Dovetail-shaped film holes, turbine blades with dovetail-shaped film holes and manufacturing methods thereof

Abstract

The present invention relates to the technical field of turbine blades, and specifically to a dovetail-type air film hole, a turbine blade containing a dovetail-type air film hole, and a processing method thereof. The structure of the dovetail-type air film hole includes a dovetail-type cone and a cylinder, and the tail end of the dovetail-type cone includes a first dovetail curve and a second dovetail curve connected in sequence head to tail, and the present invention provides a method for drawing the dovetail-type air film hole; the turbine blade containing the dovetail-type air film hole is obtained by performing a difference set between the turbine blade and the dovetail-type air film hole, and is processed using methods such as laser deflection angle and wireframe model. The dovetail-type air film hole proposed in the present invention can effectively improve the thermal insulation effect, improve the cooling efficiency of the turbine blade, save cooling air consumption, and improve the efficiency and thrust-to-weight ratio of the engine.

Description

Technical Field

[0001] The invention relates to the technical field of turbine blades, in particular to a dovetail-shaped air film hole, a turbine blade containing the dovetail-shaped air film hole and a processing method thereof. Background Art

[0002] The turbine is the core component of a gas turbine engine, a power-generating device operating in a harsh environment characterized by high temperatures, high pressures, and complex loads. As performance requirements for engine thrust-to-weight ratios and thermal conversion rates increase, turbine inlet temperatures continue to rise, currently far exceeding the temperature limits of the materials used for these high-temperature components. Therefore, advanced and efficient cooling and protection methods, as well as thermal barrier coatings, are required for these high-temperature components to ensure reliable operation in high-temperature gases exceeding their melting points.

[0003] At present, the cooling technologies for high-temperature components of turbines include disturbance-enhanced convection cooling, impingement cooling, film cooling and divergent cooling, among which film hole cooling is the most important and effective cooling method. In addition to being affected by aerodynamic parameters (such as blowing ratio, density ratio, mainstream Reynolds number, mainstream turbulence, etc.), the film cooling effect also depends to a large extent on the hole shape of the film hole. The cooling characteristics of special-shaped holes are significantly improved compared to round holes, especially under large blowing ratios that are common in actual engine operating conditions. In addition, due to the complex configuration of special-shaped film holes, it is difficult to achieve qualified processing of them with existing processing technology, especially to achieve three-dimensional processing of complex structures on hard high-temperature alloys, which places high demands on processing technology. Summary of the Invention

[0004] In response to the problems raised in the background technology, the present invention proposes a dovetail-shaped air film hole, a turbine blade containing a dovetail-shaped air film hole, and a processing method thereof. The technical solution of the present invention is achieved as follows:

[0005] On the one hand, the present invention proposes a dovetail-type air film hole, the structure of which includes a dovetail-type cone and a cylinder; the length of the cylinder is L3; the cylinder is fixedly connected to the head end of the dovetail cone through one end thereof; the distance between the head end and the tail end of the dovetail cone is L1; the orthographic projection of the tail end of the dovetail cone includes a projection circle of the cylinder, and also includes a first dovetail curve and a second dovetail curve connected in sequence head to tail; the radius of the circumscribed circle of the first dovetail curve and the second dovetail curve is R1; the distance between the vertex of the projection circle and the vertex of the first dovetail curve is L2, and the distance between the vertex of the projection circle and the vertex of the second dovetail curve is L2; the diameter of the cylinder is Φ1; the opening angle of the dovetail cone is 2β, and the width angle of the bottom of the tail end of the dovetail cone is δ; and it satisfies:

[0006]

[0007]

[0008] Furthermore, the length of L3 is 8 to 12 mm; the length of L1 is 8 to 12 mm, the length of Φ1 is 0.2 to 0.6 mm, the angle of δ is 3 to 7°, and the angle of β is 15 to 25°.

[0009] The present invention also provides a method for drawing the above-mentioned dovetail-shaped air film hole, which specifically includes the following steps:

[0010] S1: Draw a circle with a diameter of Φ1 and a center of O, and project it along the axis to a projection plane at a distance of L1 to form a projection circle with a center of O1;

[0011] S2: Draw tangent segments of the projected circle with a length of L2 in the horizontal left and right directions through the highest point of the projected circle;

[0012] S3: Shift downward at the endpoints of the two tangents distance, get O2; then take O2 as the center of the circle, Draw a circle with radius;

[0013] S4: Draw line segments from the lowest point of circle O1 in the horizontal directions and in the left and right directions. The other ends of the line segments are connected to the ends of the two circles O2 closer to circle O1 through arcs.

[0014] S5: Erase the extra lines in circle O2 to obtain the orthographic projection of the tail end of the swallowtail cone;

[0015] S6: Draw two symmetrical line segments in the z direction from the left and right ends of the orthographic projection of the tail end of the swallowtail cone, where the z direction is perpendicular to the orthographic projection surface of the tail end of the swallowtail cone. Connect the other ends of the two line segments to the left and right ends of the circle O, respectively. Use the Art Surface command to stitch the connected curves into a swallowtail cone.

[0016] S7: Stretch the circle O by a length of L3 to obtain a cylinder;

[0017] S8: Combine the cylinder and the dovetail cone to obtain a dovetail air film hole structure.

[0018] On the other hand, the present invention proposes a turbine blade, comprising the above-mentioned dovetail-type air film hole, and also comprising a blade, the dovetail-type air film hole intersects the blade, the angle between the central axis of the dovetail-type air film hole and the surface of the blade is α, the thickness of the blade is H2, and the junction of the dovetail cone part and the inclined hole is at a distance H1 from the bottom of the blade.

[0019] Furthermore, the length of H1 is 0.5-1 mm; the length of H2 is 1-2 mm, and the angle α is 30-55°.

[0020] The present invention proposes the above-mentioned method for drawing turbine blades, comprising the following steps:

[0021] S1: The middle part of the dovetail-shaped air film hole is overlapped with the blade part, and the central axis of the dovetail-shaped air film hole is placed at an angle α to the blade;

[0022] S2: Using the blade and dovetail film hole core to find the difference, a turbine blade with dovetail film holes.

[0023] The present invention also provides a method for processing the turbine blade, comprising the following steps:

[0024] S1: By stretching the surface of the dovetail-shaped air film hole, the dovetail-shaped air film hole model is segmented to obtain the dovetail plane model and the dovetail tilt model, as well as their corresponding processing laser deflection angles;

[0025] S2: According to the processing laser deflection angle obtained in step S1, the dovetail plane model and the dovetail tilt model are sliced along the processing direction, and a two-dimensional wireframe model of the cross-section edge of each layer is obtained to obtain the dovetail plane wireframe and the dovetail tilt wireframe;

[0026] S3: Based on the two-dimensional wireframe model obtained in step S2, the blade is laser scanned based on the dovetail plane wireframe to obtain a hole in the shape of the dovetail plane model. Then, according to the processing laser deflection angle corresponding to the dovetail tilt model, the blade is offset by a corresponding angle. After positioning using six degrees of freedom, the blade is laser scanned based on the dovetail tilt wireframe to obtain a hole in the shape of a dovetail cone.

[0027] S4: According to the dovetail cone-shaped hole obtained in step S3, laser rotary cutting is performed at the center of the dovetail cone-shaped hole after six-degree-of-freedom positioning to machine an inclined hole with a diameter of Φ1, and finally a dovetail-shaped air film hole is obtained on the blade.

[0028] Furthermore, in step S1, the processing laser deflection angle is 0° for the dovetail plane model and 90°-α for the dovetail tilt model.

[0029] Furthermore, in step S1, the interlayer spacing of the layered slices is 0.05 mm.

[0030] The dovetail-shaped air film hole, the turbine blade containing the dovetail-shaped air film hole, and the processing method thereof proposed in the present invention have the following beneficial effects:

[0031] (1) The cooling characteristics of the dovetail film holes are significantly improved compared to round holes, especially under high blowing ratios commonly found in actual engine operating conditions;

[0032] (2) Parametric modeling is performed for the swallowtail-type air film hole. By changing the values of parameters such as R1, Φ1, α, β, and δ in the formula, the aperture, main inclination angle, opening angle, and width angle of the swallowtail-type air film hole model can be changed, thereby easily realizing the change of the shape of the air film hole model;

[0033] (3) The shading problem in the process of laser processing dovetail-shaped air film holes was solved by cutting the dovetail-shaped air film hole model and changing the processing laser deflection angle, thereby solving the processing difficulty of dovetail-shaped air film holes and realizing the processing of dovetail-shaped air film holes on turbine blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1-2 It is a sketch plan view of a dovetail-shaped air film hole provided in an embodiment of the present invention.

[0035] Figure 3 It is a three-dimensional sketch of a dovetail-shaped air film hole provided by an embodiment of the present invention.

[0036] Figure 4 It is a three-dimensional diagram of a dovetail-shaped air film hole core provided by an embodiment of the present invention.

[0037] Figure 5 This is a diagram illustrating the positional relationship between the dovetail-shaped air film hole core and the blades provided in an embodiment of the present invention.

[0038] Figure 6 This is a diagram of a blade with a dovetail-shaped air film hole provided by an embodiment of the present invention.

[0039] Figure 7 This is a model diagram of a dovetail-shaped air film hole provided by an embodiment of the present invention.

[0040] Figure 8 This is a segmentation diagram of a dovetail-shaped air film hole model provided by an embodiment of the present invention.

[0041] Figure 9 This is a layered slice diagram of the dovetail-shaped air film hole model provided by an embodiment of the present invention.

[0042] The main components in the figure are described as follows:

[0043] 101: Projected circle, 102: Tangent line of the swallowtail curve, 103: Circumcircle of the swallowtail curve, 104: Line segment, 105: First swallowtail curve, 106: Second swallowtail curve, 107: Intersection circle of the swallowtail cone and cylinder, 108: Connecting line, 109: Swallowtail cone, 110: Cylinder, 111: Swallowtail air film hole, 201: Central axis of the swallowtail air film hole, 202: Blade, 203: Swallowtail air film hole, 301: Swallowtail air film hole model, 302: Swallowtail air film hole surface, 303: Swallowtail plane model, 304: Swallowtail tilt model, 305: Swallowtail plane wireframe, 306: Swallowtail tilt wireframe. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all 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.

[0045] Example 1

[0046] This embodiment provides a dovetail-shaped air film hole and a drawing method thereof.

[0047] refer to Figure 4 , an embodiment of the present invention provides a dovetail-type air film hole, the structure of the dovetail-type air film hole includes a dovetail-type cone 109 and a cylinder 110; the length of the cylinder 110 is L3=10mm; the cylinder 110 is fixedly connected to the head end of the dovetail-type cone 109 through one end thereof; the distance between the head end and the tail end of the dovetail-type cone 109 is L1=10mm; the orthographic projection of the tail end of the dovetail-type cone 109 includes the projection circle 101 of the cylinder 110, and also includes a first dovetail curve connected in sequence from head to tail. 105 and a second swallowtail curve 106; the circumscribed circle radius of the first swallowtail curve 105 and the second swallowtail curve 106 is R1; the distance between the vertex of the projected circle 101 and the vertex of the first swallowtail curve 105 is L2, and the distance between the vertex of the projected circle 101 and the vertex of the second swallowtail curve 106 is L2; the diameter of the cylinder 110 is Φ1 = 0.4 mm; the opening angle of the swallowtail cone 109 is 2β, and the width angle of the bottom of the tail end of the swallowtail cone 109 is δ; and the following are satisfied:

[0048]

[0049] refer to Figure 1-Figure 4 The embodiment of the present invention provides a dovetail-shaped air film hole and a drawing method thereof, comprising the following steps:

[0050] S1: Draw a circle 107 with a diameter of Φ1 = 0.4 mm and a center of O, and project it along the axis to a projection plane at a distance of L1 to form a projection circle 101 with a center of O1;

[0051] S2: Draw tangent lines 102 of length L2 of the projected circle through the highest point of the projected circle 101 in the horizontal left and right directions respectively;

[0052] S3: Shift downward at the endpoints of the two tangent lines 102 distance, get O2; then take O2 as the center of the circle, Draw a circle with radius 103;

[0053] S4: Draw line segments from the lowest point of circle O1 in the horizontal directions and in the left and right directions. The other ends of the line segments are connected to the ends of the two circles O2 closer to circle O1 through arcs.

[0054] S5: Erase the extra lines in circle O2 to obtain the orthographic projection of the tail end of the swallowtail cone;

[0055] S6: Draw two symmetrical line segments along the z direction from the left and right ends of the orthographic projection of the tail end of the swallowtail cone 109, where the z direction is perpendicular to the orthographic projection surface of the tail end of the swallowtail cone. Connect the other ends of the two line segments to the left and right ends of the circle O, respectively. Use the Art Surface command to stitch the connected curves into the swallowtail cone 109.

[0056] S7: Stretch the circle O by a length of L3 to obtain a cylinder 110;

[0057] S8: Combine the cylinder 110 and the dovetail cone 109 to obtain a dovetail air film hole 111 structure.

[0058] Example 2

[0059] This embodiment proposes a turbine blade containing the dovetail-shaped air film holes described in the first embodiment, and a drawing method and a processing method thereof.

[0060] refer to Figure 5 、 Figure 6 The turbine blade provided by an embodiment of the present invention includes a blade 202 and a dovetail-shaped air film hole provided by the present invention. The angle between the central axis 201 of the dovetail-shaped air film hole and the surface of the blade 202 is 30°, the wall thickness of the blade 202 is H2=1.5mm, and the distance between the junction of the dovetail cone part and the inclined hole and the bottom of the blade is H1=0.75mm; the dovetail-shaped air film hole is subtracted from the blade 202 to obtain the dovetail-shaped air film hole 203 on the blade 202.

[0061] The method for drawing a turbine blade provided in this embodiment includes the following steps:

[0062] S1: Align the middle portion of the dovetail-shaped air film hole with the blade 202, and place the central axis 201 of the dovetail-shaped air film hole at an angle of 30° to the blade 202;

[0063] S2: Using the blade 202 and the dovetail film hole 111 core to calculate the difference set, the turbine blade 203 with the dovetail film hole 111 is obtained.

[0064] refer to Figure 7-Figure 9 The present invention can complete the processing of dovetail-shaped air film holes on turbine blades through the following steps:

[0065] S1: By stretching the dovetail-shaped air film hole surface 302, the dovetail-shaped air film hole model 301 is segmented to obtain a dovetail plane model 303 and a dovetail tilt model 304, and their corresponding processing laser deflection angles;

[0066] S2: Based on the processing laser deflection angle obtained in step S1, the dovetail plane model 303 and the dovetail tilt model 304 are sliced along the processing direction, and a two-dimensional wireframe model of the cross-section edge of each layer is obtained to obtain a dovetail plane wireframe 305 and a dovetail tilt wireframe 306;

[0067] S3: Based on the two-dimensional wireframe model obtained in step S2, the blade is laser scanned based on the dovetail plane wireframe 305 to obtain a hole in the shape of the dovetail plane model 303. Then, based on the processing laser deflection angle corresponding to the dovetail tilt model 304, the blade is offset by a corresponding angle. After positioning using six degrees of freedom, the blade is laser scanned based on the dovetail tilt wireframe 306 to obtain a hole in the shape of a dovetail cone.

[0068] S4: According to the dovetail cone-shaped hole obtained in step S3, laser rotary cutting is performed at the center of the dovetail cone-shaped hole after six-degree-of-freedom positioning to machine an inclined hole with a diameter of Φ1 = 0.4 mm, and finally a dovetail-shaped air film hole 203 is obtained on the blade 202.

[0069] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A dovetail-shaped air film hole, characterized in that: The structure of the dovetail-shaped air film hole includes a dovetail cone and a cylinder; the length of the cylinder is L3; the cylinder is fixedly connected to the head end of the dovetail cone through one end thereof; the distance between the head end and the tail end of the dovetail cone is L1; the orthographic projection of the tail end of the dovetail cone includes the projection circle of the cylinder, and also includes a first dovetail curve and a second dovetail curve connected in sequence end to end; the radius of the circumscribed circle of the first dovetail curve and the second dovetail curve is R1; the distance between the vertex of the projection circle and the vertex of the first dovetail curve is L2, and the distance between the vertex of the projection circle and the vertex of the second dovetail curve is L2; the diameter of the cylinder is Φ1; the opening angle of the dovetail cone is 2β, and the width angle of the bottom of the tail end of the dovetail cone is δ; and it satisfies: The method for drawing a dovetail-shaped air film hole comprises the following steps: S1: Draw a circle with a diameter of Φ1 and a center of O, and project it along the axis to a projection plane at a distance of L1 to form a projection circle with a center of O1; S2: Draw tangent segments of the projected circle with a length of L2 in the horizontal left and right directions through the highest point of the projected circle; S3: Shift downward at the endpoints of the two tangents distance, get O2; then take O2 as the center of the circle, Draw a circle for the radius; S4: Draw line segments from the lowest point of circle O1 in the horizontal directions and in the left and right directions. The other ends of the line segments are connected to the ends of the two circles O2 closer to circle O1 through arcs. S5: Erase the extra lines in circle O2 to obtain the orthographic projection of the tail end of the swallowtail cone; S6: Draw two symmetrical line segments in the z direction from the left and right ends of the orthographic projection of the tail end of the swallowtail cone. Connect the other ends of the two line segments to the left and right ends of the circle O, and stitch the connected curves into a swallowtail cone using the Art Surface command. S7: Stretch the circle O by a length of L3 to obtain a cylinder; S8: Combine the cylinder and the dovetail cone to obtain a dovetail air film hole structure.

2. The dovetail-shaped air film hole according to claim 1, characterized in that: The length of L3 is 8 to 12 mm; the length of L1 is 8 to 12 mm, the length of Φ1 is 0.2 to 0.6 mm, the angle of δ is 3 to 7°, and the angle of β is 15 to 25°.

3. A turbine blade, characterized in that: It includes a dovetail-shaped air film hole as described in claim 1, and also includes a blade, the dovetail-shaped air film hole intersects the blade, the angle between the central axis of the dovetail-shaped air film hole and the surface of the blade is α, the thickness of the blade is H2, and the junction of the dovetail cone part and the inclined hole is at a distance H1 from the bottom of the blade.

4. A turbine blade according to claim 3, characterized in that: The length of H1 is 0.5-1 mm; the length of H2 is 1-2 mm, and the angle α is 30-55°.

5. A method for drawing a turbine blade according to claim 3, characterized in that: The following steps are involved: S1: Align the middle part of the dovetail-shaped air film hole with the blade, and place the central axis of the dovetail-shaped air film hole at an angle α to the blade; S2: Use the blade and the dovetail film hole core to find the difference set and obtain the turbine blade with dovetail film holes.

6. A method for machining a turbine blade according to claim 3, characterized in that: The following steps are involved: S1: By stretching the surface of the dovetail-shaped air film hole, the dovetail-shaped air film hole model is segmented to obtain the dovetail plane model and the dovetail tilt model, as well as their corresponding processing laser deflection angles; S2: According to the processing laser deflection angle obtained in step S1, the dovetail plane model and the dovetail tilt model are sliced along the processing direction, and a two-dimensional wireframe model of the cross-section edge of each layer is obtained to obtain the dovetail plane wireframe and the dovetail tilt wireframe; S3: Based on the two-dimensional wireframe model obtained in step S2, the blade is laser scanned based on the dovetail plane wireframe to obtain a hole in the shape of the dovetail plane model. Then, according to the processing laser deflection angle corresponding to the dovetail tilt model, the blade is offset by a corresponding angle. After positioning using six degrees of freedom, the blade is laser scanned based on the dovetail tilt wireframe to obtain a hole in the shape of a dovetail cone. S4: According to the dovetail cone-shaped hole obtained in step S3, laser rotary cutting is performed at the center of the dovetail cone-shaped hole after six-degree-of-freedom positioning to machine an inclined hole with a diameter of Φ1, and finally a dovetail-shaped air film hole is obtained on the blade.

7. A method for processing a turbine blade according to claim 6, characterized in that: In step S1 , the processing laser deflection angle is 0° for the dovetail plane model and 90°-α for the dovetail tilt model.

8. The method for processing a turbine blade according to claim 6, characterized in that: In step S1, the inter-layer spacing of the layered slices is 0.05 mm.

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