Type B film cooling hole structure and construction method for gas turbines

Abstract

This invention relates to the field of hot-end cooling technology for gas turbines, and discloses a B-type film cooling hole structure and construction method for gas turbines. The structure includes a solid wall with an outer wall surface and an inner wall surface, the outer wall surface being used to contact the high-temperature mainstream. Film cooling holes are obliquely arranged on the solid wall, each comprising a coaxial and connected cylindrical section and an expansion section. A connection port is formed at the junction of the cylindrical and expansion sections, and the profile of the connection port is a circular inlet profile. The end of the cylindrical section away from the expansion section penetrates the inner wall surface to form a cold air inlet, and the end of the expansion section away from the cylindrical section penetrates the outer wall surface to form a cold air outlet, the profile of the cold air outlet being an outlet profile. This invention can form an ideal reverse kidney vortex structure, promoting the lateral expansion of cold air, increasing the transverse coverage area of ​​the film cooling system, improving the film cooling adhesion effect, and thus improving the film cooling efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas turbine hot end cooling, in particular to a B-type film cooling hole structure applied to a gas turbine and a construction method thereof. BACKGROUND

[0002] A gas turbine engine is a heat engine that extracts some of the heat energy of a fuel and converts it into useful work according to the principles of thermodynamic cycles, with the aid of an air compressor, a turbine, and a combustion chamber. Gas turbine engines are extremely robust and reliable and have gained popularity due to their high power-to-weight ratio, enhanced part life and reduced maintenance costs. The working environment of gas turbine engine is extremely severe, with high temperature, high pressure and high speed. Among them, the high temperature working environment is especially embodied in the turbine, one of the three core components. Experience shows that, under the premise of constant engine size, the turbine inlet temperature increases by 56K, the thrust of the gas turbine increases by 8-13%, and the cycle efficiency increases by 2-4%. The turbine inlet temperature of the current advanced aero-engine has exceeded 2000K, while the temperature resistance limit of the turbine blade material is far less than the turbine inlet temperature, so high-efficiency cooling technology must be used to ensure normal work.

[0003] As one of the most widely used high-efficiency cooling technologies, film cooling technology widely uses cylindrical holes in the early stage. With the in-depth research of domestic and foreign scholars, it is found that in the flow field structure formed by the cylindrical hole cooling gas jet, the counter-rotating kidney-shaped vortex has the highest strength relative to other vortex systems. The kidney vortex will suck the main flow under the cooling gas, strengthen the mixing and make the cooling gas lift off the wall, which is extremely unfavorable to the film cooling effect. Based on this, scholars design the outlet expansion type special-shaped hole represented by the dustpan hole, which increases the outlet area and width of the film cooling hole through the expansion in the flow direction or the span direction, thereby reducing the cooling gas jet momentum, increasing the span coverage width of the film, and reducing the induced lift by increasing the kidney vortex spacing to induce the formation of the counter-kidney vortex. However, the classical outlet expansion type special-shaped hole has obvious shortcomings in the flow field structure, and the kidney vortex pair still plays a leading role in the flow field, and cannot actively form the counter-kidney vortex structure which is beneficial to the film cooling. SUMMARY

[0004] The purpose of the present application is to provide a B-type film cooling hole structure applied to a gas turbine and a construction method thereof, which aims to solve or improve at least one of the above technical problems.

[0005] To achieve the above-mentioned purpose, the present application provides the following scheme: the present application provides a B-type film cooling hole structure applied to a gas turbine, comprising:

[0006] A solid wall has an outer wall surface and an inner wall surface, and the outer wall surface is used to contact a high-temperature main flow;

[0007] The gas film hole is obliquely arranged on the solid wall, and comprises a cylindrical segment and an expansion segment which are coaxial and connected, a connecting port is formed at the joint of the cylindrical segment and the expansion segment, the connecting port has a circular inlet profile, a cold gas inlet is formed at one end of the cylindrical segment away from the expansion segment and penetrating the inner wall surface, a cold gas outlet is formed at one end of the expansion segment away from the cylindrical segment and penetrating the outer wall surface, and the cold gas outlet has an outlet profile;

[0008] The outlet profile is obtained by drawing a rectangle on the outer wall surface, the short side of the rectangle is horizontal to the high-temperature main flow direction, the two long sides of the rectangle are perpendicular to the high-temperature main flow direction and are respectively a first side and a second side, first chamfers with a radius of R0 are symmetrically made at both ends of the first side along the short side of the rectangle, second chamfers with a radius of R1 are symmetrically made at both ends of the second side along the short side of the rectangle, and a third chamfer with a radius of R2 is made between the two second chamfers, with the center of the third chamfer being located outside the rectangle.

[0009] Optionally, the flow direction inclination angle α of the gas film hole ranges from 30 to 90 degrees.

[0010] Optionally, the spanwise inclination angle of the gas film hole ranges from 30 to 150 degrees.

[0011] Optionally, the diameter D of the cylindrical segment ranges from 0.4 mm to 1.0 mm.

[0012] Optionally, the ratio of the length Le of the expansion segment to the total length L of the cylindrical segment and the expansion segment ranges from 0 to 1.

[0013] Optionally, the ratio of the spacing P between the axes of two adjacent gas film holes to the diameter D of the cylindrical segment is not less than 3.

[0014] The application further provides a construction method of the B-type gas film cooling hole structure, comprising:

[0015] The rectangle is drawn on the outer wall surface, and the short side of the rectangle is horizontal to the high-temperature main flow direction.

[0016] The two long sides of the rectangle are perpendicular to the high-temperature main flow direction and are respectively a first side and a second side, first chamfers with a radius of R0 are symmetrically made at both ends of the first side along the short side of the rectangle, second chamfers with a radius of R1 are symmetrically made at both ends of the second side along the short side of the rectangle, and a third chamfer with a radius of R2 is made between the two second chamfers, with the center of the third chamfer being located outside the rectangle.

[0017] Optionally, the center point of the rectangle is O, the distance between the first side and the center point O is H0, and the distance between the second side and the center point O is H.

[0018] The flow direction angle of the gas film hole is α;

[0019] The diameter of the cylindrical section is D;

[0020] The H0=D / (2*sinα).

[0021] Optionally, the radius R0 of the first fillet is 0.4D-0.6D.

[0022] Optionally, the distance between the two short sides of the rectangle and the center point O is W / 2.

[0023] The following technical effects are disclosed in the present application: the outlet profile line of B-type structure is formed by setting the first fillet, the second fillet and the third fillet on the rectangle, and the straight surface is formed by extending the inlet profile line along the outlet profile line, when the cold gas enters the cold gas inlet of the cylindrical section and passes through the inside of the expansion section, the characteristics of the B-type expansion structure generated by the expansion section guide the cold gas, the branch structure is constructed to induce the formation of the counter kidney vortex, after the gas film hole, the cold gas is mixed with the high-temperature mainstream to form an ideal counter kidney vortex structure, the expansion of the cold gas in the transverse direction is promoted, the gas film spanwise coverage area is increased, the gas film wall attachment effect is improved, and the gas film cooling efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0024] The drawings constituting a part of the present application are used to provide a further understanding of the present application, the illustrative embodiments of the present application and the description thereof are used to explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0025] Figure 1 It is a schematic view of the present application;

[0026] Figure 2 It is a schematic view of the gas film hole in the present application;

[0027] Figure 3 It is a schematic view of the outlet profile line in the present application;

[0028] Figure 4 It is a tangent view of the gas film hole in the present application;

[0029] Figure 5 It is a top view of the gas film hole in the present application;

[0030] Figure 6 It is an axial view of the gas film hole in the present application;

[0031] Figure 7 It is a comparison curve of the spanwise average gas film cooling efficiency of the B-type hole formed by the gas film hole and the classical dustpan hole with the same outlet width in the range of 40D downstream of the gas film hole in the present application;

[0032] Figure 8 The streamwise vorticity cloud and velocity vector diagram of the gas film hole in the present application at the cross section 15D downstream of the gas film hole;

[0033] Figure 9 The streamwise vorticity cloud and velocity vector diagram of the classical dustpan hole with the same outlet width as the gas film hole in the present application at the cross section 15D downstream of the gas film hole;

[0034] Figure 10 The cold effect cloud of the gas film hole in the present application within the range of 40D downstream of the gas film hole;

[0035] Figure 11 The cold effect cloud of the classical dustpan hole with the same outlet width as the gas film hole in the present application within the range of 40D downstream of the gas film hole;

[0036] Figure 12 The three-dimensional structure diagram of the topologically similar structural change of the gas film hole in the present application.

[0037] In the figure: 1, solid wall; 1.1, outer wall surface; 1.2, inner wall surface; 2, gas film hole; 2.1, cylindrical section; 2.2, expansion section; 2.3, inlet profile; 2.4, outlet profile; 3, rectangle; 3.1, first side; 3.2, second side; 4, first fillet; 5, second fillet; 6, third fillet. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0039] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0040] Reference Figures 1-12 The present application provides a B-type gas film cooling hole structure applied to a gas turbine, comprising:

[0041] The solid wall 1 has an outer wall surface 1.1 and an inner wall surface 1.2, and the outer wall surface 1.1 is used to contact the high-temperature main flow;

[0042] The gas film hole 2 is obliquely arranged on the solid wall 1, and the gas film hole 2 comprises a cylindrical segment 2.1 and an expansion segment 2.2 which are coaxial and connected, and a connecting port is formed at the connection of the cylindrical segment 2.1 and the expansion segment 2.2, the connecting port has a circular inlet profile 2.3, the cylindrical segment 2.1 penetrates the inner wall surface 1.2 to form a cold gas inlet at the end away from the expansion segment 2.2, and the expansion segment 2.2 penetrates the outer wall surface 1.1 to form a cold gas outlet at the end away from the cylindrical segment 2.1, and the cold gas outlet has an outlet profile 2.4;

[0043] The outlet profile 2.4 is a rectangle 3 drawn on the outer wall surface 1.1, the short side of the rectangle 3 is horizontal to the flow direction of the high-temperature main flow, the two long sides of the rectangle 3 are perpendicular to the flow direction of the high-temperature main flow and are respectively a first side 3.1 and a second side 3.2, first fillets 4 with a radius of R0 are symmetrically formed at the two ends of the first side 3.1 along the short side of the rectangle 3, second fillets 5 with a radius of R1 are symmetrically formed at the two ends of the second side 3.2 along the short side of the rectangle 3, and a third fillet 6 with a radius of R2 is formed between the two second fillets 5, and the center of the third fillet 6 is located outside the rectangle.

[0044] The outlet profile 2.4 with the B-type structure is formed by arranging the first fillets 4, the second fillets 5 and the third fillet 6 on the rectangle 3, and the expansion segment 2.2 is formed into a straight surface by extending the inlet profile 2.3 along the outlet profile 2.4, when the cold gas enters from the cold gas inlet of the cylindrical segment 2.1 and passes through the expansion segment 2.2, the B-type expansion structure generated by the expansion segment 2.2 guides the cold gas, constructs a branch structure to induce the formation of the counter kidney vortex, and after flowing out of the gas film hole 2, the cold gas is mixed with the high-temperature main flow to form an ideal counter kidney vortex structure, promotes the expansion of the cold gas in the transverse direction, increases the spanwise coverage area of the gas film, improves the gas film wall attachment effect, and thus improves the gas film cooling efficiency.

[0045] In a further optimization scheme, the flow direction inclination angle α of the gas film hole 2 is in a range of 30-90 degrees.

[0046] In a further optimization scheme, the flow direction inclination angle of the gas film hole 2 is in a range of 30-150 degrees.

[0047] In a further optimization scheme, the diameter D of the cylindrical segment 2.1 is in a range of 0.4mm-1.0mm.

[0048] In a further optimization scheme, the ratio of the length Le of the expansion segment 2.2 to the total length L of the cylindrical segment 2.1 and the expansion segment 2.2 is in a range of 0<Le / L≤1.

[0049] In a further optimization scheme, the ratio of the spacing P between the axes of two adjacent gas film holes 2 to the diameter D of the cylindrical segment 2.1 is not less than 3.

[0050] A construction method of a B-type gas film cooling hole structure, comprising:

[0051] A rectangle 3 is drawn on the outer wall surface 1.1, and the short sides of the rectangle 3 are horizontal to the flow direction of the high-temperature main stream;

[0052] The two long sides of the rectangle 3 are perpendicular to the flow direction of the high-temperature main stream, and are respectively a first side 3.1 and a second side 3.2. First fillets 4 with a radius of R0 are symmetrically drawn on both ends of the first side 3.1 along the short sides of the rectangle 3. Second fillets 5 with a radius of R1 are symmetrically drawn on both ends of the second side 3.2 along the short sides of the rectangle 3. Third fillets 6 with a radius of R2 are drawn between the two second fillets 5, and the center of the third fillets 6 is located outside the rectangle 3. The center point of the rectangle 3 is O, the distance between the first side 3.1 and the center point O is H0, the distance between the second side 3.2 and the center point O is H, the flow direction inclination angle of the film hole 2 is α, the diameter of the cylindrical section 2.1 is D, and H0=D / (2*sinα). The radius R0 of the first fillets 4 is 0.4D-0.6D. The distance between the two short sides of the rectangle 3 and the center point O is W / 2.

[0053] For example, a rectangle 3 with a length W of 23.4 mm and a width of 14.14 mm is drawn, H0 is 7.07 mm, H is 7.07 mm, and the distance between the two short sides of the rectangle 3 and the center point O is 11.7 mm.

[0054] The radius R0 of the first fillets 4 is 4 mm, the radius R1 of the second fillets 5 is 10 mm, and the radius R2 of the third fillets 6 is 12 mm.

[0055] The first fillets 4, the second fillets 5, and the third fillets 6 are connected to form an outlet profile 2.4.

[0056] The film hole 2 is arranged on the solid wall 1, the diameter D of the cylindrical section 2.1 is 10 mm, the axis length L of the film hole 2 is 3D, the length of the expansion section 2.2 accounts for 3 / 5 of the total length of the film hole 2, the transverse spacing P between the axes of adjacent film holes 2 is 5D, the flow direction inclination angle α of the film hole 2 is 45 degrees, no spanwise inclination angle is set, the cooling gas flows through the film hole 2 and is sprayed out, forms a gas film covering on the surface of the outer wall surface 1.1 of the solid wall 1, and is mixed with the high-temperature main stream to be finally dissipated.

[0057] The present application can directly control the flow direction width of the cold gas outlet of the film hole 2 by adjusting the width of the rectangle 3 of the outlet profile 2.4, directly control the spanwise width of the cold gas outlet of the film hole 2 by adjusting the length of the rectangle 3 of the outlet profile 2.4, and directly control the bending degree of the expansion section 2.2 by adjusting the radius R1 of the second fillets 5 and the radius R2 of the third fillets 6 of the outlet profile 2.4, so that the shape of the film hole can be more conveniently adjusted. At the same time, the method of adjusting the outlet profile 2.4 to change the expansion section 2.2 can make the structure of the special-shaped hole more abundant, and has a larger structure optimization sample space.

[0058] For example, a rectangle 3 with a length W of 23.4 mm and a width of 14.14 mm is drawn, H0 is 7.07 mm, H is 7.07 mm, and the distance between the two short sides of the rectangle 3 and the center point O is 11.7 mm. Figures 7-9The numerical simulation of the wall surface cooling efficiency in the downstream 40D range under the application of the gas film hole 2 and the classical dustpan hole to the two solid walls 1 respectively under the same outlet width is shown. The working condition used in the numerical simulation is: the main flow hole diameter Reynolds number ReD=10000, the main flow turbulence Tu=1%, the cold gas and the main flow density ratio DR=1.5, and the blowing ratio M=1.0. The calculation process uses UG modeling, FluentMeshing to generate unstructured grid, and uses CFX solver to solve.

[0059] Figure 7 The spanwise average gas film cooling efficiency distribution of the gas film hole 2 in the embodiment and the classical dustpan hole with the same outlet width in the downstream flow distance 40D range of the gas film hole is compared. The abscissa represents the distance in the flow direction, and the ordinate represents the spanwise average gas film cooling efficiency. It can be seen that the gas film hole 2 in the embodiment has higher spanwise average gas film cooling efficiency in the downstream area of x / D>3, and the gas film cooling efficiency is increased by about 10% compared with the classical dustpan hole.

[0060] Figure 8 And Figure 9 The streamwise vorticity cloud diagram and the velocity vector diagram of the gas film hole 2 in the embodiment and the classical dustpan hole with the same outlet width in the downstream flow distance 15D plane of the gas film hole are shown respectively. It can be seen that the gas film hole 2 in the embodiment forms a counter-kidney vortex structure which is beneficial to gas film cooling in the downstream, the counter-kidney vortex is relatively stronger than the kidney vortex, promotes the lateral expansion of the cold gas, and improves the gas film wall attachment effect, while the classical dustpan hole is still dominated by the kidney vortex.

[0061] Figure 10 And Figure 11 The cold efficiency cloud diagram of the gas film hole 2 in the embodiment and the classical dustpan hole with the same outlet width in the downstream flow distance 40D range of the gas film hole is shown respectively. It can be seen that the gas film wake of the gas film hole 2 in the embodiment forms two high cold efficiency areas extending in the flow direction under the action of the counter-kidney vortex, so that the gas film spanwise coverage range is wider and the gas film cooling effect is better.

[0062] Figure 12 The three-dimensional structure diagram of the topologically similar structure change of the gas film hole 2 of the application is shown. The topologically similar structure replaces the rectangle 3 of the outlet profile 2.4 with the outlet profile of the classical dustpan hole, and connects the dustpan hole outlet profile and the second rounding 5 and the third rounding 6 to obtain the outlet profile 2.4 of the topologically similar structure. The topologically similar structure can also form a counter-kidney vortex structure which is beneficial to gas film cooling, thereby improving the gas film cooling efficiency.

[0063] In the description of the present application, it needs to be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0064] The above-described embodiments are only to describe the preferred modes of the present application, and not to limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A B-type film cooling hole structure applied to a gas turbine, characterized by, Comprising: a solid wall (1) having an outer wall surface (1.1) for contacting a high-temperature main flow and an inner wall surface (1.2); a gas film hole (2) obliquely arranged on the solid wall (1), the gas film hole (2) comprising a coaxial and connected cylinder segment (2.1) and an expansion segment (2.2), a connecting port being formed at the connection of the cylinder segment (2.1) and the expansion segment (2.2), the connecting port having a circular inlet profile (2.3), an end of the cylinder segment (2.1) away from the expansion segment (2.2) penetrating the inner wall surface (1.2) to form a cold gas inlet, an end of the expansion segment (2.2) away from the cylinder segment (2.1) penetrating the outer wall surface (1.1) to form a cold gas outlet, the cold gas outlet having an outlet profile (2.4); the outlet profile (2.4) is a rectangle (3) drawn on the outer wall surface (1.1), the short side of the rectangle (3) being horizontal to the flow direction of the high-temperature main flow, the two long sides of the rectangle (3) being perpendicular to the flow direction of the high-temperature main flow and being respectively a first side (3.1) and a second side (3.2), a first fillet (4) with a radius of R0 being symmetrically made at both ends of the first side (3.1) along the short side of the rectangle (3), a second fillet (5) with a radius of R1 being symmetrically made at both ends of the second side (3.2) along the short side of the rectangle (3), a third fillet (6) with a radius of R2 being made between the two second fillets (5) with the center being located outside the rectangle (3); the diameter D of the cylinder segment (2.1) ranges from 0.4mm to 1.0mm; the radius R0 of the first fillet (4) ranges from 0.4D to 0.6D; the proportional relationship R1:R2:W between the radius R1 of the second fillet (5), the radius R2 of the third fillet (6) and the width W of the rectangle (3) is 1.00:1.20:2.

34.

2. The B-type film cooling hole structure for use in a gas turbine according to claim 1, characterized by: the flow direction inclination angle α of the gas film hole (2) ranges from 30 degrees to 90 degrees.

3. The B-type film cooling hole configuration for use in a gas turbine according to claim 1, characterized by: the spanwise inclination angle of the gas film hole (2) ranges from 30 degrees to 150 degrees.

4. The B-type film cooling hole configuration for use in a gas turbine according to claim 1, characterized by: the ratio of the length Le of the expansion segment (2.2) to the total length L of the cylinder segment (2.1) and the expansion segment (2.2) ranges from 0 to 1.

5. The B-type film cooling hole configuration for use in a gas turbine according to claim 1, characterized by: the ratio of the spacing P between the axes of two adjacent gas film holes (2) to the diameter D of the cylinder segment (2.1) is not less than 3.

6. A method of constructing a B- type film cooling hole configuration for constructing the exit profile in the B- type film cooling hole configuration for a gas turbine as claimed in claim 1, characterized in that, Comprising: drawing the rectangle (3) on the outer wall surface (1.1), the short side of the rectangle (3) being horizontal to the flow direction of the high-temperature main flow; The two long sides of the rectangle (3) are perpendicular to the high-temperature main flow direction, and are respectively a first side (3.1) and a second side (3.2). A first rounded corner (4) with a radius of R0 is symmetrically formed along the short side of the rectangle (3) at both ends of the first side (3.1). A second rounded corner (5) with a radius of R1 is symmetrically formed along the short side of the rectangle (3) at both ends of the second side (3.2). A third rounded corner (6) with a radius of R2 is formed between the two second rounded corners (5), and the center of the third rounded corner (6) is located outside the rectangle (3).

7. The method for constructing a B-type gas film cooling hole structure according to claim 6, characterized in that: The center point of the rectangle (3) is O, the distance between the first side (3.1) and the center point O is H0, and the distance between the second side (3.2) and the center point O is H; The flow direction inclination angle of the gas film hole (2) is α; The diameter of the cylindrical section (2.1) is D; The H0=D / (2*sinα).

8. The method of constructing a B-type gas film cooling hole structure according to claim 6, wherein: The radius R0 of the first rounded corner (4) is 0.4D-0.6D.

9. The method of constructing a B-type gas film cooling hole structure according to claim 7, wherein: The distance between the two short sides of the rectangle (3) and the center point O is W / 2.

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