Flat cat ear air film hole cooling structure applied to gas turbine and construction method

Abstract

The invention relates to the technical field of gas turbine hot end cooling, and discloses a flat cat ear air film hole cooling structure applied to a gas turbine and a construction method.The flat cat ear air film hole cooling structure comprises a solid wall, the solid wall is provided with an outer wall face and an inner wall face, and the outer wall face is used for making contact with a high-temperature mainstream; each air film hole comprises an elliptic cylinder section arranged on the solid wall and an expansion section communicated and coaxial with the elliptic cylinder section, the joint of the elliptic cylinder section and the expansion section is an inlet molded line, a cold air inlet is formed in the inner wall face of the end, away from the expansion section, of the elliptic cylinder section, and a cold air outlet is formed in the outer wall face of the end, away from the elliptic cylinder section, of the expansion section. An ideal anti-kidney-vortex structure can be formed, cold air is promoted to expand in the transverse direction, the spanwise coverage area of an air film is increased, and the wall attachment effect of the air film is improved, so that the cooling efficiency of the air film is improved, meanwhile, uniform seam-shaped outflow can be formed, and the pneumatic loss caused by mixing of the cold air and main flow is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of gas turbine hot end cooling, and in particular to a flat cat-ear air film hole cooling structure applied to a gas turbine and a construction method thereof. Background Art

[0002] The gas turbine engine is a thermal power device based on the Brayton cycle. It has been widely used in modern military and industry due to its powerful output power and high thermal efficiency. The gas turbine engine has an extremely harsh working environment, with three major characteristics: high temperature, high pressure and high speed. Among them, the high temperature working environment is particularly reflected in the turbine, one of the three core components. Experience shows that under the premise that the engine size remains unchanged, the thrust of the gas turbine can be increased by 8-13% and the cycle efficiency can be increased by 2-4% for every 56K increase in the turbine inlet temperature. At present, the turbine inlet temperature of advanced aircraft engines has exceeded 2000K, while the temperature resistance limit of the turbine blade material is much lower than the turbine inlet temperature. Therefore, efficient cooling technology must be used to ensure its normal operation.

[0003] Although the prior art can actively form anti-kidney vortices that are beneficial to film cooling, the vortex structure of a single film hole unit is usually composed of two pairs of adjacent kidney vortices, and it is difficult to form a vortex structure in which the anti-kidney vortex dominates, which is not conducive to the spanwise extension of the cold air. In addition, when the film hole forms a larger outlet width, the large expansion angle makes it easy for serious flow separation to occur in the hole, aggravating the mixing of cold air and the mainstream, increasing flow losses, and being not conducive to the cooling effect. Summary of the invention

[0004] The object of the present invention is to provide a flat cat-ear air film hole cooling structure and a construction method for a gas turbine, aiming to solve or improve at least one of the above-mentioned technical problems.

[0005] To achieve the above object, the present invention provides the following solution: The present invention provides a flat cat-ear air film hole cooling structure applied to a gas turbine, comprising:

[0006] A solid wall having an outer wall surface and an inner wall surface, wherein the outer wall surface is used for contacting the high-temperature mainstream;

[0007] The air film hole comprises an elliptical column section opened on the solid wall and an expansion section connected to and coaxial with the elliptical column section, the connection between the elliptical column section and the expansion section is an inlet profile, one end of the elliptical column section away from the expansion section forms a cold air inlet on the inner wall surface, and one end of the expansion section away from the elliptical column section forms a cold air outlet on the outer wall surface, and the profile of the cold air outlet is an outlet profile;

[0008] The outlet profile is a first rectangle drawn on the outer wall surface with the intersection 01 of the axis of the air film hole and the high-temperature mainstream, the short side of the first rectangle is parallel to the flow direction of the high-temperature mainstream, and the second rectangle is drawn with the vertex A and vertex B of the first rectangle close to the downstream of the high-temperature mainstream, and the short side of the second rectangle is parallel to the flow direction of the high-temperature mainstream. An ellipse is drawn with a pair of diagonals AC and BD of the second rectangle respectively, and a pair of tangents tangent to the pair of ellipses are drawn with the center point E of the long side of the first rectangle close to the downstream of the high-temperature mainstream, and the pair of tangents are chamfered with a radius of R1 to obtain an inverted arc, and an arc with a radius of R2 is drawn with the center 03 of the inverted arc, and the pair of ellipses, the pair of tangents, the inverted arc and the arc are connected to obtain the outlet profile.

[0009] Optionally, the inlet profile is parallel to the flow direction of the high-temperature mainstream.

[0010] Optionally, the equivalent diameter of the elliptical cylinder segment ranges from 0.4 mm to 1 mm.

[0011] Optionally, the ratio L of the length of the expansion section to the total length of the air film hole is e / L is 0-1.

[0012] Optionally, the flow direction inclination angle of the air film hole ranges from 30 to 90 degrees.

[0013] Optionally, the spanwise inclination angle of the air film hole ranges from 30 to 150 degrees.

[0014] Optionally, the ratio of the spacing P between the axes of two adjacent air film holes to the equivalent diameter is not less than 3.

[0015] Optionally, the air film holes are arranged obliquely.

[0016] The present invention also provides a method for constructing a flat cat ear air membrane hole, comprising:

[0017] A first rectangle is drawn on the outer wall surface at the intersection 01 of the axis of the air film hole and the high-temperature mainstream, wherein the short side of the first rectangle is parallel to the flow direction of the high-temperature mainstream;

[0018] Draw a second rectangle using vertex A and vertex B of the first rectangle close to the downstream of the high-temperature mainstream, respectively, with the short sides of the second rectangle being parallel to the flow direction of the high-temperature mainstream;

[0019] Draw an ellipse using a pair of diagonals AC and BD of the second rectangle respectively;

[0020] A pair of tangent lines respectively tangent to the pair of ellipses are drawn with the center point E of the long side of the first rectangle close to the downstream of the high-temperature mainstream, and the pair of tangent lines are chamfered with a radius of R1 to obtain a chamfered arc;

[0021] Draw an arc with a radius of R2 with the center 03 of the inverted arc;

[0022] The outlet profile is obtained by connecting a pair of the ellipses, a pair of the tangent lines, the inverted arc and the circular arc.

[0023] Optionally, a preset relationship between the long side a2 and the short side b2 of the second rectangle and the major axis a3 and the minor axis b3 of the ellipse is a2 / b2=a3 / b3.

[0024] The present invention discloses the following technical effects:

[0025] 1. The present invention directly constructs a branch structure in the hole to induce the formation of an anti-kidney vortex by controlling the outlet profile, inheriting the advantages of the bifurcated hole and the slit hole, and can form a larger outlet width in the air film hole without serious flow separation, thereby forming an ideal anti-kidney vortex structure, promoting the lateral expansion of cold air, increasing the air film coverage area in the direction of extension, and enhancing the air film wall attachment effect, thereby improving the air film cooling efficiency, and at the same time forming a more uniform slit-shaped outflow, reducing the aerodynamic loss of the mixing of cold air and mainstream.

[0026] 2. The length of the first rectangle of the outlet profile can be adjusted to directly control the width of the air film hole outlet flow direction, and the width and rounding radius of the second rectangle of the outlet profile can be adjusted to control the curvature of the expansion section, so as to more conveniently adjust the shape of the air film hole. The method of adjusting the outlet profile to change the expansion section can make the air film hole structure richer and have a larger sample space for structural optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0028] Figure 1 is a schematic diagram of the present invention;

[0029] Figure 2 It is a schematic diagram of the structure of the air film hole of the present invention;

[0030] Figure 3 It is a schematic diagram of the construction of the outlet profile of the present invention;

[0031] Figure 4 A top view of the air film hole of the present invention;

[0032] Figure 5 It is a side view of the air film hole of the present invention;

[0033] Figure 6 An axial view of the air film hole of the present invention;

[0034] Figure 7 The spanwise film cooling efficiency distribution curve of the film hole of the present invention and the crescent-shaped film hole with the same area ratio at a flow direction distance of 10D downstream of the film hole;

[0035] Figure 8 A comparison curve of the spanwise average film cooling efficiency of the film hole of the present invention and the crescent-shaped film hole of the same area ratio within a flow direction distance of 40D downstream of the film hole;

[0036] Fig. 9 The vorticity cloud diagram and velocity vector diagram of the air film hole flow direction of the present invention;

[0037] Fig.10 The flow direction vortex cloud diagram and velocity vector diagram of the air film hole in the prior art;

[0038] Fig.11 It is the cooling effect cloud diagram of the air film hole of the present invention;

[0039] Fig.12 This is a cooling effect cloud diagram of the air film hole in the prior art.

[0040] In the figure: 1. outlet profile; 2. expansion section; 3. inlet profile; 4. elliptical cylinder section; 5. first rectangle; 6. second rectangle; 7. ellipse; 8. tangent; 9. inverted arc; 10. circular arc; 11. cooling gas; 12. solid wall; 13. high-temperature mainstream. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] Reference Figure 1-Figure 12 The present invention provides a flat cat-ear air film hole cooling structure applied to a gas turbine, comprising:

[0044] The solid wall 12 has an outer wall surface and an inner wall surface, and the outer wall surface is used to contact the high-temperature mainstream 13;

[0045] The air film hole comprises an elliptical column section 4 opened on the solid wall 12 and an expansion section 2 connected to and coaxial with the elliptical column section 4, the connection between the elliptical column section 4 and the expansion section 2 is an inlet profile 3, the end of the elliptical column section 4 away from the expansion section 2 forms a cold air inlet on the inner wall surface, the end of the expansion section 2 away from the elliptical column section 4 forms a cold air outlet on the outer wall surface, and the profile of the cold air outlet is an outlet profile 1;

[0046] The outlet profile 1 is an intersection 01 of the axis of the air film hole and the high-temperature mainstream 13. A first rectangle 5 is drawn on the outer wall surface. The short side of the first rectangle 5 is parallel to the flow direction of the high-temperature mainstream 13. A second rectangle 6 is drawn with the vertex A and the vertex B of the first rectangle 5 close to the downstream of the high-temperature mainstream 13. The short side of the second rectangle 6 is parallel to the flow direction of the high-temperature mainstream 13. An ellipse 7 is drawn with a pair of diagonals AC and BD of the second rectangle 6 respectively. A pair of tangents 8 tangent to the pair of ellipses 7 are drawn with the center point E of the long side of the first rectangle 5 close to the downstream of the high-temperature mainstream 13. The pair of tangents 8 are chamfered with a radius of R1 to obtain a chamfered arc 9. An arc 10 with a radius of R2 is drawn with the center 03 of the chamfered arc 9. The pair of ellipses 7, the pair of tangents 8, the chamfered arc 9 and the arc 10 are connected to obtain the outlet profile 1.

[0047] The present invention inherits the advantages of bifurcated holes and slit holes, and can form a larger outlet span width without serious flow separation in the air film hole, thereby forming an ideal anti-kidney vortex structure, promoting the lateral expansion of cold air, increasing the span coverage area of ​​the air film, and enhancing the wall attachment effect of the air film, thereby improving the air film cooling efficiency. At the same time, a more uniform slit-shaped outflow can be formed, reducing the aerodynamic loss of the mixing of cold air and mainstream.

[0048] Furthermore, the expansion section 2 is composed of a ruled surface formed by connecting the inlet profile 3 and the outlet profile 1 .

[0049] In one embodiment of the present invention, the inlet profile 3 is parallel to the flow direction of the high-temperature mainstream 13 .

[0050] In one embodiment of the present invention, the equivalent diameter of the elliptical cylinder segment 4 is in the range of 0.4 mm to 1 mm.

[0051] Furthermore, the inlet profile 3 is an ellipse with a major axis a0 and a minor axis b0, wherein the minor axis b0 is parallel to the flow direction of the high-temperature mainstream 13, and the major axis a0> the equivalent diameter D of the elliptical column segment 4, and the minor axis b0 <D / sinα。

[0052] In one embodiment of the present invention, the ratio Le / L of the length of the expansion section 2 to the total length of the air film hole is 0-1.

[0053] In one embodiment of the present invention, the flow direction inclination angle of the air film hole ranges from 30 to 90 degrees.

[0054] In one embodiment of the present invention, the spanwise inclination angle of the air film holes ranges from 30 to 150 degrees.

[0055] In one embodiment of the present invention, the ratio of the spacing P between the axes of two adjacent air film holes to the equivalent diameter of the elliptical cylinder segment 4 is not less than 3.

[0056] In one embodiment of the present invention, it is characterized in that the air film holes are arranged obliquely.

[0057] The present invention also provides a method for constructing a flat cat ear air membrane hole, comprising:

[0058] A first rectangle 5 is drawn on the outer wall surface at the intersection 01 of the axis of the air film hole and the high-temperature mainstream 13. The short side of the first rectangle 5 is parallel to the flow direction of the high-temperature mainstream 13. Specifically, the long side a1 of the first rectangle 5 is 16 mm, and the short side b1 is 12 mm.

[0059] The second rectangle 6 is drawn with the vertex A and the vertex B of the first rectangle 5 close to the downstream of the high-temperature mainstream, and the short side of the second rectangle 6 is parallel to the flow direction of the high-temperature mainstream 13. Specifically, the long side a2 of the second rectangle is 12 mm, and the short side b2 is 8 mm.

[0060] An ellipse 7 is drawn using a pair of diagonal lines AC and BD of the second rectangle 6. Specifically, the major axis a3 of the ellipse 7 is 13.44 mm, and the minor axis b3 is 7.84 mm.

[0061] A pair of tangent lines 8 tangent to a pair of ellipses 7 are drawn with the center point E of the long side of the first rectangle 5 close to the downstream of the high-temperature mainstream 13, and the pair of tangent lines 8 are rounded with a radius of R1 to obtain a rounded arc 9, where the tangent line 8 is tangent to the ellipse 7, and specifically, R1 is 7 mm;

[0062] Draw an arc 10 with a radius R2 with the center 03 of the inverted arc 9. Specifically, R2 is 40.2 mm.

[0063] The outlet profile is obtained by connecting a pair of ellipses 7, a pair of tangent lines 8, a chamfered arc 9 and a circular arc 10.

[0064] In one embodiment of the present invention, the preset relationship between the long side a2 and the short side b2 of the second rectangle 6 and the major axis a3 and the minor axis b3 of the ellipse 7 is a2 / b2=a3 / b3, and the ellipse 7 is tangent to the short side of the second rectangle 6.

[0065] In this embodiment, the air film holes are arranged on the solid wall 12, the equivalent aperture D of the elliptical cylinder segment 4 is 10 mm, the axial length L of the air film hole is 3D, the ratio of the length of the expansion segment 2 to the total length Le / L is 3 / 5, the lateral spacing P between adjacent air film holes is 6D, the flow direction inclination angle α is 45 degrees, and the spanwise inclination angle is not set. The cooling gas 11 flows through the air film holes of the present invention and is ejected, forming an air film covering the surface of the solid wall 12, while mixing with the high-temperature mainstream 13 and finally dissipating.

[0066] Furthermore, if Figure 7 As shown, the air film holes in this embodiment and the crescent-shaped air film holes shown in the Chinese invention patent application publication 202210520834.X with the same area ratio are distributed in the spanwise air film cooling efficiency at a distance of 10D downstream of the air film holes. The horizontal axis represents the distance in the spanwise direction, and the vertical axis represents the air film cooling efficiency. It can be seen that at 10D downstream of the air film hole, the air film of the flat cat ear hole in this embodiment has a better spanwise coverage effect, and the anti-kidney vortex formed is stronger, thereby promoting the extension of cold air from the vicinity of the center line to both sides, so that the cooling effect near the center line is lower, and the air film has a wider spanwise coverage width and more uniform coverage. .

[0067] Furthermore, if Figure 8 As shown, the air film holes in this embodiment and the crescent-shaped air film holes shown in the Chinese invention patent application publication 202210520834.X with the same area ratio are distributed in the spanwise average air film cooling efficiency within a range of 40D in the downstream flow direction of the air film holes. The horizontal axis represents the distance in the flow direction, and the vertical axis represents the spanwise average air film cooling efficiency. It can be seen that the flat cat ear air film holes in this embodiment have the highest spanwise average air film cooling efficiency in the downstream area where x / D>3, and the air film cooling efficiency is improved by about 19% compared with the crescent-shaped air film holes.

[0068] Furthermore, if Fig. 9 , Fig.10 As shown, the air film hole in this embodiment and the crescent-shaped air film hole shown in the Chinese invention patent application publication 202210520834.X with the same area ratio are the flow vortex cloud diagram and velocity vector diagram of the plane 5D downstream of the air film hole. It can be seen that the flat cat ear air film hole in this embodiment forms an anti-kidney vortex structure that is beneficial to air film cooling in the downstream, promotes the lateral expansion of cold air, and improves the air film wall attachment effect, while the flow vortex system formed by the crescent-shaped air film hole is mainly dominated by kidney-shaped vortices.

[0069] Furthermore, if Fig.10 , Fig.11As shown, the cooling effect cloud diagram of the air film hole in this embodiment and the crescent-shaped air film hole shown in the Chinese invention patent application publication 202210520834.X with the same area ratio within the range of 40D downstream of the air film hole. It can be seen that although the outlet span width of the air film hole in this embodiment is slightly wider than that of the crescent-shaped air film hole, due to the lateral expansion effect of the anti-kidney vortex, the span width of the air film wake of the flat cat ear air film hole in this embodiment occupies the span width of the air film hole outlet, while the span width of the air film wake of the crescent-shaped air film hole shrinks at the outlet, which is significantly smaller than the span width of the air film hole outlet.

[0070] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0071] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A flat cat-ear air film hole cooling structure applied to a gas turbine, characterized in that: include: A solid wall (12) having an outer wall surface and an inner wall surface, wherein the outer wall surface is used to contact the high-temperature mainstream (13); The air film hole comprises an elliptical column section (4) opened on the solid wall (12) and an expansion section (2) connected to and coaxial with the elliptical column section (4), the connection between the elliptical column section (4) and the expansion section (2) is an inlet profile (3), one end of the elliptical column section (4) away from the expansion section (2) forms a cold air inlet on the inner wall surface, and one end of the expansion section (2) away from the elliptical column section (4) forms a cold air outlet on the outer wall surface, and the profile of the cold air outlet is an outlet profile (1); The outlet profile (1) is a first rectangle (5) drawn on the outer wall surface at the intersection 01 of the axis of the air film hole and the high-temperature mainstream (13), the short side of the first rectangle (5) is parallel to the flow direction of the high-temperature mainstream (13), and a second rectangle (6) is drawn at the vertex A and vertex B of the first rectangle (5) close to the downstream of the high-temperature mainstream (13), the short side of the second rectangle (6) is parallel to the flow direction of the high-temperature mainstream (13), and a pair of diagonal lines AC and B of the second rectangle (6) are respectively drawn. BD draws an ellipse (7), draws a pair of tangent lines (8) tangent to the pair of ellipses (7) respectively with the center point E of the long side of the first rectangle (5) close to the downstream of the high-temperature mainstream (13), rounds the pair of tangent lines (8) with a radius of R1 to obtain a rounded arc (9), draws an arc (10) with a radius of R2 with the center point O3 of the rounded arc (9), and connects the pair of ellipses (7), the pair of tangent lines (8), the rounded arc (9) and the arc (10) to obtain the outlet profile (1).

2. A flat cat-ear air film hole cooling structure for a gas turbine according to claim 1, characterized in that: The inlet profile (3) is parallel to the flow direction of the high-temperature mainstream (13).

3. The flat cat-ear air film hole cooling structure for gas turbine according to claim 1, characterized in that: The equivalent diameter of the elliptical cylinder segment (4) is in the range of 0.4 mm to 1 mm.

4. The flat cat-ear air film hole cooling structure for gas turbine according to claim 1, characterized in that: The ratio L of the length of the expansion section (2) to the total length of the air film hole e / L is 0-1.

5. The flat cat-ear air film hole cooling structure for gas turbine according to claim 1, characterized in that: The flow direction inclination angle of the air film hole ranges from 30 to 90 degrees.

6. The flat cat-ear air film hole cooling structure for gas turbine according to claim 1, characterized in that: The spanwise inclination angle of the air film hole ranges from 30 to 150 degrees.

7. The flat cat-ear air film hole cooling structure for gas turbine according to claim 1, characterized in that: The ratio of the spacing P between the axes of two adjacent air film holes to the equivalent diameter of the elliptical cylinder segment (4) is not less than 3.

8. The flat cat-ear air film hole cooling structure for gas turbine according to claim 1, characterized in that: The air film holes are arranged obliquely.

9. A method for constructing a flat cat-ear air film hole, used to construct the outlet profile in a flat cat-ear air film hole cooling structure for a gas turbine according to claim 1, characterized in that: include: A first rectangle (5) is drawn on the outer wall surface at the intersection 01 of the axis of the air film hole and the high-temperature mainstream (13), wherein the short side of the first rectangle (5) is parallel to the flow direction of the high-temperature mainstream (13); A second rectangle (6) is drawn using vertex A and vertex B of the first rectangle (5) close to the downstream of the high-temperature mainstream (13), wherein the short side of the second rectangle (6) is parallel to the flow direction of the high-temperature mainstream (13); Draw an ellipse (7) using a pair of diagonal lines AC and BD of the second rectangle (6); A pair of tangent lines (8) are drawn with the center point E of the long side of the first rectangle (5) close to the downstream of the high-temperature mainstream (13), and are tangent to the pair of ellipses (7) respectively; and the pair of tangent lines (8) are chamfered with a radius of R1 to obtain a chamfered arc (9); Draw an arc (10) with a radius R2 using the center 03 of the inverted arc (9); The outlet profile is obtained by connecting a pair of the ellipses (7), a pair of the tangent lines (8), the inverted arc (9) and the circular arc (10).

10. The method for constructing a flat cat ear air membrane hole according to claim 9, characterized in that: The preset relationship between the long side a2 and the short side b2 of the second rectangle (6) and the long axis a3 and the short axis b3 of the ellipse (7) is a2 / b2=a3 / b3.

Images