JP2005220861A - Gas turbine moving blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently cool a platform through simple constitution by using cooling air, in a platform for a moving blade liable to be influenced especially by heat. <P>SOLUTION: In a cooling mechanism for a platform for a gas turbine moving blade, a cooling air flow passage 6 extending in the radial direction of a rotor is formed in the platform 3 and a seal air flow passage 7 extending from the cooling air flow passage 6 to a side 3c of the platform is formed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cooling structure for a platform in a gas turbine blade.

  Inside the gas turbine, the platform is effectively cooled with a simple structure by using cooling air or seal air in a moving blade platform that is particularly susceptible to heat by the high-temperature gas supplied into the gas turbine. Many such gas turbine rotor blades are provided.

  For example, in Japanese Patent Laid-Open No. 10-238302, a cooling passage that is divided into both sides of a blade head side, a blade belly side, and a blade back side and finally reaches the blade tail side is provided through the inside of the platform. Discloses a gas turbine rotor blade that opens into a blade cooling passage and opens downstream to the end surface of the blade tail to cool the platform with cooling air for cooling the blade.

  Further, in Japanese Patent No. 3040660, a seal air passage hole penetrating in the radial direction of the platform is provided, and a seal air flowing on the lower surface of the platform is provided by providing an air outlet on the upper surface of the seal air passage hole. Flows out to the upper surface of the platform in the radial direction through the seal air passage hole. There is disclosed a gas turbine rotor blade that cools the upper surface of the platform by flowing while expanding the upper surface of the platform by an air outlet provided on the upper surface of the platform when it flows out.

  Furthermore, in Japanese Patent No. 3337393, when the cooling air is guided to the moving blade, the route for supplying the inside of the moving blade is devised so that the air is ejected from the lower portion of the stationary blade to the lower portion of the moving blade platform through a short route. A gas turbine rotor blade is disclosed in which the cooling performance is improved by minimizing the temperature rise of the cooling air and reducing the pressure loss.

JP-A-10-238302 Japanese Patent No. 3040660 Japanese Patent No. 3337393

  By the way, generally, when a high-temperature gas is supplied to the turbine rotor cascade, this high-temperature gas is blown to the front edge portion 102 of the blade portion 101 as shown in FIG. At this time, it is known that the horseshoe vortex A caused by the high temperature gas is generated in the hub portion 103 formed at the base of the wing portion 101 and the high temperature gas forms a vortex around the moving blade and spreads. As a result, the flow of hot gas around the moving blade is pushed back to the platform 104 by the vortex of the blade leading edge 102 and enters the gap between the adjacent platforms 104, so that the effect of the horseshoe vortex A shown in the platform 104 The hatched portion 104a, which is a region that is susceptible to exposure, is exposed to high temperatures.

  As a result, as shown in FIGS. 6 and 7, the high temperature gas is blown onto the platform 104, whereby the wing portion 101 is cooled by providing a cooling air flow path inside the wing, and the platform 104 held at a high temperature. And the temperature difference increases. Thereby, compressive stress due to high temperature is generated on the side surface 104b of the platform, whereas tensile stress due to low temperature is generated in the interior 104c of the platform formed below the wing portion 101. That is, the temperature gradually increases from the inside 104c of the platform toward the side surface 104b. Accordingly, a crack D due to low cycle fatigue as shown in FIG. 8 occurs on the side surface 104b of the platform.

  Further, when the platform 104 is kept at a high temperature by the horseshoe vortex A, particularly on the side surface 104b adjacent to each platform 104, as shown in FIG. 8, the thermal barrier coating exfoliated D on the surface of the platform 104 is removed. Will occur.

  However, in the three conventional gas turbine rotor blades described above, although the wing and the platform are cooled, the high temperature gas entering the side of the platform is not sufficiently cooled. For this reason, no measures are taken against cracks due to compressive stress and peeling of the thermal barrier coating due to high-temperature gas. In other words, gas turbine blades are required to efficiently cool the platform while preventing high temperature gas from entering between the platforms.

  Accordingly, the present invention solves such problems, and in a gas turbine platform, particularly a moving blade platform that is easily affected by heat, the platform can be efficiently constructed with a simple structure using cooling air. An object of the present invention is to provide a gas turbine rotor blade and a gas turbine which are cooled.

  A gas turbine rotor blade according to a first aspect of the present invention for solving the above-described problems is provided with a cooling mechanism for a gas turbine rotor blade platform, wherein a cooling air flow path extending in a rotor radial direction is provided on the platform, and the cooling air A sealing air flow path extending from the flow path to the circumferential end surface of the platform is provided.

  A gas turbine rotor blade according to a second aspect of the present invention that solves the above-described problem is the gas turbine rotor blade according to the first aspect, wherein the cooling air flow path is provided on a front edge side of the wing portion of the platform. It is characterized by.

  A gas turbine rotor blade according to a third aspect of the present invention for solving the above-mentioned problems is the gas turbine rotor blade according to the first or second invention, wherein the cooling air supplied to the cooling air flow path is on the vehicle compartment side. It is supplied from the opening part opened to the wall which partitions off and the axial part side.

  A gas turbine rotor blade according to a fourth aspect of the present invention for solving the above-described problems is characterized in that, in the gas turbine rotor blade according to the third aspect of the present invention, the opening is formed in an intermediate shaft cover.

  In the cooling mechanism of the platform of the gas turbine blade, a cooling air flow path extending in the rotor radial direction is provided on the platform, and a sealing air flow path extending from the cooling air flow path to a circumferential end surface of the platform is provided. Therefore, the cooling air ejected from the seal air flow path is filled between the adjacent platforms, and the high temperature gas entering between the adjacent platforms is prevented, and the platform 3 can be efficiently cooled. Thereby, peeling of the thermal barrier coating on the surface of the platform and cracking due to compressive stress can be prevented. Accordingly, the platform can be efficiently cooled with a simple configuration using cooling air, particularly in the platform that is easily affected by the high-temperature gas.

  In addition, since the cooling air flow path is provided on the front edge side of the wing portion of the platform, it can be surely filled between the adjacent platforms. Accordingly, it is possible to reliably prevent the high temperature gas from entering and to efficiently cool the platform 3.

  In addition, since the cooling air supplied to the cooling air flow path is supplied from an opening that opens in a wall that partitions the compartment side and the shaft side, the cooling air that is maintained at a low temperature and a high pressure is the cooling air. It is supplied from the flow path to the seal air flow path and ejected. Therefore, the platform 3 can be further efficiently cooled, and the cooling air filled between the adjacent platforms can prevent the hot gas from entering.

  Further, since the opening is formed in the intermediate shaft cover, it is possible to supply high-pressure cooling air with low temperature and low loss.

  FIG. 1 is a perspective view of a blade back side of a gas turbine blade according to an embodiment of the present invention, FIG. 2 is a perspective view of a blade side of a gas turbine blade according to an embodiment of the present invention, and FIG. FIG. 4 is a sectional view showing a cooling air system according to one embodiment of the present invention.

  As shown in FIGS. 1 to 3, the moving blade 1 is composed of a blade portion 2 exposed to a high-temperature gas flow, a platform 3 of the blade portion 2, a shank portion 4 and a blade root portion 5 formed in the lower portion of the platform 3. Has been. In order to cool the platform 3, the platform 3 is provided with a cooling air flow path 6 formed in the radial direction from the bottom surface 3 a of the platform. Two cooling air flow paths 6 are provided on the side of the front edge 2a of the wing part of the platform 3, and do not penetrate to the upper surface 3b of the platform, but are formed to have a predetermined length from the bottom 3a of the platform. It is. Each of the cooling air passages 6 is provided with a plurality (four in the embodiment) of sealing air passages 7 that are formed in the circumferential direction from the cooling air passage 6 and penetrate the side surface 3c of the platform.

  Next, as shown in FIG. 4, the moving blade 1 is rotatably supported by a rotor (not shown) via a rotor disk 8, and stationary blades 9 are arranged in the front and rear of the rotor axial direction. An inner shroud 10 is installed inside the stationary blade 9 and an outer shroud 11 is installed outside. The stationary blade 9 is supported by the casing 12 through the outer shroud 11.

  Further, the stationary blade 9 installed in front of the moving blade 1 is provided with an end portion of a combustor 14 installed in the passenger compartment 13, and a high-temperature gas flow is transmitted from the combustor 14 to the moving blade 1 and the stationary blade 9. It is sent to the parallel passage. Further, a pipe 17 that passes through the intermediate shaft cover 15 and communicates with the space 16 is installed in the vehicle compartment 13. The pipe 17 is for supplying cooling air to the space 16, and a ring cover 18 for diverting the supplied cooling air to the space 16 is supported by the intermediate shaft cover 15.

  In order to efficiently supply the cooling air in the space 16, the cooling air hole 8 a of the rotor disk 8 is formed, and the cooling air formed in the intermediate shaft cover 15 for taking in the cooling air from the passenger compartment 13. The hole 15a and the cooling air hole 15b for taking in the cooling air supplied to the space 16 from the pipe 17 to the moving blade 1 side are formed. The cooling air holes 15a and 15b are holes that open in the rotor axial direction. The cooling air hole 15a can immediately supply the cooling air of the casing 13 to the moving blade 1 side, and the cooling air hole 15b can supply the cooling air supplied to the space 16 to the moving blade 1 side in the shortest distance. The holes 15a and 15b can supply high-pressure cooling air with little loss without increasing the temperature. The rotor disk 8 is formed with a cooling air passage hole 8b for cooling the inside of the blade 1. The cooling air passage hole 8 b communicates with the lower portion of the moving blade 1 and communicates with a flow path (not shown) passing through the blade root portion 5, the shank portion, and the blade portion 2.

  Therefore, as described above, one row of moving blades and 9 rows of stationary blades are alternately arranged in the axial direction of the rotor in the high-temperature gas flow path, and the moving blade 1 is rotatably supported by the rotor via the rotor disk 8. In addition, the stationary blade 9 is supported by the casing 12 via the outer shroud 11. Further, a plurality of moving blades 1 and stationary blades 9 are attached in parallel in the circumferential direction of the rotor.

  Then, when the high-temperature gas flow supplied from the combustor 14 is taken in, the high-temperature gas flow is given a circumferential speed by the stationary blade 9 and enters the moving blade row. The rotor blade 1 is also rotated at a circumferential speed by a high-temperature gas flow in the rotor blade 1. The hot gas stream exiting one row of moving blades passes through the rear 9 stationary blades and enters the subsequent moving blade 1 row. During this time, energy is given to the hot gas by the moving blades, and the pressure is increased by repeating acceleration and deceleration.

  At the same time, cooling air for cooling the rotor blades 1 is supplied to the vehicle compartment 16 through the pipe 17. Here, let X be a flow in which cooling air is supplied to the space 16 through the pipe 17. The cooling air X includes cooling air x1 passing through the cooling air hole 15b of the intermediate shaft cover, cooling air x2 flowing between the intermediate shaft cover 15 and the ring cover 18, and cooling flowing between the ring cover 18 and the rotor disk 8. It is divided into air x3.

  The divided cooling airs x1 and x2 flow in the axial direction of the rotor and merge as a flow of the cooling air x4. On the other hand, x3 is divided into cooling air x5 flowing through the cooling air passage hole 8b of the rotor disk and cooling air x6 flowing through the cooling air hole 8a of the rotor disk.

  The cooling air x5 cools the inside of the moving blade 1 through the cooling air passage hole 8b and the cooling passage of the blade root portion 5, the shank portion 4 and the blade portion 2, and after circulating inside the moving blade 1, the blade It is discharged from the vicinity of the wing head, tip, and wing tail of part 2, and joins the high pressure gas flow. On the other hand, the cooling air x6 that has flowed into the cooling air hole 8a of the rotor disk is supplied to a moving blade (not shown) arranged at the next stage of the moving blade 1, and then the moving blade is cooled.

  The cooling air x4 is combined with the cooling air y1 supplied from the compressed air Y in the passenger compartment 13 through the cooling air hole 15a of the intermediate shaft cover to the space 16, and becomes the sealing air and the cooling air Z. Thereafter, the sealing air and the cooling air Z become sealing air that prevents leakage of the hot gas flow from between the moving blade 1 and the stationary blade 9, and are included in the hot gas flow while cooling the surface of the platform 3.

  At this time, the cooling air z1 that is a part of the flow of the cooling air Z is supplied to the cooling air flow path 6 that opens to the bottom surface 3a of the platform. The cooling air z <b> 1 flows through the cooling air flow path 6 due to a pump-up effect that is a pressure in the radial direction generated by the rotation of the moving blade 1. Further, the cooling air z1 supplied to the cooling air flow path 6 is supplied to the sealing air flow path 7 having a passage in the circumferential direction in communication with the cooling air flow path 6 by the forced vortex due to this pressure, and then the side surface of the platform. It is ejected from the 3c side.

  That is, by passing the cooling air z1 through the cooling air flow path 6 and the sealing air flow path 7, the platform 3 exposed to the horseshoe vortex at a high temperature can be cooled. Further, the cooling air z1 is ejected from the sealing air flow path toward the side surface 3c of the platform, so that the clearance between the side surfaces 3c of the adjacent moving blades 1 is filled with the cooling air z1, and the clearance between the side surfaces 3c of the platform is filled. It is possible to prevent the high temperature gas from entering. This is because the filled cooling air z1 serves as a seal. Thereby, since the high temperature gas does not contact the side surface 3c of the platform, the cooling effect is enhanced, and at the same time, it is possible to prevent the thermal barrier coating from peeling off or cracking caused by the compressive stress, particularly, generated on the side surface 3c of the platform. .

  Further, the cooling air z1 is composed of the cooling air y1 supplied from the cooling air hole 15a and the cooling air x1 supplied from the cooling air hole 15b, and as described above, the cooling air z1 is cooled at a low temperature and a high pressure. Since the air is used, the cooling efficiency can be further obtained, and after being supplied to the cooling air flow path 6, it can be supplied to the sealing air flow path 7 without difficulty and ejected. For this reason, even in a state where the space between the side surfaces 3c of the platform is filled, the side surface 3c of the platform can be cooled to prevent the high temperature gas from entering.

  That is, since the cooling air z1 filled between the side surfaces 3c of the platform serves as a seal, it is possible to prevent high temperature gas entering between the side surfaces 3c of the adjacent platforms. Further, the side surface 3c of the platform is always cooled by being filled with the cooling air z1, and at the same time, the cooling air z1 supplied to the cooling air flow path 6 and the sealing air flow path 7 passes through the inside of the platform 3. Since cooling is performed, the side surface 3c and the inside of the platform 3 can be efficiently cooled. In addition, since the platform 3 can be efficiently cooled in this way, even if it receives a horseshoe vortex caused by high-temperature gas, the peeling of the thermal barrier coating that is likely to occur on the side surface 3c of the platform is suppressed, and the side surface 3c of the platform has a cooled wing. Since there are few temperature differences with the part 2, the crack by the low cycle fatigue of a compressive stress can be suppressed.

  Therefore, according to the present invention, the cooling air flow path 6 extending in the radial direction of the rotor is provided on the platform 3 and the sealing air flow path 7 extending from the cooling air flow path 6 to the side surface 3c of the platform is provided. The cooling air z1 ejected from the flow path 7 is filled between the side surfaces 3c of the platform, and the high temperature gas entering between the adjacent platforms can be prevented, so that the platform 3 can be efficiently cooled. Further, since the platform 3 can be efficiently cooled in this way, even if it receives a horseshoe vortex caused by high-temperature gas, it is possible to suppress peeling of the thermal barrier coating that is likely to occur on the side surface 3c of the platform, and the side surface 3c of the platform is cooled. Since there is little temperature difference with the wing | blade part 2, the crack by the low cycle fatigue of a compressive stress can be suppressed. That is, in the platform 3 that is particularly susceptible to high temperature gas, the cooling air z1 can be used to efficiently cool the platform 3 with a simple configuration, and the thermal barrier coating can be prevented from peeling and cracking occurring on the platform.

  Moreover, since the cooling air flow path 7 is provided in the front edge side 2a of the wing | blade part of the platform 3, it can be reliably filled between the side surfaces 3c of a platform. Accordingly, it is possible to reliably prevent the high temperature gas from entering and to efficiently cool the platform 3.

  Furthermore, since the cooling air supplied to the cooling air flow path 7 is supplied from the cooling air holes 15a and 15b opened in the intermediate cover 15 that partitions the vehicle compartment 13 side and the rotor side, the cooling air is kept at a low temperature and a high pressure. The cooling air z1 is supplied from the cooling air channel 6 to the seal air channel 7 and can be ejected. Therefore, when the cooling air z1 is filled between the side surfaces 3c of the platform, the side surface 3c of the platform is always cooled, and the cooling air z1 supplied to the cooling air flow path 6 and the sealing air flow path is changed to the platform 3. Since the interior of the platform 3 is cooled, the side surface 3c and the interior of the platform 3 can be further efficiently cooled.

  In this embodiment, the cooling air flow path 6 is provided on the front edge 2a side of the wing part of the platform 3, but for example, the wing tail side, wing back side, and wing belly side platform of the wing part 1 are provided. 3 may be provided as appropriate, and the number of the sealing air flow paths 7 may be set in consideration of the sealing performance of the cooling air and the cooling condition of the platform 3. Further, the flow channel shapes of the cooling air flow channel 6 and the seal air flow channel 7 can be freely set according to the amount of cooling air ejected. Further, even if the cooling air flow path 6 and the sealing air flow path are provided on either one of the side surfaces 3 of the adjacent platform, the same effect can be obtained.

  Furthermore, the cooling air z1 is a part of the cooling air Z in which the cooling air x4 supplied from the pipe 17 and the cooling air y1 supplied from the passenger compartment 13 merge, but is not limited thereto. For example, a part of the cooling air 5x passing through the cooling air passage hole 8b may be supplied to the cooling air passage 6.

  The present invention can be applied to a gas turbine blade that efficiently cools a platform while preventing high-temperature gas entering between adjacent platforms.

It is a blade back side perspective view of a gas turbine rotor blade concerning one example of the present invention. It is a blade side perspective view of a gas turbine rotor blade concerning one example of the present invention. It is a lower side view of FIG. It is sectional drawing which shows the cooling air system | strain which concerns on one Example of this invention. It is a perspective view of the conventional gas turbine rotor blade which receives a horseshoe vortex. FIG. 6 is a detailed view of part B in FIG. 5. FIG. 7 is a detailed view of part C in FIG. 6. It is a perspective view of the conventional gas turbine rotor blade which the crack and coating peeling generate | occur | produced.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotating blade 2 Blade | wing part 2a Front edge part 3 Platform 3a Bottom face 3b Upper surface 3c Side face 4 Shank part 5 Blade root part 6 Cooling air flow path 7 Seal air flow path 8 Rotor disk 8a Cooling air hole 8b Cooling air passage hole 9 Stator blade 10 Inner shroud 11 Outer shroud 12 Casing 13 Car compartment 14 Combustor 15 Intermediate shaft cover 15a Cooling air hole 15b Cooling air hole 16 Space 17 Pipe 18 Ring cover

Claims (4)

In the cooling mechanism of the gas turbine blade platform,
A gas turbine rotor blade comprising: a cooling air passage extending in a radial direction of a rotor in the platform; and a sealing air passage extending from the cooling air passage to a circumferential end surface of the platform. The gas turbine rotor blade according to claim 1, wherein
The gas turbine rotor blade according to claim 1, wherein the cooling air flow path is provided on a front edge side of a blade portion of the platform. In the gas turbine rotor blade according to claim 1 or 2,
The gas turbine rotor blade according to claim 1, wherein the cooling air supplied to the cooling air flow path is supplied from an opening that opens in a wall that partitions the compartment side and the shaft side. In the gas turbine rotor blade according to claim 3,
The gas turbine rotor blade according to claim 1, wherein the opening is formed in an intermediate shaft cover.

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