Multi-stage axial compressor and gas turbine

Abstract

A multi-stage axial compressor comprises a rotating shaft on which a plurality of impeller blades are mounted, a casing surrounding the rotating shaft, the casing forming a flow path of a working fluid between the rotating shaft and the casing, a wall section having an annular shape and extending in a circumferential direction of the rotating shaft to surround the casing, the wall section forming a dispensing chamber having an annular shape and connected to the flow passage, a plurality of connection sections connected to the outer circumferential surface of the wall section, the connection sections forming respective outlet flow passages connected to the dispensing chamber, and a plurality of dispensing pipes connected to the respective connection sections.In a cross-sectional view orthogonal to the rotating shaft, of two corner regions where an inner surface of each of the connection sections and an inner surface of the wall section intersect or cross, at the corner region located on a rear side in a direction of rotation of the working fluid in the dispensing chamber, where θ1 is defined as an angle formed between an inner surface of the connection section and the inner surface of the wall section, the angle 01 is not greater than 225°.

Description

[0001] The present disclosure relates to a multi-stage axial compressor and a gas turbine.

[0002] In a multi-stage axial compressor, the flow of a working fluid, such as air, becomes unstable during slow rotation, such as during start-up or when the machine is decelerated to stop. To prevent this, some multi-stage axial compressors incorporate a dispensing or extraction structure.

[0003] For example, in the generic lathe disclosed in JP 2014-145 265 A, a compressor housing comprises a dispensing chamber or extraction chamber, a main flow passage, a communication passage, and a dispensing nozzle or extraction nozzle formed therein, and a dispensing tube or extraction tube is connected to the dispensing nozzle. A flow rate control valve is arranged in the dispensing tube. By adjusting the opening degree of the flow rate control valve, the air flowing under pressure through the main flow passage is extracted to the outside of the compressor housing through the communication passage, the dispensing chamber or extraction chamber, the dispensing nozzle, and the dispensing tube.

[0004] Furthermore, in the lathe disclosed in JP 2014-145 265 A, at least the first surface of the first and second inner circumferential surfaces of the dispensing nozzle, which is arranged centrally on the axis of rotation on the first and second sides in the circumferential direction, comprises a direction reversal avoidance part that gradually extends radially outwards from the radial outside of the dispensing chamber in one direction towards the second side in the circumferential direction.

[0005] Within the ring-shaped communication passage and the dispensing chamber, air swirls or flows to the second side in the circumferential direction around the axis of rotation, i.e., in one direction of rotation of the compressor rotor.

[0006] Even if the air swirls around as described above, compressed air flowing through the dispensing chamber to the second side in the circumferential direction along the radially outer side surface of the dispensing chamber flows along the direction reversal avoidance part of the first surface, even when it reaches the dispensing chamber side of the dispensing nozzle, and can flow into the dispensing nozzle almost without detaching from the radially outer side surface of the dispensing chamber and the first surface of the dispensing nozzle.

[0007] From DE 10 2008 014 957 A a gas turbine compressor with bleed air extraction is known, wherein the document specifies a formula for determining a connection angle of a bleed nozzle with respect to a bleed chamber.

[0008] If separation of the airflow from the dispensing chamber to the dispensing nozzle occurs, the pressure drop in the dispensing or extraction system extending from the communication passage to the dispensing tube increases, leading to a reduction in the dispensing or extraction flow rate. Consequently, to reduce the pressure drop in the dispensing system and increase the dispensing flow rate, it is desirable to minimize the separation of the airflow from the dispensing chamber to the dispensing nozzle. Therefore, the connection angle of the dispensing nozzle with respect to the dispensing chamber is important. However, JP 2014-145 265 A does not disclose a specific connection angle in this regard.

[0009] In view of the above, it is an object of the present invention to propose a multi-stage axial compressor and a gas turbine with an increased exhaust gas flow rate, which can be operated stably during slow rotation.According to the present invention, a multi-stage axial compressor comprises the features of claim 1, including, inter alia, a rotating shaft on which a plurality of impeller blades are mounted, a housing surrounding the rotating shaft, wherein the housing forms a flow passage for a working fluid between the rotating shaft and the housing, a wall section having an annular shape and extending in a circumferential direction of the rotating shaft so as to surround the housing, wherein the wall section forms a dispensing chamber having an annular shape and is connected to the flow passage, a plurality of connection sections connected to an outer circumferential surface of the wall section, wherein the connection sections form respective outlet flow passages connected to the dispensing chamber, and a plurality of dispensing pipes connected to the respective connection sections.In a cross-sectional view orthogonal to the rotating shaft, of two corner regions where an inner surface of each of the connection sections and an inner surface of the wall section intersect or cross, at the corner region located on a rear side in a direction of rotation of the working fluid in the dispensing chamber, if θ1 is defined as an angle formed between the inner surface of the connection section and the inner surface of the wall section, the angle θ1 is not greater than 225°.

[0010] With the above configuration (1), the angle θ1 is no greater than 225°, thus preventing flow separation of the working fluid at the corner region on the rear side in the direction of rotation of the working fluid when the working fluid flows from the dispensing chamber into the connection section. This reduces the pressure loss of the working fluid flowing from the dispensing chamber into the connection section, and the working fluid flows smoothly and without problems from the dispensing chamber into the connection section, thereby increasing the dispensing flow rate and the extraction flow rate. Consequently, the multi-stage axial compressor with the above configuration (1) can operate stably even during slow rotation.

[0011] (2) In the invention, in the above embodiment (1) in the cross-sectional view which is orthogonal to the rotating shaft, of the two corner regions where the inner surface of each of the connecting sections and the inner surface of the wall section intersect or cross each other, at the corner region which is arranged on a front side in the direction of rotation of the working fluid in the dispensing chamber, if θ2 is defined as an angle formed between the inner surface of the connecting section and the inner surface of the wall section, the angle θ2 is not less than 315°.

[0012] With the above configuration (2), since the angle θ2 is not less than 315°, the working fluid can flow uniformly and smoothly from the dispensing chamber into the connection section. This reduces the pressure loss of the fluid flowing from the dispensing chamber into the connection section, and the working fluid flows uniformly and smoothly from the dispensing chamber into the connection section, thereby increasing the dispensing flow rate. Consequently, the multi-stage axial compressor having the above configuration (2) can operate stably even during slow rotation.

[0013] (3) In the invention, in the above embodiment (2), if, in the cross-sectional view which is orthogonal to the rotating shaft, d is an inner diameter of each of the connecting sections and D is an outer diameter of the tap chamber, the angle θ satisfies a relationship which is expressed by the following expression: 270°−sin−1((1−dD)0.5)∗180)° / π≤θ1, and the angle θ2 satisfies a relationship that is expressed by the following expression θ2≤270°+sin−1((1−dD)0.5)∗180° / π.

[0014] The smaller the angle θ1, the better it is for preventing flow separation of the working fluid. However, the angle θ1 cannot be smaller than the angle at the point when the connection section is tangentially connected to the dispensing chamber (tangential direction angle). If θt1 is the tangential direction angle at the corner region on the back in the direction of rotation of the working fluid, as defined above according to the definition of angle θ1, then the following expression is satisfied: θt1=270°−sin−1((1−dD)0.5)∗180° / π. Accordingly, the tangential direction angle θt1 can be determined based on the outer diameter of the dispensing chamber and the inner diameter of the connection section. Thus, with the above embodiment (3), the minimum value of the angle θ1 can be set based on the outer diameter of the dispensing chamber and the inner diameter of the connection section in order to be the tangential direction angle θt1.

[0015] Similarly, the larger the angle θ2, the better for achieving a uniform flow of the working fluid from the dispensing chamber to the connection section. However, the angle θ2 cannot be larger than the angle at the point when the connection section is tangentially connected to the dispensing chamber (tangential direction angle). If θt2 is the tangential direction angle at the corner region on the front face in the direction of rotation of the working fluid, as defined above by the angle θ2, then the following expression is satisfied. θt2=270°+sin−1((1−dD)0.5)∗180° / π. Accordingly, the tangential direction angle θt2 can be determined based on the outer diameter of the dispensing chamber and the inner diameter of the connection section. Thus, with the above embodiment (3), the maximum value of the angle θ2 is set based on the outer diameter of the dispensing chamber and the inner diameter of the connection section in order to be the tangential direction angle θt2.

[0016] (4) In some preferred embodiments, in one of the above configurations (1) to (3), at least one of the plurality of tap tubes comprises at least one bent or curved section, and where d is an inner diameter of each of the connection sections in the cross-sectional view orthogonal to the rotating shaft, and R is a radius of curvature of the at least one bent section, a ratio R / d of the radius of curvature R of the at least one bent section to the inner diameter d of the connection section satisfies a relationship which is expressed by the following expression: 2 ≤ R / d.

[0017] With the above configuration (4), the ratio R / d of the radius of curvature R of the bent section to the inner diameter d of the connection section is not less than two, and thus the pressure loss of the working fluid in the dispensing pipe is reduced, and the working fluid can flow smoothly and without problems through the dispensing pipe. Consequently, the flow rate of the working fluid flowing through the dispensing pipe, i.e., the dispensing flow rate, can be increased, and the multi-stage axial compressor, which has the above configuration (4), can be operated stably even during slow rotation with a simple configuration.

[0018] (5) In some preferred embodiments, in the above configuration (4), the rotating shaft extends in a horizontal direction. The plurality of connection sections comprises a first connection section, a second connection section, a third connection section, and a fourth connection section, arranged in that order in the circumferential direction of the rotating shaft. The first and second connection sections are arranged orthogonally to the rotating shaft in a cross-sectional view at a first side of a center of the rotating shaft in a horizontal direction. The third and fourth connection sections are arranged orthogonally to the rotating shaft in a cross-sectional view at a second side opposite the first side of the center of the rotating shaft in a horizontal direction.The multiple dispensing pipes comprise a first dispensing pipe, a second dispensing pipe, a third dispensing pipe, and a fourth dispensing pipe, each connected to the first, second, third, and fourth connection sections, respectively. In cross-sectional view, the first and second dispensing pipes extend orthogonally to the rotating shaft, to the second side of the shaft's center, and horizontally orthogonally to the rotating shaft. The at least one curved section comprises a first curved section, which forms part of the first dispensing pipe, and a second curved section, which forms part of the second dispensing pipe.The first curved section and the second curved section are bent in such a way that a direction of rotation of the working fluid flowing through the first curved section and the second curved section, orthogonal to the rotating shaft in the cross-sectional view, is the same as a direction of rotation of the working fluid in the dispensing chamber.

[0019] With the above embodiment (5), the first bent section and the second bent section are bent such that the direction of rotation of the working fluid flowing through the first and second bent sections is, in a cross-sectional view orthogonal to the rotating shaft, the same direction as the direction of rotation of the rotating shaft. Thus, the working fluid can flow smoothly and without difficulty through the first and second bent sections. Consequently, the flow rate of the working fluid flowing through the first and second dispensing pipes, i.e., the dispensing flow rate, can be increased. Therefore, the multi-stage axial compressor, which has the above embodiment (5), can be operated stably even during slow rotation with a simple design.

[0020] (6) In some preferred embodiments, in the above configuration (5), the at least one curved section comprises a third curved section forming part of the third dispensing tube, and a fourth curved section forming part of the fourth dispensing tube, and the third curved section and the fourth curved section are curved such that a direction of rotation of the working fluid flowing through the third curved section and the fourth curved section is orthogonal to the rotating shaft in the cross-sectional view opposite to the direction of rotation of the working fluid in the dispensing chamber.

[0021] With the above embodiment (6), the third and fourth bent sections are bent such that the direction of rotation of the working fluid flowing through them is orthogonal to the direction of rotation of the rotating shaft in a cross-sectional view, but the ratio R / d is not less than two, so that the pressure loss across the third and fourth bent sections is reduced. Consequently, the flow rate of the working fluid flowing through the third and fourth dispensing pipes, i.e., the dispensing flow rate, can be increased, and thus the multi-stage axial compressor with the above embodiment (6) can operate stably even during slow rotation with a simple design.

[0022] (7) In some preferred embodiments, in one of the above configurations (4) to (6), the rotating shaft extends in a horizontal direction. The plurality of connection sections comprises a first connection section, a second connection section, a third connection section, and a fourth connection section, arranged in that order in the circumferential direction of the rotating shaft. The first and second connection sections are arranged orthogonally to the rotating shaft in cross-sectional view at a first side of a center of the rotating shaft in a horizontal direction. The third and fourth connection sections are arranged orthogonally to the rotating shaft in cross-sectional view at a second side opposite the first side of the center of the rotating shaft in a horizontal direction.The first connecting section and the third connecting section extend along the horizontal direction orthogonal to the rotating shaft, and the second connecting section and the fourth connecting section extend along a vertical direction.

[0023] With the above configuration (7), the first and third connection sections extend in the horizontal direction, and the second and fourth connection sections extend in the vertical direction. This prevents flow separation of the working fluid entering the first, second, third, and fourth connection sections with a simple design. Consequently, the multi-stage axial compressor having the above configuration (7) can ensure a sufficient bleed flow rate and extraction flow rate and can operate stably even during slow rotation with a simple design.

[0024] (8) In some preferred embodiments, in one of the above configurations (4) to (7), the rotating shaft extends in a horizontal direction. The plurality of connection sections comprises a first connection section, a second connection section, a third connection section, and a fourth connection section.If a circumferential position of an upper section of an outer circumferential surface of the wall section is orthogonal to the rotating shaft in the cross-sectional view, an intersection point between the outer circumferential surface of the wall section and an axis of the first connection section lies at a circumferential position not less than 30° and not greater than 60°, an intersection point between the outer circumferential surface of the wall section and an axis of the second connection section lies at a circumferential position not less than 120° and not greater than 150°, an intersection point between the outer circumferential surface of the wall section and an axis of the third connection section lies at a circumferential position not less than 200° and not greater than 230°, and an intersection point between the outer circumferential surface of the wall section and an axis of the fourth connection section lies at a circumferential position not less than 290° and not greater than 320°.

[0025] With the above configuration (8), the intersection point between the outer circumferential surface of the wall section and the axis of the first connection section lies at a circumferential position between 30° and 60°, the intersection point between the outer circumferential surface of the wall section and the axis of the second connection section lies at a circumferential position between 120° and 150°, the intersection point between the outer circumferential surface of the wall section and the axis of the third connection section lies between 200° and 230°, and the intersection point between the outer circumferential surface of the wall section and the axis of the fourth connection section lies between 290° and 320°. Thus, the height of the dispensing pipe in the top-bottom direction can be reduced or eliminated. Consequently, the installation space of the multi-stage axial compressor, which has the above configuration (8), can be reduced.

[0026] (9) In some preferred embodiments, in one of the above configurations (4) to (8), the rotating shaft extends in a horizontal direction. The plurality of connection sections comprises a first connection section, a second connection section, a third connection section, and a fourth connection section, arranged in that order in the circumferential direction of the rotating shaft. The first and second connection sections are arranged orthogonally to the rotating shaft in cross-sectional view at a first side of a center of the rotating shaft in a horizontal direction. The third and fourth connection sections are arranged orthogonally to the rotating shaft in cross-sectional view at a second side opposite the first side of the center of the rotating shaft in a horizontal direction.The multiple dispensing pipes comprise a first dispensing pipe, a second dispensing pipe, a third dispensing pipe, and a fourth dispensing pipe, each connected to the first, second, third, and fourth connection sections, respectively. If the cross-sectional view is divided into four quadrants along a vertical and a horizontal axis, perpendicular to the axis of rotation, with an origin at the center of the rotating shaft, the farthest ends of the first, second, third, and fourth dispensing pipes, located furthest from the dispensing chamber, are situated in the same of the four quadrants.

[0027] With the above embodiment (9) the remote ends of the first tap tube, the second tap tube, the third tap tube and the fourth tap tube are located in the same quadrant and thus the remote ends of the first tap tube, the second tap tube, the third tap tube and the fourth tap tube can be easily coupled to an axial tube extending in the axial direction of the rotating shaft.

[0028] (10) In some preferred embodiments, in the above configuration (9), the remote ends of the first dispensing tube, the second dispensing tube, the third dispensing tube and the fourth dispensing tube are arranged orthogonally to the rotating shaft in the horizontal direction on an outside of the housing.

[0029] In some cases, a concrete base or similar structure is positioned beneath the housing to support it. This makes it difficult to position the axial tube, extending in the axial direction of the rotating shaft, beneath the housing.

[0030] In view of this, with the above embodiment (10) the remote ends of the first tap tube, the second tap tube, the third tap tube and the fourth tap tube are arranged in the same quadrant and on the outside of the housing in the horizontal direction, thus the remote ends of the first tap tube, the second tap tube, the third tap tube and the fourth tap tube can be easily coupled to the axial tube extending in the axial direction of the rotating shaft.

[0031] (11) According to the present invention, a gas turbine comprises the features of claim 12 comprising a multi-stage axial compressor according to the invention, a combustion chamber which can generate a combustion gas by burning fuel using air compressed by the multi-stage axial compressor as the working fluid, and a turbine which can output energy by using the combustion gas generated in the combustion chamber.

[0032] With the above configuration (11), the angle θ1 is no greater than 225°, thus preventing flow separation of the working fluid at the corner region on the rear side in the direction of rotation when the working fluid flows from the dispensing chamber into the connection section. This reduces the pressure loss of the fluid flowing from the dispensing chamber into the connection section, and the working fluid flows smoothly and without problems from the dispensing chamber into the connection section, thereby increasing the dispensing flow rate. Consequently, a multi-stage axial compressor can operate stably even during slow rotation, and thus the gas turbine, which has the above configuration (11), can operate stably during slow rotation, such as during start-up and deceleration to stop the machine.

[0033] With the above configurations (4) to (10) the dispensing quantity or the extraction quantity can be increased by avoiding the pressure loss in the dispensing pipe.

[0034] According to the present invention, a multi-stage axial compressor and a gas turbine with an increased exhaust gas flow rate, which can be operated stably during slow rotation, can be proposed. Fig. Figure 1 is a schematic diagram of a gas turbine according to an embodiment of the present invention. Fig. Figure 2 is a schematic diagram of a section of a multi-stage axial compressor used in the gas turbine. Fig. 1 is applied. Fig. 3 is a schematic cross-sectional view along a line III - III from Fig. 2. Fig. 4 is an enlarged view of area IV from Fig. 3. Fig. Figure 5 is a schematic cross-sectional view of a multi-stage axial compressor according to another embodiment, which Fig. 3 corresponds.

[0035] Embodiments of the present invention are now described in detail with reference to the accompanying drawings. However, unless otherwise identified, dimensions, materials, shapes, relative positions, and the like of components described in the embodiments are intended to be interpreted as illustrative only and are not meant to limit the scope of the present invention.

[0036] For example, an expression of a relative or absolute arrangement such as "in a direction", "along a direction", "parallel", "orthogonal", "central", "concentric" and "coaxial" should not be interpreted as describing the arrangement only in a strictly literal sense, but should also include a state in which the arrangement is shifted relative to itself by a tolerance or by an angle or a distance, thereby achieving the same function.

[0037] For example, an expression of an equal state such as "equal", "same" and "uniform" should not be interpreted as describing only the state in which the feature is strictly equal, but also as including a state in which there is a tolerance or difference that can still achieve the same function.

[0038] Furthermore, for example, an expression of a shape such as a rectangular shape or a cylindrical shape should not be interpreted as the geometrically strict shape, but should also include a shape with irregularities or flattened corners in the area where the same effect can be achieved.

[0039] In contrast, expressions such as "comprise", "with", "exhibit", "include" and "form" are not intended to exclude other components.

[0040] Fig. Figure 1 is a schematic diagram of a gas turbine 1 according to an embodiment of the present invention. Fig. Figure 2 is a schematic diagram of a part of a multi-stage axial compressor 2a, 2b, which is used in the gas turbine 1. Fig. 1 is applied. Fig. 3 is a schematic cross-sectional view along a line III - III from Fig. 2. Fig. 4 is an enlarged view of area IV from Fig. 3. Fig. Figure 5 is a schematic cross-sectional view of a multi-stage axial compressor 2b according to another embodiment, which Fig. 3 corresponds.

[0041] In the following description, multi-stage axial compressors 2a, 2b are referred to together as a multi-stage axial compressor 2.

[0042] As in Fig. Figure 1 shows that the gas turbine 1 according to an embodiment of the present invention comprises a multi-stage axial compressor 2, a combustion chamber 4 and a turbine 6.

[0043] The combustion chamber 4 can generate combustion gas at high temperature by burning fuel using air compressed by the multi-stage axial compressor 2.

[0044] Turbine 6 can output power using the combustion gas generated in combustion chamber 4. Part of the power output by turbine 6 is fed to the multi-stage axial compressor 2, and the remaining power is fed to a generator (not shown) for use in power generation.

[0045] As in Fig. 1, Fig. 2, Fig. 3, Fig. 4 to Fig. Figure 5 shows that the multi-stage axial compressor 2 comprises a rotating shaft 10, a housing 12, a wall section 14, a plurality of connection sections 16 and a plurality of dispensing pipes or extraction pipes 18.

[0046] A plurality of impeller blade rows are attached to the rotating shaft 10. The plurality of impeller blade rows are arranged at intervals along the axial direction of the rotating shaft 10. Each impeller blade row comprises a plurality of impeller blades 20, each of which is attached to the rotating shaft 10, and in each impeller blade row, the plurality of impeller blades 20 are arranged in the circumferential direction of the rotating shaft 10.

[0047] The housing 12 surrounds the rotating shaft 10, and a flow passage 22 for a working fluid is formed between the housing 12 and the rotating shaft 10. In the case of the multi-stage axial compressor 2, which is used in the gas turbine 1, the working fluid is air.

[0048] Furthermore, a plurality of guide vane rows are attached to the housing 12. The plurality of guide vane rows are arranged at intervals along the axial direction of the rotating shaft 10. The impeller vane rows and the guide vane rows are arranged alternately in the axial direction of the rotating shaft 10. Each guide vane row comprises a plurality of guide vanes 24, each mounted on the housing 12, and in each guide vane row, the plurality of guide vanes 24 are arranged in the circumferential direction of the rotating shaft 10.

[0049] The wall section 14 extends circumferentially around the rotating shaft 10, surrounding the housing 12 and forming an annular space (dispensing chamber or extraction chamber) 26, which is connected to or in communication with the flow passage 22. For example, the dispensing chamber 26 is connected to the flow passage 22 via a slot or gap (connection passage or communication passage) 28 formed in the housing 12. Furthermore, the dispensing chamber 26 is connected to a central region of the flow passage 22 in the axial direction of the rotating shaft 10, allowing the working fluid to be extracted under pressure. The central region refers not to the center or midpoint, but to the region excluding the opposite ends.

[0050] The numerous connection sections (dispensing nozzles or extraction nozzles) 16 are connected to the outer circumferential surface of the wall section 14. Each connection section 16 has a hollow cylindrical shape and forms an outlet flow passage 30, which is connected to or in communication with the dispensing chamber 26.

[0051] A multitude of dispensing pipes 18 are connected to the respective connection sections 16. Each dispensing pipe 18 forms a pipe passage 32 that connects to the outlet flow passage 30. Furthermore, the connection section 16 can be formed integrally with the wall section 14 or integrally with the dispensing pipe 18. In the latter case, an end section of the dispensing pipe 18 can be directly connected to the wall section 14 to form the outlet flow passage.

[0052] A number of flow rate control valves 19 are arranged in the respective dispensing tubes 18, and the flow rate of the working fluid flowing through the dispensing tubes 18 can be adjusted by changing the opening degree of the flow rate control valves 19. The working fluid extracted through the dispensing tubes 18 can be used, for example, to cool the turbine 6. Fig. 3 and Fig. The flow rate control valves 19 are not shown in Figure 5.

[0053] Here's how in Fig. 4 shown in a cross-sectional view orthogonal to the rotating shaft 10 from the two corner regions 34a, 34b, where the inner surface 17 of the connection section 16 and the inner surface 15 of the wall section 14 (outer circumferential surface of the dispensing chamber 26) intersect, θ1 is defined as the angle formed between the inner surface 17 of the connection section 16 and the inner surface 15 of the wall section 14 at the corner region 34a, which is located on the rear side in the direction of rotation Rf of the working fluid in the dispensing chamber 26.

[0054] Furthermore, to describe the angle θ1 more precisely in the present description, in the cross-sectional view, the inner surface 17 of the connection section 16 is defined orthogonally to the rotating shaft 10 by the line L, which passes through two intersection points X, Y of the inner surface 15 of the wall section 14 and the inner surface 17 of the connection section 16. In a case where the corner regions 34a, 34b are produced by R-machining, the intersection points X, Y can be intersections between extensions of the inner surface 15 of the wall section 14 and the inner surface 17 of the connection section 16.

[0055] Furthermore, the multi-stage axial compressor 2, which is in Fig. 1, Fig. 2, Fig. 3, Fig. 4 to Fig. As shown in Figure 5, the angle θ1, which is defined as described above, is not greater than 225°.

[0056] In the above configuration, the angle θ1 is no greater than 225°, thus preventing flow separation of the working fluid at the corner region 34a on the rear side in the direction of rotation Rf of the working fluid in the dispensing chamber 26 when the working fluid flows from the dispensing chamber 26 into the connection section 16. This reduces the pressure loss of the working fluid flowing from the dispensing chamber 26 into the connection section 16, and the working fluid flows smoothly and without difficulty from the dispensing chamber 26 into the connection section 16, thereby increasing the dispensing flow rate. Consequently, the multi-stage axial compressor 2 can operate stably even during slow rotation, and thus the gas turbine 1, which has the above configuration, can operate stably during slow rotation, such as during start-up and deceleration to stop the machine.

[0057] In the invention, in a cross-sectional view orthogonal to the rotating shaft 10 of the two corner regions 34a, 34b, where the inner surface 17 of the connecting section 16 and the inner surface 15 of the wall section 14 intersect or cross, when θ2 is defined as the angle formed between the inner surface 17 of the connecting section 16 and the inner surface 15 of the wall section 14, at the corner region 34b, which is arranged on the front in the direction of rotation Rf of the working fluid in the dispensing chamber 26, the angle θ2 is not less than 315°.

[0058] Furthermore, to define the angle θ2 more precisely in the present description, in a cross-sectional view orthogonal to the rotating shaft 10, the inner surface 17 of the connection section 16 is defined by the line L, which connects two intersection points X, Y of the inner surface 15 of the wall section 14 and the inner surface 17 of the connection section 16. In a case where the corner regions 34a, 34b are produced by R-machining, the intersection points X, Y can be intersections between extensions of the inner surface 15 of the wall section 14 and the inner surface 17 of the connection section 16.

[0059] With the above configuration, since the angle θ2 is not less than 315°, the working fluid can flow uniformly and without difficulty from the dispensing chamber 26 into the connection section 16. Thus, the pressure loss of the fluid flowing from the dispensing chamber 26 into the connection section 16 is reduced, and the working fluid flows uniformly and without difficulty from the dispensing chamber 26 into the connection section 16, thereby increasing the dispensing flow rate. Consequently, with the above configuration, the multi-stage axial compressor 2 can operate stably even during slow rotation.

[0060] In the invention, as in Fig. 3, Fig. 4 to Fig. 5 shown where d is defined as the inner diameter of the connection section 16 in a cross-sectional view orthogonal to the rotating shaft 10 and D is defined as the outer diameter of the tap chamber 26 in a cross-sectional view orthogonal to the rotating shaft 10, the angle θ1 a relationship which is expressed by the following expression: 270°−sin−1((1−dD)0.5)∗180° / π≤θ1, and the angle θ2 satisfies a relationship that is expressed by the following expression: θ2≤270°+sin−1((1−dD)0.5)∗180° / π.

[0061] The smaller the angle θ1, the better the flow separation of the working fluid can be prevented. However, the angle θ1 cannot be smaller than the angle at the time when the connection section 16 is tangentially connected to the dispensing chamber 26 (tangential direction angle). If θt1 is the tangential direction angle at the corner region 34a on the rear side in the direction of rotation Rf of the working fluid, as defined above according to the definition of angle θ1, then the following expression is satisfied: θt1=270°−sin−1((1−dD)0.5)∗180° / π.

[0062] Accordingly, the tangential direction angle θt1 can be determined based on the outer diameter D of the dispensing chamber 26 and the inner diameter d of the connection section 16. Thus, with the above configuration, based on the outer diameter D of the dispensing chamber 26 and the inner diameter D of the connection section 16, the minimum value of the angle θ1 is set to the tangential direction angle θt1.

[0063] Similarly, the larger the angle θ2, the better a uniform or trouble-free flow of the working fluid from the dispensing chamber 26 to the connection section 16 can be achieved, but the angle θ2 cannot be larger than the angle at the time when the connection section 16 is connected to the dispensing chamber 26 in the tangential direction (tangential direction angle). If θt2 is the tangential direction angle at the corner region 34b on the front in the direction of rotation Rf of the working fluid, as described by the above definition of the angle θ2, then the following expression is satisfied: θt2=270°+sin−1((1−dD)0.5)∗180° / π.

[0064] Accordingly, the tangent direction angle θt2 can be determined based on the outer diameter D of the dispensing chamber 26 and the inner diameter d of the connection section 16. Thus, with the above configuration, the maximum value of the angle θ2 is set based on the outer diameter D of the dispensing chamber 26 and the inner diameter d of the connection section 16 in order to be the tangent direction angle θt2.

[0065] In some embodiments, the connecting section 16 has a cylindrical shape with a constant inner diameter d. Furthermore, in a cross-sectional view orthogonal to the rotating shaft 10, the corner region 34b, which is located on the front face in the direction of rotation Rf of the working fluid, can be produced by R-machining, and the inner surface 17 of the connecting section 16 and the inner surface 15 of the wall section 14 can be connected via a curved surface 35.

[0066] In some embodiments, as shown in Fig. 3 and Fig. Figure 5 shows that at least one of the multiple tap pipes 18 has at least one bent or curved section 36. If R is the radius of curvature of the bent section 36, then the ratio R / d of the radius of curvature R of the bent section 36 to the inner diameter d of the connecting section 16 (or to the inner diameter of the tap pipe 18) satisfies a relationship expressed by the following expression: 2 ≤ R / d.

[0067] With the above configuration, the ratio R / d of the radius of curvature R of the bent section to the inner diameter d of the connection section 16 (or to the inner diameter of the dispensing pipe 18) is not less than two. Therefore, the pressure loss of the working fluid in the dispensing pipe 18 is reduced, and the working fluid can flow smoothly and without difficulty through the dispensing pipe 18. Thus, the flow rate of the working fluid flowing through the dispensing pipe 18, i.e., the dispensing flow rate, can be increased. Consequently, with the above configuration, the multi-stage axial compressor 2 can operate stably even during slow rotation with a simple design.

[0068] Furthermore, the radius of curvature R of the bent section 36 is the radius of curvature at the pipe axis (central axis of the bent section 36).

[0069] In some embodiments, as in Fig. Figure 1 shows the rotating shaft 10 in the horizontal direction. Furthermore, as shown in Fig. 3 and Fig. 5 shown, the multitude of connection sections 16 the first connection section 16a, the second connection section 16b, the third connection section 16c and the fourth connection section 16d.

[0070] The first connection section 16a, the second connection section 16b, the third connection section 16c, and the fourth connection section 16d are arranged in this order around the circumference of the rotating shaft 10. In a cross-sectional view, the first connection section 16a and the second connection section 16b are arranged orthogonally to the rotating shaft 10 on the first side of the center C of the rotating shaft 10, and are horizontally orthogonal to the rotating shaft 10. In a cross-sectional view, the third connection section 16c and the fourth connection section 16d are arranged orthogonally to the rotating shaft 10 on the second side opposite the first side of the center C of the rotating shaft 10, and are horizontally orthogonal to the rotating shaft 10.

[0071] The multiple dispensing pipes 18 comprise the first dispensing pipe 18a, the second dispensing pipe 18b, the third dispensing pipe 18c, and the fourth dispensing pipe 18d, each of which is connected to the first connection section 16a, the second connection section 16b, the third connection section 16c, and the fourth connection section 16d, respectively. The first dispensing pipe 18a and the second dispensing pipe 18b extend horizontally orthogonally to the rotating shaft 10 to the second side of the center C of the rotating shaft 10.

[0072] Furthermore, as in Fig. Figure 5 shows at least one curved section 36, the first curved sections 36a1, 36a2, which form part of the first dispensing tube 18a, and the second curved section 36b, which forms part of the second dispensing tube 18b. The first curved sections 36a1, 36a2 and the second curved section 36b are bent or curved such that the direction of rotation of the working fluid flowing through them, in a cross-sectional view orthogonal to the rotating shaft 10, is the same direction as the direction of rotation Rf of the working fluid in the dispensing chamber 26.

[0073] With the above configuration, the first curved sections 36a1, 36a2 and the second curved section 36b are bent such that the direction of rotation of the working fluid flowing through them, in a cross-sectional view orthogonal to the rotating shaft 10, is the same direction as the direction of rotation Rf of the working fluid in the dispensing chamber 26. Thus, the working fluid can flow smoothly and without difficulty through the first curved sections 36a1, 36a2 and the second curved section 36b. This allows the flow rate of the working fluid flowing through the first dispensing pipe 18a and the second dispensing pipe 18b, i.e., the dispensing flow rate, to be increased. Consequently, with the above configuration, the multi-stage axial compressor 2b can be operated stably even during slow rotation with a simple design.

[0074] In some embodiments, the at least one curved section 36 comprises the third curved section 36c, which forms part of the third dispensing tube 18c, and the fourth curved section 36b, which forms part of the fourth dispensing tube 18d. The third curved section 36c and the fourth curved section 36c are curved such that, in a cross-sectional view, the direction of rotation of the working fluid flowing through them is orthogonal to the rotating shaft 10 and opposite to the direction of rotation Rf of the working fluid in the dispensing chamber 26.

[0075] With the above configuration, the third bent section 36c and the fourth bent section 36d are bent such that the direction of rotation of the working fluid flowing through them is orthogonal to the rotating shaft 10 in a cross-sectional view and opposite to the direction of rotation Rf of the working fluid in the dispensing chamber 26, but the ratio R / d is not less than two, so that the pressure loss at the third bent section 36c and the fourth bent section 36d is reduced. Thus, the flow rate of the working fluid flowing through the third dispensing pipe 18c and the fourth dispensing pipe 18d, i.e., the dispensing flow rate, can be increased. Consequently, the multi-stage axial compressor 2b with the above configuration can be operated stably even during slow rotation with a simple design.

[0076] In some embodiments, as in Fig. Figure 1 shows the rotating shaft 10 in the horizontal direction. Furthermore, as shown in Fig. 3 and Fig. Figure 5 shows the plurality of connection sections 16, the first connection section 16a, the second connection section 16b, the third connection section 16c and the fourth connection section 16d. The first connection section 16a, the second connection section 16b, the third connection section 16c and the fourth connection section 16d are arranged in this order in the circumferential direction of the rotating shaft 10.

[0077] The first connection section 16a and the second connection section 16b are arranged orthogonally to the rotating shaft 10 in a cross-sectional view on the first side of the center C of the rotating shaft 10 in the horizontal direction. The third connection section 16c and the fourth connection section 16d are arranged orthogonally to the rotating shaft 10 in a cross-sectional view on the second side opposite the first side of the center C of the rotating shaft 10 in the horizontal direction.

[0078] Furthermore, as in Fig. 3 and Fig. 5 shown, the first connection section 16a and the third connection section 16c extend along the horizontal direction orthogonal to the rotating shaft 10 and the second connection section 16b and the fourth connection section 16d extend along the vertical direction.

[0079] With the above configuration, the first connection section 16a and the third connection section 16c extend horizontally, and the second connection section 16b and the fourth connection section 16d extend vertically. This design prevents the flow of the working fluid entering the first connection section 16a, the second connection section 16b, the third connection section 16c, and the fourth connection section 16d from separating. Consequently, with the above configuration, the multi-stage axial compressor 2 can ensure a sufficient extraction flow rate and operate stably even during slow rotation.

[0080] In some embodiments, the rotating shaft 10 extends, as shown in Fig. Figure 1 is shown, in the horizontal direction. As in Fig. 3 and Fig. Figure 5 shows that the multiple connection sections 16 comprise the first connection section 16a, the second connection section 16b, the third connection section 16c, and the fourth connection section 16d. In a cross-sectional view orthogonal to the rotating shaft 10, the circumferential position of the upper section (vertex section) of the outer circumferential surface of the wall section 14 is defined as 0°. Furthermore, as shown in Fig. Figure 4 shows a cross-sectional view orthogonal to the rotating shaft 10. The intersection point between the outer circumferential surface of the wall section 14 and the axis (centerline) of the connection section 16 is defined as Z. According to the definitions above, the intersection point Z between the outer circumferential surface of the wall section 14 and the axis of the first connection section 16a is at a circumferential position between 30° and 60°, the intersection point Z between the outer circumferential surface of the wall section 14 and the axis of the second connection section 16b is at a circumferential position between 120° and 150°, the intersection point Z between the outer circumferential surface of the wall section 14 and the axis of the third connection section 16c is between 200° and 230°, and the intersection point Z between the outer circumferential surface of the wall section 14 and the axis of the fourth connection section 16d is between 290° and 320°.

[0081] With the above configuration, the intersection point Z between the outer circumferential surface of the wall section 14 and the axis of the first connection section 16a is located between 30° and 60° at the circumferential position; the intersection point Z between the outer circumferential surface of the wall section 14 and the axis of the second connection section 16b is located between 120° and 150° at the circumferential position; the intersection point Z between the outer circumferential surface of the wall section 14 and the axis of the third connection section 16c is located between 200° and 230°; and the intersection point Z between the outer circumferential surface of the wall section 14 and the axis of the fourth connection section 16d is located between 290° and 320°. Thus, the height of the dispensing pipes 18 in the top-bottom direction can be reduced. Consequently, the installation space of the multi-stage axial compressor 2 can be reduced with the above configuration.

[0082] In some embodiments, when the rotating shaft 10 extends in the horizontal direction and a cross-sectional view orthogonal to the rotating shaft 10 is divided into four quadrants on the vertical and horizontal axes, such that its origin is at the center C of the rotating shaft 10 and the second ends 37a, 37b, 37c, 37d of the first dispensing tube 18a, the second dispensing tube 18b, the third dispensing tube 18c and the fourth dispensing tube 18d are arranged in the same quadrant. The second ends 37a, 37b, 37c, 37d of the first dispensing tube 18a, the second dispensing tube 18b, the third dispensing tube 18c and the fourth dispensing tube 18d are the ends furthest from the dispensing chamber 26.

[0083] Furthermore, as in Fig. 3 and Fig. As shown in Figure 5, the first dispensing pipe 18a and the second dispensing pipe 18b are joined, and the third dispensing pipe 18c and the fourth dispensing pipe 18d can be joined. In this case, the second end of the first joining pipe 38a, formed by joining the first dispensing pipe 18a and the second dispensing pipe 18b, and the second end of the second joining pipe 38b, formed by joining the third dispensing pipe 18c and the fourth dispensing pipe 18d, can be arranged in the same quadrant.

[0084] With the above configuration, the second ends 37a, 37b, 37c, 37d of the first tap tube 18a, the second tap tube 18b, the third tap tube 18c and the fourth tap tube 18d are arranged in the same quadrant and thus the second ends 37a, 37b, 37c, 37d of the first tap tube 18a, the second tap tube 18b, the third tap tube 18c and the fourth tap tube 18d can be easily connected to a tube (axial tube) 40 which extends in the axial direction of the rotating shaft (see Fig. 1) extends, be connected.

[0085] In some embodiments, the second ends 37a, 37b, 37c, 37d of the first tap tube 18a, the second tap tube 18b, the third tap tube 18c and the fourth tap tube 18d are arranged in a cross-sectional view orthogonally to the rotating shaft 10 in the same quadrant and on the outside of the housing 12 in the horizontal direction orthogonally to the rotating shaft 10.

[0086] In some cases, a concrete base or similar structure is arranged beneath the housing 12 to support it. Therefore, it is difficult to position the axial tube 40, which extends in the axial direction of the rotating shaft 10, beneath the housing 12.

[0087] In this respect, with the above embodiment, the second ends 37a, 37b, 37c, 37d of the first tap tube 18a, the second tap tube 18b, the third tap tube 18c and the fourth tap tube 18d are arranged on the outside of the housing 12 in the horizontal direction in the same quadrant, and thus the second ends 37a, 37b, 37c, 37d of the first tap tube 18a, the second tap tube 18b, the third tap tube 18c and the fourth tap tube 18d can be easily connected to the axial tube 40, which extends in the axial direction of the rotor shaft.

[0088] In some embodiments, the second ends 37a, 37b, 37c, 37d of the first tap tube 18a, the second tap tube 18b, the third tap tube 18c and the fourth tap tube 18d are arranged in the same quadrant, which is located under the center C of the rotating shaft 10.

[0089] In some embodiments, in a cross-sectional view orthogonal to the rotating shaft 10, the ratio d / D of the inner diameter d of the connection section 16 to the outer diameter D of the dispensing chamber 26 is not less than 1 / 20 and not greater than 1 / 2, and the plurality of connection sections 16 comprises only the first connection section 16a, the second connection section 16b, the third connection section 16c, and the fourth connection 16d, as shown in Fig. 3 and Fig. Figure 5 is shown. Nevertheless, the number of connection sections is not necessarily limited to four.

[0090] In some embodiments, the direction of rotation Rf of the working fluid in the dispensing chamber 26 is the same as the direction of rotation of the rotating shaft 10. Normally, the direction of rotation Rf of the working fluid in the dispensing chamber 26 is the same as the direction of rotation of the rotating shaft 10.

[0091] In some embodiments, the direction of rotation Rf of the working fluid in the dispensing chamber 26 is opposite to the direction of rotation of the rotating shaft 10. The direction of rotation Rf of the working fluid in the dispensing chamber 26 can be opposite to the direction of rotation of the rotating shaft 10 depending on the shape of the guide vane 24 or the position of the slot 28.

[0092] Embodiments of the present invention have been described in detail above, but the present invention is not limited thereto and various changes and modifications are possible. For example, the multi-stage axial compressor 2 can be used with a compressor of a working fluid other than air. Reference symbol list 1 gas turbine 2 multi-stage axial compressors 4 Combustion chamber 6 Turbine 10 Rotary shaft 12 cases 14 Wall section 15 Inner surface of the wall section (outer circumferential surface of the tap chamber) 16 Connection section (dispensing nozzle) 16a first connection section 16b second connection section 16c third connection section 16d fourth connection section 17 Inner surface of the connection section 18 Tap pipe 18a first tap pipe 18b second tap pipe 18c third tap pipe 18d fourth tap pipe 19 Flow rate control valve 20 Running shovel 22 Flow passage 24 guide vanes 26. Dispensing chamber or extraction chamber 28 slots (connecting flow passages) 30 Outlet flow passage 32 rotor passages 34a Corner area on the back in the direction of rotation 34b Corner area on the front in the direction of rotation 30 curved surface or curved surface 36 curved section or curved section 36a1, 36a2 first curved section 36b second curved section 36c third curved section 36d fourth curved section 37a remote end of the first tap pipe 37b remote end of the second tap pipe 37c remote end of the third tap pipe 37d remote end of the fourth tap pipe 38a first junction pipe 38b second junction pipe 40 pipe (axial pipe) C Center of the rotating shaft d Inner diameter of the connection section D Outer diameter of the dispensing chamber X, Y, Z intersection points L line passing through X and Y Rf Rotation direction of the working fluid in the dispensing chamber R radius of curvature

Claims

[1] A multi-stage axial compressor (2) comprising: a rotating shaft (10) on which a plurality of running blades (20) are mounted, a housing (12) surrounding the rotating shaft (10), wherein the housing (12) forms a flow passage (22) of a working fluid between the rotating shaft (10) and the housing (12), a wall section (14) having a ring shape and extending in a circumferential direction of the rotating shaft (10) so that it surrounds the housing (12), wherein the wall section (14) forms a tap chamber (26) with a ring shape and is connected to the flow passage (22), a plurality of connection sections (16) which are connected to an outer circumferential surface of the wall section (14), wherein the connection sections (16) form respective outlet flow passages (30) which are connected to the dispensing chamber (26), and a large number of dispensing pipes (18) which are connected to the respective connection sections (16), characterized by , that in a cross-sectional view orthogonal to the rotating shaft (10), of two corner regions (34a, 34b) where an inner surface (17) of each of the connecting sections (16) and an inner surface (15) of the wall section (14) intersect or cross, at the corner region (34a) which is located on a rear side in a direction of rotation (Rf) of the working fluid in the dispensing chamber (26), where θ1 is defined as an angle formed between the inner surface (17) of the connecting section (16) and the inner surface (15) of the wall section (14), the angle θ1 is not greater than 225°, in the cross-sectional view, which is orthogonal to the rotating shaft (10), from the two corner regions (34a, 34b), where the inner surface (17) of each of the connecting sections (16) and the inner surface (15) of the wall section (14) intersect or cross, at the corner region (34b), which is on a front face in the direction of rotation (R) f ) of the working fluid in the dispensing chamber (26) is arranged when θ2 is defined as an angle formed between the inner surface (17) of the connection section (16) and the inner surface (15) of the wall section (14), the angle θ2 is not less than 315°, and, If, in the cross-sectional view orthogonal to the rotating shaft (10), d is an inner diameter of each of the connecting sections (16), and D is an outer diameter of the tap chamber (26), the angle θ1 satisfies a relationship expressed by the following expression: 270°−sin−1((1−dD)0,5)∗180° / π≤θ1, and The angle θ2 satisfies a relationship that is expressed by the following expression: θ2≤270°+sin−1((1−dD)0.5)∗180° / π. [2] The multi-stage axial compressor (2) according to claim 1, wherein at least one of the plurality of dispensing pipes (18) comprises at least one bent or curved section (36), and where, if d is the inner diameter of each of the connecting sections (16) in the cross-sectional view orthogonal to the rotating shaft (10) and R is a radius of curvature of the at least one bent or curved section (36), a ratio R / d of the radius of curvature R of the at least one bent or curved section (36) to the inner diameter d of the connecting section (16) satisfies a relationship which is expressed by the following expression: 2 ≤ R / d. [3] The multi-stage axial compressor (2) according to claim 2, wherein the rotating shaft (10) extends in a horizontal direction, wherein the plurality of connection sections (16) comprises a first connection section (16a), a second connection section (16b), a third connection section (16c) and a fourth connection section (16d) arranged in this order in the circumferential direction of the rotating shaft (10), wherein the first connection section (16a) and the second connection section (16b) are arranged orthogonally to the rotating shaft (10) in the cross-sectional view at a first side of a center (C) of the rotating shaft (10) in a horizontal direction orthogonal to the rotating shaft (10), wherein the third connection section (16c) and the fourth connection section (16d) are arranged orthogonally to the rotating shaft (10) in the cross-sectional view on a second side opposite the first side of the center (C) of the rotating shaft (10) in the horizontal direction orthogonal to the rotating shaft (10), wherein the plurality of dispensing pipes (18) comprises a first dispensing pipe (18a), a second dispensing pipe (18b), a third dispensing pipe (18c) and a fourth dispensing pipe (18d), each of which is connected to the first connection section (16a), the second connection section (16b), the third connection section (16c) and the fourth connection section (16d), wherein the first tap pipe (18a) and the second tap pipe (18b) extend in the cross-sectional view orthogonally to the rotating shaft (10) to the second side of the center (C) of the rotating shaft (10) in the horizontal direction orthogonally to the rotating shaft (10), wherein the at least one curved section (36) comprises a first curved section (36a) forming part of the first tap pipe (18a) and a second curved section (36b) forming part of the second tap pipe (18b), and wherein the first curved section (36a) and the second curved section (36b) are bent such that a direction of rotation (R) f ) of the working fluid flowing through the first curved section (36a) and the second curved section (36b), in cross-sectional view orthogonal to the rotating shaft (10) is the same as a direction of rotation (R f ) of the working fluid in the dispensing chamber (26). [4] The multi-stage axial compressor (2) according to claim 3, wherein the at least one curved section (36) comprises a third curved section (36c) forming part of the third tap tube (18c) and a fourth curved section (36d) forming part of the fourth tap tube (18d), and wherein the third bent section (36c) and the fourth bent section (36d) are bent such that a direction of rotation (R f) of the working fluid flowing through the third curved section (36c) and the fourth curved section (36d), in cross-sectional view orthogonal to the rotating shaft (10), the direction of rotation (R f ) of the working fluid in the dispensing chamber (26) is opposite. [5] The multi-stage axial compressor (2) according to claim 2, wherein the rotating shaft (10) extends in a horizontal direction, wherein the plurality of connection sections (16) comprises a first connection section (16a), a second connection section (16b), a third connection section (16c) and a fourth connection section (16d) arranged in this order in the circumferential direction of the rotating shaft (10), wherein the first connection section (16a) and the second connection section (16b) are arranged orthogonally to the rotating shaft (10) in the cross-sectional view at a first side of a center (C) of the rotating shaft (10) in a horizontal direction orthogonal to the rotating shaft (10), wherein the third connection section (16c) and the fourth connection section (16d) are arranged orthogonally to the rotating shaft (10) in the cross-sectional view on a second side opposite the first side of the center (C) of the rotating shaft (10) in the horizontal direction orthogonal to the rotating shaft (10), wherein the first connecting section (16a) and the third connecting section (16c) extend along the horizontal direction orthogonal to the rotating shaft (10), and wherein the second connecting section (16b) and the fourth connecting section (16d) extend along a vertical direction. [6] The multi-stage axial compressor (2) according to claim 3 or 4, wherein the first connecting section (16a) and the third connecting section (16c) extend along the horizontal direction orthogonal to the rotating shaft (10), and wherein the second connecting section (16b) and the fourth connecting section (16d) extend along a vertical direction. [7] The multi-stage axial compressor (2) according to claim 2, wherein the rotating shaft (10) extends in a horizontal direction, wherein the plurality of connection sections (16) comprises a first connection section (16a), a second connection section (16b), a third connection section (16c) and a fourth connection section (16d), wherein, if a circumferential position of an upper section of the outer circumferential surface of the wall section (14) is 0° in the cross-sectional view orthogonal to the rotating shaft (10), an intersection point between the outer circumferential surface of the wall section (14) and an axis of the first connecting section (16a) lies at a circumferential position not less than 30° and not greater than 60°, an intersection point between the outer circumferential surface of the wall section (14) and an axis of the second connection section (16b) lies at a circumferential position not less than 120° and not greater than 150°, an intersection point between the outer circumferential surface of the wall section (14) and an axis of the third connection section (16c) lies at a circumferential position not less than 200° and not greater than 230°, and an intersection point between the outer circumferential surface of the wall section (14) and an axis of the fourth connection section (16d) lies at a circumferential position not less than 290° and not greater than 320°. [8] The multi-stage axial compressor (2) according to any one of claims 3 to 6, wherein, if a circumferential position of an upper section of the outer circumferential surface of the wall section (14) is 0° in the cross-sectional view orthogonal to the rotating shaft (10), an intersection point between the outer circumferential surface of the wall section (14) and an axis of the first connecting section (16a) lies at a circumferential position not less than 30° and not greater than 60°, an intersection point between the outer circumferential surface of the wall section (14) and an axis of the second connection section (16b) lies at a circumferential position not less than 120° and not greater than 150°, an intersection point between the outer circumferential surface of the wall section (14) and an axis of the third connection section (16c) lies at a circumferential position not less than 200° and not greater than 230°, and an intersection point between the outer circumferential surface of the wall section (14) and an axis of the fourth connection section (16d) lies at a circumferential position not less than 290° and not greater than 320°. [9] The multi-stage axial compressor (2) according to claim 2, wherein the rotating shaft (10) extends in a horizontal direction, wherein the plurality of connection sections (16) comprises a first connection section (16a), a second connection section (16b), a third connection section (16c) and a fourth connection section (16d) arranged in this order in the circumferential direction of the rotating shaft (10), wherein the first connection section (16a) and the second connection section (16b) are arranged orthogonally to the rotating shaft (10) in the cross-sectional view at a first side of a center (C) of the rotating shaft (10) in a horizontal direction orthogonal to the rotating shaft (10), wherein the third connection section (16c) and the fourth connection section (16d) are arranged orthogonally to the rotating shaft (10) in the cross-sectional view on a second side opposite the first side of the center (C) of the rotating shaft (10) in the horizontal direction orthogonal to the rotating shaft (10), wherein the plurality of dispensing pipes (18) comprises a first dispensing pipe (18a), a second dispensing pipe (18b), a third dispensing pipe (18c) and a fourth dispensing pipe (18d), each of which is connected to the first connection section (16a), the second connection section (16b), the third connection section (16c) and the fourth connection section (16d), wherein, if the cross-sectional view is divided into four quadrants orthogonal to the rotating shaft (10) on a vertical axis and a horizontal axis such that an origin is located on the center (C) of the rotating shaft (10), remote ends of the first dispensing tube (18a), the second dispensing tube (18b), the third dispensing tube (18c) and the fourth dispensing tube (18d), which are furthest from the dispensing chamber (26), are arranged in the same of the four quadrants. [10] The multi-stage axial compressor (2) according to claim 3, 4, 6 or 8 in combination with claim 3 or 4, wherein, when the cross-sectional view is divided into four quadrants orthogonal to the rotating shaft (10) on a vertical axis and a horizontal axis such that an origin is located on the center (C) of the rotating shaft (10), remote ends of the first dispensing tube (18a), the second dispensing tube (18b), the third dispensing tube (18c) and the fourth dispensing tube (18d), which are furthest from the dispensing chamber (26), are arranged in the same of the four quadrants. [11] The multi-stage axial compressor (2) according to claim 9 or 10, wherein the remote ends of the first dispensing tube (18a), the second dispensing tube (18b), the third dispensing tube (18c) and the fourth dispensing tube (18d) are arranged orthogonally in the horizontal direction to the rotating shaft (10) on an outside of the housing (12). [12] A gas turbine (1) comprising: a multi-stage axial compressor (2) according to any one of claims 1 to 11, a combustion chamber (4) which can generate a combustion gas by burning fuel using air compressed by the multi-stage axial compressor (2) as the working fluid, and a turbine (6) that can output energy by using the combustion gas produced in the combustion chamber (4).

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