JP2000274261A - Gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve efficiency, while reducing consumption of the dynamic blade coolant by interposing tubes having a flange at one end thereof so to be fitted in a groove formed in a dub tail part of a root of a dynamic blade between the coolant flow passage of the dynamic blade and the coolant flow passage of a disk. SOLUTION: A dynamic blade 21 of a gas turbine is formed with a coolant flow passage extended in the radial direction inside thereof, and a root of the dynamic blade is formed with a coolant lead-in port 24 and a coolant lead-out port 25. A fastening part of a rotor is formed with a coolant supply flow passage, and a coolant recovery flow passage are formed in the axial direction, and a flow-out port 33 and a flow-in port 34 of each flow passage end are opened in the periphery of a disk 11. Tubes 41, 42 are interposed between the flow-out port 33, the flow-in port 34 and the coolant lead-in port 24, the coolant lead-out port 25, and the flow passage is formed through these tubes 41, 42. Each tube 41, 42 houses a rectangular flange 43 formed in one end thereof with a spring 53 in a groove 51 formed in the root of the dynamic blade, whereas a spherical tube seal 44 provided at the other end is fitted in the flow-out port 33 and the flow-in port 34 for airtight holding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine for cooling blades by using a refrigerant, and more particularly, to a structure for connecting a refrigerant passage between a disk supporting the moving blades and the moving blades.

[0002]

2. Description of the Related Art A moving blade of a gas turbine is cooled by forming a cooling flow path therein to protect the blade from high-temperature combustion gas. Generally, a part of the compressed air for combustion is used as the refrigerant, but after cooling, the compressed air is discharged into the combustion gas path, so that not only the temperature of the combustion gas decreases, but also the flow of the gas path is disturbed. Therefore, the efficiency of the gas turbine decreases.

[0003] Therefore, a so-called closed cooling gas turbine for recovering the refrigerant after cooling the blades has been proposed. The refrigerant is not limited to air.
Steam can also be used, as in the '02 publication.

In a closed cooling gas turbine, a refrigerant is supplied and recovered from a root inlet / outlet of a rotor blade, and is connected to the outside via a supply / recovery flow passage in a rotor.

[0005]

The moving blade is supported by a dovetail fitting having a wavy surface formed on the root of the blade and the outer periphery of the rotor disk so as to withstand a strong centrifugal force due to high speed rotation. . In order to absorb the difference in thermal expansion between the rotor blade and the disk, a clearance is formed in the dovetail fitting portion.

[0006] Since the inlet / outlet of the rotor blade root is connected to the inlet / outlet of the disk across the above-mentioned dovetail clearance, the refrigerant flows out of the rotor through the clearance to reduce the cooling ability of the rotor blade. In other words, the efficiency of the gas turbine decreases due to the consumption of the refrigerant. In particular, in a steam-cooled gas turbine, it is necessary to constantly supply pure water as a refrigerant, and it is necessary to expand a supply facility.

As one means for solving this problem, a method of connecting the inlet / outlet of the blade root and the inlet / outlet of the disk with a tube can be considered. It is necessary to have a structure that does not restrict the movement of the wing.

[0008] Further, a seal is required at the connecting portion between the both ends of the tube and the flow path.

Further, when assembling the moving blade to the disk, the dovetail at the root of the moving blade is inserted into the dovetail groove of the disk in the axial direction, but the tube must not be obstructed.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to reduce the consumption of the moving blade refrigerant to provide a highly efficient gas turbine.

[0011]

Therefore, according to the present invention, a flange is formed at one end of the tube between the refrigerant flow path of the moving blade and the refrigerant flow path of the disk via a tube. Further, a groove having the same shape as the cross section of the tube flange portion is formed in the dovetail portion at the root of the moving blade in the axial direction of the turbine.

At the time of assembling, while the tube is inserted into the disk flow path, the collar is transferred in the axial direction while being included in the groove at the root of the bucket, so that the dovetail can be fitted. The moving blade and the coolant flow path of the disk are connected.

Further, a spring is mounted between the frame outside the groove formed at the root of the moving blade and the flange of the tube, and the tube end face and the flow path end face of the moving blade are pressed against each other by a spring force, so that the tube is brought into contact with the tube. In addition to sealing the connection of the flow path,
The tube will be displaced following the movement of the bucket,
Even if the rotor blade is displaced relative to the disk, there is no fear that a gap is formed between the sealing surfaces.

On the other hand, by forming a tube seal or the like utilizing the elastic deformation of a sphere on the outer peripheral portion of the tube included in the flow path between the tube and the disk flow path, a leak is generated even if the tube seal is displaced. Very few seals can be made.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to FIG.

FIG. 1 shows a partial cross section of a closed-cooled gas turbine rotor equipped with a flanged tube according to the present invention, in which a rotor 1 constituted by disks 11 and 12, spacers 13 and 14 and a distant piece 15.
The rotor blades 21 and 22 are mounted on the outer periphery of the zero.

A cooling channel 23 is formed inside the moving blade, and a refrigerant inlet 24 and a outlet 25 are formed at the root of the moving blade. On the other hand, a coolant supply flow path 31 and a recovery flow path 32 are formed at the fastening portion of the rotor, and the outflow holes 3 at the flow path end are formed.
3 and an inlet 34 are opened on the outer periphery of the disk, and tubes 41 and 42 are mounted between the outlet 33 and the inlet 34 and the refrigerant inlet 24 and outlet 25 at the root of the moving blade.

The refrigerant supplied from the shaft end of the rotor is supplied to the cooling flow path 23 of the rotor blade through the supply flow path 31, the outflow hole 33, the tube 41, and the introduction port 24 as shown by an arrow 91. Is the outlet 25, the tube 42, the inflow hole 34,
Through the recovery channel 32, it is recovered outside the machine from the shaft end.

FIG. 2 is an enlarged view of a portion A in FIG. 1, and FIG. 3 is a sectional view taken along the line AA in FIG.

The tubes 41 and 42 have exactly the same shape. A rectangular flange 43 is formed at one end of the tube, and a spherical tube seal 44 is formed at the other end.

A dovetail 26 having a wavy side surface is formed at the root side of the rotor blade, and a groove 5 having an open end at one end is formed at the end.
1 are formed in the axial direction of the turbine. The portion of the flange 43 of the tube is housed inside the groove 51,
The refrigerant introduction port 24 of the moving blade is pressed against the inner wall of the opened groove 51 by the spring force of a spring 53 mounted between the frame 52 and the flange 43 outside the groove. In this embodiment, the spring is fixed to the back surface of the flange 43 by means such as spot welding.

On the other hand, a tube seal 44 at the other end of the tube.
Is inserted into the refrigerant outlet hole 33 on the outer periphery of the disk 11 such that the outer spherical surface of the seal contacts the inner wall of the hole.

When assembling the moving blade, first, the tube 4
1, 42 are inserted into the inflow / outflow holes 33, 34 on the outer periphery of the disk. After that, the exposure height is adjusted so that the flange of the tube fits into the groove, and the blade is transferred in the axial direction to engage the dovetail. The ring wire 16 is mounted for positioning in the axial direction.

The dovetail of the rotor blade and the dovetail groove of the disk are formed with a clearance to absorb the difference in thermal expansion between the two, and are designed so that one side of the wave comes into contact when a centrifugal force is applied by rotation. I have. For this reason, in the process of starting and stopping the gas turbine, the moving blade is displaced relative to the disk in the radial direction.

However, according to this structure, since the tube is displaced integrally with the rotor blade, no gap is formed on the sealing surface between the tube and the inlet / outlet, and the center of the disk hole is not formed. The sealing performance does not change even if the tube is displaced in the axial direction of the hole.

Therefore, unlike the case of the structure in which the tube is displaced following the disk side, no gap is generated between the sealing surfaces depending on the operating condition, and the leak can be greatly reduced.

There is a fear that the seal surface of the tube seal may be partially hit due to the misalignment between the flow passage hole of the disk and the tube, thereby causing a leak. Since the gap 54 is formed between the outer edge of the flange and the side wall of the groove 51 and there is no step in the axial direction of the groove, the movement of the rotor in the circumferential direction and the axial direction is not restricted, so that misalignment is caused. There is no worry about absorption and leakage.

FIG. 4 shows another embodiment of the seal structure. In this case, a spacer 61 was mounted instead of the spring mounted on the back surface of the above-mentioned flange, and a seal ring 62 was mounted on the sealing surface.

FIG. 5 is a view taken in the direction of arrows Y in FIG. 4, and the spacer 61 is U-shaped. Further, the frame 65 outside the groove 64 does not necessarily need to be formed over the entire width of the disk. For example, in the case where the tube connecting the supply path and the recovery path cannot be formed in the same shape due to the structure of the rotor, the center part is not formed. There is no problem with resection.

Assembling is performed by attaching the seal ring 6 to the tube 60.
After mounting the bucket 2 and mounting the bucket, the spacer 61 is press-fitted in the axial direction, and the seal ring and the sealing surface 66 of the bucket introduction port are brought into close contact with each other. In this case, since there is a gap in the spacer portion when the moving blade is incorporated into the disk, there is an advantage that the moving blade is easily transferred without the frictional force due to the spring force acting as in the previous embodiment. The thickness of the spacer 61 is the thickness of the metal seal ring 6.
Since the amount of restoration is small, the plate thickness may be adjusted between the flange 63 of the tube and the inner wall of the blade tip groove 64 so as to form a small gap 66 that does not exceed the elastic deformation of the seal ring.

Except for a very small thermal elongation, the clearance 66 does not open beyond a set value depending on the operating condition of the gas turbine, a stable sealing effect is obtained, and the dovetail is not restricted because the rotor blade is not restrained by the clearance. It also has the effect of improving the fit of the fit.

While the spacer 61 may come off during rotation, it can be prevented without damaging the disk by caulking the end of the spacer after assembly. Also, when rearranging the moving blades, it is not necessary to first remove the spacer, and the whole can be disassembled simply by extracting the moving blades.

The embodiment described above can be applied irrespective of the type of refrigerant, and can be applied not only to a closed cooling type gas turbine but also to a conventional gas turbine which does not collect refrigerant.

[0034]

As described above, according to the present invention, the refrigerant inlet / outlet at the base of the moving blade and the inlet / outlet of the disk are connected by a tube with a flange, and the tube is supported by the moving blade. By doing so, the leakage of the refrigerant from the connection portion is reduced, and a highly efficient gas turbine with low refrigerant consumption is obtained.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a gas turbine rotor showing one embodiment of the present invention.

FIG. 2 is an enlarged view of a portion A in FIG.

FIG. 3 is a sectional view taken along line XX of FIG. 1;

FIG. 4 is an enlarged view of a portion A in FIG. 1 showing another embodiment.

FIG. 5 is a sectional view taken along line YY of FIG. 4;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Gas turbine rotor, 11 ... Disk, 21 ... Blade, 24 ... Inlet, 25 ... Outlet, 31 ... Refrigerant supply channel, 32 ... Refrigerant recovery channel, 33 ... Outlet, 34 ... Inlet, 40 ... Static wings, 41,42 ... Tube, 43 ... Tsubame, 4
4. Tube seal, 51, 64 groove, 52, 65 frame, 53 spring, 61 spacer, 62 seal ring.

Claims (3)

[Claims] A compressor, a combustor, a turbine, etc.,
A gas turbine, wherein at least the first stage rotor blades of the turbine are cooled using a refrigerant, and the refrigerant is supplied or recovered through a flow path formed in a disk supporting the rotor blades, A flange is formed at one end of the tube via a tube between the flow path formed in the disk and the refrigerant introduction / exit of the moving blade, and is inserted into a groove having the same cross-sectional shape as the flange of the tube at the root of the moving blade. A gas turbine wherein the rotor blades are connected to the refrigerant flow path of the disk. 2. The gas turbine according to claim 1, wherein a spring is mounted between a back surface of a flange formed at one end of the tube and a frame outside a groove formed at a root of the rotor blade. 3. A seal member is interposed between a flange formed at one end of the tube and a refrigerant inlet / outlet of the moving blade, and a back surface of the flange and a frame outside a groove formed at a root of the moving blade. The gas turbine according to claim 1, wherein a spacer is mounted between the gas turbines.