JP2004137958A - Gas turbine rotor blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent occurrence of a crack by suppressing a thermal stress. <P>SOLUTION: Ribs 15 are provided on surfaces of inner walls of passages 12b, 12c at positions after a cooling medium makes the first turn. A relative cooling difference between the passages 12a, 12b and 12c is reduced. A cooling fluid after a blade part 5 is cooled, is made to flow to a shank side. The fluid uniformly cools the blade part 5 and reduces in a temperature difference between the blade part 5 and the shank 3 via a platform 3. Thus, the occurrence of the crack is prevented by suppressing the thermal stress. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a gas turbine blade having a hollow passage into which a cooling medium is introduced.
[0002]
[Prior art]
A gas turbine is provided with moving blades in a circumferential direction of a rotating shaft, and the rotating shaft is driven to rotate by combustion gas flowing between the moving blades, for example, to drive a compressor and a generator.
[0003]
Since high-temperature combustion gas is introduced into the gas turbine, and especially the rotor blades and the stationary blades on the front stage are exposed to high temperatures, the cooling blades having a hollow passage through which the cooling medium is introduced are formed by the gas turbine. It is used as a moving blade of a turbine (for example, see Patent Documents 1, 2, and 3).
[0004]
[Patent Document 1]
JP 2001-234703 A
[Patent Document 2]
JP 2000-291406
[Patent Document 3]
JP-A-2001-55901
[0005]
[Problems to be solved by the invention]
The moving blade of the gas turbine has a Christmas tree-shaped embedded portion held on the rotating shaft side, and a blade portion (blade profile portion) is formed across the shank and the platform.
[0006]
For this reason, there is a large difference in the total mass, and a temperature difference occurs. Further, when the cooling medium flows, the temperature of the cooling medium on the downstream side increases, and a temperature difference between the passages also occurs. For this reason, there is a possibility that a thermal stress is generated on the trailing edge side between the shank and the wing portion particularly across the platform, and cracks or the like are generated.
[0007]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a gas turbine rotor blade capable of uniformly cooling a blade portion.
[0008]
Another object of the present invention is to provide a gas turbine rotor blade in which a temperature difference between a blade portion and a shank hardly occurs between platforms, with the platform interposed therebetween.
[0009]
[Means for Solving the Problems]
The gas turbine rotor blade of the present invention for achieving the above object,
A passage through which cooling air flows from the blade root on the leading edge side of the blade to the blade top is provided, and a plurality of passages are formed continuously at the top end by turning back toward the blade root and at the blade root turnback toward the blade top. The blades connected to the ejection holes provided in the cascade of trailing edges are formed in the passages on the trailing edge side of the blades, and the leading edge side cooling passages are flat cavities. In the rear passage, a turbulator is provided on the inner wall of the passage.
[0010]
The space for the blade root turn-back portion is provided at a position of a shank portion below a platform attached to the blade root.
[0011]
Further, the wall thickness between the blade trailing edge provided with the ejection hole and the blade trailing edge side cooling passage is formed so as to gradually increase from the top to the hub.
[0012]
Further, a plurality of ejection holes are provided in a vertical portion in a thick portion between the moving blade trailing edge and a cooling passage.
[0013]
Further, the ejection hole is characterized in that a hole in a hub portion of the rotor blade has a larger area than an ejection hole in an upper portion.
[0014]
Further, the ejection hole near the hub is a vertically long hole.
[0015]
In addition, three holes near the hub of the ejection holes have an area larger than other ejection holes.
[0016]
Further, the ejection angle of the ejection hole is formed upward.
[0017]
Further, a passage independent of the serpentine passage is provided on the leading edge side of the blade, so that cooling air is introduced from the root of the blade and discharged to the top of the blade.
[0018]
In order to achieve the above object, a gas turbine rotor blade of the present invention is provided with a passage for flowing cooling air from a blade root on the leading edge side of the blade to the blade top, a passage turned back at the top end to the blade root, a blade root. A serpentine cooling passage formed by continuously forming a plurality of passages toward the blade tip at the turnback portion is formed, and the passage on the trailing edge side of the passage is connected to a jet hole provided in a column of trailing edges. In the gas turbine rotor blade having a platform, the shape of the blade root of the rotor blade and the root portion of the platform is changed so that the shape of the fillet portion on the back side and the ventral side of the blade trailing edge is on the back side of the blade leading edge side. And an elliptical shape larger than the shape of the fillet portion on the ventral side.
[0019]
Further, a passage independent of the serpentine passage is provided on the leading edge side of the blade to introduce cooling air from the blade root portion and discharge the cooling air to the blade top portion.
[0020]
In addition, a machined ejection hole is provided without using a core.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a perspective view showing the overall configuration of a gas turbine rotor blade according to an embodiment of the present invention, FIG. 2 is a cross section of the gas turbine rotor blade, and FIG. 3 is a view taken along line III-III in FIG. 4 shows details of an arrow IV part in FIG. 3, and FIG. 5 shows a view taken in the direction of an arrow V in FIG. 6 to 8 show the condition of the wing and the platform. FIG. 6 is an overall perspective view showing a fillet at the base, FIG. 7 is an external view of the front edge side, and FIG. The appearance as viewed from the front is shown.
[0022]
The gas turbine includes a compressor, a combustor, and a turbine. Compressed air compressed by the compressor is burned together with fuel in the combustor, and combustion gas is introduced into the turbine to drive the turbine. The compressor is operated by the power of the turbine, and power is generated by the generator.
[0023]
The gas turbine rotor blade 1 shown in FIG. 1 is provided in multiple stages in the axial direction on the rotating shaft side of the turbine. The gas turbine blade 1 has a Christmas tree-shaped embedded portion 2 held on the rotating shaft side, and a blade portion (blade profile portion) 5 formed with a shank 3 and a platform 4 interposed therebetween.
[0024]
As shown in FIGS. 2 and 3, a cavity extending vertically is formed in the gas turbine rotor blade 1, and, for example, three passages 12 a, 12 b, and 12 c are formed from a leading edge to a trailing edge. A cooling channel 11 through which a cooling fluid (for example, air) is sent from the rotor side is connected to the passage 12a on the leading edge side.
[0025]
The leading edge passage 12a and the central passage 12b communicate with each other at a folded portion 13a at the top of the top end, and the cooling fluid flowing upward through the passage 12a is folded at the folded portion 13a and flows downward through the passage 12b. The passage 12b and the trailing edge passage 12c communicate with each other at a folded portion 13b below the blade root portion, and the cooling fluid flowing down the passage 12b is folded at the folded portion 13b and flows upward through the passage 12c. The cooling fluid flowing upward through the passage 12c is discharged from the discharge port 14 at the upper end.
[0026]
That is, the three passages 12a, 12b, and 12c form a serpentine passage state in which a plurality of passages are continued by the folded portions 13a and 13b.
[0027]
The inner wall of the cavity of the passage 12a is formed as a flat surface, and the inner wall surfaces of the passage 12b and the passage 12c which is the trailing edge passage extend in a direction intersecting the flowing direction of the cooling fluid (turbulence generating means). Many ribs 15 are formed.
[0028]
The cooling fluid flowing through the passages 12b and 12c generates a turbulent flow toward the wall surface by the rib 15, so that heat transfer is promoted. That is, the ribs 15 are provided on the inner wall surfaces of the passages 12b and 12c after the cooling medium is first turned back.
[0029]
On the other hand, a folded portion 13b (end of the passage) that connects the passage 12b and the passage 12c on the trailing edge side is disposed on the shank 3 side with the platform 4 interposed therebetween. That is, a continuous passage state in which the cooling fluid flowing through the passage 12b is turned back at the shank 3 is formed.
[0030]
In the above-described gas turbine blade 1, the cooling fluid is sent from the cooling flow channel 11 to the passage 12a on the leading edge side, and the cooling fluid flows upward through the passage 12a.
[0031]
The cooling fluid that has flowed upward through the passage 12a turns back at the turn-back portion 13a and flows downward through the central passage 12b. When flowing through the central passage 12b, the ribs 15 cause a reattachment flow toward the wall surface of the cooling fluid to promote heat transfer.
[0032]
The cooling fluid that has flowed downward through the passage 12b is folded back at the folded portion 13b located at the shank 3 and flows upward through the passage 12c on the trailing edge side. When flowing through the passage 12c on the trailing edge side, a reattachment flow toward the wall surface is generated by the ribs 15 in the cooling fluid to promote heat transfer. The cooling fluid flowing upward through the passage 12c is discharged from the discharge port 14 at the upper end.
[0033]
In the gas turbine rotor blade 1 having the above-described structure, the ribs 15 are not provided in the leading edge side passage 12a as hollows whose inner walls are flat and flush, so that the cooling air from the rotor blade root cools the leading edge side blade. And the cooling fluid can be sent to the passage 12b while keeping it cold. For this reason, a cooling fluid in a state of maintaining a high cooling capacity in which heat transfer is not sufficiently generated in the passage 12a is sent to the passage 12b. Therefore, the relative cooling difference between the passage 12a and the passage 12b is reduced, and the temperature difference can be reduced.
[0034]
Further, in the gas turbine rotor blade 1 having the above-described configuration, the cooling fluid that has flowed downward in the passage 12b is turned back at the turn-back portion 13b located at the shank 3, so that the cooling medium that has cooled the passage 12b and is warmed can be cooled. 3 will be distributed. Since the shank 3 below the platform 4 is not directly exposed to the hot combustion gas, the temperature is lower than that of the wing 5.
[0035]
Therefore, when the warmed cooling medium flows through the shank 3, the low-temperature shank 3 is warmed by the cooling medium, and the temperature difference between the shank 3 and the wing 5 can be reduced.
[0036]
As shown in FIGS. 3 and 4, the trailing edge side passage 12 c has a rib 15 formed on the inner wall surface, and the abdominal side and the back side are not directly connected. For this reason, the length H of the rear edge portion (solid portion) from the rear edge to the passage 12c is ensured to be large, and a decrease in rigidity due to an unconnected state between the abdomen and the back is suppressed.
[0037]
Further, a folded portion 13b for folding back the passage 12b and the trailing edge passage 12c is disposed at the shank 3 at the lower portion of the platform. That is, since the passage 12 extends to the shank 3, the heating is rather performed. The shank is warmed by the cooling air to eliminate the temperature difference between the platform and the shank.
[0038]
For this reason, the thickness of the wing part 5 can be configured such that the root side is thin and the tip side is thin.
[0039]
The conventional trailing edge side passage 12c is cast with a core in the same manner as the other passages, and the passage 12c is formed in the middle except for a portion where a pedestal is provided to form a jet hole with a trailing edge. A jet hole is formed by the child. The periphery of the blowout hole has a small number of metal crystals and is relatively mechanically weak. On the other hand, as shown in FIGS. 3 and 4, a fluid ejection hole 16 penetrating the trailing edge is provided at the trailing edge (backmost edge) of the passage 12c on the trailing edge side. The fluid ejection holes 16 are formed by machining (drilling) after casting a thick portion of the wing portion 5.
[0040]
By jetting a part of the cooling fluid from the fluid jetting holes 16, film cooling by the cooling fluid at the trailing edge portion is performed.
[0041]
When the member corresponding to the fluid ejection hole is formed by casting as described above, the wing portion 5 is divided into an abdominal member and a dorsal member, and the wing portion 5 is appropriately connected by a connecting member and cast. For this reason, the thickness of the casting at the portion where the member corresponding to the fluid ejection hole is formed becomes thin, and the state in which the number of metal crystals is small is obtained.
[0042]
On the other hand, when the fluid ejection hole 16 is formed by machining (drilling) after casting the thickness portion of the wing portion 5, the thickness of the cast portion in the thickness portion of the wing portion 5 is sufficiently ensured during casting. As a result, a large number of metal crystals are present and a homogenized state is obtained.
[0043]
Since the number of metal crystals does not decrease even if the hole processing is performed, the wing portion 5 of the present embodiment example is compared with a case where a member corresponding to the fluid ejection hole is formed by casting (compared with a case where a thin object is cast). Has an advantageous structure in terms of strength.
[0044]
As shown in FIG. 2, the thickness between the cooling passage of the trailing edge and the ridge line of the ejection hole 16 is formed so as to gradually increase from the blade top to the hub portion. The influence of the temperature of the flowing air and the temperature of the thick portion to be cooled is reduced. Increasing the amount of metal crystals in the portion that receives the stress of the wing and reducing the damage due to heat even if the ejection hole in the hub is enlarged.
[0045]
Further, as shown in FIG. 6, the shape of the blade root of the blade portion 5 of the gas turbine rotor blade 1 and the shape of the root portion of the platform 4 are changed to the shapes of the fillet portions on the back side and the ventral side of the blade trailing edge (FIG. 8). (See FIG. 7), which is larger than the shapes of the fillet portions on the dorsal side and the ventral side on the wing leading edge side (see FIG. 7). Thus, the fillet R between the wing portion 5 and the platform 4 on the trailing edge side is formed large to avoid stress concentration. Further, at the root of the wing 5 with the platform 4 on the trailing edge side, a curved concave groove is formed in the circumferential direction to avoid stress concentration. Is provided.
[0046]
As shown in FIG. 5, the fluid ejection hole 16 has three fluid ejection holes 16a, 16b, 16c on the hub side, that is, closer to the platform 4 (lower side). Are formed by 1: 3 long holes). Since the fluid ejection holes 16a, 16b, 16c are formed as long holes in the vertical direction, stress concentration in the vertical direction is eliminated.
[0047]
In the gas turbine rotor blade 1 described above, the relative cooling difference between the passage 12a and the passage 12b is reduced, the temperature difference can be reduced, and the warmed cooling medium flows through the shank 3, The shank 3 in the low temperature state is warmed by the cooling medium, and the temperature difference between the shank 3 and the wing 5 can be reduced.
[0048]
For this reason, thermal stress between the wing part 5 and the platform 4 can be suppressed, and in particular, cracks hardly occur at the base of the wing part 5 on the trailing edge side. Further, deformation of the platform can be prevented.
[0049]
In addition, the length H of the rear edge (solid portion) from the rear edge to the passage 12c is ensured to be large, and the natural frequency is prevented from lowering.
[0050]
In addition, since the fluid ejection hole 16 is formed by machining (drilling) after casting at the thickness portion of the wing portion 5, a large number of metal crystals are present, and the structure is advantageous in terms of strength. .
[0051]
Furthermore, the fillet R is formed large in order to avoid stress concentration, and since the three fluid ejection holes 16a, 16b, 16c are formed by vertically long slots, stress concentration in the vertical direction is eliminated.
[0052]
Another embodiment of the present invention will be described with reference to FIG. FIG. 9 shows a cross section of a gas turbine blade according to another embodiment of the present invention. Note that the same members and the same functional members as those shown in FIG. 2 are denoted by the same reference numerals, and redundant description is omitted.
[0053]
As shown in FIG. 9, a narrow cooling air passage 21 independent of the serpentine passage is provided on the leading edge side of the blade, and air is introduced from the cooling passage 22 at the root of the blade and discharged from the opening 23 at the top of the blade. . The angle of the fluid ejection hole 16 of the trailing edge is directed upward. Other configurations are the same as those shown in FIG.
[0054]
By providing the cooling air passage 21, the cooling performance can be further improved, and the fluid can be spouted smoothly by turning the angle of the fluid jetting hole 16 upward. It should be noted that there is no problem even if the angle of the fluid ejection hole 16 is horizontal as shown in FIG.
[0055]
In the above-described embodiment, the gas turbine blade 1 having three and four cooling passages has been described as an example. However, a gas turbine blade having five or more passages may be applied. It can be changed as appropriate depending on the size and the position where it is provided. Further, the turbulator may be appropriately implemented such as a horizontal one or an obliquely positioned one.
[0056]
【The invention's effect】
The gas turbine rotor blade of the present invention is provided with a passage for flowing cooling air from the blade root portion on the blade inner leading edge side to the blade tip, a passage turning back at the top end portion toward the blade root, and a blade turning portion at the blade root turning portion. A plurality of continuous passages are formed to form a serpentine cooling passage, and among the passages, a passage on the trailing edge side of the blade includes a moving blade connected to a jet hole provided in a column of trailing edges; The cooling passage is a flat cavity, and the turned-back passage is provided with a turbulator on the inner wall of the passage, so that the relative cooling difference between the passages is reduced and the gas turbine operation that can evenly cool the blades It can be a wing.
[0057]
As a result, it is possible to suppress thermal stress and prevent cracks from occurring.
[0058]
And, since the space of the blade root folded portion is provided at the position of the shank portion below the platform attached to the blade root, the cooling fluid after cooling the blade portion flows to the shank portion side and sandwiches the platform. Thus, it is possible to provide a gas turbine rotor blade in which a temperature difference is hardly generated between the blade portion and the shank portion.
[0059]
As a result, it is possible to suppress thermal stress and prevent cracks from occurring.
[0060]
Further, since the wall thickness between the blade trailing edge provided with the ejection hole and the blade trailing edge side cooling passage is formed so as to gradually increase from the top to the hub portion, the temperature of the air flowing through the cooling passage is increased. And the wall thickness portion to be cooled can reduce the influence of temperature.
[0061]
Further, since a plurality of ejection holes are provided in the upper and lower rows in a thick portion between the moving blade trailing edge and the cooling passage, the film can be cooled effectively.
[0062]
Also, since the ejection hole has a larger area at the hub portion of the rotor blade than the upper ejection hole, and since the ejection hole near the hub portion is a vertically long hole, the ejection hole The three holes close to the hub of the piercing hole can eliminate the vertical stress concentration having an area larger than the other ejection holes.
[0063]
Further, since the ejection angle of the ejection hole is formed in the upward direction, the ejection can be smoothly performed.
[0064]
Further, a passage independent of the serpentine passage is provided on the leading edge side of the blade to introduce cooling air from the root of the blade and discharge it to the top of the blade, so that the cooling performance can be further improved.
[0065]
In order to achieve the above object, a gas turbine rotor blade of the present invention is provided with a passage for flowing cooling air from a blade root on the leading edge side of the blade to the blade top, a passage turned back at the top end to the blade root, a blade root. A serpentine cooling passage formed by continuously forming a plurality of passages toward the blade tip at the turnback portion is formed, and the passage on the trailing edge side of the passage is connected to a jet hole provided in a column of trailing edges. In the gas turbine rotor blade having a platform, the shape of the blade root of the rotor blade and the root portion of the platform is changed so that the shape of the fillet portion on the back side and the ventral side of the blade trailing edge is on the back side of the blade leading edge side. And since it is an elliptical shape larger than the shape of the fillet portion on the ventral side, the fillet R between the wing portion and the platform on the trailing edge side is formed large to avoid stress concentration.
[0066]
A passage independent of the serpentine passage is provided on the leading edge side of the blade to introduce cooling air from the root of the blade and discharge it to the top of the blade, so that the cooling performance can be further improved.
[0067]
Further, since the ejection hole machined without using the core is provided, the fluid ejection hole for cooling the film can be formed at the rearmost edge where many metal crystals are present.
[Brief description of the drawings]
FIG. 1 is a perspective view illustrating an entire configuration of a gas turbine rotor blade according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a gas turbine blade.
FIG. 3 is a view taken along line III-III in FIG. 2;
FIG. 4 is a detailed view of an arrow IV part in FIG. 3;
FIG. 5 is a view as seen from an arrow V in FIG. 2;
FIG. 6 is an overall perspective view showing a fillet at the base.
FIG. 7 is an external view of the front edge side as viewed from the front.
FIG. 8 is an external view as viewed from the front on the trailing edge side.
FIG. 9 is a cross-sectional view of a gas turbine bucket according to another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Gas turbine rotor blade 2 Embedded part 3 Shank 4 Platform 5 Blade part 11 Cooling channel 12 Passage 12a Front edge side passage 12b Central part passage 12c Trailing edge side passage 13a Upper folded part 13b Lower folded part 14 Discharge Outlet 15 Rib 16 Fluid ejection hole 17 Slack portion 21 Cooling air passage 22 Cooling passage 23 Opening

Claims (12)

A passage through which cooling air flows from the blade root on the leading edge side of the blade to the blade top is provided, and a plurality of passages are formed continuously at the top end by turning back toward the blade root and at the blade root turnback toward the blade top. The blades connected to the ejection holes provided in the cascade of trailing edges are formed in the passages on the trailing edge side of the blades, and the leading edge side cooling passages are flat cavities. A gas turbine rotor blade characterized in that a turbulator is provided on an inner wall of a passage in a rear passage. 2. The gas turbine rotor blade according to claim 1, wherein a space of the blade root turning portion is provided at a position of a shank portion below a platform attached to the blade root. 2. The gas according to claim 1, wherein the wall thickness between the blade trailing edge provided with the ejection hole and the blade trailing edge side cooling passage is formed so as to gradually increase from the top to the hub. Turbine blades. 4. The gas turbine rotor blade according to claim 3, wherein a plurality of ejection holes are provided in upper and lower rows in a thick portion between the rotor blade trailing edge and a cooling passage. The gas turbine rotor blade according to claim 4, wherein a hole in a hub portion of the blade has a larger area than an upper nozzle hole. 6. The gas turbine blade according to claim 5, wherein the ejection hole near the hub is a vertically long hole. 6. The gas turbine blade according to claim 5, wherein three holes near the hub portion of the ejection holes have an area larger than other ejection holes. 6. The gas turbine blade according to claim 5, wherein the ejection angle of the ejection hole is formed in an upward direction. 9. The gas turbine rotor blade according to claim 1, wherein a passage independent of the serpentine passage is provided on a leading edge side of the blade to introduce cooling air from a blade root portion and discharge the cooling air to a blade top portion. A passage through which cooling air flows from the blade root on the leading edge side of the blade to the blade top is provided, and a plurality of passages are formed continuously at the top end by turning back toward the blade root and at the blade root turnback toward the blade top. A serpentine cooling passage formed in a gas turbine moving blade having a platform connected to a jet hole provided in a tandem of trailing edges in a passage on a trailing edge side of the blade. The shape of the root and the base of the platform is an elliptical shape in which the shape of the fillet portion on the dorsal and ventral sides of the wing trailing edge is larger than the shape of the fillet portion on the dorsal and ventral sides of the wing leading edge. A gas turbine rotor blade characterized by the above-mentioned. 11. The gas turbine blade according to claim 10, wherein a passage independent of the serpentine passage is provided on a leading edge side of the blade to introduce cooling air from a blade root portion and discharge the cooling air to a blade top portion. 11. The gas turbine rotor blade according to claim 1, wherein a jet hole machined without using a core is provided.

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