JP3188105B2 - Gas turbine blades - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving blade of a gas turbine applied to thermal power generation and the like.

[0002]

2. Description of the Related Art FIG. 3 is an explanatory view of a moving blade of a conventional gas turbine used for thermal power generation or the like. In the figure,
The blades of the present gas turbine are called integral shroud blades.
2 are integrally formed, and the shroud 12 is
The gas leaking from the tip of the shroud 12 is reduced, and the end face of the shroud 12 is pressed against the end face of the adjacent shroud 12 to form a continuous shroud 12, thereby improving the vibration resistance of the rotor blade 11. . Vibration in both the axial direction and the circumferential direction of the rotor is generated in the moving blade 11, but the vibration in both directions is suppressed by forming the end face of the shroud 12 obliquely. The shroud 12 is provided with fins 13 projecting therefrom in order to reduce gas leaking from the tip of the moving blade 11 and in preparation for contact with the casing.

[0003] In addition, the moving blades of the gas turbine are cooled to cope with high-temperature gas.
At a temperature of 00 to 1200 ° C., a convection cooling method using a perforation 14 penetrating the moving blade 11 in the length direction is generally employed. Arrows indicate the flow of the cooling air.

[0004]

As described above, in the moving blade of the conventional gas turbine, the convection cooling is performed by the perforations 14 penetrating the moving blade 11 in the longitudinal direction.
The cooling air that has cooled the inside and raised the temperature also cools the top of the moving blade 11 and flows out from the tip of the perforated hole 14, but the cooling effect of the top of the moving blade 11 is extremely low. The shroud 12 at the top of the rotor blade 11 has a small heat capacity, and if the cooling is insufficient, the temperature of the shroud 12 rises until it corresponds to a high gas temperature. For this reason, creep deformation occurs at the base of the shroud 12 with respect to the moving blade 11 due to high temperature in addition to high centrifugal force, and the top of the moving blade 11 may come into contact with the casing and burn.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a gas turbine moving blade which is convectively cooled through a longitudinally penetrating hole. provided branches along the shroud from the porous and has a plurality of grooves for cooling the moving blade top through the cooling gas was performed convective cooling through the porous.

[0006] Then the plurality of grooves are engraved in a recess provided on the surface of the shroud, both ends of the groove in the recess
A plug plate provided with a cut-out hole is fitted into a portion corresponding to the above and brazed.

[0007]

That is, in the moving blade of the gas turbine according to the present invention, a plurality of blades provided along the shroud are provided from the holes in the moving blade of the gas turbine which are convectively cooled through the holes penetrating in the longitudinal direction. The rotor blade top is cooled by convective cooling gas through a hole in the groove of the blade, and a plurality of grooves are branched from the hole along the shroud to provide cooling air at the rotor blade top. The cooling air flows along the shroud to increase the distance for heat exchange, thereby sufficiently cooling the blade top.

[0008] The plurality of grooves are engraved in a recess provided on the surface of the shroud, and in the recess both of the groove
Nde write fitting the plug plate cut holes are bored at positions corresponding to the end <br/> are brazed rotor blade top by a plurality of grooves exit holes provided branches along the shroud , The passage area of the cooling air flowing along the shroud increases, and the distance for performing the heat exchange becomes longer, so that the top of the rotor blade is sufficiently cooled. In addition, these grooves are formed in the recess on the shroud surface, and the plug plate is fitted into the recess and brazed, so that it can be easily manufactured without particularly requiring advanced processing technology, and the influence on the manufacturing cost is small. .

[0009]

1 and 2 are explanatory views of a moving blade of a gas turbine according to an embodiment of the present invention. In the figure, the moving blade of the gas turbine according to the present embodiment is a gas turbine used for thermal power generation and the like, and is referred to as an integral shroud blade.
Are formed integrally, and the shroud 1 reduces the gas leaking from the tip of the rotor blade 3 and the shroud 1
The end face of the blade 3 is pressed against the end face of the adjacent shroud 1 to form a continuous shroud 1 so that the vibration resistance of the moving blade 3 is improved. Vibrations in both the axial direction and the circumferential direction of the rotor are generated on the rotor blades 3. By forming the end face of the shroud 1 obliquely, the vibrations in both directions are suppressed. The shroud 1 is provided with fins 4 protruding in order to reduce gas leaking from the tip of the rotor blade 3 and in preparation for contact with the casing side.

The blade of the gas turbine is cooled in order to cope with a gas having an inlet temperature of 1000 to 1200 ° C., and as shown in FIG. A convection cooling system using a through-hole 5 is employed. The arrows indicate the flow of cooling air. Further, in the present gas turbine rotor blade, a rectangular or rectangular depression a is provided in the shroud 1 as shown in FIG. 2, and a plurality of grooves b for cooling air are formed in the depression a in the rotation direction. Have been. The plug plate 2 is fitted into the recess a, and the plug plate 2 is provided with cuts c having the same width as the groove width at portions corresponding to both ends of the groove b of the cooling air. The plug plate 2 is fitted into the recess a and is fixed by brazing the entire periphery that comes into contact with the periphery of the recess a.

The cooling air flows through the perforations 5 penetrating the moving blades 3 and cools the moving blades 3 to reach the shroud 1, the flow direction is changed in both directions by the plug plate 2, and the grooves b in the recesses a The shroud 1 cools through and flows out radially as indicated by the arrows. Even if an attempt is made to convectively cool the top of the moving blade 3 by the perforations 5 penetrating the moving blade 1 in the longitudinal direction, it is almost impossible to increase the number of holes and increase the amount of cooling air because of the shape of the moving blade 3. Also, since the cooling air flows linearly through the perforations 5, the heat exchange distance is very short. However, as described above, the groove b for the cooling air is cut into the rectangular or rectangular recess a. By inserting and brazing the plug plate 2 having the notch c at a portion corresponding to b, the passage area of the cooling air is greatly increased, and the amount of the cooling air is also greatly increased. Further, since the cooling air flows out from the cuts c on both sides via the plug plate 2, the distance over which the cooling air flows along the shroud 1 is increased, and the distance at which heat is exchanged is increased, thereby improving the cooling effect.

In a conventional blade of a gas turbine, convection cooling is performed by a hole penetrating the blade in the longitudinal direction. Cooling air that has cooled the inside of the blade and raised the temperature also cools the top of the blade. However, the cooling effect of the blade top is extremely low. The shroud at the top of the bucket has a small heat capacity, and if the cooling is insufficient, the temperature of the shroud rises to correspond to a high gas temperature. For this reason, creep deformation occurs due to high temperature in addition to high centrifugal force at the root of the shroud with respect to the moving blade, and the moving blade top may come into contact with the casing side and burn out. In order to solve the problem, a rectangular or rectangular depression a is machined in the shroud 1, and a plurality of grooves b for cooling air are cut in the depression a in the direction of rotation of the rotor.
A notch c having the same width as the groove width is provided in a portion corresponding to the end of the groove b for cooling air of the plug plate 2 fitted into the plug plate 2. Is fixed to the recess a by brazing. Such a cooling structure of the shroud 1 sufficiently cools the shroud 1 and the top of the moving blade 3, and a high centrifugal force is applied to the root of the shroud 1 with respect to the moving blade 3. Creep deformation caused by high temperature can be prevented. The recess a does not necessarily have to be rectangular or square, and the shroud 1
It may be changed according to the shape of the device or the condition of the place where cooling is required. Further, the groove b does not necessarily need to be formed in the rotation direction, but may be formed in the axial direction of the rotor, obliquely, or bent. In addition, the processing of the recess a in the shroud 1, the processing of the groove b for cooling air, the processing of the cut c, and the brazing of the plug plate 2 do not require particularly advanced techniques, and are easy, so that the influence on the production cost is obtained. Also less.

[0013]

The moving blade of the gas turbine according to the present invention is configured as described above, and the top of the moving blade is sufficiently cooled. Therefore, the centrifugal force and the high temperature are applied to the root of the shroud with respect to the moving blade. The resulting creep deformation is prevented.
Moreover, these grooves are engraved in depressions on the shroud surface.
By inserting the plug plate into the recess and brazing it
In particular, it can be easily manufactured without requiring advanced processing technology
The influence on the production cost is small.

[Brief description of the drawings]

FIG. 1A is a perspective view of a moving blade of a gas turbine according to one embodiment of the present invention, and FIG. 1B is a sectional view.

FIG. 2 is an exploded view.

3 (a) is a perspective view of a rotor blade of a conventional gas turbine, FIG. 3 (b) is a sectional view, and FIG. 3 (c) is a perspective view of a perforation thereof.

[Explanation of symbols]

 Reference Signs List 1 shroud 2 plug plate 3 rotor blade 4 fin 5 perforated a recess b groove for cooling air c cut

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F01D 5/18 F02C 7/18

Claims (1)

(57) [Claims] 1. A rotor blade of a gas turbine which is convection cooled through a perforated penetrating in longitudinal direction, provided branches along the shroud from the porous, cooling was performed convective cooling through the porous It has a plurality of grooves for cooling the blade top through gas , and the grooves are provided on the surface of the shroud.
Engraved in the recess, corresponding to both ends of the groove
Insert and braze a plug plate with a cut hole
A rotor blade for a gas turbine, characterized in that: