JP2006105084A - Gas turbine moving blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas turbine having a structure for effectively cooling a tip part of a moving blade of the small gas turbine. <P>SOLUTION: A cooling hole of a tip surface is arranged in a position near the positive pressure side. Since there is a flow to the negative pressure side from the positive pressure side on the tip surface, such a cooling hole further uniformly cools the tip surface. An inclination is formed in a rear edge part of an outer shroud and a front edge part of a divided ring so as to guide air on the outer peripheral side of the outer shroud of a stationary blade to the tip surface side of the moving blade adjacent to the rear stage side. A slot is arranged in the divided ring so that air on the outer peripheral side of the divided ring cools the tip surface of the moving blade. A projection for blocking up clearance for delaying a flow speed of the air of the tip surface, is arranged in a seal piece between the adjacent divided rings. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to cooling of gas turbine rotor blades.

  The tip (tip) of the gas turbine blade is exposed to a very severe environment due to the effects of tip leakage (gas flow from the ventral side to the back side of the tip) and secondary flow. It is. A technique for effectively cooling the tip portion is desired.

  A division in a gas turbine characterized in that a partition wall and an impingement cooling plate arranged on the outer periphery thereof are partitioned in the axial direction by a pressure partition extending in the circumferential direction, and a plurality of cavities adjusted to different pressures are provided. A ring cooling structure is known (see Patent Document 1).

  Compressed air supplied from a compressor and fuel injected from a fuel nozzle are combusted in a combustion cylinder and the combustion gas is guided to a moving blade to obtain power. The blade tip cooling structure for cooling the blade tip of the rotor blade includes a recess formed with a depth in the axial direction from the blade end surface of the blade main body, and a recess formed through the inside of the leading edge member of the blade main body. A blade tip cooling air introduction passage having an outlet opening on the wall surface on the leading edge side, an inlet opening on the wall surface on the trailing edge side of the recess, passing through the inside of the trailing edge member of the moving blade body, and the blade surface near the trailing edge or the trailing edge A blade end cooling air discharge passage having an outlet opening, and a lid member that is molded separately from the rotor blade main body and is tightly joined and fixed to the inner wall of the recess, and is a surface that is tightly joined to the inner wall of the recess of the lid member , The outlet opening of the blade tip cooling air introduction passage and the inlet opening of the blade tip cooling air discharge passage communicate with each other. Grooves are provided, and the gas turbine rotor assembly end cooling structure is known, wherein the (see Patent Document 2).

Japanese Patent Laid-Open No. 11-247621 JP 2002-195003 A

  In the case of a moving blade of a large gas turbine, the tip portion and a number of film cooling holes are provided on the back side and the abdominal side near the tip, and the tip portion is cooled by cooling the film. However, in the case of a small gas turbine used for the power of a helicopter or the like, the d / C (d is a film hole diameter and C is a cord length) is larger than that of a large industrial gas turbine due to processing convenience. Therefore, if a large number of film holes are installed in a small gas turbine, the flow rate of the film cooling air becomes excessive, resulting in overcooling.

  An object of the present invention is to provide a gas turbine having a structure in which a tip portion of a moving blade of a small gas turbine is effectively cooled.

  Another object of the present invention is to reduce the amount of cooling air in a small gas turbine.

  In the following, means for solving the problem will be described using the numbers used in [Best Mode for Carrying Out the Invention] in parentheses. These numbers are added to clarify the correspondence between the description of [Claims] and [Best Mode for Carrying Out the Invention]. However, these numbers should not be used to interpret the technical scope of the invention described in [Claims].

  The gas turbine rotor blade (6) according to the present invention is provided therein with a cooling passage (22) having an opening (24) at a position close to the pressure side (30) of the blade end surface (26).

  In the gas turbine rotor blade (6) according to the present invention, the cooling passage (22b) includes a guide (34) for guiding the cooling medium flowing through the inside so that the inner wall of the positive pressure side (30) is impingement cooled. .

  The gas turbine rotor blade (6) according to the present invention is connected to the cooling passage (22d) for impingement cooling the blade end surface (26) from the inner wall and the cooling passage (22d), and the blade of the gas turbine rotor blade (6) A film cooling passage (38) for introducing a cooling medium to a film cooling hole (40) for film cooling the outer wall on the pressure side (30) near the end face (26) is provided.

  The gas turbine rotor blade (6) according to the present invention includes a second cooling passage (22c) having an opening in the blade end surface (26). The cooling passage (22d) is located on the downstream side of the second cooling passage (22c), and the film cooling hole (40) is provided at a position near the downstream end of the rotor blade (6).

  The gas turbine according to the present invention comprises a gas turbine rotor blade (6) according to the present invention.

  A gas turbine according to the present invention is installed on the outer periphery of a stationary blade (5) having an outer shroud (9), a moving blade (6) adjacent to the rear stage of the stationary blade (5), and the moving blade (6). Momentum directed toward the leading edge of the rotor blade (6) from the outer ring side of the outer ring (10) and the leaked air (42) entering the inner peripheral side of the ring (10) from the outer side of the outer shroud (9). A feeding guide (41).

  In the gas turbine according to the present invention, the guide (41) is constituted by the rear edge of the outer shroud (9) and the front edge of the split ring (10).

  In the gas turbine according to the present invention, the split ring (10) includes a slot (44) communicating the inner peripheral side and the outer peripheral side of the split ring (10) with the circumferential direction as the longitudinal direction. The opening on the inner peripheral side of the slot (44) is located downstream of the opening on the outer peripheral side.

  The gas turbine according to the present invention includes a moving blade (6) and a split ring (10) installed on the outer periphery of the moving blade (6). The split ring (10) includes a slot (44) that communicates the inner peripheral side and the outer peripheral side of the split ring (10) with the circumferential direction as the longitudinal direction. The opening on the inner peripheral side of the slot (44) is located downstream of the opening on the outer peripheral side.

  The gas turbine according to the present invention includes a plurality of split rings (10) arranged in the circumferential direction and a seal piece (46) inserted between adjacent split rings (10). The seal piece (46) includes a protrusion (48) that reduces a gap formed by the adjacent split ring (10) and the blade end surface (26) of the moving blade (6).

  In the gas turbine according to the present invention, the seal piece (46) is larger in viscoelasticity than the split ring (10).

  In the gas turbine according to the invention, the seal piece (46) comprises graphite.

  The gas turbine according to the present invention is mounted as power for a helicopter.

  The helicopter according to the present invention uses the gas turbine according to the present invention as the rotational power of the rotor.

  ADVANTAGE OF THE INVENTION According to this invention, the gas turbine of the structure where the tip part of the moving blade of a small gas turbine is cooled effectively is provided.

  Furthermore, according to the present invention, the amount of cooling air in a small gas turbine is reduced.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. The gas turbine according to the present invention is a small gas turbine used, for example, as power for a helicopter.

(First embodiment)
Referring to FIG. 1, a cross-sectional view of a gas turbine is shown. The gas turbine 3 includes stationary blades 5 and moving blades 6 that are alternately arranged in the flow direction. The rotating shaft (not shown) of the moving blade 6 is in the downward direction of the drawing. An inner shroud 8 is attached to the inner peripheral side of the stationary blade 5. An outer shroud 9 is attached to the outer peripheral side of the stationary blade 5. A split ring 10 is provided on the outer peripheral side of the moving blade 6 so as to face the tip of the moving blade. The upstream side of the gas turbine is connected to the combustor 2 of the combustor. The mainstream gas 15 fed from the tail cylinder 2 is rectified by the stationary blade 5 and rotates the moving blade 6.

  Referring to FIG. 2, a cross-sectional view of the rotor blade 6 is shown. The rotor blade 6 has a cooling passage 22 extending in the radial direction of the turbine (a direction orthogonal to the rotation axis of the turbine). The blade end surface of the moving blade 6, that is, the surface facing the split ring 10 on the outermost peripheral side of the moving blade is called a tip surface 26. The cooling passage 22 has an opening called a chip cooling hole 24 in the chip surface 26. The cooling medium is supplied from the inner peripheral side of the cooling passage 22, flows toward the outer peripheral side, flows out of the rotor blade 6 from the tip cooling hole 24, and cools the tip surface.

  Referring to FIG. 3A, a top view of the rotor blade 6 (a view of the rotor blade 6 viewed from the tip surface 26 side) is depicted. When the rotor blade 6 is viewed from above, the pressure side surface is called the ventral side 30 and the suction side surface is called the dorsal side 32. In the present embodiment, the chip cooling hole 24 a is provided at a position close to the ventral side 30 in the chip surface 26. Referring to FIG. 3B, a BB cross section in FIG. 3A is depicted. The cooling passage 22 a has an opening constricted at a position biased to the ventral side 30 on the tip surface 26.

  The effect by which the chip | tip cooling hole 24 is provided in the position close | similar to the belly side 30 is demonstrated. In the vicinity of the tip surface 26, gas flows due to a pressure difference between the ventral side 30 and the dorsal side 32 from the ventral side 30 toward the dorsal side 32 in the gap between the split ring 10 and the tip surface 26. Yes. Therefore, the cooling medium exiting from the chip cooling hole 24 tends to flow from the ventral side 30 toward the dorsal side 32. Therefore, it is preferable that the chip cooling hole 24 is provided at a position close to the ventral side 30 because the chip surface 26 is more uniformly cooled.

  A modified example of the present embodiment will be described with reference to FIG. 4A. Also in this modified example, the chip cooling hole 24 opens at a position close to the ventral side 30. Referring to FIG. 4B, the CC cross section of FIG. 4A is depicted. The cooling passage 22 b includes a cooling passage refracting portion 34 at a position close to the chip surface 26. The flow of the cooling medium toward the chip surface 26 is once given momentum toward the ventral side 30 in the cooling passage refracting section 34, and impingement cooling the wall on the ventral side 30 near the chip surface 26 from the inside. . Thereafter, the cooling medium flows out from the tip cooling hole 24 provided at a position biased to the ventral side 30 of the tip surface 26 to the outside of the rotor blade 6 to cool the tip surface 26.

(Second embodiment)
Referring to FIG. 5, a top view of the moving blade 6 in the second embodiment is shown. The rotor blade 6 has a tip cooling hole 24 c in the tip surface 26. The moving blade 6 further has a film cooling hole 40 on the ventral side 30 of the rear edge portion close to the tip surface 26 (portion close to the downstream end portion of the mainstream gas flow).

  Referring to FIG. 6, a side view of the moving blade 6 in the present embodiment as viewed from the ventral side is shown. A part of the cooling passages 22 c and 22 d extending in the radial direction provided inside the rotor blade 6 has a tip cooling hole 24 c in the tip surface 26. The other cooling passage 22 d is closed with a lid 36 on the chip surface 26. The cooling passage 22d is connected to the cooling passage 38. The cooling passage 38 opens at a film cooling hole 40 provided at the rear edge portion close to the chip surface 6.

  The cooling medium flowing in the direction of the tip surface 26 through the cooling passage 22c flows out of the rotor blade from the tip cooling hole 24c and cools the tip surface 26. The cooling medium flowing in the direction of the tip surface 26 through the cooling passage 22d impingement cools the tip surface 26 from the inner wall in the lid portion 36, and then flows through the cooling passage 38 to the outside of the rotor blade from the film cooling hole 40. The trailing edge close to the chip surface 6 is film-cooled. Since this part is a part that particularly needs cooling, it is preferable to supply film cooling air.

  In the present embodiment, it is preferable that the chip cooling hole 24c is provided at a position close to the ventral side 30 as in the first embodiment in order to cool the chip surface 26 more uniformly. Furthermore, it is also preferable that a cooling passage refracting portion 34 is provided inside the cooling passage 22c.

(Third embodiment)
A third embodiment of the present invention will be described with reference to FIG. Between the rear edge of the outer shroud 9 attached to the stationary blade 5 and the front edge of the split ring 10 facing the tip surface 26 of the moving blade 6 adjacent to the rear stage side of the stationary blade 5, There is a gap. In the present embodiment, the gap serves as a guide portion 41 having a shape for introducing the gas on the outer peripheral side of the outer shroud 9 near the tip surface 26 of the rotor blade 6. In the example shown in FIG. 7, the guide portion 41 is configured such that a gap between the rear edge portion of the outer shroud 9 and the front edge portion of the split ring 10 is inclined toward the rear stage side from the outer peripheral side to the inner peripheral side. Yes.

  The split ring 10 has a slot 44 near the center in the axial direction. Referring to FIG. 8, a top view of the split ring 10 is shown. The slot 44 has a long groove shape in the circumferential direction. The position where the slot 44 is provided may be a position where the chip surface 26 is desired to be cooled, even if it is not near the center in the axial direction. A plurality of slots 44 may be provided.

  Leaked air 42 introduced from the outer peripheral side of the outer shroud 9 to the front edge portion near the tip surface 26 of the rotor blade 6 by the guide portion 41 cools the vicinity of the tip surface 26 of the rotor blade 6, particularly the vicinity of the front edge portion. To do. The gas introduced from the outer peripheral side of the split ring 10 toward the tip surface 26 of the rotor blade 6 by the slot 44 is in a portion where the slot 44 is provided in the axial direction of the rotor blade 6 such as near the center or near the rear edge. The side surface is cooled near the chip surface 26. Since the slot 44 has the shape of a groove that is long in the circumferential direction, the chip surface is more effectively cooled over a wide range.

(Fourth embodiment)
A fourth embodiment of the present invention will be described with reference to FIG. FIG. 9 is a partial view of the moving blade 6 and the split ring 10 as viewed from the upstream side in the axial direction of the gas turbine 3. A seal piece 46 is disposed between the split rings 10 adjacent to each other. The seal piece 46 includes a protrusion 48. The protrusion 48 closes the gap formed between the rotor blade 6 and reduces the gap. It is preferable that the material of the seal piece 46 is a sticky material having a large viscoelasticity exemplified by graphite so that the gap is better closed.

  When the rotor blade 6 rotates, tip leakage air 50 is generated on the tip surface 26 from the ventral side 30 toward the dorsal side 32. When the seal piece 46 does not have the protrusion 48, the gas temperature in the gap becomes high and the heat load increases due to the flow velocity of the chip leakage air 50 being slow and the vortex being generated in the gap formed there. Due to the presence of the protrusions 48, it is possible to avoid a slow flow rate and to avoid a local increase in gas temperature.

FIG. 1 is a cross-sectional view of a gas turbine. FIG. 2 is a sectional view of the moving blade. FIG. 3A is a top view of the rotor blade. FIG. 3B is a cross-sectional view of the rotor blade. FIG. 4A is a top view of the rotor blade. FIG. 4B is a cross-sectional view of a moving blade. FIG. 5 is a top view of the moving blade. FIG. 6 is a cross-sectional view of a moving blade. FIG. 7 shows adjacent stationary blades and moving blades. FIG. 8 shows a top view of the split ring. FIG. 9 shows adjacent split rings and seal pieces between them.

Explanation of symbols

2 ... tail tube 5 ... stationary blade 6 ... moving blade 8 ... inner shroud 9 ... outer shroud 10 ... outer shroud 10 ... divided ring 15 ... mainstream gas 22 ... cooling passage 24 ... tip cooling hole 26 ... tip portion 30 ... ventral side 32 ... back side 34 ... cooling passage refracting portion 36 ... lid portion 38 ... cooling passage 40 ... film cooling hole 41 ... guide portion 42 ... leaking air 44 ... slot 46 ... seal piece 48 ... projection 50 ... tip leakage air

Claims (14)

A gas turbine rotor blade in which a cooling passage having an opening at a position close to the pressure side of the blade end face is provided. A gas turbine rotor blade according to claim 1, comprising:
The cooling passage includes a guide that guides a cooling medium flowing inside so that the positive pressure side inner wall is impingement cooled. A cooling passage for impingement cooling the blade tip surface from the inner wall;
A gas turbine rotor blade comprising: a film cooling passage that is connected to the cooling passage and guides a cooling medium to a film cooling hole that cools the outer wall on the pressure side near the blade end surface of the gas turbine rotor blade. A gas turbine rotor blade according to claim 3, wherein
And a second cooling passage having an opening at the blade tip surface.
The gas turbine rotor blade, wherein the cooling passage is located downstream of the second cooling passage, and the film cooling hole is provided at a position near the downstream end of the rotor blade. A gas turbine comprising the gas turbine rotor blade according to any one of claims 1 to 4. A stationary vane with an outer shroud,
A moving blade adjacent to the rear side of the stationary blade;
A split ring installed on the outer periphery of the rotor blade;
A gas turbine comprising: a guide that imparts momentum directed toward the leading edge of the moving blades to leaked air that enters the inner peripheral side of the split ring from the outer peripheral side of the outer shroud. A gas turbine according to claim 6, wherein
The guide is configured by a rear edge of the outer shroud and a front edge of the split ring. A gas turbine according to claim 6 or 7, wherein
The split ring includes a slot that communicates the inner peripheral side and the outer peripheral side of the split ring with the circumferential direction as a longitudinal direction,
The opening on the inner peripheral side of the slot is located downstream of the opening on the outer peripheral side. Moving blades,
A split ring installed on the outer periphery of the rotor blade,
The split ring includes a slot that communicates the inner peripheral side and the outer peripheral side of the split ring with the circumferential direction as a longitudinal direction,
The opening on the inner peripheral side of the slot is located downstream of the opening on the outer peripheral side. A plurality of split rings arranged in the circumferential direction;
A seal piece inserted between the adjacent split rings,
The said seal piece is equipped with the processus | protrusion which makes small the clearance gap formed by the said division ring adjacent and the blade end surface of a moving blade. The gas turbine according to claim 10, wherein
The seal piece has a viscoelasticity larger than that of the split ring. The gas turbine according to claim 11, wherein
The seal piece includes a graphite gas turbine. A gas turbine according to any one of claims 5 to 12, comprising:
The gas turbine is mounted as power for a helicopter.   A helicopter equipped with the gas turbine according to claim 13.

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