A turbine guide wheel blade trailing edge strength test specimen, system, and method

Abstract

A turbine guide vane trailing edge strength test piece is obtained by cutting a middle section of a turbine guide vane, wherein the test piece comprises a first wall body and a second wall body. The test piece further comprises a loading area and a test area: the loading area is arranged on one side of a leading edge of the turbine guide vane, and the test area is arranged on one side of a trailing edge of the turbine guide vane. At least one through cut is arranged in the loading area, so that the first wall body and the second wall body are connected together only through the test area. The test piece can accurately reflect the stress distribution state and strength of the trailing edge area of the turbine guide vane, and can effectively evaluate the trailing edge strength and production process stability of the turbine guide vane. The application further provides a test system and a test method.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of aero-engines, and particularly relates to a turbine guide vane trailing edge strength test piece, a system and a testing method. BACKGROUND

[0002] With the continuous development of the aviation industry, more and more composite materials are applied to the manufacturing of aero-engine parts, and ceramic matrix composite material is a typical representative. The ceramic matrix composite material (CMC) has the advantages of low density, high temperature resistance and corrosion resistance, and the structure made of the ceramic matrix composite material is usually 1 / 4-1 / 3 of the weight of the same nickel-based high-temperature alloy structure, which is of great significance to reduce the weight of the engine and improve the fuel economy. For example, the turbine guide vane made of ceramic matrix composite material is one of the new directions of aero-engine research and development.

[0003] However, the ceramic matrix composite material is usually a brittle material, and cracks are prone to occur due to local stress concentration under the condition of manufacturing complex structures and complex stress conditions. For the ceramic matrix composite turbine guide vane with a hollow structure, the trailing edge region of the vane is the weakest link, and how to correctly detect the strength of the trailing edge region and the like is an important issue for engine design, manufacturing and process stability evaluation. The existing detection methods for the ceramic matrix composite material usually use standard single-edge notched beam test pieces or compact tension test pieces for tensile testing, or use microhardness or micro sampling for semi-non-destructive testing. However, the inventors realize that the trailing edge region of the turbine guide vane has a complex structure and small size, and the stress distribution is complex under the working condition, and the existing detection methods cannot accurately reflect and evaluate the strength of the trailing edge position of the guide vane. SUMMARY

[0004] The purpose of the present application is to provide a turbine guide vane trailing edge strength test piece which can accurately reflect the stress distribution characteristics of the trailing edge region of the turbine guide vane, and further accurately evaluate the strength of the trailing edge region. The present application also provides a turbine guide vane trailing edge strength test system and method.

[0005] According to one aspect of an embodiment of the present application, a turbine guide vane trailing edge strength test piece is provided for the strength of the trailing edge region of a turbine guide vane, and the test piece is characterized in that: the test piece is a middle section of a vane body obtained by cutting a turbine guide vane, wherein the test piece comprises a first wall body and a second wall body, and the test piece further comprises a loading area and a test area; the loading area is arranged on the leading edge side of the turbine guide vane, and the test area is arranged on the trailing edge side of the turbine guide vane; the loading area is provided with at least one through cut, so that the first wall body and the second wall body are connected together only through the test area. The sample can make the trailing edge region become an independent force structure while retaining the basic structure and stress distribution state of the trailing edge region, so as to facilitate the testing and evaluation of the strength of the region.

[0006] Preferably, the length of the test piece along the height direction of the turbine guide vane is not less than 20 mm, so as to ensure that the test piece has sufficient rigidity.

[0007] According to another aspect of the embodiment of the present application, there is provided a turbine guide vane trailing edge strength test system using the above-mentioned turbine guide vane trailing edge strength test piece, the system further comprising a loading device and a base. The loading device comprises a movable loading end and a fixedly arranged fixed end, which are used to clamp the loading area of the test piece, and the loading end and the fixed end are connected with the first wall body and the second wall body, respectively, and the test piece between the two connection positions is connected as a whole only through the test area. The base allows the test area of the test piece to abut against, so as to keep the test piece stable during loading. The device can load the test piece according to the structural characteristics of the turbine guide vane, and accurately evaluate the mechanical properties of the trailing edge region.

[0008] Preferably, the installation positions of the loading end and the fixed end are arranged in the internal cavity of the test piece.

[0009] Preferably, the loading end and the fixed end are rod-shaped structures which are conformally matched with the contact surface of the internal cavity of the test piece. The cavity wall surface in the turbine guide vane is often not straight due to the production process, and the conformally matched rod-shaped structure can avoid stress concentration in the loading area.

[0010] Preferably, the contact positions of the loading end and the fixed end with the test piece are provided with flexible pads. The flexible soft pads can further avoid stress concentration in the loading area.

[0011] Optionally, the contact position of the base and the test piece is provided with a groove, so as to allow the test piece to rotate with loading when the test piece bears torque. Due to the complex shape of the turbine guide vane trailing edge strength test piece, the test piece may be deflected due to the loading direction or the position of the center of gravity during loading, and the setting of the groove allows the test piece to rotate slightly, avoiding the interference of the base on the load of the test piece during testing.

[0012] According to still another aspect of the present application, there is provided a turbine guide vane trailing edge strength test method using the above-mentioned test piece and test system, the method comprising moving the loading end of the loading device away from the fixed end, loading the test area of the test piece, and then making the test piece fail. Loading test on the turbine guide vane test piece along the thickness direction of the blade can better evaluate the strength of the trailing edge region.

[0013] Further, the loading end bias is installed on one side of the test piece to apply a torsional load to the test area of the test piece. According to the test requirement, the test piece to be tested can be loaded with a torsional load to test the strength performance of the blade trailing edge under more complex stress conditions.

[0014] Further, the test piece for testing comprises a plurality of internal cavities, and the loading end and the fixing end are clamped in the same internal cavity when loading. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 A schematic diagram of a turbine guide vane trailing edge strength test piece in an embodiment;

[0016] Figure 2 A schematic diagram of a turbine guide vane trailing edge strength test piece cutting position in an embodiment;

[0017] Figure 3 A partial schematic diagram of a turbine guide vane trailing edge test system in an embodiment;

[0018] Figure 4 A cross-sectional view of a turbine guide vane trailing edge test piece loading area in an embodiment;

[0019] Figure 5 A partial schematic diagram of a turbine guide vane trailing edge test system in another embodiment;

[0020] Figure 6 A cross-sectional view of a turbine guide vane trailing edge test piece loading area in another embodiment;

[0021] Figure 7 A schematic diagram of a low-pressure turbine guide vane cross section in still another embodiment.

[0022] The purpose of the above drawings is to make a detailed description of the embodiments of the present application so that those skilled in the art can understand the technical concept of the present application, and is not intended to limit the present application. In the drawings, only the parts and structures related to the technical features of the present application are schematically shown, and all parts, devices and details unrelated to the technical features are not strictly drawn according to the scale. DETAILED DESCRIPTION

[0023] The present application will be further described in detail below with reference to specific embodiments in conjunction with the drawings.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the meanings commonly understood by one of ordinary skill in the art; the terms used herein are intended to describe specific embodiments and are not intended to limit the present application; the terms "comprise" and "have" and their synonymous expressions in the specification and claims and the above description of drawings are intended to cover non-exclusive inclusion.

[0025] In this document, the terms "a", "an", "the" etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. In this document, the term "adapted to" means specifically configured or arranged to, even if that configuration or arrangement is caused by or triggered by an external influence or shifted by an external influence.

[0026] Reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase "in one embodiment" or "an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily all directed to the same application.

[0027] In the description of the embodiments of the present application, the relative terms "horizontal", "vertical", "lateral", "longitudinal", "length", "width", "depth", "thickness", "radial", "tangential", "upper", "lower", and the like are used to facilitate the description of the embodiments and are not intended to limit or confine the orientation or configuration of the devices or elements being described to a particular orientation, configuration, or operation in which the terms are used, and thus are not limiting to the embodiments of the present application.

[0028] In the description of the embodiments of the present application, unless otherwise explicitly specified or linearly, the terms "mount", "connect", "connection" and the like should be interpreted broadly, such as can be fixed connection or detachable connection or integral; can be mechanical connection or electrical connection; can be direct connection or through intermediate medium connection. Those skilled in the art should be able to understand the specific meaning of the above terms in the embodiments of the present application according to the specific circumstances.

[0029] According to one aspect of the embodiments of the present application, a turbine guide vane trailing edge strength test piece is provided, in one embodiment, the structure of which is as shown in Figure 1 Figure 2 ​The present application provides a turbine guide vane 2, which comprises a vane body 21, an upper edge plate 22 and a lower edge plate 23, and the vane body 21 has a leading edge 24 and a trailing edge 13. A middle section of the vane body 21 is cut by a cutting line 25 to obtain a turbine guide vane trailing edge strength test piece 1. The cutting line 25 is usually a parallel line, and in some embodiments, the cutting line 25 can also be a non-parallel line or an inclined line. The test piece 1 comprises a test area 11 arranged on one side of the trailing edge 13 and a loading area 12 arranged on one side of the leading edge 24. The width of the loading area 12 is preferably not less than that of the test area 11 in the length direction of the vane body, so as to avoid failure fracture in the loading area 12 during the test. The pressure side wall of the vane body constitutes a first wall body 14 of the test piece 1, and the suction side wall of the vane body constitutes a second wall body 15 of the test piece 1. The test area 11 comprises a connecting area of the first wall body 14 and the second wall body 15 on one side of the trailing edge 13, and the loading area 12 comprises a part of the test piece other than the test area 11. A cutting hole 16 is arranged on the leading edge 24 to cut off the part of the first wall body 14 and the second wall body 15, and a cutting hole 16' is arranged on the leading edge 24 to cut off the rib plate 17 connecting the first wall body 14 and the second wall body 15, so that the first wall body 14 and the second wall body 15 are connected only through the loading area 11. It should be noted that for some simple vane structures, only one cavity 17 is arranged in the vane, and only one cutting hole 16 is arranged on the leading edge 24. In order to ensure that the test piece 1 has sufficient rigidity, the distance between the cutting lines 25 is preferably at least 20 mm, so that the length of the test piece in the height direction of the turbine guide vane is not less than 20 mm. In other embodiments, the pressure side of the vane body can be used as the second wall body, and the suction side of the vane body can be used as the first wall body.

[0030] Generally, the test method for ceramic matrix composite material is to use a single-edge notched beam test piece or a compact tension test piece which is separately manufactured or cut from the base material. These test pieces cannot accurately reflect the stress distribution characteristics and failure mode of the trailing edge region of the turbine guide vane during the test. When evaluating the failure mode of the trailing edge of the turbine guide vane and the process stability during batch production, the test piece in the above embodiment can provide more accurate and targeted test results. At the same time, since the test piece is a non-standard piece, a test system matching the structural characteristics of the test piece should be preferably provided.

[0031] The present application also provides a turbine guide vane trailing edge strength test system, and one embodiment of the test system is as follows Figure 3The system includes a loading device for loading the loading area 12 of the test piece 1, which is provided with a loading end 31 and a fixed end 32. The loading end 31 is connected with a hydraulic driving device (not shown) and can move vertically under the action of the hydraulic driving device to load the load. The displacement and stress of the loading end 31 are recorded by a sensor, and the load-displacement curve during loading can be obtained, and then the stress and strain state of the sample during loading can be calculated. The device also includes a base 33 for supporting the test area 11 of the test piece 1. When the system is used for testing, the loading end 31 and the fixed end 32 can be clamped with the second wall body 15 and the first wall body 14 respectively, so that the test piece 1 between the two connection positions is connected as a whole through the test area 11.

[0032] In order to simplify the device and avoid the concentration of load in the loading area, the clamping mode is preferably provided to insert the loading end 31 and the fixed end 32 into the internal cavity 17 of the blade. Further, since the inner wall of the internal cavity 17 is often not straight, the loading end 31 and the fixed end 32 are preferably provided as a rod-shaped structure that is conformal with the contact surface of the internal cavity 17, and the cross-sectional structure along the A-A section is as shown in Figure 4 In order to avoid stress concentration caused by poor contact of the contact surface, and to induce the crack to first occur on the contact surface of the loading area before the test area fails during loading, a flexible soft pad can be further provided between the loading end 31 and the second wall body 15 and between the fixed end 32 and the first wall body 14. The loading end and the fixed end can also be provided as clamps or hooks to apply load to the test piece from the outside or the cutting surface of the test piece.

[0033] As shown in Figure 3 Considering the limited space of the internal cavity 17, the loading end 31 and the fixed end 32 can be installed by slightly offsetting a distance L, which makes the test piece 1 possibly subjected to an additional torque due to different axial forces during loading. To solve this problem, a groove 34 can be provided at the contact position of the base 33 and the test piece 1 to allow the test piece 1 to deflect to a certain extent to avoid excessive force at the contact position of the base, which affects the actual load borne by the test piece 1.

[0034] According to another aspect of the embodiment of the present application, a test method for the strength of the trailing edge of a turbine guide vane is provided, which uses the test piece and the test system in any of the above embodiments. In one embodiment, a high-pressure turbine guide vane is provided, which has a structure as shown in Figure 2 The vane is made of SiC fiber reinforced ceramic matrix composite material, and the vane height is 50 mm. A test piece 1 with a length of 30 mm is cut from the middle of the vane body, which has a structure as shown in Figure 1 Figure 3 ​The shown form is installed in the test system. The fixed end 32 and the loading end 31 are clamped in the internal cavity 17 of the loading area 12 near the front edge of one end, in order to clamp the fixed end 32 and the loading end 31 in the internal cavity 17, the wall surface should be clamped in the position of relatively smooth. The test area 11 is abutted on the base 33 to keep the balance of the whole test piece. When loading, the fixed end 32 remains stationary, and the loading end 31 moves upward along the direction indicated by the arrow to exert force on the first wall body 14 and the second wall body 15, so that they are forced to open until the test area 11 fails due to fracture. By recording the displacement and force data of the loading end 31, the peak load borne by the test piece can be calculated. This detection data can be used for strength comparison of multiple test pieces in the same batch to judge the quality of the blade and the stability of the production process, and can also be used as input for finite element simulation analysis to assist in further stress and strain analysis of the trailing edge area through simulation, so as to optimize the design of the blade structure.

[0035] In another embodiment, the internal cavity of the turbine guide vane has a larger size, and the installation of the test piece is as shown in Figure 5 The test piece includes two cavities 17, and the loading end 31 and the fixed end 32 are clamped in the same internal cavity 17 near the trailing edge, so that the loading position is closer to the test area 11. For test samples including multiple internal cavities 17, the loading end 31 and the fixed end 32 are preferably clamped in the same internal cavity 17 to reduce the torsion of the test piece during loading.

[0036] For the low-pressure turbine blade as shown in Figure 7 The blade has only one internal cavity, and the cut sample also has only one internal cavity 17, so it is only necessary to select a position with a relatively smooth internal wall for clamping and loading.

[0037] In yet another embodiment, the test piece 1 is installed as shown in Figure 3 The A-A cross-sectional structure of the loading area is shown in Figure 6 The loading end 31 is clamped in the test piece 1, which makes the force direction of the second wall body 15 deviate to one side, so that the second wall body 15 generates a torsional load relative to the first wall body 14, causing the test area 11 to additionally bear a torsional load in addition to the upward and downward tensile load. This loading mode can be used to detect the strength and failure mode of the trailing edge area of the turbine guide vane under a more complex stress state. In other embodiments, an inward extrusion load or a transverse shear load or an impact load or other forms of loading can be applied to the first wall body 14 and the second wall body 15, or the clamping position of the fixed end and the loading end on the test sample can be changed to further comprehensively detect the strength.

[0038] It should be understood that the embodiments described above are intended to be illustrative only and not limiting of the scope of the application. Various modifications and changes can be made thereunto without departing from the spirit and scope of the application as set forth in the claims.

Claims

1. A turbine guide vane trailing edge strength testing system, characterized in that, The test specimen includes a turbine guide vane trailing edge strength test piece, as well as a loading device and a base; The specimen is a blade midsection obtained by cutting a turbine guide vane, wherein the specimen includes a first wall and a second wall, and the specimen also includes a loading area and a testing area; wherein the turbine guide vane is a CMC turbine guide vane; The loading area is located on the leading edge side of the specimen, and the testing area is located on the trailing edge side of the specimen; The loading area is provided with at least one through cut, so that the first wall and the second wall are connected together only through the test area; The loading device includes a movable loading end and a fixed fixing end for engaging the loading area of ​​the specimen, so that the loading end and the fixed end are respectively connected to the first wall and the second wall, and the specimen between the two connection positions is connected as a whole only through the test area; the installation positions of the loading end and the fixed end are set in the internal cavity of the specimen. The base allows the test area of ​​the specimen to rest against it, and a groove is provided at the contact position between the base and the specimen.

2. The turbine guide vane trailing edge strength testing system according to claim 1, characterized in that, The loading end and the fixing end are rod-shaped structures that match the shape of the contact surface of the internal cavity of the specimen.

3. The turbine guide vane trailing edge strength testing system according to claim 2, characterized in that, Flexible pads are provided at the contact points between the loading end and the fixing end and the specimen.

4. The turbine guide vane trailing edge strength testing system according to claim 1, characterized in that, The base has a groove at the contact point with the specimen to allow the specimen to rotate as it is loaded when subjected to torque.

5. The turbine guide vane trailing edge strength testing system according to claim 1, characterized in that, The length of the specimen along the height direction of the turbine guide blade is not less than 20 mm.

6. A method for testing the trailing edge strength of a turbine guide vane, characterized in that, Using the testing system as described in any one of claims 1 to 5, the loading end of the loading device is moved away from the fixed end to load the test area of ​​the specimen until the specimen fails.

7. The method for testing the trailing edge strength of a turbine guide vane according to claim 6, characterized in that, The loading end is biased and installed on one side of the specimen, and a torsional load is applied to the test area of ​​the specimen.

8. The method for testing the trailing edge strength of a turbine guide vane according to claim 6, characterized in that, The specimen includes multiple internal cavities, and during loading, the loading end and the fixing end are engaged in the same internal cavity.

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