Flat cat-ear air film hole cooling structure and construction method for gas turbines

Abstract

The present invention relates to the technical field of gas turbine hot end cooling, and discloses a flat cat-ear air film hole cooling structure and a construction method for gas turbines, comprising a solid wall with an outer wall surface and an inner wall surface, the outer wall surface being used to contact a high-temperature mainstream; the air film hole comprising 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 being an inlet profile line, a cold air inlet being formed on the inner wall surface at one end of the elliptical column section away from the expansion section, a cold air outlet being formed on the outer wall surface at one end of the expansion section away from the elliptical column section, and the profile line of the cold air outlet being an outlet profile line. The present invention can form an ideal anti-kidney vortex structure, promote the lateral expansion of cold air, increase the air film coverage area in the direction of the air film, enhance the air film wall attachment effect, thereby improving the air film cooling efficiency, and at the same time can form a relatively uniform slit-shaped outflow, reducing the aerodynamic loss of the mixing of cold air and the mainstream.

Description

Technical Field

[0001] The present 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] Gas turbine engines, a thermal power device based on the Brayton cycle, are widely used in modern military and industrial applications due to their powerful output and high thermal efficiency. Gas turbine engines operate in an extremely harsh and demanding environment characterized by high temperature, high pressure, and high speed. The high temperature environment is particularly evident in the turbine, one of its three core components. Experience shows that, assuming the engine size remains constant, a 56K increase in turbine inlet temperature can increase gas turbine thrust by 8-13% and improve cycle efficiency by 2-4%. The turbine inlet temperature of today's advanced aircraft engines exceeds 2000K, but the temperature resistance limit of turbine blade materials is far lower than the turbine inlet temperature, necessitating the use of efficient cooling technology to ensure proper operation.

[0003] Although the existing technology 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, which makes it difficult to form a vortex structure in which anti-kidney vortices dominate, and 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 gas turbines, aiming to solve or improve at least one of the above-mentioned technical problems.

[0005] To achieve the above-mentioned object, the present invention provides the following solution: The present invention provides a flat cat-ear air film hole cooling structure for 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] An air film hole comprises an elliptical cylinder section opened on the solid wall and an expansion section connected to and coaxial with the elliptical cylinder section, wherein the connection between the elliptical cylinder section and the expansion section is an inlet profile, an end of the elliptical cylinder section away from the expansion section forms a cold air inlet on the inner wall surface, and an end of the expansion section away from the elliptical cylinder 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 at 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 a second rectangle is drawn with the vertex A and vertex B of the first rectangle close to the downstream of the high-temperature mainstream, the short side of the second rectangle is parallel to the flow direction of the high-temperature mainstream, and 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. 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 at an angle.

[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 point 01 of the axis of the 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, with the short sides of the second rectangle 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 are drawn with the center point E of the long side of the first rectangle close to the downstream of the high-temperature mainstream, respectively tangent to the pair of ellipses, and the pair of tangent lines are rounded with a radius of R1 to obtain rounded arcs;

[0021] Draw an arc with a radius of R2 with the center of the inverted arc O3;

[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 by controlling the outlet profile to induce the formation of an anti-kidney vortex, inheriting the advantages of bifurcated holes and slit holes. It 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 improving the wall attachment effect of the air film, thereby improving the cooling efficiency of the air film. At the same time, it can form a more uniform slit-shaped outflow, reducing the aerodynamic loss of the mixing of cold air and mainstream.

[0026] 2. The film hole's shape can be easily adjusted by adjusting the length of the first rectangle of the outlet profile to directly control the width of the film hole's outlet flow direction. Adjusting the width and fillet radius of the second rectangle of the outlet profile controls the curvature of the expansion section. This method of adjusting the outlet profile to alter the expansion section allows for a richer film hole structure and greater scope for structural optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

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

[0029] Figure 2 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 A side view of the air film hole of the present invention;

[0033] Figure 6 This is 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 distance 10D downstream of the film hole;

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

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

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

[0038] Figure 11 This is a cooling effect cloud diagram of the air film hole of the present invention;

[0039] Figure 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 clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts 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 Figures 1-12 The present invention provides a flat cat-ear air film hole cooling structure for a gas turbine, comprising:

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

[0045] The air film hole includes an elliptical cylinder section 4 formed on a solid wall 12 and an expansion section 2 connected to and coaxial with the elliptical cylinder section 4. The connection between the elliptical cylinder section 4 and the expansion section 2 is an inlet profile 3. The end of the elliptical cylinder 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 cylinder section 4 forms a cold air outlet on the outer wall surface. The profile of the cold air outlet is the 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 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 the diagonals AC and BD of a pair of second rectangles 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 an inverted arc 9. An arc 10 with a radius of R2 is drawn with the center 03 of the inverted arc 9. The outlet profile 1 is obtained by connecting the pair of ellipses 7, the pair of tangents 8, the inverted arc 9 and the arc 10.

[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 improving the air film wall attachment effect, thereby improving the air film cooling efficiency. At the same time, it can form a more uniform slit-shaped outflow, reducing the aerodynamic loss of 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 main flow 13 .

[0050] In one embodiment of the present invention, the equivalent diameter of the elliptical cylinder segment 4 ranges from 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 is greater than the equivalent diameter D of the elliptical cylinder section 4, and the minor axis b0 is greater than the equivalent diameter D of the elliptical cylinder section 4. <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 hole ranges from 30 to 150 degrees.

[0055] In one embodiment of the present invention, the ratio of the distance 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, 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] At the intersection point 01 of the film hole axis and the high-temperature mainstream 13, a first rectangle 5 is drawn on the outer wall. 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] Draw a second rectangle 6 using vertices A and B of the first rectangle 5 close to the downstream of the high-temperature mainstream. 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 the diagonal lines AC and BD of the pair of second rectangles 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 are drawn at the center point E of the long side of the first rectangle 5 downstream of the high-temperature main flow 13, each tangent to the pair of ellipses 7. The pair of tangent lines 8 are rounded with a radius of R1 to obtain a rounded arc 9. The tangent line 8 is tangent to the ellipse 7. Specifically, R1 is 7 mm.

[0062] Draw an arc 10 with a radius R2 using 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, an inverted arc 9 and an 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, and at the same time mixes with the high-temperature mainstream 13 and is finally dissipated.

[0066] Furthermore, if Figure 7 As shown, the spanwise film cooling efficiency distribution of the film holes in this embodiment and the crescent-shaped film holes shown in Chinese invention patent application publication 202210520834.X with the same area ratio at a distance 10D downstream of the film holes. The horizontal axis represents the distance in the spanwise direction, and the vertical axis represents the film cooling efficiency. It can be seen that 10D downstream of the film holes, the air film of the flat cat ear holes 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 near the center line to both sides. Therefore, the cooling effect near the center line is lower, and the spanwise coverage width of the air film is wider and more uniform.

[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 to the crescent-shaped air film holes.

[0068] Furthermore, if Figure 9 、 Figure 10 As shown, the directional vorticity contours and velocity vector diagrams of the film hole in this embodiment and the crescent-shaped film hole shown in Chinese Invention Patent Application Publication No. 202210520834.X with the same area ratio in the flow direction 5D downstream of the film hole are shown. It can be seen that the flat cat-ear film hole in this embodiment forms an anti-kidney vortex structure downstream that is beneficial for film cooling, promoting the lateral expansion of the cooling air and enhancing the film wall adhesion effect. In contrast, the directional vortex system formed by the crescent-shaped film hole is mainly composed of kidney-shaped vortices.

[0069] Furthermore, if Figure 10 、 Figure 11As shown in Figure 2, the cooling effect cloud diagram of the film hole in this embodiment and the crescent-shaped film hole shown in Chinese invention patent application publication 202210520834.X with the same area ratio within a flow range of 40D downstream of the film hole. It can be seen that although the film hole outlet width of this embodiment is slightly wider than that of the crescent-shaped film hole, due to the lateral expansion effect of the anti-kidney vortex, the film wake of the flat cat-ear film hole in this embodiment occupies the spanwise width of the film hole outlet, while the film wake of the crescent-shaped film hole shrinks at the outlet and is significantly smaller than the spanwise width of the film hole outlet.

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

[0071] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A flat cat-ear air film hole cooling structure for 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); An air film hole comprises an elliptical column section (4) provided on the solid wall (12) and an expansion section (2) connected to and coaxial with the elliptical column section (4), wherein the connection between the elliptical column section (4) and the expansion section (2) is an inlet profile (3), an end of the elliptical column section (4) away from the expansion section (2) forms a cold air inlet on the inner wall surface, and an 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 point of intersection 01 between the axis of the air film hole and the high-temperature mainstream (13), and 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). 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 (13). The short side of the second rectangle (6) is parallel to the flow direction of the high-temperature mainstream (13). The 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), 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); The inlet profile (3) is parallel to the flow direction of the high-temperature mainstream (13); The air film holes are arranged obliquely; 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.

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

3. The flat cat-ear air film hole cooling structure for a 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.

4. The flat cat-ear air film hole cooling structure for a 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.

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

6. The flat cat-ear air film hole cooling structure for a 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.

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