Aero-engine turbine bucket structure with self-pressing effect

Abstract

The application discloses a turbine baffle structure with self-pressing effect for an aero-engine, which comprises a spline structure of a baffle bottom, a mounting edge, an arm section, a ring groove boss, an inclined tooth and a claw section. The baffle is fixed on a turbine disc through the spline structure and the mounting edge, and the baffle has a leftward tilting deformation under centrifugal and temperature load through the configuration design of the arm section, the inclined tooth and the claw section, so that the sealing end face of the baffle is always pressed against a high-pressure turbine blade disc, axial movement of the high-pressure turbine blade and leakage of cooling air are avoided, and the high-pressure turbine blade has stable axial positioning and high cooling efficiency. The turbine baffle structure has the self-pressing effect under the working load of the engine, and is especially suitable for the high-pressure turbine structure of an advanced high-load aero-engine.

Description

TECHNICAL FIELD

[0001] The present application relates to a turbine baffle structure with self-pressing effect for aero-engine, which is suitable for high-pressure turbine structure of advanced high-load aero-engine and belongs to the field of aero-engine structure design. BACKGROUND

[0002] The turbine part in the aero-engine is in a working environment of high temperature, high pressure and high rotating speed. The physical properties of the material at high temperature are significantly reduced, and it is difficult to ensure that the structure has sufficient strength in a harsh load environment. Therefore, a cooling air flow path is designed to cool the turbine blade and disc structure. The turbine baffle plays two important roles: one is to limit the turbine blade axially, and the other is to seal the cooling air flow path at the turbine blade to prevent the cooling air from leaking from the gap between the turbine blade and the baffle, thereby affecting the cooling efficiency of the turbine blade.

[0003] With the continuous breakthroughs in aero-engine technology, the pressure ratio of the compressor, the temperature before the turbine and the rotating speed of the rotor are continuously improved, and the load environment of the turbine is increasingly harsh. Taking the current advanced high-bypass-ratio turbofan engine as an example, the maximum working speed of the high-pressure turbine baffle is as high as 19000 rpm, and the average temperature of the baffle after cooling is still above 900K. The pressure difference between the left and right sides of the baffle is in the order of 1-2 MPa. The baffle is a thin-walled hollow ring with a diameter of about 500 mm and a thickness usually below 10 mm, and the stiffness in all directions is low. Under the action of a large load, the baffle is prone to deformation. If the claw segment of the baffle tilts to the right relative to the installation edge, a gap is formed between the sealing end face of the baffle and the turbine blade, which causes the loss of the axial limiting function and the cooling flow sealing function of the baffle, thereby affecting the reliability of the engine.

[0004] The existing turbine baffle design is still based on the concept of strength design, mainly through strength checking methods to make the baffle meet the fatigue, creep and other strength design requirements, while ignoring the control of the deformation of the baffle. This type of turbine baffle structure is mainly suitable for engines with small working load, such as three generations and lower generations of aero-engines. In the fourth generation engine and advanced high-bypass-ratio turbofan engine, the more severe load environment makes the deformation of the baffle more serious. The traditional turbine baffle structure designed according to the strength requirements cannot meet the functional requirements, and the turbine baffle is prone to deformation, which leads to functional loss and further causes engine reliability failure. To solve this problem, the present application proposes a turbine baffle structure with self-pressing effect, which can control the deformation of the baffle by using the working load. SUMMARY

[0005] In order to solve the above technical problems, the present application provides a turbine baffle structure of an aero-engine with self-pressing effect, which aims to generate leftward tilting deformation under centrifugal and temperature load by the configuration design of the baffle, and offset the rightward tilting deformation of the baffle under pressure difference load by the leftward tilting deformation, so as to ensure that the baffle always presses the turbine disc structure, and realize the stable axial positioning of the turbine blade and the sealing of the cooling air flow path.

[0006] In order to achieve the above-mentioned purposes, the technical scheme adopted by the present application is:

[0007] The turbine baffle structure of the aero-engine with self-pressing effect comprises a spline structure, a mounting edge, an arm segment, a ring groove boss, an inclined tooth and a claw segment; the spline structure is located at the bottom of the baffle structure, and the mounting edge is arranged above the spline structure; the arm segment is arranged above the mounting edge; the ring groove boss is arranged at the left side of the upper part of the arm segment; the inclined tooth is arranged at the right side of the upper part of the arm segment; and the claw segment is arranged at the uppermost part of the baffle structure and connected with the ring groove boss; the arm segment is thick at the lower part and thin at the upper part, and the thickness of the arm segment is the largest at the connection between the arm segment and the mounting edge; the left and right edges of the arm segment are small in the inclination angle with the vertical direction, so as to prevent the rightward tilting deformation of the arm segment under the centrifugal and temperature load; the inclined tooth is arranged at the right side of the middle part of the baffle structure; under the high-speed rotation of the rotor, the centrifugal load generated by the inclined tooth increases the radial tensile stress and tensile deformation of the right side of the arm segment, so that the radial tensile deformation of the right side of the arm segment is greater than that of the left side, and the arm segment generates leftward tilting deformation, which is beneficial to the pressing of the baffle to the turbine disc and the generation of the self-pressing effect; the claw segment is composed of an upper cylindrical shell and a lower conical shell; the conical shell is thin at the lower part and thick at the upper part, and the thickness of the lower side of the conical shell is low at the connection with the ring groove boss, so that the conical shell is easy to generate leftward tilting deformation under the centrifugal load and press the turbine disc; the cylindrical shell is thin at the left side and thick at the right side, and the left end of the cylindrical shell is designed with a pressing end surface of the baffle claw segment which is in contact with the turbine disc, so that the claw segment generates leftward tilting deformation under the centrifugal and temperature load, and the self-pressing effect of the baffle structure is enhanced.

[0008] Further, the spline structure is distributed in the circumferential direction of the rotating shaft and matched with the key groove on the turbine disc, so as to prevent the circumferential movement of the baffle structure relative to the turbine disc during the operation of the engine.

[0009] Further, the number of the spline structure is 4 or an integer multiple of 4.

[0010] Further, the mounting edge is in the shape of Γ and comprises a left end surface of the baffle mounting edge and a right end surface of the baffle mounting edge for the axial positioning of the baffle, and a cylindrical surface of the baffle mounting edge for the radial centering, which are respectively in contact with the corresponding interfaces on the turbine disc to realize the positioning and centering of the baffle structure.

[0011] Further, the ring groove boss is arranged in the middle of the baffle structure, and a ring groove is arranged in the middle, and a sealing metal wire ring is arranged in the ring groove, which is beneficial to sealing the turbine blade cooling gas and reducing the vibration of the baffle structure.

[0012] Further, the thickness of the arm segment is in the range of 2-5 mm. The arm segment should be as vertical as possible, and the inclination angle of the left and right edges of the arm segment relative to the vertical direction should be less than 10°, so as to avoid the right tilting deformation of the arm segment under the action of centrifugal force and temperature load.

[0013] Further, the sealing metal wire ring has a diameter of about 1 mm, which is used for improving the sealing efficiency of the cooling gas flow and providing frictional damping.

[0014] Further, the thickness of the connection between the lower side of the conical shell and the ring groove boss is in the range of 1-2 mm, the thickness of the upper side of the conical shell is larger, and the thickness is in the range of 3-4 mm, and the included angle between the generatrix of the conical shell and the horizontal line is preferably designed in the range of 50-65°. The thickness of the left end of the cylindrical shell is in the range of 1-2 mm, and the thickness of the right side is in the range of 3-4 mm. The left end of the cylindrical shell is designed with a pressing end face of the baffle claw segment in contact with the turbine disc.

[0015] The present application has the following beneficial effects:

[0016] (1) The present application can make the baffle produce left tilting deformation under the action of centrifugal force and temperature load by controlling the configuration of the baffle arm segment, the inclined tooth and the claw segment, and the left tilting deformation is used to offset the right tilting deformation generated under the pressure difference, so as to ensure that the pressing end face of the baffle always presses the turbine disc, and has a self-pressing effect.

[0017] (2) The baffle structure of the present application has the characteristics of self-pressing by deformation, so that the cylindrical surface and the end face can adopt a smaller interference amount during assembly, which is beneficial to reducing the assembly difficulty and reducing the assembly stress.

[0018] (3) The baffle structure of the present application is simple and easy to manufacture, and different sizes and configurations of turbine discs can be assembled by adjusting the size of the baffle and the shape of the mounting edge, so that the applicability is strong. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a structural schematic view of an aero-engine turbine baffle structure with a self-pressing effect of the present application;

[0020] Figure 2 is a sectional view of an aero-engine turbine baffle structure with a self-pressing effect of the present application;

[0021] Figure 3 is a deformation schematic view of the baffle under the action of centrifugal force and temperature load;

[0022] Figure 4is the cooperation schematic diagram of the baffle and the turbine disc structure of the present application;

[0023] Figure 5 is the application example diagram of the baffle in the double-stage high-pressure turbine assembly of the present application;

[0024] Figure 6 is the application example diagram of the baffle in the single-stage high-pressure turbine assembly of the present application.

[0025] In the figure: A-turbine baffle, B-turbine disc, B1-first-stage turbine disc in the double-stage high-pressure turbine assembly, B2-second-stage turbine disc in the double-stage high-pressure turbine assembly, B3-turbine disc in the single-stage high-pressure turbine assembly, C-sealing wire ring, D-interstage sealing disc in the double-stage high-pressure turbine assembly, E-pressing large nut in the double-stage high-pressure turbine assembly, F-clip;

[0026] 1-spline structure, 2-mounting edge, 3-arm section, 4-ring groove boss, 5-bevel gear, 6-claw section, 7-keyway, 8-hanging hook structure;

[0027] a1-left side end face of the baffle mounting edge, a2-right side end face of the baffle mounting edge, b-cylinder surface of the baffle mounting edge, c-pressing end face of the baffle claw section. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings. Figures 1-6 The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings.

[0029] As shown in Figure 1 , Figure 2 , the embodiments of the present application relate to an aero-engine turbine baffle structure with self-pressing effect. The baffle is from bottom to top respectively a spline structure 1, a mounting edge 2, an arm section 3, a ring groove boss 4, a bevel gear 5, and a baffle claw section 6. The working principle is that, through the configuration design of the arm section 3, the bevel gear 5 and the claw section 6, the baffle produces a left tilting deformation as shown in Figure 3 under the conditions of the mounting edge 2 fixation, centrifugal load and temperature load, and the deformation is used to offset the right tilting deformation of the baffle under the action of the pressure difference load, so that the pressing end face c of the baffle claw section is always pressed against the turbine disc, and the self-pressing effect is realized.

[0030] As shown in Figure 4As shown, the spline structure 1 is located at the bottom of the baffle, which cooperates with the designed keyway 7 on the turbine disc B, and the purpose is to prevent the relative circumferential movement of the turbine baffle A relative to the turbine disc B during engine operation. The thickness and width of the spline structure 1 need to be determined by strength checking. In order to avoid the mass asymmetry of the baffle, the number of spline structures 1 on the turbine baffle A should be 4 or an integer multiple of 4 as much as possible, and the keyway 7 should be the same as the number of spline structures 1. It should be noted that the spline structure 1 is not a necessary structure of the baffle of the present application. Only when the engine needs to experience multiple rapid operating condition changes during service, due to the large angular acceleration of the baffle during rapid operating condition changes, the friction force between the baffle and the turbine disc is not enough to keep the baffle and the turbine disc circumferentially stationary, and the spline structure 1 needs to be designed.

[0031] As shown in Figure 2 The installation edge 2 is in the shape of "Γ", and a cylindrical surface b for radial centering of the baffle installation edge is machined thereon, which cooperates with the corresponding position cylindrical surface on the turbine disc B to realize the radial centering of the baffle. The left side end surface a1 and the right side end surface a2 of the baffle installation edge are machined below the installation edge 2 for axial positioning of the baffle, the left side end surface a1 cooperates with the corresponding position end surface on the turbine disc B to limit the axial displacement of the turbine baffle A to the left, and the right side end surface a2 cooperates with the component or fastener located on the right side of the turbine baffle A to limit the displacement of the baffle to the right. It should be noted that the shape of the installation edge 2 of the present application can be appropriately adjusted according to the specific application of the turbine configuration, and the design purpose is to ensure that the baffle can be reliably installed and fixed on the turbine disc.

[0032] The arm segment 3 has the feature of "thick at the bottom and thin at the top", the overall thickness is in the range of 2-5mm, and the maximum thickness is at the connection between the arm segment 3 and the installation edge 2, which is to improve the angular stiffness of the connection to prevent the baffle from producing angular deformation at the connection under the action of differential pressure load, causing the baffle to produce a large rightward tilting deformation. The arm segment 3 should be as vertical as possible, and the inclination angle of the left and right edges relative to the vertical line should be less than 10°, and the purpose of this configuration is to make the arm segment 3 produce vertical upward tensile deformation under the action of centrifugal and temperature load, avoiding its rightward tilting deformation.

[0033] The ring groove boss 4 is located in the middle of the turbine baffle A, above the arm segment 3, and a ring groove is opened in the middle of the ring groove boss 4, and a sealing metal wire ring C is placed in the ring groove. The diameter of the sealing metal wire ring C is about 1mm, and the depth of the ring groove is slightly larger than the sealing metal wire ring C, which can be 1.5-2mm. Designing the ring groove boss 4 and placing the sealing metal wire ring C has two advantages, on the one hand, the sealing metal wire ring C can enhance the sealing effect of the baffle cooling airflow; on the other hand, during engine operation, the sealing metal wire ring C and the ring groove boss have relative movement, which can produce friction damping to dissipate the vibration energy of the baffle, and play a certain damping role.

[0034] The oblique tooth 5 is located above the arm segment 3, right side of the ring groove boss 4, which is an oblique tooth structure extending to the right and up. The purpose of designing the oblique tooth is to use the centrifugal load generated by its rotation to stretch the right side of the arm segment 3, so that the stretch deformation of the right side of the arm segment 3 is greater than that of the left side, thereby making the arm segment 3 produce a left tilt deformation, providing a self-pressing effect.

[0035] The claw segment 6 is located above the ring groove boss 4, which is composed of an upper cylindrical shell and a lower conical shell. The conical shell has the feature of "thinner at the bottom and thicker at the top". The lower side has a smaller thickness, ranging from 1 to 2 mm, and the upper side has a larger thickness, ranging from 3 to 4 mm. The angle between the conical shell generatrix and the horizontal line is recommended to be designed within the range of 50 to 65 degrees. The cylindrical shell has the feature of "thinner on the left and thicker on the right". The left end has a thickness ranging from 1 to 2 mm, and the right side has a thickness ranging from 3 to 4 mm. The left side of the cylindrical shell is designed with a blocking end face c of the baffle claw segment that contacts the turbine blade structure. This configuration of the claw segment can produce a left tilt deformation under centrifugal and temperature load, so that the blocking end face c of the baffle claw segment presses the turbine blade, enhancing the self-pressing effect of the baffle.

[0036] Figure 5 An example of the application of the baffle in a two-stage high-pressure turbine assembly is provided. During assembly, the turbine baffle A is cooled by liquid nitrogen, and then a tool is used to press the mounting edge 2 of the turbine baffle A into the corresponding mounting position on the first-stage turbine disc B1 in the two-stage high-pressure turbine assembly, and the left end face a1 of the baffle mounting edge of the mounting edge 2 is kept in close contact with the end face of the corresponding position on the turbine disc. After the room temperature is restored, the tool is removed, and then the inter-stage sealing disc D in the subsequent two-stage high-pressure turbine assembly, the second-stage turbine disc B2 in the two-stage high-pressure turbine assembly, and the pressing large nut E in the two-stage high-pressure turbine assembly are installed and tightened, keeping the entire two-stage high-pressure turbine assembly axially pressed.

[0037] Figure 6 An example of the application of the baffle in a single-stage high-pressure turbine assembly is provided. To achieve the assembly of the baffle, a hook structure 8 is designed on the turbine disc B3 in the single-stage high-pressure turbine assembly. During assembly, the turbine baffle A is cooled by liquid nitrogen, and then a tool is used to press the mounting edge 2 of the turbine baffle A into the corresponding mounting position on the turbine disc B3 in the single-stage high-pressure turbine assembly. After the turbine baffle A is restored to room temperature, the retaining ring F is pressed in, with the left side of the retaining ring F in contact with the right end face a2 of the baffle mounting edge of the turbine baffle A, and the right side of the retaining ring F in contact with the hook structure 8, achieving the installation and fixation of the turbine baffle A.

[0038] The above described embodiments are only to illustrate the preferred modes of the present application, and are not intended to limit the scope of the present application. Any modification, variation, modification, and replacement of the technical solutions of the present application made by those skilled in the art without departing from the design spirit of the present application shall fall within the protection scope determined by the claims of the present application.

Claims

1. A turbine baffle structure for an aero-engine with a self-clamping effect, characterized in that: The structure includes a spline structure (1), a mounting edge (2), an arm section (3), an annular groove boss (4), a helical tooth (5), and a claw section (6). The spline structure (1) is located at the bottom of the baffle structure, with the mounting edge (2) of the baffle above it. Above the mounting edge (2) is the arm section (3). The annular groove boss (4) is located on the left side above the arm section (3), and the helical tooth (5) is located on the right side above the arm section (3). The claw section (6) is located at the top of the baffle structure and connects to the annular groove boss (4). The arm section (3) of the baffle is thicker at the bottom and thinner at the top, and has the greatest thickness at the connection between the arm section (3) and the mounting edge (2). The left and right edges of the arm section (3) have a small angle with the vertical direction to prevent it from tilting to the right under centrifugal and temperature loads. The helical tooth (5) is located on the right side of the middle part of the baffle structure. When the rotor rotates at high speed, the centrifugal load generated by the helical tooth (5) increases the radial tension on the right side of the arm section (3). Force and tensile deformation cause the radial tensile deformation on the right side of the arm segment (3) to be greater than that on the left side, thereby causing the arm segment (3) to tilt to the left, which is beneficial for the baffle to press against the turbine disk and generate a self-pressurizing effect; the claw segment (6) is composed of a cylindrical shell on the upper side and a conical shell on the lower side. The conical shell is thinner at the bottom and thicker at the top. The thickness at the connection between the lower side and the annular groove boss (4) is relatively low and the angular stiffness is relatively weak. Under centrifugal load, the conical shell is prone to tilting to the left and pressing against the turbine disk; the cylindrical shell is thinner on the left and thicker on the right. Its left end is designed with a pressing end face (c) of the baffle claw segment that contacts the turbine disk, so that the claw segment (6) will tilt to the left under centrifugal and temperature loads, enhancing the self-pressurizing effect of the baffle structure; the baffle structure can produce a tilting deformation to the left under centrifugal and temperature loads to offset the tilting deformation to the right under the action of pressure difference load, ensuring that the baffle pressing end face always presses against the turbine disk and realizes the self-pressurizing effect.

2. The aero-engine turbine baffle structure with self-clamping effect according to claim 1, characterized in that: The spline structure (1) is distributed circumferentially along the shaft and cooperates with the keyway on the turbine disk to prevent the baffle structure from moving circumferentially relative to the turbine disk during engine operation.

3. The aero-engine turbine baffle structure with self-clamping effect according to claim 1, characterized in that: The mounting edge (2) is a "Γ" shaped configuration, including the left end face (a1) and the right end face (a2) of the mounting edge for axial positioning of the baffle, and the cylindrical surface (b) of the mounting edge for radial centering; respectively, it contacts and cooperates with the interface at the corresponding position on the turbine disk to realize the positioning and centering of the baffle structure.

4. The aero-engine turbine baffle structure with self-clamping effect according to claim 1, characterized in that: The annular groove boss (4) is located in the middle of the baffle structure, with an annular groove in the middle, in which a sealing metal wire ring is installed, which is beneficial for sealing the turbine blade cooling gas and for reducing vibration of the baffle structure.

5. The aero-engine turbine baffle structure with self-clamping effect according to claim 1, characterized in that: The number of spline structures (1) is an integer multiple of 4.

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