream in the axial direction of a recess that is located furthest downstream in the axial direction among the plurality of recesses; an inner peripheral wall surface that forms, between itself and an outer peripheral surface of the shaft portion, a bleed cavity into which fluid is introduced via the gap, a bleed hole that radially penetrates the inner casing is formed in a downstream portion in the axial direction of the recessed portion that is located furthest downstream in the axial direction among the plurality of recessed portions.

2. 2. The compressor according to claim 1, wherein a portion of the inner casing downstream of the outlet guide vane extends radially inward toward the downstream side.

3. a rotor including a plurality of stages of disks stacked in an axial direction, a shaft portion connected to the disks on the downstream side in the axial direction, and a plurality of stages of rotor blades fixed to the plurality of stages of disks; a compressor casing surrounding the rotor from an outer periphery side, and a stator fixed to the compressor casing and having a plurality of stationary vane stages respectively disposed between the rotor blade stages; an outlet guide vane including blade bodies arranged at intervals in a circumferential direction so as to protrude from the compressor casing downstream in the axial direction of the disk of a final stage, and an inner shroud connecting the blade bodies in a circumferential direction on a radially inner side thereof; a rotor extension portion provided downstream of the disk of a final stage in the axial direction and having a recess for accommodating an inner shroud of the outlet guide vane; an inner casing that is arranged axially downstream of the rotor extension portion with a gap between it and the rotor extension portion and that extends cylindrically in the axial direction; Equipped with The outlet guide vanes are arranged in a plurality at intervals in the axial direction, a plurality of recesses are provided corresponding to the outlet guide vanes to accommodate the inner shrouds of the plurality of rows of outlet guide vanes, respectively; the inner casing has an outer circumferential wall surface that forms a diffuser together with an inner circumferential surface of the compressor casing, on the axial direction downstream side of a final end recessed portion that is located on the axially most downstream side among the plurality of recessed portions, and an inner circumferential wall surface that forms a bleed cavity between itself and the outer circumferential surface of the shaft portion, a portion of the final end recess located downstream in the axial direction is open toward the downstream side, and a communication portion that communicates with the bleed cavity is formed between the final end recess and the inner casing.

4. The compressor according to claim 3 , wherein the inner casing extends radially inward toward the downstream side in the axial direction.

5. The compressor according to claim 3 or 4, further comprising a seal portion provided on an inner circumferential surface of the inner shroud to seal against a flow of fluid between the inner circumferential surface and the recess.

6. A compressor according to any one of claims 1 to 5; a combustor that generates combustion gas by combusting a mixture of high-pressure fluid generated by the compressor and fuel; a turbine driven by the combustion gas; A gas turbine comprising:

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