Cooling wall part structure, high-temperature component provided with same, and method for manufacturing cooling wall part structure

Abstract

Provided is a cooling wall part structure that has high cooling efficiency, and that is easy to process and excellent in durability. This cooling wall structure is provided with: an inner surface that faces a high-temperature space in which combustion gas flows; and a cooling flow path (15) that is inclined at a first angle with respect to the inner surface, that guides cooling air from an opening formed in the inner surface toward the direction in which the combustion gas flows, and that cools the inner surface on the downstream side of the opening. The cooling flow path (15) is provided with a main flow path (17) and branch flow paths (18, 19) that are branched from a branch position (D1) partway through the main flow path (17) and are provided on both sides of the main flow path (17) when the inner surface is seen in a plan view. At the branch position (D1) there is formed a branch position wall surface (22) that is formed from the inner surface to the main flow path (17) and that has a second angle greater than the first angle.

Description

Cooling wall structure, high-temperature component equipped with same, and method for manufacturing cooling wall structure

[0001] The present disclosure relates to a cooling wall structure suitable for use in, for example, a combustor or a turbine blade, a high-temperature part including the same, and a method for manufacturing the cooling wall structure.

[0002] For high-temperature components such as the combustor and turbine blades of aircraft engines, various film cooling methods have been proposed in which a portion of compressed air is flowed over the surface of the components to improve durability.

[0003] Patent Document 1 listed below discloses a cooling flow path in which a cylindrical hole, which is a simple cylindrical cooling hole, is curved to have a crescent-shaped cross section, and three branches are added downstream.

[0004] U.S. Patent No. 8,850,828

[0005] While the cooling channel shape disclosed in Patent Document 1 is expected to have high cooling efficiency, it requires a crescent-shaped cross section and the formation of a branch channel downstream. This results in a complex channel shape that is difficult to manufacture, especially using laser processing. For example, when applied to the combustors and turbine blades of aircraft engines, the processing becomes even more difficult because the size is smaller than that of industrial gas turbines.

[0006] Furthermore, as shown in Figure 4 of Patent Document 1, an overhang portion (position indicated by reference numeral 120 in the figure) with a thin wall is formed upstream of the opening of the cooling flow path. The overhang portion is easily damaged due to its thin thickness and small heat capacity. Furthermore, when a top coat layer is formed on the surface of the wall to improve heat resistance, delamination is likely to occur due to differences in the linear expansion coefficients of the top coat layer, the base material, and the bond layer formed between them.

[0007] The present disclosure has been made in consideration of the above circumstances, and aims to provide a cooling wall structure that has high cooling efficiency, is easy to process, and has excellent durability, as well as a high-temperature component equipped with the same, and a method for manufacturing the cooling wall structure.

[0008] A cooling wall structure according to one aspect of the present disclosure comprises a first wall surface facing a high-temperature space through which a high-temperature fluid flows, and a cooling flow path inclined at a first angle with respect to the first wall surface and guiding a cooling fluid from an opening formed in the first wall surface in the direction in which the high-temperature fluid flows to cool the first wall surface downstream of the opening, wherein the cooling flow path comprises a first flow path and branch flow paths branched from a branch position midway through the first flow path and provided on each side of the first flow path when the first wall surface is viewed in a plane, and at the branch position a branch position wall surface is formed extending from the first wall surface to the first flow path and having a second angle greater than the first angle.

[0009] A high-temperature component according to one aspect of the present disclosure includes the above-described cooling wall structure.

[0010] A manufacturing method of a cooling wall structure according to one aspect of the present disclosure comprises: a first wall surface facing a high-temperature space through which a high-temperature fluid flows; and a cooling flow path inclined at a first angle with respect to the first wall surface, guiding a cooling fluid from an opening formed in the first wall surface in a direction in which the high-temperature fluid flows to cool the first wall surface downstream of the opening, wherein the cooling flow path comprises a first flow path and branch flow paths branched from a branch position midway through the first flow path and provided on each side of the first flow path when the first wall surface is viewed in a plane, and wherein a branch position wall surface is formed at the branch position, the branch position extending from the first wall surface to the first flow path and having a second angle greater than the first angle. The manufacturing method of a cooling wall structure comprises: a first step of forming each branch flow path together with the branch position wall surface by laser processing; and a second step of forming the first flow path by laser processing.

[0011] It has high cooling efficiency, is easy to process, and can improve durability.

[0012] 1. A longitudinal sectional view showing a combustor according to one aspect of the present disclosure. 1. A longitudinal sectional view showing an enlarged view of the cooling wall structure of FIG. 1. 2. A perspective view showing the cooling flow path of FIG. 2. 3. A perspective view showing an enlarged view of the outlet opening of FIG. 3. 4. A longitudinal sectional view of a wall portion showing a state in which a branch position wall surface has been formed up to the boundary position between the top coat layer and the bond layer. 5. A longitudinal sectional view showing an overhang portion corresponding to FIG. 2. 6. A longitudinal sectional view of a wall portion showing a state in which a branch position wall surface has been formed up to the boundary position between the bond layer and the base material. 7. A longitudinal sectional view of a wall portion showing a state in which a branch position wall surface has been formed up to the inside of the base material. 8. A longitudinal sectional view showing a cooling flow path of a cooling wall portion structure according to Modification 1. 9. A longitudinal sectional view showing the cooling wall portion structure of FIG. 10. 10. A perspective view showing a cooling flow path of a cooling wall portion structure according to Modification 2. 11. A perspective view showing only the main flow path of FIG. 11. 12. A plan view showing a cooling flow path of a cooling wall portion structure according to Modification 3. 13. A longitudinal sectional view showing a cooling wall portion structure according to Modification 4. 14. A longitudinal sectional view showing the modification of FIG. 14.

[0013] An embodiment of the present disclosure will be described below with reference to the drawings. FIG. 1 illustrates a combustor (hot-temperature component) 1 of an aircraft engine. As illustrated in FIG. 1 , the combustor 1 includes a combustor liner 5 provided within a main casing 3. Fuel F and compressed air A are supplied to the interior of the combustor liner 5, and a flame FL is formed. A cooling flow passage is formed in the wall of the combustor liner 5, and a portion of the compressed air A is supplied as cooling air A1 from the outer periphery toward the inner periphery of the combustor liner 5. The cooling air A1 flows in a film-like manner over the inner surface of the wall of the combustor liner 5, thereby performing film cooling. As described above, the combustor liner 5 includes a cooling wall structure 10 that protects the wall from high-temperature combustion gas G.

[0014] Figure 2 shows a cooling wall structure 10. The cooling wall structure 10 in Figure 2 is a partially enlarged view of the wall 9 of the combustor liner 5 in Figure 1. In the figure, direction x is the longitudinal direction of the combustor liner 5 (main flow direction of the combustion gas G), and direction y is the thickness direction of the wall 9.

[0015] The cooling wall structure 10 has a cooling flow passage 15 formed so as to penetrate a wall 9 of a predetermined thickness. The wall 9 has an inner surface (first wall surface) 11 facing the high-temperature space S through which the combustion gas G flows, and an outer surface 12 facing the inner surface 11 and located upstream of the flow of the cooling air A1 (see FIG. 1 ).

[0016] The cooling flow passage 15 is formed linearly between the inner surface 11 and the outer surface 12 with the first axis C1 as the central axis. The cooling flow passage 15 has an inlet opening 15a that opens to the outer surface 12 and an outlet opening 15b that opens to the inner surface 11. Cooling air A1 that flows in through the inlet opening 15a flows out from the outlet opening 15b into the high-temperature space S and flows along the inner surface 11 downstream of the outlet opening 15b, thereby performing film cooling. The cooling flow passage 15 is inclined at a first angle α1 formed by the first axis C1 with respect to the inner surface 11. The first angle α1 is, for example, equal to or greater than 15° and equal to or less than 45°.

[0017] 3 shows a three-dimensional view of the shape of the cooling flow path 15. The cooling flow path 15 is composed of a main flow path 17, a first branch flow path 18, and a second branch flow path 19. When the main flow path 17 is viewed from above (when viewed from the inner surface 11), the first branch flow path 18 is located on the left side of the flow direction of the cooling air A1 flowing through the main flow path 17, and the second branch flow path 19 is located on the right side of the flow direction of the cooling air A1 flowing through the main flow path 17. The first branch flow path 18 and the second branch flow path 19 are preferably provided symmetrically with respect to the main flow path 17.

[0018] The main flow passage 17 has a circular cross section (flow passage cross section), an inlet opening 15 a on the outer surface 12 , and a main flow passage outlet opening 15 b 1 on the inner surface 11 .

[0019] The first branch flow path 18 branches leftward from a branch position D1 including a branch point P1. The branch point P1 is located at a position corresponding to a midpoint of the first axis C1 of the main flow path 17. The first branch flow path 18 opens at its upper surface as a first branch opening 15b2 on the inner surface 11 and is formed along the second axis C2. The branch point P1 is the intersection of the first axis C1 and the second axis C2 passing through the bottom 18a. A first branch angle α3 formed between the second axis C2 and the first axis C1 of the main flow path 17 is between 15° and 90°. This first branch angle α3 represents the angle between the first axis C1 and the second axis C2 when viewed from direction V1 (perpendicular to the first axis C1) in the vertical cross section of FIG. 2 .

[0020] 2, the first branch flow path 18 is a bottomed groove that is dug to a certain depth in the thickness direction from the inner surface 11 toward the outer surface 12. That is, the first branch flow path 18 has a so-called crater shape. A bottom 18a of the first branch flow path 18 is a flat surface that extends, for example, substantially parallel to the inner surface 11.

[0021] The second branch flow path 19 branches to the right from a branch position D1 including a branch point P1. The second branch flow path 19 opens at the upper surface of the inner surface 11 as a second branch opening 15b3 and is formed along the third axis C3. The branch point P1 is the intersection of the first axis C1 and the third axis C3 passing through the bottom portion 19a. A second branch angle α4 formed between the third axis C3 and the first axis C1 of the main flow path 17 is between 15° and 90°. This second branch angle α4 represents the angle when the first axis C1 and the third axis C3 are viewed from direction V1 (perpendicular to the first axis C1) in the vertical cross section of FIG. 2 . Preferably, the second branch angle α4 is equal to the first branch angle α3 (α3 = α4).

[0022] 2, the second branch flow path 19 is a bottomed groove portion that is dug to a certain depth in the thickness direction from the inner surface 11 toward the outer surface 12. That is, the second branch flow path 19 has a so-called crater shape, similar to the first branch flow path 18. A bottom 19a of the second branch flow path 19 is a flat surface that extends, for example, substantially parallel to the inner surface 11.

[0023] A branch position wall surface 22 is formed upstream of the branch point P1 on the first axis C1. The branch position wall surface 22 is formed from the inner surface 11 to the main flow path 17, and constitutes a wall surface at the upstream ends of the first branch flow path 18 and the second branch flow path 19. As shown in FIG. 2 , the branch position wall surface 22 stands upright so as to be substantially perpendicular to the inner surface 11. That is, a second angle α2 formed by the branch position wall surface 22 and the inner surface 11 is substantially 90°.

[0024] The branch position wall surface 22 has a curved shape such as an arc shape when viewed from the inner surface 11. Specifically, the branch position wall surface 22 is formed based on an arc with the branch point P1 located inside. In other words, the branch position wall surface 22 is a part of a cylindrical surface with an axis passing through the branch point P1 located inside.

[0025] The second angle α2 of the branch position wall surface 22 is not limited to approximately 90°, but may be any angle greater than the first angle α1 of the main flow path 17, for example, 45° or more and 90° or less.

[0026] 4 is an enlarged view of the outlet opening 15b of the cooling flow path 15 shown in FIG. 3. As shown in the figure, the radius of curvature R1 of the branch position wall surface 22, the radius of curvature R2 of the downstream end of the first branch opening 15b2 of the first branch flow path 18, and the radius of curvature R3 of the downstream end of the second branch opening 15b3 of the second branch flow path 19 are preferably the same. As a result, for example, when laser processing is used to form the first branch flow path 18 and the second branch flow path 19, a common laser spot diameter can be used at the branch position wall surface 22 and the downstream ends of both branch openings 15b2 and 15b3, eliminating the need to adjust the spot diameter.

[0027] Preferably, chamfered portions CR are provided at the intersection of the first branch opening 15b2 and the main flow path outlet opening 15b1 and at the intersection of the second branch opening 15b3 and the main flow path outlet opening 15b1. The chamfered portions CR may be rounded or chamfered. This reduces stress concentration and prevents cracks from occurring.

[0028] Fig. 5 shows a longitudinal cross section of the wall portion 9 corresponding to Fig. 2. As shown in Fig. 5, the wall portion 9 has a top coat layer 9c formed on the inner surface 11 side of a base material 9a with a bond layer 9b interposed therebetween. The base material 9a is made of a heat-resistant alloy in general (e.g., Waspaloy or Inconel), the bond layer 9b is made of a metallic coating material (e.g., NiCrAlY), and the top coat layer 9c is made of a ceramic coating material (e.g., YSZ: yttrium-stabilized zirconia).

[0029] The branch position wall surface 22 is formed up to the boundary between the top coat layer 9c and the bond layer 9b. This allows the bottom 18a of the first branch flow path 18 and the bottom 19a of the second branch flow path 19 to coincide with the boundary between the top coat layer 9c and the bond layer 9b. The base material 9a, the bond layer 9b, and the top coat layer 9c are made of different materials, and therefore have different linear expansion coefficients. This may lead to delamination. Therefore, as shown in FIG. 5 , the branch position wall surface 22 is formed up to the boundary between the top coat layer 9c and the bond layer 9b. This prevents delamination between the top coat layer 9c and the bond layer 9b at the branch position wall surface 22.

[0030] Next, a description will be given of a method for processing the cooling flow path 15 having the above-described configuration. As the processing method, laser processing is used in which a high-energy density laser is irradiated onto the wall portion 9 to melt and vaporize it.

[0031] First, the first branch channel 18 and the second branch channel 19 are formed (first step), and then the main channel 17 is formed (second step).

[0032] When forming the first branch flow channel 18 and the second branch flow channel 19, the laser beam is irradiated in a direction forming a second angle α2 (see FIG. 2 ) with respect to the inner surface 11. The laser beam is processed up to a predetermined position in the thickness direction of the wall portion 9, and the laser beam is scanned in the directions of the second axis C2 and the third axis C3 (see FIG. 3 ) to form the first branch flow channel 18 and the second branch flow channel 19 as crater-shaped bottomed grooves. The shape of the laser beam at this time is circular, matching the radius of curvature R1 of the branch position wall surface 22. This allows the radius of curvature R1 of the branch position wall surface 22 to match the radius of curvature R2 of the downstream end of the first branch opening 15 b 2 of the first branch flow channel 18 and the radius of curvature R3 of the downstream end of the second branch opening 15 b 3 of the second branch flow channel 19 (see FIG. 4 ).

[0033] When forming the main flow path 17, a laser beam is irradiated in a direction having a first angle α1 (see FIG. 2 ) with respect to the inner surface 11 of the wall portion 9 to form the main flow path 17. The cross-sectional shape of the laser beam matches the cross-sectional shape of the main flow path 17, and is, for example, circular.

[0034] As described above, in the first step of forming the first branch flow passage 18 and the second branch flow passage 19, the second angle α2 (approximately 90° in this embodiment) is made larger than the first angle α1, thereby forming a branch position wall surface 22 having a cylindrical cross section with the branch point P1 (see FIG. 3 ) located on the inside. This results in removing the overhang portion 30 (see FIG. 6 ). As shown in FIG. 6 , the overhang portion 30 is a thin portion that remains between the main flow passage 17 and the inner surface 11 after the main flow passage 17 is formed in the first step. Removing the overhang portion 30 minimizes damage during the processing of the cooling flow passage 15 and during operation of the cooling wall structure 10.

[0035] The effects of the present embodiment described above are as follows: Film cooling of the cooling wall structure 10 is performed by flowing cooling air A1 through the cooling wall structure 10 whose inner surface 11 faces the high-temperature space S through which the combustion gas G flows.

[0036] The cooling flow passage 15 through which the cooling air A1 flows is inclined at a first angle α1 with respect to the inner surface 11, and the cooling air A1 flows along the inner surface 11 in the direction in which the combustion gas G flows from an outlet opening 15b formed in the inner surface 11, thereby film cooling the inner surface 11 downstream of the outlet opening 15b.

[0037] The cooling flow path 15 includes a main flow path 17 and two branch flow paths 18, 19 that branch off from a midpoint of the main flow path 17 and are provided on either side of the main flow path 17. The cooling air A1 flowing out from the main flow path 17 into the high-temperature space S forms a counter rotating vortex pair (CRVP: a pair of positive and negative vortices that reduces the adhesion of the cooling air A1 to the wall surface). In response to this, the cooling air A1 flowing out from the branch flow paths 18, 19 on both sides of the main flow path 17 generates an anti-CRVP, which suppresses the CRVP of the cooling air A1 flowing out from the main flow path 17 and promotes adhesion of the cooling air A1 to the inner surface 11. This improves the cooling performance of the inner surface 11.

[0038] At the branch point P1, a branch position wall surface 22 is formed from the inner surface 11 to the main flow passage 17. The branch position wall surface 22 has a second angle α2 that is larger than the first angle α1, which is the inclination angle of the main flow passage 17, so that the outlet opening 15b formed by the main flow passage 17 is enlarged upstream. This diffuses the flow from the leading edge and further induces a wall-attached flow.

[0039] The second angle α2, which is the inclination angle of the branch position wall surface 22, is set larger than the first angle α1 of the main flow passage 17, so that the overhang portion 30, which is a wall portion near the upstream side of the outlet opening 15b, can be eliminated. That is, if an opening is formed on the extension of the main flow passage 17 while maintaining the inclination at the first angle α1, the thin overhang portion 30 of the wall portion will remain upstream of the opening. In contrast, by forming the branch position wall surface 22 with the second angle α2 larger than the first angle α1, the thin overhang portion 30 can be eliminated. In this way, by eliminating the thin overhang portion 30, damage during the processing of the cooling flow passage 15 and during operation of the cooling wall structure 10 can be minimized, thereby improving durability.

[0040] By setting the second angle α2 to approximately 90°, the thin overhang portion can be effectively removed.

[0041] By forming the branch position wall surface 22 into a cylindrical surface shape, stress concentration can be alleviated and cracks can be prevented from occurring.

[0042] A chamfered portion CR (see FIG. 4) is provided at the position where the outlet opening 15b formed by the main flow path 17 intersects with the first branch opening 15b2 and the second branch opening 15b3 formed by the branch flow paths 18 and 19. This reduces stress concentration and prevents cracks from occurring.

[0043] The branch flow paths 18, 19 are formed as bottomed grooves that are connected to the branch position wall surface 22 and that are formed to the same depth as the branch position wall surface 22. This allows the branch flow paths 18, 19 to be formed simultaneously with the formation of the branch position wall surface 22 by laser processing (first step), making processing easier.

[0044] The arcuate shape of the branch position wall surface 22 and the arcuate shape of the downstream ends of the branch flow paths 18 and 19 have the same radii of curvature R1, R2, and R3 (see FIG. 4 ). This facilitates processing. That is, when performing laser processing, a common laser spot diameter can be used, eliminating the need for spot diameter adjustment.

[0045] The base material 9a, bond layer 9b, and top coat layer 9c that make up the wall portion 9 are made of different materials, and therefore have different linear expansion coefficients. This raises the risk of delamination. Therefore, the branch position wall surface 22 is formed up to the boundary between the top coat layer 9c and the bond layer 9b. This makes it possible to suppress delamination between the top coat layer 9c and the bond layer 9b at the branch position wall surface 22.

[0046] 7, the branch position wall surface 22 may be formed up to the boundary between the bond layer 9 b and the base material 9 a. This makes it possible to suppress delamination between the top coat layer 9 c and the bond layer 9 b, and between the bond layer 9 b and the base material 9 a, at the branch position wall surface 22.

[0047] 8, the branch position wall surface 22 may be formed to the inside of the base material 9a, thereby suppressing delamination between the top coat layer 9c and the bond layer 9b, and between the bond layer 9b and the base material 9a, at the branch position wall surface 22.

[0048] <Modification 1> This embodiment can be modified as follows. In the cooling wall structure 10 of the above-described embodiment, the first branch channel 18 and the second branch channel 19 are crater-shaped, bottomed grooves. In contrast, in a cooling channel 15' of a cooling wall structure according to this modification, as shown in FIG. 9 , the first branch channel 18' and the second branch channel 19' have cylindrical bottoms 18a', 19a' like the main channel 17. The first branch channel 18' has a second axis C2' and extends from the branch point P1. The second branch channel 19' has a third axis C3' and extends from the branch point P1.

[0049] The first branch flow path 18' and the second branch flow path 19' have the same first branch angle α3 and second branch angle α4 when viewed in a plan view of the inner surface 11. As shown in Figure 10, the first branch flow path 18' and the second branch flow path 19' are inclined at a first angle α1, which is the same inclination as the first axis C1 of the main flow path 17.

[0050] The first branch flow path 18′ and the second branch flow path 19′ are formed by irradiating the laser beam in a direction having a first angle α1 with respect to the inner surface 11. By using a laser beam with a circular cross section, cylindrical bottom portions 18 a′, 19 a′ are formed.

[0051] 10 has a branch position wall surface 22 having the second angle α2, as in the first embodiment. The step of forming the branch position wall surface 22 is performed by irradiating the inner surface 11 with a laser beam in a direction having the second angle α2 either before or after the step of forming the first branch flow path 18′ and the second branch flow path 19′.

[0052] <Modification 2> This embodiment can also be modified as follows. As shown in FIG. 11 , a cooling flow path 15" of this modification may be formed as a main flow path 17" in a fan shape, in which the cross-sectional area of ​​the flow path gradually increases toward the downstream side. The main flow path 17" has a circular cross section from the upstream side to a midpoint P2, and the cross-sectional area of ​​the flow path gradually increases from the midpoint P2 toward the downstream side. For ease of understanding, only the main flow path 17" is shown in FIG. 12 .

[0053] The main flow passage 17" has a shape in which the cross-sectional area of ​​the flow passage gradually increases toward the downstream side. This allows the flow to be more diffused downstream and allows a wall-attached flow to be formed, as compared to the case in which the main flow passage 17 has a circular hole shape with a constant diameter as shown in FIG. 2, thereby further improving the film cooling efficiency.

[0054] <Modification 3> The branch position wall surface 22" may have a shape as shown in Figure 13. That is, in Figure 3, the branch position wall surface 22 has a cylindrical cross section (see the dashed line in Figure 13), but is not limited to such a cylindrical cross section. For example, as shown in Figure 13, the branch position wall surface 22" may have a shape that is close to a plane. In this case, the first branch flow path 18" and the second branch flow path 19" will have a larger width than the flow paths shown in Figure 3 (see the dashed line in Figure 13). Alternatively, the branch position wall surface may have a combination of a flat surface and a curved surface.

[0055] <Modification 4> As shown in Fig. 14, the overhang portion 30 may be removed from the top coat layer 9c and the bond layer 9b, and the overhang portion 30 may be left only on the base material 9a. Alternatively, as shown in Fig. 15, the overhang portion 30 may be removed from the top coat layer 9c, and the overhang portion 30 may be left on the base material 9a and the bond layer 9b. The base material 9a and the bond layer 9b have a larger heat capacity than the top coat layer 9c, and therefore have a lower risk of damage due to delamination or thermal stress concentration. Therefore, it is preferable to avoid leaving the overhang portion 30 on at least the top coat layer 9c.

[0056] In the above-described embodiment and each modified example, the cooling wall structure 10 has been described on the assumption that it is used in a combustor, but the present disclosure is not limited to this and can be applied to high-temperature parts that come into contact with high-temperature gas, such as turbine blades.

[0057] The cooling wall structure, the high-temperature component including the cooling wall structure, and the method for manufacturing the cooling wall structure described in each of the above-described embodiments can be understood, for example, as follows.

[0058] A cooling wall structure (10) according to a first aspect of the present disclosure comprises a first wall surface (11) facing a high-temperature space (S) through which a high-temperature fluid (G) flows, and a cooling flow path (15) inclined at a first angle with respect to the first wall surface and guiding a cooling fluid from an opening formed in the first wall surface in the direction in which the high-temperature fluid flows to cool the first wall surface downstream of the opening, wherein the cooling flow path comprises a first flow path (17) and branch flow paths (18, 19) branched from a branch position (P1) midway along the first flow path and provided on each side of the first flow path when the first wall surface is viewed in a plane, and at the branch position, a branch position wall surface is formed that is formed from the first wall surface to the first flow path and has a second angle (α2) greater than the first angle (α1).

[0059] The cooling wall structure is cooled by flowing a cooling fluid, such as air, through a cooling wall structure whose first wall faces a high-temperature space through which a high-temperature fluid, such as combustion gas, flows. A cooling channel through which the cooling fluid flows is inclined at a first angle relative to the first wall surface. The cooling fluid flows along the first wall surface in the direction of the high-temperature fluid flow from an opening formed in the first wall surface, thereby film-cooling the first wall surface downstream of the opening. The cooling channel includes a first channel and branch channels branched from a midpoint of the first channel and provided on both sides of the first channel. The cooling fluid flowing out of the first channel into the high-temperature space forms a counter-rotating vortex pair (CRVP: a pair of positive and negative vortices that reduces the adhesion of the cooling fluid to the wall surface). In response, anti-CRVPs are generated by the cooling fluid flowing out of the branch channels on both sides of the first channel, suppressing the CRVP of the cooling fluid flowing out of the first channel and promoting adhesion of the cooling fluid to the first wall surface. This improves cooling performance at the first wall surface. A branch position wall surface is formed at the branch position, extending from the first wall surface to the first flow path. The branch position wall surface has a second angle greater than the first angle, which is the inclination angle of the first flow path. This expands the opening formed by the first flow path toward the upstream side. This diffuses the flow from the leading edge and further induces wall-attached flow. The second angle, which is the inclination angle of the branch position wall surface, is greater than the first angle, which allows for the removal of a wall portion between the branch position wall surface and the first wall surface near the upstream side of the opening. In other words, if an opening were formed on the extension of the first flow path while maintaining the inclination at the first angle, a thin overhanging portion of the wall would remain upstream of the opening. In contrast, by forming the branch position wall surface with a second angle greater than the first angle, the thin overhanging portion can be removed. Removing the thin overhanging portion in this way minimizes damage during machining of the cooling flow path and operation of the cooling wall structure, thereby improving durability. The branch position wall surface is not limited to having the entire upper surface of the flow path open.

[0060] In a cooling wall structure according to a second aspect of the present disclosure, in the first aspect, the second angle is set to be equal to or greater than 45° and equal to or less than 90°.

[0061] By setting the second angle to be equal to or greater than 45° and equal to or less than 90°, it is possible to effectively remove the thin overhang portion. The second angle is preferably as close to 90° as possible, and is, for example, set to be equal to or greater than 60°, more preferably equal to or greater than 80°.

[0062] A cooling wall structure according to a third aspect of the present disclosure is the first or second aspect, wherein the branch position wall surface has an arc shape when viewed from above from the first wall surface.

[0063] By forming the wall surface at the branching position into an arc shape, stress concentration can be alleviated, thereby preventing the occurrence of cracks.

[0064] The cooling wall structure according to the fourth aspect of the present disclosure, in any of the first to third aspects, has a chamfered portion (CR) at a position where an opening formed in the first wall surface by extending the first flow path intersects with an opening formed in the first wall surface by extending the branch flow path.

[0065] A chamfer (a rounded or chamfered surface) is provided at the position where the opening formed by the first flow path intersects with the opening formed by the branch flow path, thereby alleviating stress concentration and preventing cracks from occurring.

[0066] The cooling wall structure according to the fifth aspect of the present disclosure is such that, in any of the first to fourth aspects, the branch position wall surface is arc-shaped when viewed in a plane from the first wall surface, and the arc shape of the branch position wall surface has the same radius of curvature (R1, R2, R3) as the arc shape formed at the downstream end of the branch flow path.

[0067] The arcuate shape of the wall surface at the branch position and the arcuate shape of the downstream end of the branch flow path are made the same radius of curvature. This facilitates processing. For example, when forming the branch flow path by laser processing, the same laser spot diameter can be used for the wall surface at the branch position and the downstream end of the branch flow path, eliminating the need to adjust the spot diameter.

[0068] The cooling wall structure according to the sixth aspect of the present disclosure, in any of the first to fifth aspects, comprises a base material (9a), a bond layer (9b) formed on the surface of the base material, and a top coat layer (9c) formed on the surface of the bond layer, wherein the first wall surface is the surface of the top coat layer, and the branch position wall surface is formed up to the boundary position between the top coat layer and the bond layer.

[0069] The base material, bond layer, and top coat layer are made of different materials, and therefore have different linear expansion coefficients. This can lead to delamination. Therefore, the branching wall is formed up to the boundary between the top coat layer and the bond layer. This can prevent delamination between the top coat layer and the bond layer at the branching wall.

[0070] The cooling wall structure according to the seventh aspect of the present disclosure, in any of the first to sixth aspects, comprises a base material, a bond layer formed on the surface of the base material, and a top coat layer formed on the surface of the bond layer, wherein the first wall surface is the surface of the top coat layer, and the branch position wall surface is formed up to the boundary position between the bond layer and the base material.

[0071] Since the branching position wall surface is formed up to the boundary position between the bond layer and the base material, it is possible to suppress interlayer delamination between the top coat layer and the bond layer, and interlayer delamination between the bond layer and the base material, at the branching position wall surface.

[0072] The cooling wall structure according to the eighth aspect of the present disclosure, in any one of the first to sixth aspects, comprises a base material, a bond layer formed on the surface of the base material, and a top coat layer formed on the surface of the bond layer, wherein the first wall surface is the surface of the top coat layer, and the branch position wall surface is formed up to the base material.

[0073] Since the wall surface at the branching position is formed up to the base material, it is possible to suppress delamination between the top coat layer and the bond layer, and between the bond layer and the base material, at the wall surface at the branching position.

[0074] The cooling wall structure according to the ninth aspect of the present disclosure is, in any one of the first to eighth aspects, such that each branch flow path is a bottomed groove portion that is connected to the branch position wall surface and is formed to the same depth as the branch position wall surface.

[0075] The branch flow path is a bottomed groove that is connected to the branch position wall surface and is formed to the same depth as the branch position wall surface. This allows the branch flow path to be formed simultaneously with the formation of the branch position wall surface, making processing easier.

[0076] A cooling wall structure according to a tenth aspect of the present disclosure is the cooling wall structure of any one of the first to ninth aspects, wherein each of the branch flow paths is a cylindrical groove with a bottom.

[0077] A cooling wall structure (15") according to an eleventh aspect of the present disclosure is the cooling wall structure (15") of any of the first to ninth aspects, wherein the first flow path (17") has a shape in which the flow path cross-sectional area gradually widens toward the downstream side.

[0078] The first flow passage is shaped such that the cross-sectional area gradually widens toward the downstream side (for example, a fan shape). This allows the flow to be more diffused downstream than when the first flow passage is shaped like a round hole, resulting in the formation of a wall-attached flow, which further improves film cooling efficiency.

[0079] A high-temperature component (1) according to a first aspect of the present disclosure includes the cooling wall structure of any one of the first to eleventh aspects.

[0080] High-temperature parts include parts that come into contact with high-temperature gases such as combustion gases, and more specifically, combustors and turbine blades used in aircraft engines.

[0081] A manufacturing method of a cooling wall structure according to a first aspect of the present disclosure includes a first wall surface facing a high-temperature space through which a high-temperature fluid flows, and a cooling flow path inclined at a first angle with respect to the first wall surface, guiding a cooling fluid from an opening formed in the first wall surface in a direction in which the high-temperature fluid flows to cool the first wall surface downstream of the opening, wherein the cooling flow path includes a first flow path and branch flow paths branched from a branch position midway through the first flow path and provided on each side of the first flow path when the first wall surface is viewed in a plane, and wherein a branch position wall surface is formed at the branch position, the branch position having a second angle larger than the first angle, the manufacturing method of a cooling wall structure includes a first step of forming each branch flow path together with the branch position wall surface by laser processing, and a second step of forming the first flow path by laser processing.

[0082] After forming each branch flow path by laser processing, the first flow path is formed by laser processing. Since the wall surface at the branch position is also processed in the first step, the manufacturing process can be simplified.

[0083] DESCRIPTION OF SYMBOLS 1 Combustor (high-temperature part) 3 Main casing 5 Combustor liner 9 Wall 9a Base material 9b Bond layer 9c Top coat layer 10 Cooling wall structure 11 Inner surface (first wall) 12 Outer surface 15, 15', 15" Cooling flow passage 15a Inlet opening 15b, 15b' Outlet opening 15b1 Main flow passage outlet opening 15b2 First branch opening 15b3 Second branch opening 17, 17" Main flow passage 18, 18' First branch flow passage (branch flow passage) 18a, 18a', 18" Bottom 19, 19', 19" Second branch flow passage (branch flow passage) 19a, 19a' Bottom 22, 22" Branch position wall surface 30 Overhang portion A Compressed air A1 Cooling air C1 First axis C2, C2' Second axis C3, C3' Third axis D1 Branch position F Fuel FL Flame S High temperature space P1 Branch point R1, R2, R3 Radius of curvature CR Chamfered portion x Longitudinal direction of combustor liner (main flow direction of combustion gas) y Thickness direction of wall portion α1 First angle α2 Second angle α3 First branch angle α4 Second branch angle

Claims

1. A cooling wall structure comprising: a first wall facing a high-temperature space through which a high-temperature fluid flows; and a cooling flow path inclined at a first angle with respect to the first wall, for guiding a cooling fluid from an opening formed in the first wall in the direction in which the high-temperature fluid flows, to cool the first wall downstream of the opening, wherein the cooling flow path comprises a first flow path and branch flow paths branched at a branching position midway through the first flow path, and provided on each side of the first flow path when the first wall is viewed in a plane, and wherein at the branching position, a branching position wall surface is formed from the first wall surface to the first flow path, the branching position having a second angle greater than the first angle.

2. A cooling wall structure as described in claim 1, wherein the second angle is greater than or equal to 45° and less than or equal to 90°.

3. A cooling wall structure as set forth in claim 1, wherein the branching position wall surface is arc-shaped when viewed in a plan view from the first wall surface.

4. A cooling wall structure as described in claim 1, in which a chamfered portion is provided at a position where an opening formed in the first wall surface by an extension of the first flow path intersects with an opening formed in the first wall surface by an extension of the branch flow path.

5. A cooling wall structure as described in any one of claims 1 to 4, wherein the branch position wall surface is arc-shaped when viewed in a plane from the first wall surface, and the arc shape of the branch position wall surface has the same radius of curvature as the arc shape formed at the downstream end of the branch flow path.

6. A cooling wall structure as described in any one of claims 1 to 4, comprising: a base material; a bond layer formed on a surface of the base material; and a top coat layer formed on the surface of the bond layer, wherein the first wall surface is the surface of the top coat layer, and the branch position wall surface is formed up to the boundary position between the top coat layer and the bond layer.

7. A cooling wall structure as described in any one of claims 1 to 4, comprising: a base material; a bond layer formed on a surface of the base material; and a top coat layer formed on the surface of the bond layer, wherein the first wall surface is the surface of the top coat layer, and the branch position wall surface is formed up to the boundary position between the bond layer and the base material.

8. A cooling wall structure as described in any one of claims 1 to 4, comprising: a base material; a bond layer formed on a surface of the base material; and a top coat layer formed on the surface of the bond layer, wherein the first wall surface is the surface of the top coat layer, and the branch position wall surface is formed up to the base material.

9. A cooling wall structure according to any one of claims 1 to 4, wherein each of the branch flow passages is a bottomed groove that is connected to the branch position wall surface and is formed to the same depth as the branch position wall surface.

10. A cooling wall structure according to any one of claims 1 to 4, wherein each of the branch passages is a cylindrical groove with a bottom.

11. A cooling wall structure as described in any one of claims 1 to 4, wherein the first flow passage has a shape in which the flow passage cross-sectional area gradually increases toward the downstream side.

12. A high-temperature component having a cooling wall structure according to any one of claims 1 to 4.

13. A manufacturing method for a cooling wall structure comprising: a first wall surface facing a high-temperature space through which a high-temperature fluid flows; and a cooling flow path inclined at a first angle with respect to the first wall surface, and guiding a cooling fluid from an opening formed in the first wall surface in a direction in which the high-temperature fluid flows, to cool the first wall surface downstream of the opening, wherein the cooling flow path comprises a first flow path and branch flow paths branched at a branching position midway through the first flow path and provided on each side of the first flow path when the first wall surface is viewed in a plane, and wherein at the branching position, a branching position wall surface is formed that is formed from the first wall surface to the first flow path and has a second angle larger than the first angle, the manufacturing method for a cooling wall structure comprising: a first step of forming each of the branching flow paths together with the branching position wall surface by laser processing; and a second step of forming the first flow path by laser processing.

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