Gas turbine cooling arrangement with cooling manifold guides

A gas turbine includes a compressor; a combustor; a turbine configured to drive a rotational shaft of the compressor using combustion gas generated by the combustor; a cooling device configured to generate cooling air by bleeding compressed air from the compressor and cooling the compressed air, and to supply the cooling air to the turbine along the rotational shaft; a pressurizing device configured to increase pressure of the cooling air; a pressurizing device diffuser configured to provide a passage continuing in a turbine circumferential direction, on the outer side in the turbine radial direction to guide the cooling air having the increased pressure to the outer side of the pressurizing device; and a manifold disposed between the pressurizing device diffuser and a plurality of turbine vanes so that a ring-shaped passage communicates with the passage in the pressurizing device diffuser and a cooling passage provided inside each turbine vane.

FIELD

The present invention relates to a gas turbine.

BACKGROUND

A general gas turbine includes a compressor that generates compressed air, a combustor that generates combustion gas using the compressed air generated by the compressor, and a turbine that is driven in rotation by the combustion gas generated by the combustor. Japanese Patent Application Laid-open No. H5-86901, for example, discloses providing such a gas turbine with an air pressurizing device between the compressor and cooled vanes (turbine vanes) for increasing the pressure of the air discharged from the compressor.

The air pressurizing device disclosed in Japanese Patent Application Laid-open No. H5-86901 is implemented as a centrifugal compressor having vanes provided in a manner extending in radial directions, so that the air pressure is increased as the turbine shaft is rotated. In this centrifugal compressor, the vanes are surrounded by partitioning plates jutting out from turbine vanes toward the inner circumferential side. The cooling air having the pressure increased between the partitioning plates is supplied to the turbine vanes, through the holes provided on the inner circumferential wall on the inner circumference of the turbine vanes. However, with such a configuration, the pressure drops disadvantageously in the space leading from the centrifugal compressor to the turbine vanes.

The present invention is intended to address the issue described above, and an object of the present invention is to provide a gas turbine capable of suppressing a drop in the pressure of the cooling air to be supplied to the turbine vanes.

SUMMARY OF THE INVENTION

To achieve the object described above, a gas turbine according to an aspect of the present invention includes a compressor configured to rotate about a rotational shaft to generate compressed air; a combustor configured to generate combustion gas using the compressed air generated by the compressor; a turbine configured to drive the rotational shaft in rotation using the combustion gas generated by the combustor; a cooling device configured to generate cooling air by bleeding the compressed air from the compressor and cooling the compressed air, and to supply the cooling air to the turbine along the rotational shaft; a pressurizing device disposed between the cooling device and the turbine to increase pressure of the cooling air toward an outer side in a turbine radial direction as the rotational shaft rotates; a pressurizing device diffuser configured to provide a passage continuing in a turbine circumferential direction, on the outer side of the pressurizing device in the turbine radial direction so as to guide the cooling air having pressure increased by the pressurizing device to the outer side of the pressurizing device in the turbine radial direction; and a manifold disposed between the pressurizing device diffuser and a plurality of turbine vanes that are arranged in a row along the turbine circumferential direction so as to provide a ring-shaped passage continuing in the turbine circumferential direction so that the ring-shaped passage communicates with the passage in the pressurizing device diffuser and a cooling passage provided inside each of the turbine vanes.

With this gas turbine, the pressurizing device diffuser guides the cooling air having the pressure increased by the pressurizing device toward the outer side in the turbine radial direction, and the manifold supplies the cooling air guided toward the outer side in the turbine radial direction by the pressurizing device diffuser to the cooling passage provided in each of the turbine vanes. As a result, it is possible to suppress a drop in the pressure of the cooling air having the pressure increased by the pressurizing device and to be supplied to the turbine vanes.

Furthermore, it is preferable that the gas turbine according to an aspect of the present invention includes a guide vane provided inside the ring-shaped passage of the manifold to guide the cooling air toward the cooling passage in the turbine vane.

With this gas turbine, it is possible to suppress a drop in the pressure of the cooling air to be supplied from the manifold to the cooling passage. As a result, it is possible to further suppress a drop in the pressure of the cooling air having the pressure increased by the pressurizing device and to be supplied to the turbine vanes.

Furthermore, it is preferable that the gas turbine according to an aspect of the present invention includes a curved section that guides the cooling air in an inlet section of the cooling passage in the turbine vane, the inlet section being a section where the cooling passage communicates with the manifold.

With this gas turbine, it is possible to suppress a drop in the pressure of the cooling air to be supplied from the manifold to the cooling passage. As a result, it is possible to further suppress a drop in the pressure of the cooling air having the pressure increased by the pressurizing device and to be supplied to the turbine vanes.

Advantageous Effects of Invention

According to the present invention, it is possible to suppress a drop in the pressure of the cooling air to be supplied to the turbine vanes.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

An embodiment according to the present invention will now be explained in detail with reference to some drawings. The embodiment is, however, not intended to limit the scope of the present invention in any way. Furthermore, elements described in the embodiment below include elements that allow the skilled person to easily replace, or elements that are substantially the same.

FIG. 1is a schematic illustrating a general structure of a gas turbine according to the embodiment.FIG. 2is an enlarged sectional view near a combustor in the gas turbine according to the embodiment.FIG. 3is a generalized enlarged view of a part of the meridional section of the gas turbine according to the embodiment.

As illustrated inFIG. 1, this gas turbine101includes a compressor1, a combustor2, and a turbine3. In this gas turbine101, a turbine shaft4that is the rotational shaft is disposed in a manner passing through the center of the compressor1, the combustor2, and the turbine3. The compressor1, the combustor2, and the turbine3are arranged in a row, sequentially from the front side to the rear side in the direction of the air flow along the center axis C of the turbine shaft4. In the explanation hereunder, a turbine axial direction refers to a direction extending in parallel to the center axis C. A turbine circumferential direction refers to a direction rotating about the center axis C. A turbine radial direction refers to a direction perpendicularly intersecting with the center axis C. An inner side in the turbine radial direction refers to a side nearer to the center axis C in the turbine radial direction, and an outer side in the turbine radial direction refers to a side more distanced from the center axis C in the turbine radial direction.

The compressor1compresses the air into compressed air. The compressor1includes compressor vanes13and compressor blades14that are provided inside a compressor casing12having an air intake11through which the air is collected. A plurality of the compressor vanes13are arranged in rows along the turbine circumferential direction in a manner attached to the compressor casing12. A plurality of the compressor blades14are arranged in rows along the turbine circumferential direction with the turbine shaft4at the center in a manner attached to the turbine shaft4. The compressor vanes13and the compressor blades14are provided alternatingly along the turbine axial direction. The compressor1has an outlet16provided with a plurality of last stage vanes13athat are arranged in a row along the turbine circumferential direction. In the compressor1, the outlet16is sometimes provided with a plurality of exit guide vanes15that are arranged in a row along the turbine circumferential direction, at a position downstream of the last stage vanes13a.

The combustor2generates high-temperature and high-pressure combustion gas by supplying fuel to the compressed air compressed by the compressor1. The combustor2includes a combustion chamber21in which the compressed air is mixed with fuel and combusted, and a transition piece22that guides the combustion gas from the combustion chamber21to the turbine3. A plurality of (e.g., sixteen) the combustion chambers21are arranged in a row along the turbine circumferential direction with the turbine shaft4at the center inside a combustor casing23having a cylindrical shape that provides a combustor casing chamber R.

Each of the combustion chambers21has a tubular shape, as illustrated inFIG. 2. Inside of the combustion chamber21, a pilot combustion burner21A is disposed at the center. A plurality of main combustion burners21B are disposed along the inner circumferential surface of the combustion chamber21in a manner surrounding the pilot combustion burner21A. The pilot combustion burner21A includes a pilot cone21Aa that is supported by the combustion chamber21and a pilot nozzle21Ab that is disposed inside the pilot cone21Aa. Each of the main combustion burners21B includes a main nozzle21Ba and a swirler vane21Bb that is provided on the outer circumference of the main nozzle21Ba. In the combustion chamber21, a pilot fuel line, not illustrated, is coupled to the pilot nozzle21Ab, and a main combustion line, not illustrated, is coupled to each of the main nozzles21Ba. In the combustion chamber21, an inner cylinder21C surrounding the pilot combustion burner21A provides a channel for sending the compressed air to the pilot combustion burner21A, on the inner side of the inner cylinder21C, and also provides a channel for sending the compressed air to the main combustion burners21B, on the outer side of the inner cylinder21C. The tubular shape of the combustion chamber21has its axis along the turbine axial direction, and an air inlet24is provided as an opening of the tubular shape. This air inlet24is disposed facing the outlet16of the compressor1. When high-temperature and high-pressure compressed air flows into the combustion chamber21through the air inlet24, the compressed air becomes mixed with the fuel injected from the main combustion burners21B, and is turned into swirling flows of pre-mixed gas. The compressed air also becomes mixed with the fuel injected from the pilot combustion burner21A, is ignited by pilot light not illustrated, becomes combusted and is turned into combustion gas, and discharged into the combustion chamber21. At this time, a part of the combustion gas is discharged with flames, in a manner diffusing inside the combustion chamber21, is ignited by the pre-mixed gas flowed out from the main combustion burners21B to the inside of the combustion chamber21, and becomes combusted. In other words, with the diffusion flames resulting from the pilot fuel injected from the pilot combustion burner21A, it is possible to achieve the flame stabilization for ensuring the stable combustion with the lean pre-mixed fuel from the main combustion burner21B.

Each of the combustion chambers21is connected with the compressor1via a compressor diffuser5. The compressor diffuser5is a tubular body providing an air passage for leading the compressed air from the compressor1to the combustion chamber21. One end51of the compressor diffuser5is connected to the outlet16of the compressor1, and the other end52is connected to the air inlet24of the combustion chamber21included in the combustor2, so that the compressor1and each of the combustors2are connected thereby.

The turbine3generates a rotational driving force using the combustion gas resultant of the combustion in the combustor2. The turbine3has a turbine vane32and a turbine blade33that are provided inside a cylindrical turbine casing31. A plurality of the turbine vanes32are arranged in rows along the turbine circumferential direction in a manner attached on the side of the turbine casing31. A plurality of the turbine blades33are arranged in rows along the turbine circumferential direction in a manner attached on the side of the turbine shaft4. The turbine vanes32and the turbine blades33are provided alternatingly in the turbine axial direction. In the rear side of the turbine casing31, an exhaust34having an exhaust diffuser34adisposed continuously to the turbine3is provided.

The end of the turbine shaft4on the side of the compressor1is supported by a bearing41, and the end on the side of the exhaust34is supported by a bearing42. In this manner, the turbine shaft4is provided rotatably about the center axis C. The end of the turbine shaft4on the side of the compressor1is coupled with a driving shaft of a generator, although not illustrated.

In such a gas turbine101, the air collected from the air intake11of the compressor1is passed between the compressor vanes13and the compressor blades14, and compressed into high-temperature and high-pressure compressed air. The compressed air is then mixed with the fuel and combusted in the combustor2, so that high-temperature and high-pressure combustion gas is generated thereby. This combustion gas is then passed between the turbine vanes32and the turbine blades33provided to the turbine3, and drives the turbine shaft4in rotation, applying a rotational driving force to the generator that is coupled to the turbine shaft4. In this manner, power is generated. Flue gas having driven the turbine shaft4in rotation is passed through the exhaust diffuser34ain the exhaust34, and is discharged to the atmosphere as flue gas.

In the gas turbine101according to the embodiment, the compressor diffuser5includes an air bleed port55. The air bleed port55is provided as a hole communicating with the inside and the outside of the compressor diffuser5, to bleed the compressed air from the compressor diffuser5. In this embodiment, the air bleed port55is provided to at least one of one end51and the other end52of the compressor diffuser5. For example, the air bleed port55is a hole formed at the edge of the one end51or the other end52of the compressor diffuser5. Therefore, the air bleed port55takes out a part of compressed air P that is to be sent from the compressor1to the combustion chamber21via the compressor diffuser5, to the inside of the combustor casing23having a cylindrical shape that provides the combustor casing chamber R.

In relation to the air bleed port55, the gas turbine101has an intermediate shaft cover6that is attached to the outer circumference of the turbine shaft4, and having a ring-like shape extending along the turbine circumferential direction. On the outer circumference of this intermediate shaft cover6, the combustor casing chamber R is defined inside the combustor casing23, on the outer side of the combustion chambers21.

The gas turbine101according to the embodiment also includes a cooling device7. The cooling device7includes an air discharge pipe71leading from the combustor casing chamber R to the outside of the combustor casing23, an air supply pipe72leading from the outside of the combustor casing23to the inside of the intermediate shaft cover6(to the side of the turbine shaft4) by penetrating the combustor casing23, a cooling air pipe73by which the air discharge pipe71communicates with the air supply pipe72, and a heat exchanger (turbine-cooling air (TCA) cooler)74that is provided at a midpoint along the cooling air pipe73.

Therefore, the compressed air P taken out via the air bleed port55into the combustor casing chamber R is discharged to the cooling air pipe73provided outside of the combustor casing23via the air discharge pipe71, exchanges heat with coolant in a heat exchanger74, and is turned into cooling air. The cooling air is then supplied to the inside of the intermediate shaft cover6via the air supply pipe72. With this cooling air, which is the cooled compressed air P, parts such as the turbine vanes32, the turbine blades33, and the turbine shaft4can be cooled.

The gas turbine101according to the embodiment also includes a pressurizing device8, a pressurizing device diffuser9, and a manifold10.

The pressurizing device8is provided inside the intermediate shaft cover6, on the inner side of the turbine vanes32(the first stage turbine vanes32disposed in an inlet of the turbine3in this embodiment), in the turbine radial direction. The pressurizing device8is provided as what is called a centrifugal compressor that includes a shroud8athat is fixed to the turbine shaft4, a hub8bfacing the shroud8ain the turbine axial direction, and blades8cprovided between the shroud8aand the hub8b. The centrifugal compressor also includes internal channels8dextending along the turbine axial direction and then directed toward the outer side in the turbine radial direction between the shroud8aand the hub8b. In this pressurizing device8, as the turbine shaft4is rotated, the shroud8a, the hub8b, and the blades8care caused to rotate, and the cooling air, which is the cooled compressed air P, supplied by the cooling device7to the inside of the intermediate shaft cover6is then suctioned from the turbine axial direction into the internal channels8dbetween the shroud8aand the hub8b. The cooling air is then discharged from the internal channels8dto the outer side in the turbine radial direction while having the pressure increased.

The pressurizing device diffuser9is fixed to the turbine casing31, and is provided in a manner continuous to the pressurizing device8in the turbine circumferential direction, on the outer side of the pressurizing device8in the turbine radial direction. The pressurizing device diffuser9includes a pair of guide plates9athat are plate members together form a ring shape by being disposed in a manner facing each other along the turbine axial direction with the turbine shaft4at the center, and provides a passage9bhaving a sectional area increasing toward the outer side in the turbine radial direction. The passage9bis disposed in such a manner that the end of the passage9bon the inner side in the turbine radial direction faces the outer end of the internal channels8dof the pressurizing device8in the turbine radial direction, that is, the outlets of the internal channels8d. Therefore, the pressurizing device diffuser9decelerates the cooling air, which is the cooled compressed air P, while guiding the cooling air having pressure increased by the pressurizing device8on the outer side of the pressurizing device8in the turbine radial direction, and having been discharged from the internal channels8d. The pressurizing device diffuser9may include, as the passage9b, an annular space formed by the turbine casing31without being provided with the guide plates9a. Furthermore, the pressurizing device diffuser9may be provided with fixed vanes for adjusting the flows of the cooling air, which is the cooled compressed air P, toward the outer side in the turbine radial direction in the passage9b.

The manifold10is fixed to the turbine casing31, as illustrated inFIG. 3, and is disposed between the pressurizing device diffuser9and the turbine vanes32that are arranged in rows along the turbine circumferential direction. The manifold10has a ring-shaped passage10athat is continuous in the turbine circumferential direction with the turbine shaft4at the center. The ring-shaped passage10ain the manifold10has an opening10bthat is continuous in the turbine circumferential direction on the inner side in the turbine radial direction, and the manifold10is coupled to the pressurizing device diffuser9in such a manner that this opening10bcommunicates with the outer end in the turbine radial direction of the passage9bof the pressurizing device diffuser9. The manifold10also has a plurality of holes10cpenetrating the outer side in the turbine radial direction of the ring-shaped passage10a, and arranged in a row along the turbine circumferential direction. The manifold10is then coupled to shroud portions32bof the turbine vanes32in such a manner that the hole10ccommunicates with a cooling passage32aprovided to the respective turbine vanes32. A plurality of the cooling passages32aare formed inside one turbine vane32, and the cooling passages32aare merged to one inlet section32bain the shroud portion32bon the inner side in the turbine radial direction, and the holes10care provided in a manner communicating with respective inlet sections32ba. Therefore, the manifold10serves to supply the cooling air, which is the cooled compressed air P, having been guided by the pressurizing device diffuser9to the outer side in the turbine radial direction into the cooling passages32aof the turbine vanes32while guiding the cooling air along the turbine circumferential direction.

With such a gas turbine101, the pressurizing device diffuser9guides the cooling air, which is the cooled compressed air P, having the pressure increased by the pressurizing device8to the outer side in the turbine radial direction, and the manifold10supplies the cooling air, which is the cooled compressed air P, guided by the pressurizing device diffuser9to the outer side in the turbine radial direction into the cooling passages32ain the turbine vanes32. Therefore, it is possible to suppress a drop in the pressure of the cooling air, which is the cooled compressed air P, having the pressure increased by the pressurizing device8and to be supplied to the turbine vanes32.

FIG. 4is a generalized enlarged view of another example of a partial meridional section of the gas turbine according to the embodiment.

As illustrated inFIG. 4, in the gas turbine101according to the embodiment, guide vanes10dare provided to the manifold10. The guide vanes10dare disposed beside the respective holes10cin the turbine circumferential direction. Each hole10cis provided correspondingly to the inlet section32baof the cooling passages32aformed in the turbine vane32. Specifically, the guide vanes10dare disposed downstream of the respective holes10cin a direction in which the turbine shaft4is rotated as indicated by the arrow A inFIG. 4and the cooling air, which is the cooled compressed air P, swirls (i.e., downstream with respect to a cooling air flow direction). Furthermore, the tip ends of the guide vanes10dthat are extending in the ring-shaped passage10aand are on the outer side in the turbine radial direction are provided toward the upstream side in the turbine circumferential direction and with respect to the direction in which the cooling air, which is the cooled compressed air P, swirls, and each of the guide vanes10dcurves from a base end on the outer side to the tip end on the inner side in the turbine radial direction (the holes10c). In other words, each of the guide vanes10dprojects upstream from its base end to its tip end so as to provide the guide vanes10dwith a curved shape as shown inFIG. 4. In this manner, the guide vanes10dguide the cooling air, which is the cooled compressed air P, toward the cooling passages32aformed in the turbine vanes32, in the ring-shaped passage10aof the manifold10.

With the gas turbine101having the structure illustrated inFIG. 4, the guide vanes10dguiding the cooling air, which is the cooled compressed air P, toward the cooling passages32ain the turbine vanes32suppresses a drop in the pressure of the cooling air, which is the cooled compressed air P, before the cooling air is supplied to the cooling passages32avia the manifold10. Therefore, it is possible to suppress a drop in the pressure of the cooling air, which is the cooled compressed air P, having the pressure increased by the pressurizing device8and to be supplied to the turbine vanes32.

FIG. 5is a generalized enlarged view of another example of a partial meridional section of the gas turbine according to the embodiment.

As illustrated inFIG. 5, in the gas turbine101according to the embodiment, a curved portion is provided to the inlet section32baof the cooling passages32aformed in each of the turbine vanes32. The curved portion is a passage in which the inlet section32baof the cooling passages32acurves from the turbine circumferential direction toward the outer side in the turbine radial direction. Specifically, the curved portion forms a passage in which the inlet section32baof the cooling passages32aopens to the ring-shaped passage10ain the manifold10toward the upstream side of the direction in which the turbine shaft4is rotated as indicated by the arrow A inFIG. 5and the cooling air, which is the compressed air P, swirls. This passage leads from this opening to the cooling passages32a, the passage being curved from the turbine circumferential direction toward the outer side in the turbine radial direction. In this manner, the curved portion in the inlet section32baof the cooling passages32aguides the cooling air, which is the compressed air P, into the inside of the cooling passages32ain the turbine vanes32.

With the gas turbine101having the structure illustrated inFIG. 5, the curved portion in the inlet section32baof the cooling passage32aenabling the cooling air, which is the cooled compressed air P, to be guided into the cooling passages32ain the turbine vanes32suppresses a drop in the pressure of the cooling air, which is the cooled compressed air P, to be supplied into the cooling passages32avia the manifold10. As a result, it is possible to further suppress a drop in the pressure of the cooling air, which is the cooled compressed air P, having the pressure increased by the pressurizing device8and to be supplied to the turbine vanes32.

It is also preferable as illustrated inFIG. 5for the holes10con the manifold10to open to the ring-shaped passage10aalong the direction in which the curved section of the inlet section32baof the cooling passage32aopens toward the upstream side in the direction in which the turbine shaft4is rotated as indicated by the arrow A inFIG. 5and the cooling air, which is the cooled compressed air P, swirls. By providing the manifold10with such holes10c, it is possible to suppress a drop in the pressure of the cooling air, which is the cooled compressed air P, to be supplied from the manifold10into the cooling passages32a.

Furthermore, the curved section of the inlet section32baof the cooling passages32aillustrated inFIG. 5may be used together with the guide vanes10dillustrated inFIG. 4.

FIG. 6is an enlarged sectional view around the combustor in another example of the gas turbine according to the embodiment. In the gas turbine101illustrated inFIG. 6, the parts that are equivalent to those in the gas turbine101illustrated inFIGS. 1 and 2are given the same reference signs, and explanations thereof will be omitted.

The gas turbine101illustrated inFIG. 6is different from the gas turbine101illustrated inFIGS. 1 and 2in a compressor diffuser50and the structure of a combustor2.

In the gas turbine101illustrated inFIG. 6, the compressor diffuser50is provided in a manner opening to the combustor casing chamber R so that the compressed air P can be discharged into the combustor casing chamber R.

The combustor2includes an outer casing21D covering outside of the combustion chamber21. The outer casing21D is fixed to the combustor casing23, and one end of the outer casing21D opens to the combustor casing chamber R on the outer side of the combustion chamber21, and the other end communicates with the combustion chamber21. The compressed air P compressed in the compressor1is discharged into the combustor casing chamber R via the compressor diffuser50, and the compressed air P discharged into the combustor casing chamber R is supplied into the combustion chamber21from the one end of the outer casing21D through the gap between the outer casing21D and the combustion chamber21. The combustor2then generates combustion gas using the compressed air P supplied into the combustion chamber21in the manner described above.

In the manner described above, with the gas turbine101having the structure illustrated inFIG. 6, providing the pressurizing device8, the pressurizing device diffuser9, and the manifold10described above suppresses a drop in the pressure of the cooling air, which is the cooled compressed air P, having the pressure increased by the pressurizing device8, and to be supplied to the turbine vanes32.

Explained in the embodiment above is an example in which the pressurizing device8, the pressurizing device diffuser9, and the manifold10are provided correspondingly to the first stage turbine vanes, but the pressurizing device8, the pressurizing device diffuser9, and the manifold10may be provided correspondingly to any other turbine vanes.

REFERENCE SIGNS LIST

21A Pilot combustion burner

21B Main combustion burner

6Intermediate shaft cover

72Air supply pipe

73Cooling air pipe

A Arrow

C Center axis

P Compressed air

R Combustor casing chamber