JP2016125380A - Cooling structure of turbine blade - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling structure capable of efficiently cooling medium type and small-sized type turbine blades.SOLUTION: In a structure for cooling a turbine blade 1 of a turbine driven by high-temperature gas G from thereinside, provided are: a lattice structure 11 configured by overlapping and combining a plurality of rib sets in a lattice manner, the rib set comprising a plurality of ribs 14 arranged on the wall surface of a cooling passage 7 provided in the turbine blade 1; and a pin fin structure 13 arranged at a rear side in a flow direction of the high-temperature gas G to the lattice structure 11, in the cooling passage where the lattice structure 11 is arranged, and comprising a plurality of pin fins 21.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a structure for cooling a stationary blade and a moving blade in a turbine of a gas turbine engine from the inside.

  The turbine constituting the gas turbine engine is disposed downstream of the combustor and is supplied with high-temperature gas combusted in the combustor. Therefore, the turbine is exposed to high temperatures during operation of the gas turbine engine. Therefore, it is necessary to cool the stationary blades and the moving blades of the turbine. As a structure for cooling such turbine blades, it is known that a part of air compressed by a compressor is introduced into a cooling passage formed in the blades, and the turbine blades are cooled by using compressed air as a cooling medium. (For example, refer to Patent Document 1).

  When a part of compressed air is used for cooling turbine blades, there is no need to introduce a cooling medium from the outside, and there is an advantage that the cooling structure can be simplified. On the other hand, if a large amount of air compressed by the compressor is used for cooling Since this leads to a decrease in engine efficiency, it is necessary to efficiently perform cooling with a minimum amount of air. As a structure for cooling the turbine blades with high efficiency, it has been proposed to adopt a so-called lattice structure in which a plurality of ribs are combined in a lattice pattern (see, for example, Patent Documents 2 and 3).

US Pat. No. 5,603,606 Japanese Patent No. 4957131 US Pat. No. 6,382,907

  However, it is difficult to provide a complicated cooling structure such as a lattice structure in a narrow space by casting. On the other hand, the turbine blade is generally formed with a thin trailing edge. In particular, in a turbine blade of a medium or small-sized gas turbine, the blade trailing edge is designed to be extremely thin. Therefore, it is difficult to apply the structure disclosed in Patent Documents 2 and 3 in which a lattice structure is provided in the entire cooling passage inside the turbine blade to a medium / small gas turbine.

  Accordingly, an object of the present invention is to provide a cooling structure capable of efficiently cooling medium and small turbine blades in order to solve the above-described problems.

  To achieve the above object, a turbine blade cooling structure according to the present invention is a structure for cooling a turbine blade of a turbine driven by high-temperature gas from the inside, and is provided in the turbine blade. A lattice structure formed by combining a plurality of rib sets each including a plurality of ribs arranged on the wall surface of the passage in a lattice pattern, and a cooling passage in which the lattice structure is arranged, with respect to the lattice structure A pin fin structure including a plurality of pin fins disposed rearward in the flow direction of the hot gas.

  According to this configuration, since the cooling medium further collides with the pin fin in a state in which the cooling medium flow is disturbed by the lattice structure, in addition to the highly efficient cooling by the lattice structure itself, the lattice structure As a result, the cooling efficiency by the pin fin structure having a low cooling efficiency is also improved. Therefore, the turbine blade can be cooled with extremely high efficiency. In addition, by using a pin fin structure for the rear cooling structure designed to be thinner than the front of the hot gas flow direction, it is possible to manufacture turbine blades for medium and small gas turbines with high cooling efficiency. Can be realized.

  In one embodiment of the present invention, it is preferable that the pin fin structure is disposed apart from the lattice structure. In this case, when the interval L between the lattice structure and the pin fin structure is w, the flow path width of the exit portion of the lattice structure is h, the flow path height is h, Dh = 2wh / (w + h), It is preferably in the range of 2Dh ≦ L ≦ 7Dh. According to this configuration, the cooling medium can collide with the pin fins after the flow direction of the cooling medium flowing out from the lattice structure is made uniform. As a result, the flow of the cooling medium inside the pin fin structure is prevented from becoming non-uniform, and the cooling efficiency of the pin fin structure can be suppressed from decreasing.

  In one embodiment of the present invention, the cooling structure composed of the lattice structure and the pin fin structure has a plurality of cooling structure divided bodies divided in the height direction of the turbine blades by a partition. May be. According to this configuration, the distance between the side walls of the lattice structure is shortened, and the number of times the cooling medium flowing through the flow path of the lattice structure collides with the side wall and turns back is increased. Thereby, the disturbance of the cooling medium flow flowing through the lattice structure is promoted, and more efficient cooling is possible.

  In one embodiment of the present invention, it is preferable that a plurality of partition pin fins are provided as the partition body. According to this structure, a partition body can be reduced in weight and generation | occurrence | production of stress is suppressed.

  According to the present invention, it is possible to efficiently cool medium-sized and small turbine blades.

It is a perspective view showing an example of a turbine blade to which a cooling structure concerning a 1st embodiment of the present invention is applied. It is a longitudinal cross-sectional view which shows typically the cooling structure of the turbine blade of FIG. It is a perspective view which shows the lattice structure 11 used for the cooling structure of FIG. FIG. 3 is a schematic diagram illustrating a positional relationship between a lattice structure 11 and a pin fin structure 13 having a cooling structure in FIG. 2. It is a cross-sectional view of the turbine blade of FIG. It is a longitudinal cross-sectional view which shows typically an example of arrangement | positioning of the cooling structure in a turbine blade. It is a longitudinal section showing a 2nd embodiment of the present invention typically. It is sectional drawing which shows typically the example of the cooling structure of the turbine blade which concerns on 2nd Embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a turbine blade 1 of a turbine of a gas turbine engine to which a turbine blade cooling structure according to an embodiment of the present invention is applied. The turbine rotor blade 1 forms a turbine T that is driven by a hot gas G that is supplied from a combustor (not shown) and flows in the direction of the arrow. Specifically, as shown in FIG. 2, the turbine rotor blade 1 is connected to the outer periphery of the turbine disk 5 so that a large number of the turbine blades 1 are implanted in the circumferential direction to form a turbine T. . In the present specification, the upstream side (the left side in FIG. 1) along the flow direction of the hot gas G is referred to as the front, and the downstream side (the right side in FIG. 1) is referred to as the rear.

  In the following description, the turbine blade 1 is mainly shown as an example of the turbine blade provided with the cooling structure. However, the cooling structure according to the present embodiment is similarly applied to the turbine stationary blade unless otherwise described. can do.

  As shown in FIG. 2, a front cooling passage 6 extending in the blade height direction H and turning back is formed inside the front portion 1 a of the turbine blade 1. A rear cooling passage 7 is formed inside the rear portion 1 b of the turbine rotor blade 1. A part of the compressed air (cooling medium CL) from the compressor passes through the front cooling medium introduction passage 8 and the rear cooling medium introduction passage 9 formed inside the turbine disk 5 on the radially inner side, and then radially outside. To the front cooling passage 6 and the rear cooling passage 7 respectively. The cooling medium CL supplied to the front cooling passage 6 and the rear cooling passage 7 is discharged to the outside through a discharge hole (not shown) communicating with the outside of the turbine rotor blade 1. Hereinafter, an example in which the cooling structure according to the present embodiment is provided in the rear portion 1b of the turbine rotor blade 1 will be described. However, the cooling structure according to the present embodiment may be provided in any portion in the front-rear direction of the turbine rotor blade 1. .

  A cooling structure 10 is provided in the rear cooling passage 7 as a cooling structure for cooling the turbine rotor blade 1 from the inside. The cooling structure 10 includes a lattice structure 11 and a pin fin structure 13. The cooling structure 10 allows the cooling blade CL to contact or collide with the ribs of the lattice structure erected on the inner wall surface of the rear cooling passage 7 and the pin fins of the pin fin structure 13 to bring the turbine rotor blade 1 from the inside. Cooling. The pin fin structure 13 is disposed behind the lattice structure 11 in the rear cooling passage 7.

  In the rear cooling passage 7, the entire cooling medium CL flows in a direction crossing the cooling structure 10 from the front to the rear. In the following description, the flow direction of the entire cooling medium CL is referred to as a refrigerant moving direction M.

  As shown in FIG. 3, the lattice structure 11 is formed by combining a plurality of ribs 14 including a plurality of ribs 14 arranged in parallel to each other at equal intervals on the wall surface of the rear cooling passage 7. It is formed by. In the present embodiment, two rib sets, that is, a first rib set (lower rib set in FIG. 3) 15A and a second rib set (upper rib set in FIG. 3) 15B are arranged in the height direction of the ribs 14. The lattice structure 11 is formed by combining by overlapping in a lattice shape. Note that the arrangement of the plurality of ribs 14 in each rib set need not be parallel to each other and equally spaced, and may be appropriately set according to the structure of the turbine blade, the required cooling performance, and the like.

  In the lattice structure 11, the gap between the adjacent ribs 14, 14 of each rib set 15 </ b> A, 15 </ b> B forms a flow path (lattice flow path) 17 for the cooling medium CL. In the rear cooling passage 7, the lattice structure 11 is arranged between the two side walls 19, 19 extending in the refrigerant movement direction M so that the lattice flow path 17 is inclined with respect to the refrigerant movement direction M. The cooling medium CL introduced into the lattice structure 11 first flows through the lattice flow path 17 of one rib set (the first rib set 15A in the lower stage in the example of FIG. 3), as indicated by broken line arrows in FIG. It collides with one side wall 19 and turns back, and flows into the lattice channel 17 of the other rib set (the upper second rib set in the example of FIG. 3) as shown by the solid line arrow in FIG. The cooling medium CL flowing through the other lattice channel 17 then collides with the other side wall 19 and turns back, and flows again into the lattice channel 17 of the first rib set. As described above, in the lattice structure 11, the cooling medium CL flows through the lattice channel 17, collides with the side wall 19, turns back, and repeatedly flows into the other lattice channel 17, and then is discharged from the lattice structure 11. Is done. When the cooling medium CL repeatedly collides with the side wall 19, turbulence occurs in the flow of the cooling medium CL, and cooling is promoted.

  In the embodiment shown in FIG. 2, the upper and lower end walls 7a and 7b of the rear cooling passage 7 correspond to the side wall 19 in FIG. In the embodiment of FIG. 2, the cooling medium CL that has flowed into some of the lattice channels 17 flows out of the lattice structure 11 without colliding with the upper and lower end walls 7a and 7b.

  In the present embodiment, as shown in FIG. 3, the height of each of the upper and lower ribs 14 in each outlet portion of the lattice channel 17, that is, the lattice channel height h in the blade thickness direction is the same. The interval between the ribs 14 and 14 in the first rib set 15A is the same as the interval between the ribs 14 and 14 in the second rib set 15B. That is, the lattice flow path width w in the first rib set 15A and the lattice flow path width w in the second rib set 15B are the same. The angle formed by the extending direction of the first rib set 15A and the extending direction of the second rib set 15B is set to approximately 90 °.

  The pin fin structure 13 shown in FIG. 2 includes a plurality of pin fins 21 erected between the inner wall surfaces of the rear cooling passage 7. In the pin fin structure 13 according to the present embodiment, a plurality of pin fin rows 13R including a plurality of pin fins 21 arranged at equal intervals substantially along the height direction H (the radial direction of the turbine T) of the turbine rotor blade 1 are provided in the front-rear direction ( In the example shown in FIG.

The arrangement of the plurality of pin fins 21 in the pin fin structure 13 may be arbitrarily set. As shown in FIG. 4, in the present embodiment, the interval P _r between the pin fins 21, 21 in each row are equal. Also arranged pin fins 21, as the interval P _l the same between any pin fins 21, 21 which are adjacent back and forth. Each pin fin 21 of the pin fin rows 13R adjacent in the longitudinal direction are shifted by 1/2 of the pin spacing _{P r.} As a result, the pin fins 21 of each pin fin row 13R are arranged in a staggered manner along the refrigerant moving direction M.

In the present embodiment, the pin fin structure 13 is disposed away from the lattice structure 11. By separating the lattice structure 11 and the pin fin structure 13 from each other, the direction of the cooling medium CL flowing out backward from the plurality of lattice channels 17 of the lattice structure 11 toward the pin fin structure is made uniform. can do. However, if the distance L between the lattice structure 11 and the pin fin structure 13 (the distance along the refrigerant moving direction M) is too long, the area of the cooling structure 10 that does not contribute to cooling increases. From this point of view, more specifically, the distance L between the lattice structure 11 and the pin fin structure 13 may be in the range of 2D _h ≦ L ≦ 7D _h , where D _h = 2wh / (w + h). Preferably, it is in the range of 4D _h ≦ L ≦ 5D _h . Here, “D _h ” is the hydraulic diameter of the rectangular lattice channel 17 at the exit portion of the lattice structure 11. The “interval L between the lattice structure 11 and the pin fin structure 13” refers to the rear end 11 a of the exit portion of the lattice structure 11 and the plurality of pin fins 21 in the pin fin row located in the front row of the pin fin structure 13. The distance along the refrigerant moving direction M with the virtual line C connecting the centers of the two points.

  The cooling structure 10 can be disposed at any position and range of the turbine rotor blade 1. However, as shown in FIG. 5, the pin fin structure 13 has a cooling passage width (distance between wall surfaces of the cooling passage) D as compared with the lattice structure 11 configured by overlapping a plurality of rib sets 15 </ b> A and 15 </ b> B. It can be easily provided even in a short region. Therefore, in the cooling passage 7 having a structure in which the cooling passage width D gradually narrows toward the rear as shown in FIG. 5, the cooling structure 10 is at least blade length (along the center line of the blade cross section as shown in FIG. 2). It is preferable to provide in the range of the rear half with respect to (length).

  Further, as shown in FIG. 5, the pin fin structure 13 can be easily provided even in a region where the cooling passage width D is short. Therefore, the boundary between the region where the lattice structure 11 is provided and the region where the pin fin structure 13 is provided. May be determined by the cooling passage width D. For example, the lattice structure 11 is disposed in a region where the cooling passage width D is 2 mm or more, and the pin fin structure 13 is disposed in a region where the cooling passage width D is less than 2 mm.

  For the same reason, the cooling structure according to the present embodiment is particularly suitable for use in the turbine blades of a medium to small gas turbine engine. More specifically, it is suitable for use in cooling a turbine blade of a gas turbine engine having an output of 40 MW or less.

  In addition, as shown in FIG. 2, the cooling structure 10 can be provided over almost the entire height direction H (the radial direction of the turbine) of the turbine rotor blade 1, but in a part of the height direction H. Only, for example, as shown in FIG. 6, the turbine rotor blade 1 may be provided only on the root side (in the illustrated example, the region on the root side half), that is, on the radially inner side. Thereby, the root part which is a part to which a big stress is applied in the turbine rotor blade 1 can be cooled effectively. For the same reason, when the cooling structure 10 is provided on the turbine stationary blade, the cooling structure 10 may be provided only on the root side of the turbine stationary blade that is the radially outer side of the turbine.

  As described above, according to the cooling structure according to the present embodiment, the lattice structure 11 causes the cooling medium CL to further collide with the pin fins 21 in a state in which the lattice structure 11 causes a disturbance in the cooling medium CL flow. In addition to the highly efficient cooling by 11 itself, the cooling efficiency by the pin fin structure 13 is also improved. Therefore, the turbine blade can be cooled with extremely high efficiency. In addition, by using the pin fin structure 13 as the rear cooling structure designed to be thinner than the front in the flow direction of the high-temperature gas, it is possible to manufacture the turbine blades of medium and small gas turbines. High cooling efficiency can be realized.

  FIG. 7 shows a cooling structure according to the second embodiment of the present invention. The cooling structure 10 according to the present embodiment is different from the first embodiment in that the cooling structure 10 includes a plurality of cooling structure divided bodies 29 that are divided in the height direction H of the turbine rotor blade 1 by a partition body 25. Hereinafter, the points different from the first embodiment will be mainly described in detail, and the description of the points common to the first embodiment will be omitted.

  In the example of FIG. 7, the cooling structure 10 includes three cooling structure division bodies 29 divided in the height direction by two partition bodies 25 and 25. The partition body 25 that partitions the adjacent cooling structure division bodies 29 can substantially prevent the flow of the cooling medium CL between the adjacent cooling structure division bodies 29 and 29, and is on the side of the lattice structure body 11. As long as the cooling medium CL can be collided in the part and can be turned back so as to flow from one lattice channel 17 to the other lattice channel 17 (FIG. 4), any material may be used. As an example, it is conceivable to use a flat partition plate as a partition body, but in the present embodiment, a plurality of partition pin fins 31 are used as the partition body 25.

  By using the partition pin fin 31 as the partition body 25 that partitions between the adjacent cooling structure division bodies 29, 29, the partition body 25 can be reduced in weight, and the generation of stress is suppressed. The outer diameter of the partition pin fin 31 may be the same as or different from the outer diameter of the pin fin 21 used for the pin fin structure 13.

  In the example of FIG. 7, the three cooling structure division bodies 29 have the same height direction dimension. The front-rear direction dimensions of the lattice structure 11 in the three cooling structure divided bodies are the same, and the front-rear direction dimensions of the pin fin structure 13 are also the same. But the height direction dimension of the cooling structure division body 29 may differ for every cooling structure division body 29, and the front-back direction dimension of the lattice structure 11 in each cooling body structure division body 29 and the pin fin structure 13 The front-rear direction dimensions may also be different for each cooling structure divided body 29. As an example, in FIG. 8, among the three cooling structure divided bodies 29, the height direction dimension of the cooling structure divided body 29 in the center in the height direction H is shown as the height direction of the other two cooling structure divided bodies 29. The dimension in the front-rear direction of the pin fin structure 13 of the cooling structure division 29 at the top in the height direction is shorter than the dimension in the front-rear direction of the pin fin structure 13 in the other two cooling structure divisions 29. An example in which the length is increased and the dimension in the front-rear direction of the lattice structure 11 is shortened accordingly.

  As described above, the cooling structure 10 including the lattice structure 11 and the pin fin structure 13 includes the plurality of cooling structure divided bodies 29 divided in the height direction H of the turbine blade 1 by the partition 25. The distance between the side walls of the lattice structure 11 is shortened, and the number of times the cooling medium CL flowing through the flow path of the lattice structure 11 collides with the side wall and turns back. Thereby, the disturbance of the flow of the cooling medium CL flowing through the lattice structure 11 is promoted, and more efficient cooling is possible. Further, by dividing the lattice structure 11, the cooling structure divided bodies 29 can have different dimensions. Thereby, it becomes possible to set optimal cooling efficiency according to the part of the turbine rotor blade 1.

  As described above, the preferred embodiments of the present invention have been described with reference to the drawings, but various additions, modifications, or deletions can be made without departing from the spirit of the present invention. Therefore, such a thing is also included in the scope of the present invention.

1 Turbine blade (turbine blade)
7 Rear cooling passage (cooling passage)
10 Cooling Structure 11 Lattice Structure 13 Pin Fin Structure 14 Lattice Structure Rib 21 Pin Fin CL Cooling Medium G Hot Gas

Claims (5)

A structure for cooling a turbine blade of a turbine driven by hot gas from the inside,
A lattice structure obtained by combining a plurality of rib sets each including a plurality of ribs arranged on a wall surface of a cooling passage provided in the turbine blade,
A pin fin structure composed of a plurality of pin fins, arranged rearward in the flow direction of the hot gas with respect to the lattice structure in the cooling passage in which the lattice structure is disposed;
A turbine blade cooling structure comprising:   The cooling structure according to claim 1, wherein the pin fin structure is disposed away from the lattice structure.   3. The cooling structure according to claim 2, wherein an interval L between the lattice structure and the pin fin structure is such that the flow path width of the exit portion of the lattice structure is w, the flow path height is h, and Dh = 2wh / A turbine blade cooling structure in a range of 2Dh ≦ L ≦ 7Dh when (w + h).   4. The cooling structure according to claim 1, wherein the cooling structure composed of the lattice structure and the pin fin structure is divided in a height direction of the turbine blade by a partition body. 5. The cooling structure of the turbine blade which has the following cooling structure division body.   The cooling structure according to claim 4, wherein a plurality of partition pin fins are provided as the partition body.

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