TECHNICAL FIELD 
       [0001]    The present invention relates to a compressor which includes a rotor that rotates around an axis and a casing that surrounds the rotor, and a gas turbine which includes the compressor. 
         [0002]    Priority is claimed on Japanese Patent Application No. 2013-216696, filed on Oct. 17, 2013, the content of which is incorporated herein by reference. 
       BACKGROUND ART 
       [0003]    A compressor which is provided in a gas turbine or the like, includes a rotor that rotates around an axis and a casing that surrounds the rotor from the outer peripheral side, and compresses a fluid such as air is known. There is a type of compressor that employs a bleed structure for guiding a portion of a compressed fluid to the outside of the compressor. 
         [0004]    PTL 1 discloses a compressor which employs a bleed structure in which a bleed slot that extends in a circumferential direction to reduce energy loss during bleeding by a diffuser effect is provided on the outer band of a casing. 
       CITATION LIST 
     Patent Literature 
       [0005]    [PTL 1] Japanese Unexamined Patent Application Publication No. 4-284136 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0006]    In general, in the bleed structure, a bleed pipe which guides a bleed fluid toward the outside of the compressor via a bleed chamber from the bleed slot is provided. Furthermore, the bleed fluid has a swirling component in the circumferential direction due to the rotation of the rotor. According to such factors, the flow rate of the fluid is increased in a region including a circumferential position at which the bleed pipe is provided, which is upstream of the bleed slot. Accordingly, it is checked by analysis using computational fluid dynamics (CFD) that the irregularity of a flow rate distribution in a main flow path in the circumferential direction is increased. 
         [0007]    Due to the irregular flow rate distribution, pulsation occurs, and a stall occurs in the vicinity of the tip of a rotor blade disposed downstream of the bleed slot. Therefore, there is a possibility that surging may occur in the entire flow of the compressed air. There is a possibility that the operation efficiency of the compressor may be reduced due to such a stall and surging. Particularly, in a case where the number of bleed pipes is reduced for the purpose of a reduction in weight or the like, the irregularity of the flow rate increases, resulting in a reduction in a surge margin. Accordingly, the possibility of the occurrence of surging increases, and this may cause a reduction in the operation efficiency of the compressor. 
         [0008]    The present invention provides a compressor capable of suppressing a reduction in operation efficiency by achieving the regularity of the flow rate of a fluid in a main flow path in the vicinity of a slot through which the fluid is bled from the main flow path, and a gas turbine including the same. 
       Solution to Problem 
       [0009]    According to a first aspect of the present invention, a compressor includes: a rotor which rotates around an axis; a rotor casing which surrounds the rotor from an outer peripheral side thereof to allow a main flow path of a fluid to be defined between the rotor casing and the rotor; a plurality of stator blades which are provided with intervals therebetween in a circumferential direction so as to be directed toward an inside in a radial direction from the rotor casing; a bleed chamber casing which is provided on the outer peripheral side of the rotor casing and defines a bleed chamber that communicates with the main flow path via a slot that is formed to extend in the circumferential direction on a downstream side of the stator blade; and a pipe which is connected to the bleed chamber casing from an outer peripheral side thereof and has a bleed flow path formed therein, the bleed flow path guiding the fluid in the bleed chamber to an outside. Among the plurality of stator blades, when a plurality of stator blades positioned in a region including a circumferential position corresponding to the pipe are defined as a first stator blade group and a plurality of stator blades excluding the first stator blade group are defined as a second stator blade group, an interval between end portions of the adjacent stator blades in the first stator blade group on an outside in the radial direction is smaller than an interval between end portions of the adjacent stator blades in the second stator blade group on the outside in the radial direction. 
         [0010]    According to the compressor, since the first stator blade group is positioned in the vicinity of the circumferential position at which the pipe is provided, the interval between the end portions of the stator blades on the outside in the radial direction at this position is reduced. Therefore, the flow of the fluid from the main flow path toward the slot through the first stator blade group is impeded at this position, and thus the flow rate of the fluid can be reduced. Accordingly, an increase in the flow rate of the fluid, which is caused by the rotation of the rotor, in the main flow path at the circumferential position at which the pipe is provided in the vicinity of the slot can be suppressed, and thus it becomes possible to achieve the regularity of the distribution of the flow rate of the fluid in the circumferential direction. 
         [0011]    According to a second aspect of the present invention, regarding the plurality of stator blades, among the plurality of stator blades, a plurality of stator blades, which are positioned in the region including the circumferential position corresponding to the pipe and are positioned in a region including a circumferential position closer to a first side in a rotation direction of the rotor than the pipe, may function as the first stator blade group. 
         [0012]    At the circumferential position at which the pipe is provided on the first side in the rotation direction of the rotor, the flow rate of the fluid which tries to flow into the pipe from the slot via the bleed chamber is increased due to an effect of the rotation of the rotor. Therefore, since the first stator blade group is provided on the first side in the rotation direction of the rotor, it becomes possible to more effectively achieve the regularity of the distribution of the flow rate of the fluid in the circumferential direction in the vicinity of the slot. 
         [0013]    According to a third aspect of the present invention, in the plurality of stator blades, the first stator blade group may have a larger number of stator blades provided in a predetermined circumferential region than that of the second stator blade group such that the interval between the end portions of the stator blades therein is small on the outside in the radial direction. 
         [0014]    Since the first stator blade group has a larger number of stator blades than that of the second stator blade group, the interval between the end portions of the stator blades on the outside in the radial direction can be easily reduced. Therefore, the flow of the fluid from the main flow path toward the slot through the first stator blade group is impeded, and thus it becomes possible to achieve the regularity of the distribution of the flow rate of the fluid in the circumferential direction in the main flow path in the vicinity of the slot. 
         [0015]    According to a fourth aspect of the present invention, in the plurality of stator blades, at least two stator blades which are adjacent to each other in the circumferential direction in the first stator blade group may be provided to become close to each other when moving toward the outside in the radial direction such that the interval between the end portions of the stator blades therein is small on the outside in the radial direction. 
         [0016]    Since the stator blades of the first stator blade group are inclined as described above, the interval between the end portions of the stator blades on the outside in the radial direction can be reduced without changing the number of stator blades. Therefore, while suppressing costs by facilitating a manufacturing process, the flow of the fluid from the main flow path toward the slot through the first stator blade group can be impeded, and the regularity of the distribution of the flow rate of the fluid in the circumferential direction in the main flow path in the vicinity of the slot can be achieved. 
         [0017]    In addition, since the number of stator blades is not changed, the pressure loss of the fluid that flows through the stator blades is not increased. Therefore, it becomes possible to achieve the regularity of the distribution of the flow rate of the fluid in the circumferential direction while minimizing the profile loss of the stator blades. 
         [0018]    According to a fifth aspect of the present invention, a gas turbine includes: the compressor described above, which compresses air as the fluid by rotating the rotor; a combustor which generates combustion gas by combusting a fuel in compressed air that is compressed by the compressor; and a turbine which is driven by the combustion gas from the combustor. 
         [0019]    According to the gas turbine, since the compressor described above is included, an increase in the flow rate of the fluid, which is caused by the rotation of the rotor, in the main flow path at the circumferential position at which the pipe is provided in the vicinity of the slot can be suppressed, and thus it becomes possible to achieve the regularity of the distribution of the flow rate of the fluid in the circumferential direction. 
       Advantageous Effects of Invention 
       [0020]    According to the compressor and the gas turbine, by providing the first stator blade group in the stator blades, the regularity of the flow rate of the fluid in the main flow path in the vicinity of the slot through which the fluid is bled from the main flow path is achieved. Accordingly, it becomes possible to suppress a reduction in operation efficiency. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0021]      FIG. 1  is a schematic side view of a gas turbine which includes a compressor according to a first embodiment of the present invention. 
           [0022]      FIG. 2  is a sectional view of the main parts of the compressor according to the first embodiment of the present invention. 
           [0023]      FIG. 3  is a view of a main flow path and a slot of the compressor according to the first embodiment of the present invention, when viewed from an outside in a radial direction, and illustrates a view taken along arrow III of  FIG. 2 . 
           [0024]      FIG. 4  is a view of the compressor according to the first embodiment of the present invention, when viewed in an axial direction, and illustrates a view taken along line IV-IV of  FIG. 2 . 
           [0025]      FIG. 5  is a view of a main flow path and a slot of a compressor in a case where the solidity of stator blades is constant, when viewed from an outside in a radial direction, and illustrates a view taken along arrow at the same position as that of the view take along arrow III of  FIG. 2 . In addition,  FIG. 5  illustrates the analysis result of the distribution of the flow rate of the air in the main flow path in the vicinity of the slot using the shade of color. 
           [0026]      FIG. 6  is a view of a compressor according to a second embodiment of the present invention, when viewed in an axial direction, and illustrates a sectional view viewed at the same position as that of the sectional view taken along line IV-IV of  FIG. 2 . 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
     First Embodiment 
       [0027]    Hereinafter, an axial flow type compressor  1  according to an embodiment of the present invention will be described. 
         [0028]    First, a gas turbine  200  which includes the compressor  1  will be described. 
         [0029]    As illustrated in  FIG. 1 , the gas turbine  200  includes the compressor  1  which generates compressed air A by compressing outside air A 0 , a plurality of combustors  202  which generate combustion gas G by mixing a fuel F supplied from a fuel supply source with the compressed air A and combusting the mixture, and a turbine  203  which is driven by the combustion gas G. Hereinafter, the compressed air A is referred to as air A. 
         [0030]    The turbine  203  includes a turbine rotor  204  which rotates around a rotational axis Ar, a cylindrical casing  205  which covers the turbine rotor  204 . A main flow path  206  is defined between the turbine rotor  204  and the turbine casing  205 . 
         [0031]    The turbine rotor  204  is connected to a rotor  2  in the compressor  1 , which will be described later, and rotates around the rotational axis Ar together with the rotor  2 . 
         [0032]    Hereinafter, a direction in which the rotational axis Ar extends is referred to as an axial direction Da. A radial direction with respect to the rotational axis Ar is referred to as a radial direction Dr. A side which becomes distant from the rotational axis Ar in the radial direction Dr is referred to as an outside in the radial direction Dr. A side which becomes close to the rotational axis Ar in the radial direction Dr is referred to as an inside in the radial direction Dr. A circumferential direction with respect to the rotational axis Ar is referred to as a circumferential direction Dc. 
         [0033]    In addition, in this embodiment, a direction in which the rotor  2  rotates is referred to as a rotation direction R. As illustrated in  FIG. 3 , regarding the rotation direction R, a front side in the rotation direction is referred to as a first side R 1 , and a rear side in the rotation direction is referred to as a second side R 2 . 
         [0034]    The plurality of combustors  202  are fixed to the turbine casing  205  with equal intervals therebetween in the circumferential direction Dc around the rotational axis Ar. 
         [0035]    Next, the compressor  1  will be described. 
         [0036]    As illustrated in  FIG. 2 , the compressor  1  includes the rotor  2  which rotates around the rotational axis Ar, and a cylindrical rotor casing  3  which covers the rotor  2 . 
         [0037]    Between the rotor casing  3  and the rotor  2 , the annular main flow path  4  through which the compressed air A flows is defined. In addition, the rotor casing  3  includes a plurality of stator blade stages  9  which are provided on the inner peripheral surface thereof with intervals therebetween in the axial direction Da. 
         [0038]    Each of the stator blade stages  9  includes a plurality of stator blades  10 . The plurality of stator blades  10  are arranged in an annular shape with intervals therebetween in the circumferential direction Dc around the rotational axis Ar and constitute a single stator blade stage  9 . Each of the stator blades  10  extends from the inner peripheral surface of the rotor casing  3  toward the inside in the radial direction Dr. 
         [0039]    The rotor  2  includes a rotor body  5  which extends in the axial direction Da, and a plurality of rotor blade stages  7  which are fixed to the outer periphery of the rotor body  5  and are provided with intervals therebetween in the axial direction Da. 
         [0040]    The rotor body  5  is a shaft-like member having the rotational axis Ar as its central axis, and extends in the axial direction Da. 
         [0041]    Each of the rotor blade stages  7  includes a plurality of rotor blades  8 . The plurality of rotor blades  8  are arranged in an annular shape with intervals therebetween in the circumferential direction Dc around the rotational axis Ar and constitute a single rotor blade stage  7 . Each of the rotor blades  8  extends from the outer periphery of the rotor body  5  toward the outside in the radial direction Dr. A single rotor blade stage  7  is disposed downstream of a single stator blade stage  9 , and the rotor blade stage  7  and the stator blade stage  9  are alternately arranged. 
         [0042]    As described above, in this embodiment, the compressor  1  is a multi-stage type axial flow compressor which receives the outside air A 0  through the main flow path  4  and generates the compressed air A by compressing the outside air A 0  in stages through the plurality of stator blade stages  9  and the plurality of rotor blade stages  7 . 
         [0043]    The compressor  1  further includes a bleed chamber casing  6  provided on the outer peripheral side of the rotor casing  3 , and a plurality of bleed pipes  15  connected to the bleed chamber casing  6 . 
         [0044]    The bleed chamber casing  6  is formed in an annular shape around the rotational axis Ar so as to protrude from the rotor casing  3  toward the outside in the radial direction Dr. A bleed chamber  12  which becomes an annular space between the bleed chamber casing  6  and the rotor casing  3  is defined. 
         [0045]    Furthermore, between the stator blade stage  9  and the rotor blade stage  7  which are adjacent to each other in the axial direction Da, a slot  13  which extends in an annular shape in the circumferential direction Dc around the rotational axis Ar and allows the bleed chamber  12  and the main flow path  4  to communicate with each other is formed in the rotor casing  3 . More specifically, the slot is inclined toward the upstream side from the downstream side in the axial direction Da when moving from the inside of the bleed chamber  12  in the radial direction Dr toward the main flow path  4 . 
         [0046]    The bleed pipe  15  is connected to the bleed chamber casing  6  from the outer peripheral side thereof and extends toward the outside in the radial direction Dr. A bleed flow path  14  which communicates with the bleed chamber  12  is formed on the inside of the bleed pipe  15 . 
         [0047]    In this embodiment, the bleed pipe  15  is connected to the bleed chamber casing  6  with an interval in the circumferential direction Dc. The number of bleed pipes  15  varies depending on the type of the compressor  1 . 
         [0048]    As described above, the air A is bled from the main flow path  4  through the slot  13 , the bleed chamber  12 , and the bleed pipe  15 . The bleed air A is guided to the outside of the compressor  1 . 
         [0049]    Here, the stator blade stages  9  will be described in more detail. 
         [0050]    Among the stator blade stages  9 , the stator blade stage  9  which is provided closest to the slot  13  on the upstream side of the slot  13  is referred to as a stator blade stage  91 . 
         [0051]    As illustrated in  FIGS. 3 and 4 , among the stator blades  10  constituting the stator blade stage  91 , a plurality of stator blades  10  positioned in a region including a circumferential position Dc corresponding to the bleed pipe  15  are referred to as a first stator blade group  101 . In addition, a plurality of stator blades  10  excluding the first stator blade group  101  are defined as a second stator blade group  102 . 
         [0052]    In this embodiment, the first stator blade group  101  is positioned in a region including the position of the rotor body  5  in the circumferential direction Dc closer to the first side R 1  in the rotation direction R than a position at which the bleed pipe  15  is provided in the circumferential direction Dc. 
         [0053]    The interval between the end portions of the adjacent stator blades  10  in the first stator blade group  101  on the outside in the radial direction Dr is smaller than the interval between the end portions of the adjacent stator blades  10  in the second stator blade group  102  on the outside in the radial direction Dr. 
         [0054]    More specifically, in this embodiment, the first stator blade group  101  has a larger number of stator blades  10  provided in a predetermined circumferential region than that of the second stator blade group  102 . That is, the solidity C/S of the stator blades  10  of the first stator blade group  101  is higher than that of the second stator blade group  102 . 
         [0055]    The solidity C/S is a value obtained by dividing the dimension of the stator blades  10  in the axial direction Da by the distance in the circumferential direction Dc between the stator blades  10  which are adjacent to each other in the circumferential direction Dc. Here, the solidity C/S in this embodiment represents a value measured at the end portions of the stator blades  10  on the outside in the radial direction Dr. 
         [0056]    According to the compressor  1  described above, since the first stator blade group  101  is provided in the stator blade stage  91  on the upstream side of the slot  13 , the first stator blade group  101  is positioned in the vicinity of the position at which the bleed pipe  15  is provided in the circumferential direction Dc, and the interval between the end portions of the stator blades  10  on the outside in the radial direction Dr at this position is reduced. 
         [0057]      FIG. 5  illustrates a case where the first stator blade group  101  is not provided in the stator blade stage  91  and all of the stator blades  10  have the same solidity C/S as that of the second stator blade group  102 , that is, a case where the solidity C/S of the stator blades  10  is constant. In this case, the air A has a swirling component due to the rotation of the rotor  2  and thus the flow rate of the air A has a distribution in the circumferential direction Dc in the main flow path  4  in the vicinity of the slot  13 . More specifically, parts having light color illustrated in  FIG. 5  are parts having a low flow rate, and parts having dark color are parts having a high flow rate. 
         [0058]    Referring to  FIG. 5 , a phenomenon in which the flow rate of the air A is increased is shown in the vicinity of the position at which the bleed pipe  15  is provided in the circumferential direction Dc. Moreover, on the first side R 1  in the rotation direction R of the rotor  2  and on the upstream side in the axial direction Da, the phenomenon in which the flow rate of the air A is increased becomes significant. 
         [0059]    In this embodiment, by providing the first stator blade group  101  in a region including the position in the circumferential direction Dc of the rotor  2  closer to the first side R 1  in the rotation direction R than the position at which the bleed pipe  15  is provided in the circumferential direction Dc, the flow of the air A from the main flow path  4  into the slot  13  through the first stator blade group  101  can be effectively impeded. 
         [0060]    As a result, the flow rate of the air A in the region in which the first stator blade group  101  is provided in the circumferential direction Dc can be reduced. Therefore, it becomes possible to effectively achieve the regularity of the distribution of the flow rate of the air A in the circumferential direction Dc in the main flow path  4  in the vicinity of the slot. 
         [0061]    According to the compressor  1  of this embodiment, by providing the first stator blade group  101  in the stator blades  10  which are close to the upstream side of the slot  13 , it becomes possible to achieve the regularity of the flow rate of the air A in the vicinity of the slot  13  through which air is bled from the main flow path  4 . Accordingly, it becomes possible to increase a surge margin and suppress a reduction in operation efficiency. 
         [0062]    Even in a case where the number of bleed pipes  15  needs to be reduced to achieve a reduction in weight, by adjusting the solidity C/S of the stator blade stage  91  as described above, it becomes possible to achieve the regularity of the flow rate of the air A in the main flow path  4  in the vicinity of the slot  13 . Accordingly, it becomes possible to suppress a reduction in operation efficiency. 
       Second Embodiment 
       [0063]    Next, a compressor  1 A according to a second embodiment of the present invention will be described with reference to  FIG. 6 . 
         [0064]    A first stator blade group  101 A in the compressor  1 A of this embodiment is different from that of the first embodiment. 
         [0065]    In the first stator blade group  101 A, the stator blades  10  are inclined in the circumferential direction Dc when moving toward the outside in the radial direction Dr. 
         [0066]    More specifically, in this embodiment, among three stator blades  10  provided in the first stator blade group  101 A, stator blades  10   a  and  10   c  positioned at both ends in the circumferential direction Dc are inclined to become close to a stator blade  10   b  interposed therebetween. Accordingly, the solidity C/S of the stator blades  10   a  and  10   b  and the solidity C/S of the stator blades  10   c  and  10   b  are higher than the solidity C/S of the second stator blade group  102 . 
         [0067]    According to the compressor  1 A of this embodiment, since the stator blades  10  in the first stator blade group  101 A are inclined, the interval between the end portions of the adjacent stator blades  10  in the first stator blade group  101 A on the outside in the radial direction can be reduced without increasing the number of stator blades  10 . That is, it becomes possible to reduce the interval between the stator blades  10 . 
         [0068]    Therefore, while suppressing costs by facilitating a manufacturing process, the flow of the air A from the main flow path  4  toward the slot  13  through the first stator blade group  101 A can be impeded, and thus the flow rate of the air A can be further reduced. As a result, it becomes possible to achieve the regularity of the distribution of the flow rate of the air A in the circumferential direction Dc in the main flow path  4  in the vicinity of the slot  13 . 
         [0069]    In addition, by not changing the number of stator blades  10  in the first stator blade group  101 , the pressure loss of the air A that flows through the stator blades  10  is not increased. Therefore, it becomes possible to reduce the flow rate of the air A that flows from the main flow path  4  toward the slot  13  through the first stator blade group  101 A while minimizing the profile loss of the stator blades  10 . 
         [0070]    In this embodiment, the solidity C/S is increased by inclining the two stator blades  10  in the first stator blade group  101 A. However, it is possible to increase the solidity C/S by providing at least two stator blades  10  which are adjacent to each other in the circumferential direction Dc to become close to each other when moving toward the outside in the radial direction Dr. 
         [0071]    While the details of the embodiments of the present invention have been described, slight changes in design can be made without departing from the technical spirit of the present invention. 
         [0072]    For example, the first stator blade group  101  ( 101 A) is provided closer to the first side R 1  in the rotation direction R than the bleed pipe  15 . However, as shown in the analysis result of  FIG. 5 , even in the vicinity of a position at which the bleed pipe  15  is provided outside of the first side R 1  in the rotation direction R, there is a part in which the flow of the air A increases in the main flow path  4  in the vicinity of the slot  13 . Therefore, the first stator blade group  101  ( 101 A) may also be provided in a region including a position corresponding to the part in which the flow rate increases, that is, a region including a position in the circumferential direction Dc corresponding to the position at which the bleed pipe  15  is provided while being on the second side R 2  in the rotation direction R. 
       INDUSTRIAL APPLICABILITY 
       [0073]    According to the compressor and the gas turbine, by providing the first stator blade group in the stator blades, the regularity of the flow rate of the fluid in the main flow path in the vicinity of the slot, through air is bled from the main flow path, can be achieved. Accordingly, it becomes possible to suppress a reduction in operation efficiency. 
       REFERENCE SIGNS LIST 
       [0074]      1 ,  1 A compressor 
         [0075]      2  rotor 
         [0076]      3  rotor casing 
         [0077]      4  main flow path 
         [0078]      5  rotor body 
         [0079]      6  bleed chamber casing 
         [0080]      7  rotor blade stage 
         [0081]      8  rotor blade 
         [0082]      9  stator blade stage 
         [0083]      10 ,  10   a,    10   b,    10   c  stator blade 
         [0084]      12  bleed chamber 
         [0085]      13  slot 
         [0086]      14  bleed flow path 
         [0087]      15  bleed pipe 
         [0088]      91  stator blade stage 
         [0089]      101 ,  101 A first stator blade group 
         [0090]      102  second stator blade group 
         [0091]    R rotation direction 
         [0092]    R 1  first side in rotation direction 
         [0093]    R 2  second side in rotation direction 
         [0094]    Ar rotational axis 
         [0095]    Da axial direction 
         [0096]    Dr radial direction 
         [0097]    Dc circumferential direction 
         [0098]    A air (compressed air, fluid) 
         [0099]    A 0  outside air 
         [0100]      200  gas turbine 
         [0101]      202  combustor 
         [0102]      203  turbine 
         [0103]      204  turbine rotor 
         [0104]      205  turbine casing 
         [0105]      206  main flow path 
         [0106]    F fuel 
         [0107]    G combustion gas
A compressor includes: a plurality of vanes at a vane stage provided to a rotor casing demarcating the primary duct; an air bleed chamber casing that demarcates an air bleed chamber interconnecting with the primary duct; and an air bleed tubing connected to the air bleed chamber casing. Of the plurality of vanes, when a plurality of vanes positioned at a region including the position in the peripheral direction corresponding to the air bleed tubing are a first vane group and a plurality of vanes other than the first vane group are a second vane group, the spacing between the ends at the outside in the radial direction of the vanes that are adjacent in the first vane group is closer than the spacing between the ends at the outside in the radial direction of the vanes that are adjacent in the second vane group.