JP2001234701A - Refrigerant recovery type gas turbine rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerant recovery type gas turbine rotor which can easily be manufactured and sufficiently reduce stress based on thermal stress and centrifugal load generated due to refrigerant recovery. SOLUTION: In this refrigerant recovery type gas turbine rotor, a disc 5 is so constructed that a moving blade is planted in the outer peripheral part and an axial refrigerant passage for circulating a refrigerant in the axial direction is provided in the interior, plural discs 51 are axially stacked through spacers 52, and a heat insulating duct 7 for supplying and discharging a refrigerant from the axial refrigerant passage to the moving blade is provided between the disc and the space. In the gas turbine rotor, the heat insulating duct 7 is stored in a groove 57 provided extending in the radial direction in the side wall of the disc, a projecting part 73 is provided on the side wall of the heat insulating duct 7, and the groove wall of the disc where the heat insulating duct is stored is provided with an engagement groove 59 for fitting the projecting part of the heat insulating duct.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant recovery type gas turbine rotor, and more particularly, to a disk having a rotor blade implanted on an outer peripheral portion and having an axial refrigerant flow passage through which a refrigerant flows in an axial direction. The present invention relates to a refrigerant recovery type gas turbine rotor having a plurality of heat-shielding ducts laminated in the axial direction via a spacer and provided between the disk and the spacer to supply and discharge the refrigerant from the axial refrigerant flow passage to the rotor blades. It is.

[0002]

2. Description of the Related Art A gas turbine is an engine that generates power by rotating a turbine with high-temperature and high-pressure combustion gas generated by burning fuel with compressed air, and is disposed in a gas path (high-temperature and high-pressure combustion gas flow passage). The stationary blades and the moving blades each have a refrigerant flow passage formed therein, and are formed so as to be cooled by flowing a cooling medium through the refrigerant flow passage.

[0003] In a gas turbine generally used in the past, it is common to discharge a refrigerant after cooling a stationary blade or a moving blade into a gas path. In such a case, since the low-temperature refrigerant is mixed into the working gas, the efficiency of the gas turbine may be reduced. For this reason, recently, a closed cooling type gas turbine (refrigerant recovery type gas turbine) that collects and reuses the cooled refrigerant has been developed.

[0004] In order to recover the refrigerant after cooling the rotor blades with a closed cooling gas turbine, it is necessary to form both a supply flow path and a recovery flow path inside the gas turbine rotor. As a result, the temperature of the refrigerant becomes 200
Since the temperature rises by more than ° C., a temperature gradient is formed in the rotor component due to the temperature difference between the supplied refrigerant and the recovered refrigerant, and a large thermal stress is generated. In closed-cooled gas turbines, there are many restrictions on the refrigerant flow path arrangement in the rotor,
How to reduce this thermal stress is one of the major issues in development.

Therefore, for example, Japanese Patent Application Laid-Open No. H11-153001
In the publication, a heat shield member is attached to the refrigerant supply and recovery flow passage inside the rotor to suppress heat transfer between the refrigerant and the rotor constituent members,
The thermal stress is reduced.

[0006]

The heat shielding member to be mounted on the refrigerant channel is (1) a material that can withstand the temperature of the recovered refrigerant, (2) a structure that can withstand a strong centrifugal force, 3) that the coolant does not flow outside the heat shield member to reduce the heat shield effect, (4) that the heat shield member has a gap that absorbs the difference in thermal expansion between the heat shield member and the rotor at the time of startup, (5) processing and It is required to be easy to assemble, and (6) not to induce rotational imbalance by moving the mounting radius position.

In the prior art described above, the supply and recovery channels for the refrigerant are formed at the stacking joints of the rotor on which the disks are stacked, and the heat shield tubes and the radial disk joints are formed at the axial circular passages. A heat shield duct having a circular pipe at one end (see FIG. 3 of JP-A-11-153001) is attached to the slit flow path formed at the end of the slit flow path. Is inserted into the hole of the axial flow path.

However, in this case, since the heat shield duct is interposed between the joining surfaces of the stacking, the circular pipes at both ends are inserted into holes of different members with misalignment caused by processing and assembling. Will be. For this reason, when a centrifugal load is applied, it becomes a single support state, the stress at the base increases, and it cannot be said that it is a preferable support structure as a high-speed rotating body.

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing, and it is an object of the present invention to make it easy to manufacture and sufficiently reduce thermal stress generated due to refrigerant recovery and stress caused by centrifugal load. It is an object of the invention to provide a possible gas turbine rotor of this kind.

[0010]

That is, according to the present invention, there is provided a disk in which a rotor blade is implanted on an outer peripheral portion and which has an axial refrigerant flow passage through which a refrigerant flows in an axial direction. In a refrigerant recovery type gas turbine rotor comprising a plurality of stacked, and a heat shield duct for supplying and discharging the refrigerant from the axial refrigerant flow passage to the rotor blade between the disk and the spacer, the heat shield duct, A groove wall formed on the side wall of the disk so as to be accommodated in a groove extending in a radial direction, a protrusion is provided on a side wall of the heat shield duct, and a groove wall of the disk in which the heat shield duct is housed. And an engagement groove into which the protruding portion of the heat shield duct is fitted, thereby achieving an intended purpose.

Further, according to the present invention, a rotor blade is implanted on an outer peripheral portion,
A plurality of disks each having an axial refrigerant flow passage through which the refrigerant flows in the axial direction are stacked in the axial direction via a spacer, and the disk is moved from the axial refrigerant flow passage to the space between the disk and the spacer. In a refrigerant recovery type gas turbine rotor provided with a heat shield duct for supplying and discharging a refrigerant to and from a blade, the heat shield duct is housed in a groove extending in a radial direction on a side wall of the disk, and the heat shield duct is provided. Protrusions of the same member as the heat shield duct are respectively provided outside the opposite side walls of the heat duct, and the protrusions of the heat shield duct are fitted into groove walls of a disk in which the heat shield duct is housed, respectively. The engagement groove is provided.

In this case, a cylindrical body having substantially the same diameter as the axial refrigerant flow passage is provided at an end of the heat shield duct on the shaft core side, and the cylindrical body and the inside of the heat shield duct communicate with each other. It was formed as follows. Further, at the axial end of the heat shield duct, a half-moon cylinder having substantially the same diameter as the axial refrigerant flow passage is provided, and the half-moon cylinder and the heat shield duct are formed so as to communicate with each other, In addition, a half-moon tube portion that is combined with the half-moon tube to form a cylinder is provided in the axial refrigerant flow passage. Further, the protrusion provided on the side wall of the heat shield duct is provided at an intermediate portion in the longitudinal direction of the heat shield duct. Also,
The shape of the deep bottom of the engagement groove provided in the groove in which the heat shield duct is housed is a circular bottom.

That is, in the refrigerant recovery type gas turbine rotor formed as described above, the heat shield duct is formed so as to be housed in a groove provided to extend radially on the side wall of the disk. A protrusion is provided on the side wall of the heat shield duct, and an engagement groove for fitting the protrusion of the heat shield duct is provided on the groove wall of the disk in which the heat shield duct is housed. Since the duct is supported by the engagement between the protrusion provided on the side wall of the heat shield duct and the engagement groove provided on the disk groove, the centrifugal force of the heat shield duct is sufficiently held by the disk, and the refrigerant Thermal stress due to recovery and stress due to centrifugal load are sufficiently reduced, and only the protruding part of the heat shield duct and the groove of the disk need to be machined, making it easy to manufacture and very simple in construction. Is

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. FIG. 1 shows a cross section of the upper half of a closed air-cooled gas turbine according to the present invention and a heat shield duct. The closed air-cooled gas turbine includes a casing 1, a compressor 2, a combustor 3, and a turbine unit including four stages, a stationary blade 41, a moving blade 42, and a rotor 5 disposed therein. ing.

In the gas turbine, the high-temperature and high-pressure combustion gas generated in the combustor 3 is supplied to a gas path section, that is, a stationary blade 4.
By flowing through the gas path 4 formed by alternately arranging the rotor blades 1 and the moving blades 42, the rotor 5 supported by the bearing 11 rotates to generate power.

In this case, since the stationary blades 41 and the moving blades 42 are exposed to the high-temperature combustion gas, a refrigerant passage is formed inside the stationary blades 41 and the moving blades 42, and are cooled by the refrigerant flowing through the passages. It is formed as follows. In this embodiment, a part of the compressed air for combustion is used as the refrigerant, and the refrigerant of the first stage and the second stage rotor blades is collected in the combustor 3 after cooling. For this reason, as shown by an arrow A in the figure, inside the rotor 5 formed by alternately stacking the disks 51 and the spacers 52 that support the moving blades, pass through the stacking joints 53 from the shaft ends to the moving blades. A refrigerant supply flow path 54 and a recovery flow path 55 from the rotor blade to the combustor 3 via the stacking joint 53 are formed. A heat shield tube 6 is mounted in the axial flow path, and a heat shield duct 7 is mounted in the radial flow path.

FIG. 2 shows a cross section of FIG. 1A, in which a supply channel 54 and a recovery channel 55 are formed in the middle of stacking bolt holes 56 which are arranged at intervals in the circumferential direction. Have been. In this case, since they are alternately arranged with a changed phase, they do not intersect.

Returning to FIG. 1, FIG. 1B is a perspective view showing a single unit of the heat shield tube 6 and the heat shield duct 7. The heat shield tube 6 is formed of a tube having ribs 61 at both ends, and a flow path 62 is formed inside. On the other hand, the heat shield duct 7 is formed by connecting a cylinder 72 having a flow path of the same diameter as the heat shield tube 6 to the inner diameter side of a duct 71 having a rectangular cross section (width a × b). Hooks (projections) 73 are provided on both sides of the duct 71 in the circumferential direction.

FIG. 3 shows a part of the shape of the disk 51. On the side surface of the disk 51, a storage portion for the heat shield tube 6 and the heat shield duct 7 is formed. That is, the disk 5
A slit (groove) 57 having a width a and a depth b and a hole 58 penetrating in the axial direction are formed in the stacking joint portion 53, and a hook groove 59 is perpendicular to the slit at an intermediate position of the slit. It is formed. In this case, the bottom of the hook groove 59 is formed in a circular shape.

At the time of assembling the rotor, first, the heat shield tube 6 is mounted on the through hole 58 of the disk 51 and the heat shield duct 7 is mounted on the slit 57, and the side of the duct 71 is not more exposed than the side of the disk 51. After confirming this, the rotor 5 is stacked.

The centrifugal load acting on the heat shield duct 7 due to the rotation of the rotor is supported by the two hooks 73. However, since the touch surface radius position R of the hook groove 59 can be machined simultaneously on both sides with high accuracy, the load is reduced. Can be evenly dispersed and supported. Also, in the radial direction of the duct, a tensile load acts on the outer diameter side and a compressive load acts on the inner diameter side from the hook touch surface, and the distribution of both changes depending on the setting of the radius position R, so if the radius is designed at an appropriate position Stress can be minimized.

The recesses 63 and 74 provided on the outside of the heat shield tube and on the side surface of the duct are formed to provide a gap between the disk wall surface after assembly and to enhance the heat shielding effect. When generated, the heat transfer is promoted, so that the heat shielding effect is reduced. Since the gap 63 on the axial flow path side and the gap 74a on the radial flow path side are blocked by tightly fitting the ribs 61 of the heat shield pipe 6, the above-mentioned flow around the heat shield duct is a heat shield duct cylinder. A coolant leaked from the coolant passage 62 is formed between the ring-shaped gap 64 formed on the end face of the 72 and the gap 75 on the four sides on the outer diameter side of the duct. It is regulated by the gap 75 on the four sides of the duct.

The rib 76 is formed on the axial side wall at the radius of the hook, so that the hook 73 comes into surface contact with the hook groove 59 of the disk.
Since the size is reduced to (a + b), the present support structure is also effective in effectively maintaining the heat shielding.

FIG. 4 shows another embodiment of the heat shield duct. In this case, the shape of the hook for supporting the centrifugal load is different from that of the above-described embodiment. Heat shield duct 8
Consists of a duct 81 having a radial flow path and a cylinder 82 having an axial flow path, and has a depression 83 on the side surface. However, the outside of the cylinder 82 has an oval shape expanded toward the duct, and the centrifugal load is supported by the hook 84 using the outer wall of the oval portion as a support surface.

The elliptical shape is used to increase the strength around the hook. When a load acts on the hook 84, a bending moment in the direction of crushing the duct and cylinder indicated by the arrow B acts on the hook 84. However, the rigidity of the part is increased by making it oval, and if the eccentricity of the oval is appropriately designed, it can be supported without being crushed by centrifugal load.

The projection surface of the heat shield duct 8 may be engraved on the disk, and the hook storage portion is formed by cutting in the radial direction with an end mill cutter having the same diameter as the outer diameter D of the cylinder 82. Therefore, the radial position of the hook touch surface can be processed with high precision, and even if it is a curved surface, the centrifugal load is not supported by only one side hook. Rather, by making the touch area curved, the load can be dispersed and the effect of reducing the touch surface pressure can be obtained.

Although the present invention is common to the prior art in that a centrifugal load is supported by a cylinder, the intent of the present invention is to support a centrifugal load acting on a heat shield duct by a disk or spacer as a rotor constituent member. In addition, there is a structure in which the working gland of the supporting resultant force is supported in accordance with the centrifugal load working gland of the heat shield duct.

FIG. 5 shows still another embodiment.
In this embodiment, the heat shield structure of the branch part is changed, and the heat shield duct 9 forms a heat shield wall 92 corresponding to the semicircle of the cylinder by circling the end of the duct 91 in a semilunar shape. And a hook 93 on the side of the duct. In this case, since the wall surface of the disk hole corresponding to the remaining semicircle is exposed to the refrigerant, the semi-cylindrical heat shield wall 6 is formed in the axial flow path.
7 was fitted with a heat shield tube 66 extended.

Since the heat shield duct 9 can be formed simply by removing the end of the duct 91 in a half-moon shape, the production is greatly simplified. In addition, the appearance of the heat shield duct 7 is the same as that of the heat shield duct 7 by incorporating both of them into the rotor. Is formed, the same heat shielding effect can be obtained.

However, since the gap 68 is formed at the boundary between the end of the heat shield duct 9 and the heat shield wall 67 of the heat shield tube, there is a concern that the refrigerant leaks from the gap and the heat shield effect is reduced. . Since the gap 68 is designed in consideration of thermal expansion during operation, it is necessary to expand the gap by a length ratio L / b more than the gap 64, but the length of the gap extends the heat shield wall 67. By this, 4b / πD (b = 15 mm, D = 40 mm
Therefore, there is no significant difference in the cross-sectional area of the leak passage in the gap, and the heat shielding effect does not decrease.

In addition to reducing the centrifugal load acting on the hook 93 by an amount corresponding to the separation of the heat shield wall 67 from the heat shield duct, the bending stress generated when the heat shield wall of the branch portion is formed in a cylindrical shape is reduced. Since the problem can be eliminated, a great advantage that the strength design becomes easy can be obtained.

Although bending stress is newly generated due to the cantilever support of the heat shield wall 67, it is not a serious problem since it can be further reduced by measures such as thickening and reinforcing the base 69.

In the above-described embodiment, the recess forming the gap for improving the heat shielding is formed by the ribs at the corners of the duct. However, if the wall has sufficient strength, the ribs other than the ribs at the four sides of the duct end are omitted. On the contrary, when the strength is insufficient, a gap can be formed even if a grid-like rib is formed on the wall.

In the embodiment, the heat shield duct is applied to the branch flow path. However, depending on the gas turbine, a supply flow path is formed at the center of the rotor, and the flow path is formed only across the stacking joint in the radial direction. Although it may be formed, it can be applied to the centrifugal load supporting structure on the side of the duct according to the present invention, a straight type heat shield duct without branching, and the cross section of the duct is not limited to a rectangle but may be a circle.

The refrigerant is not limited to air, and the heat shield duct according to the present invention can be applied to, for example, a gas turbine of a combined power generation plant using steam generated by utilizing exhaust heat of a gas turbine as a blade refrigerant. .

As described above, in the gas turbine rotor formed as described above, the heat shield duct formed by the duct is mounted on the groove of the disk, and the intermediate radial position of the heat shield duct circumferential side wall is provided. A hook for supporting a centrifugal load, especially a hook of the same member as the heat shield duct, is formed. Therefore, the heat shield duct is supported by the same member. It is not necessary to consider the relationship, and it is easy to work to align the radial positions of the hooks on both sides, so that a suitable support structure in which the support load is distributed to both hooks, that is, a support structure that is robust in terms of stress can be obtained.

The above-described support structure can be similarly applied to the heat shielding member of the flow path where the radial direction and the axial direction intersect as shown in the cited example. Then, a branch flow path is formed inside, and a hook is formed at an intermediate radius position of the heat shielding duct circumferential side wall. Thus, if the cylinder is formed symmetrically with respect to the axis of the duct, the centrifugal load can be dispersed and supported in a well-balanced manner as described above.

Further, the above-mentioned heat shielding structure for the branch flow path can be formed even if one end of the duct is cut off in a half-moon shape. In this case, since the inner wall of the branch flow path facing the remaining semicircular portion is exposed to the refrigerant, a heat shield tube having a semi-cylindrical heat shield wall on the branch side is attached to the axial flow path. . As a result, a heat shielding effect equivalent to the case where the above-described conduit is provided is obtained. Further, since a cylindrical portion is not formed, manufacturing is facilitated. Further, a centrifugal load acting on the duct can be reduced. The great advantage of reducing the stress of the above is obtained.

[0039]

As described above, according to the present invention, a refrigerant having a simple structure and easy manufacture, and capable of sufficiently reducing thermal stress generated due to refrigerant recovery and stress based on centrifugal load. A recovery type gas turbine rotor can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing one embodiment of a gas turbine provided with a refrigerant recovery type gas turbine rotor of the present invention.

FIG. 2 is a cross-sectional view taken along line XX of FIG.

FIG. 3 is a perspective view showing a groove shape of a heat shielding duct accommodating portion of the disk.

FIG. 4 is a perspective view showing another embodiment of the heat shield duct used in the gas turbine rotor of the present invention.

FIG. 5 is a perspective view showing another embodiment of the heat shield duct used in the gas turbine rotor of the present invention.

[Explanation of symbols]

5: Turbine rotor, 6, 66: Heat shield tube, 7, 8, 9 ...
Heat shielding duct, 42 ... Blade, 51 ... Disk, 53 ... Stacking joint, 54 ... Supply channel, 55 ... Recovery channel, 5
7: slit, 59: hook groove (engagement groove), 61: rib, 63, 68, 74, 75: gap, 67, 92: heat shield wall, 71, 81: duct, 72, 82: cylinder, 73, 8
4,93 ... hook (projection).

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Ueno Execution 7-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside Power and Electricity Research Laboratory, Hitachi, Ltd. (72) Inventor Tsuyoshi Takano Omika-cho, Hitachi City, Ibaraki 7-2-1, Hitachi, Ltd. Electric Power and Electricity Development Laboratory (72) Inventor Takashi Ikeguchi 7-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture F-term in Hitachi, Ltd. Electric Power and Electricity Development Laboratory Reference) 3G002 AA06 AB01 AB08

Claims (6)

[Claims] 1. A plurality of disks each having an axial direction refrigerant flow passage through which a rotor blade is implanted on an outer peripheral portion and through which a refrigerant flows in an axial direction are stacked in the axial direction via a spacer, and And a spacer, between the spacer and the spacer, a heat recovery duct that supplies and discharges the refrigerant from the axial refrigerant flow passage to the rotor blades. The heat shield duct is housed in a groove provided so as to extend, a protrusion is provided on a side wall of the heat shield duct, and the protrusion of the heat shield duct fits into a groove wall of a disk in which the heat shield duct is housed. A refrigerant recovery type gas turbine rotor, characterized in that the engagement groove is provided. 2. A plurality of disks each having an axial direction refrigerant flow passage in which a rotor blade is implanted in an outer peripheral portion and through which a refrigerant flows in an axial direction are stacked in the axial direction via a spacer, and And a spacer, between the spacer and the spacer, a heat recovery duct that supplies and discharges the refrigerant from the axial refrigerant flow passage to the rotor blades. A disk which is housed in a groove provided so as to extend and which is provided with a protrusion of the same member as the heat shield duct on the outer side of each of the opposite side walls of the heat shield duct, and in which the heat shield duct is housed. A groove for fitting the protrusion of the heat shield duct into the groove wall of the gas turbine rotor. 3. A cylindrical body having substantially the same diameter as the axial refrigerant flow passage is provided at an end of the heat shield duct on the shaft core side, and formed so that the cylindrical body and the inside of the heat shield duct communicate with each other. The refrigerant recovery type gas turbine rotor according to claim 1 or 2, wherein 4. A semi-lunar cylinder having substantially the same diameter as the axial refrigerant flow passage is provided at an end of the heat shield duct on the shaft core side, and the semi-cylindrical body and the inside of the heat shield duct communicate with each other. 3. The refrigerant recovery type gas turbine rotor according to claim 1, further comprising a half-moon tube portion formed in the axial direction refrigerant flow passage and combined with the half-moon tube to form a cylinder. 5. A refrigerant recovery type gas turbine rotor according to claim 1, wherein the protrusion provided on the side wall of the heat shield duct is provided at an intermediate portion in the longitudinal direction of the heat shield duct. . 6. The refrigerant recovery type gas turbine rotor according to claim 1, wherein the inner bottom of the engagement groove is formed in a circular bottom.