Thermal mismatch tolerant assembly, cmc component, and metal connector

Abstract

The present application relates to a heat mismatch prevention assembly, a CMC member and a metal connecting piece. The assembly comprises a metal member, a CMC member with an assembly hole, and a metal connecting piece with a base portion at one end, a connecting portion at the other end, and a shaft portion between the base portion and the connecting portion. The shaft portion of the metal connecting piece passes through the assembly hole of the CMC member, the base portion abuts against one side surface of the CMC member, and the connecting portion is connected with the metal member. The assembly hole has a hole inclined surface inclined in a height direction and inclined in a direction perpendicular to the height direction in each of at least one set of opposite side walls, the shaft portion has a shaft inclined surface inclined in the height direction and inclined in the direction perpendicular to the height direction in each of at least one set of opposite side walls, the set of opposite hole inclined surfaces and the set of opposite shaft inclined surfaces correspond to each other and match with each other, and the section close to the base portion is in contact fit in the height direction, while the section close to the connecting portion is in gap fit.

Description

TECHNICAL FIELD

[0001] The present application relates to a thermal mismatch prevention assembly, in particular to a thermal mismatch prevention assembly between a CMC turbine blade and a metal case. BACKGROUND

[0002] Ceramic matrix composite (CMC) has high specific strength, specific stiffness, light weight, corrosion resistance at high temperature, and can adapt to the working environment of the hot end part of the aero-engine turbine, significantly improve the upper limit of the use temperature of the hot end part and the overall performance of the engine and reduce pollution emissions, making it extremely promising in the field of aero-engine. Currently, advanced aero-engine manufacturing enterprises at home and abroad have successively applied CMC materials to hot end parts of aero-engines, such as combustion chamber flame tubes, turbine outer rings, turbine blades, etc.

[0003] Compared with metal, the existing CMC process is difficult to form, has low forming precision, and is difficult to form a complex assembly structure for assembly and connection with other metal parts. In addition, CMC is an anisotropic material and has low tensile strength in the thickness direction. In the assembly structure of the CMC turbine blade, the existing solution is to construct a flange on the CMC blade rim plate, and to assemble the flange with the assembly surface of the front and rear metal cases, but this is easy to cause the delamination stress of the flange position to exceed the tensile strength of the material in the thickness direction. SUMMARY

[0004] An object of the present application is to provide a thermal mismatch prevention assembly to avoid the problem of excessive delamination stress of the CMC component caused by the assembly structure.

[0005] Another object of the present application is to provide a CMC component suitable for the aforementioned assembly.

[0006] Still another object of the present application is to provide a metal connecting piece suitable for the aforementioned assembly.

[0007] According to another aspect of the present application, a thermal mismatch prevention assembly includes a metal member, a CMC member having an assembly hole, and a metal connector having a base portion at one end, a connecting portion at the other end, and a shaft portion between the base portion and the connecting portion. In this assembly, the shaft portion of the metal connector passes through the assembly hole of the CMC member, the base portion abuts a side surface of the CMC member, and the connecting portion is connected to the metal member. The assembly hole has, in each of at least one pair of opposing side walls, a hole chamfer that is inclined in a height direction and in a direction perpendicular to the height direction, and the shaft portion has, in each of at least one pair of opposing side walls, a shaft chamfer that is inclined in the height direction and in the direction perpendicular to the height direction. The pair of opposing hole chamfers and the pair of opposing shaft chamfers correspond to each other and are engaged with each other, and a section near the base portion is in a close fit in the height direction, while a section near the connecting portion is in a clearance fit.

[0008] In one embodiment, the connecting portion of the metal connector is a hook.

[0009] In one embodiment, the CMC member has an opening at an edge corresponding to the assembly hole, and in the metal connector, the shaft portion transitions to the connecting portion and the base portion in a stepped shape, respectively. The connecting portion of the metal connector enters the assembly hole through the opening, and in turn allows the shaft portion to be pushed into the assembly hole from the side of the base portion.

[0010] In one embodiment, the connecting portion of the metal connector is connected to the metal member by a fastener.

[0011] In one embodiment, the connecting portion of the metal connector is configured to allow entry from one side of the CMC member and then exit through the assembly hole, to guide the hole chamfer and the shaft chamfer into a state of engagement with each other.

[0012] In one embodiment, the CMC member is a shroud provided for a CMC turbine blade, and the metal member is a metal casing. The shroud has the assembly hole at each of the front and rear side edges, so that the metal casing and the shroud at the front and rear side edges are connected by the metal connector.

[0013] In one embodiment, the direction perpendicular to the height direction is a front-rear direction of the shroud.

[0014] In one embodiment, the assembly hole and the shaft portion each have side walls at the front and rear sides that are inclined in the height direction, and a section near the base portion is in a close fit in the height direction, while a section near the connecting portion is in a clearance fit.

[0015] A CMC component according to another aspect of the present application, suitable for use in any of the heat mismatch prevention assemblies described, comprises a mounting hole having a set of opposing hole ramps in each of at least one set of opposing side walls, the hole ramps being inclined in a height direction and in a direction perpendicular to the height direction,

[0016] The set of opposing hole ramps and the set of opposing shaft ramps correspond to each other and cooperate with each other, with a section proximate to the base portion being in contact fit and a section proximate to the connecting portion being in clearance fit in the height direction.

[0017] A metal connecting piece according to yet another aspect of the present application, suitable for use in any of the heat mismatch prevention assemblies described, has a base portion at one end, a connecting portion at the other end and a shaft portion between the base portion and the connecting portion, the shaft portion having a set of opposing shaft ramps in each of at least one set of opposing side walls, the shaft ramps being inclined in a height direction and in a direction perpendicular to the height direction,

[0018] The set of opposing hole ramps and the set of opposing shaft ramps correspond to each other and cooperate with each other, with a section proximate to the base portion being in contact fit and a section proximate to the connecting portion being in clearance fit in the height direction.

[0019] According to an embodiment of the present application, a metal connecting piece is introduced to connect with a CMC component, and the assembly is made by the metal connecting piece and a metal component, without the need of flanging the CMC component to form a mounting surface, thus avoiding the problem of excessive delamination stress at the flange. BRIEF DESCRIPTION OF DRAWINGS

[0020] The above and other features, aspects and advantages of the present application will become more apparent from the following description of an embodiment thereof, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the application.

[0021] Figure 1 is a schematic view of a CMC turbine blade and a metal case;

[0022] Figure 2 is a schematic view of a CMC turbine blade with a metal connecting piece;

[0023] Figure 3 is a schematic view of a CMC component with a metal connecting piece; Figure 2 is a partial enlarged view of I in FIG. 4;

[0024] Figure 4 is a partial cross-sectional view along the ZY plane of an embodiment of a CMC component with a metal connecting piece;

[0025] Figure 5 is a partial cross-sectional view along the XY plane of an embodiment of a CMC component with a metal connecting piece;

[0026] Figure 6is a partial cross-sectional view along the ZY plane of another embodiment of a CMC component with a metallic attachment;

[0027] Figure 7 is a partial cross-sectional view along the XY plane of another embodiment of a CMC component with a metallic attachment;

[0028] Figure 8 is a schematic view of a CMC turbine vane with a metallic attachment;

[0029] Figure 9 is Figure 8 is a close-up view of II in FIG. 4. DETAILED DESCRIPTION

[0030] Reference will now be made in detail to embodiments of the application, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the application, not limitation of the application. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present application without departing from the scope or spirit of the application. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield still a further embodiment. Thus, it is intended that the present application covers modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.

[0031] In the embodiments described below, the assembly to prevent thermal mismatch is described with respect to a shroud of a CMC turbine vane and a metallic casing, but the practice of the present application is not limited thereto. In the following description, a shroud of a CMC turbine vane, a CMC component, or a metallic casing, a metallic component, when used in conjunction with the drawings, refer to like components in the drawings.

[0032] Figure 1 A CMC turbine vane and a metallic casing are shown in an assembled state, where a forward metallic casing 105 and an aft metallic casing 107 are shown in a simplified configuration. The term "CMC turbine vane" refers to a turbine vane having a primary material of CMC, i.e., ceramic matrix composite, and the term "metallic casing" refers to a casing having a primary material of metallic material. A plurality of turbine vanes are arranged side-by-side in a circumferential direction to form one stage of a turbine, and a plurality of Figure 1 The turbine vanes shown form a stator portion of one stage of a turbine. The circumferential sides of the shrouds of adjacent turbine vanes abut, and the inner side surfaces of the shrouds are surfaces that are proximate to the airfoils of the turbine vanes, and constitute part of the flowpath surface. In Figure 1In the drawings, a coordinate system XYZ is used as a reference, and the directions parallel to the X-axis, Y-axis, and Z-axis are the X-direction, Y-direction, and Z-direction, respectively. The front side of the airfoil 102 in the Y-direction is the leading edge of the airfoil, and the rear side is the trailing edge of the airfoil. The terms "upstream" and "downstream" refer to the relative direction with respect to the flow of fluid in the fluid path. For example, "upstream" refers to the direction from which the fluid flows, and "downstream" refers to the direction to which the fluid flows. The leading edge of the airfoil 102 is upstream of the trailing edge of the airfoil. The CMC turbine vane includes an upper shroud 101 and a lower shroud 103, between which the airfoil 102 is disposed. The lower shroud 103 is located inward of the upper shroud 101 as viewed from the stator of one stage of the turbine. The Z-direction is the spanwise direction of the airfoil 102, or the radial direction of the stator of one stage of the turbine. The airfoil 102 has two sidewalls in the X-direction, one of which is the suction surface and the other of which is the pressure surface.

[0033] Continuing to refer to Figure 1 In the illustrated thermal mismatch mitigation assembly, the CMC component or CMC turbine vane is connected to the metal component or metal case by metal connectors 104, 106. The metal connectors 104, 106 will be understood by the following description, which can be the same structure or different structures.

[0034] Figure 2 Figure 8 The illustrated thermal mismatch mitigation assembly conceals the metal case to facilitate viewing the mating structure of the metal connectors to the CMC component.

[0035] Figure 2 It can be understood that Figure 8 The right side view of the illustrated assembly. In Figure 2 and Figure 8 In the illustrated assembly, the metal connectors on the left and right sides are different structures, with the metal connector on the left having a hook at the upper end and the metal connector on the right having a connection hole at the upper end. In another embodiment, the metal connectors on the left and right sides are the same structure, such as both having a hook or both having a connection hole.

[0036] Figure 4 The illustrated cross-sectional view can be understood as a cross-section taken along the ZY plane from the position of the left side assembly hole of the CMC component shown in Figure 2 or Figure 8 The illustrated cross-sectional view can be understood as a cross-section taken along the ZY plane from the position of the left side assembly hole of the CMC component shown in Figure 4 and Figure 5 The illustrated structures are the same embodiment.

[0037] ​The CMC member 101 has a fitting hole 101c. The metal fitting 106 has a base portion 106a at a lower end, a connecting portion 106c at an upper end, and a shaft portion 106b between the base portion 106a and the connecting portion 106c. The shaft portion 106b of the metal fitting 106 passes through the fitting hole 101c of the CMC member, the base portion 106a abuts against a side surface 101a of the CMC member 101, and the connecting portion 106c is connected to the metal member 107.

[0038] Figure 5 is a cross-sectional view taken along the XY plane at a position approximately halfway along the thickness or height of the CMC member shown in FIG. 1. Figure 4 Each of a pair of opposing side walls of the fitting hole 101c in the X direction has a hole chamfer 301 inclined in the height direction and inclined in one direction perpendicular to the height direction. The Z direction is the height direction and the Y direction is the one direction perpendicular to the height direction in the figure. The inclination in the Z direction is not shown in the figure, but if viewed from a cross-sectional view taken along the XZ plane, the inclination in the Z direction makes the side of the fitting hole 101c near the base portion 106a larger and the side near the connecting portion 106c smaller.

[0039] Similarly, each of a pair of opposing side walls of the shaft portion 106b in the X direction has a shaft chamfer 306 inclined in the height direction and inclined in one direction perpendicular to the height direction. Figure 5 In FIG. 1, the shaft chamfer 306 and the hole chamfer 301 are in a substantially abutting state, and are expressed by a common projection line. The pair of opposing side walls of the shaft portion 106b in the X direction is not shown in the figure, but if viewed from a cross-sectional view taken along the XZ plane, the inclination in the Z direction makes the side of the shaft portion 106b near the base portion 106a larger and the side near the connecting portion 106c smaller.

[0040] The pair of opposing hole chamfers 301 and the pair of opposing shaft chamfers 306 correspond to each other and cooperate with each other, and the section near the base portion 106a is in a contact fit and the section near the connecting portion 106c is in a clearance fit in the height direction. The boundary between the contact fit and the clearance fit can be determined by testing according to the actual conditions, dimensions, and heat load of the product, for example, at a position of 1 / 3 to 1 / 2 of the height of the fitting hole 101c.

[0041] When the thermal deformation of the metal connecting member 106 is much larger than that of the CMC member due to the change of thermal load, for example, switching from normal temperature state to high temperature state, the fitting position between the shaft portion 106b of the metal connecting member 106 and the assembly hole 10c is a bevel / bevel fitting, and relative sliding is allowed, thus releasing the thermal deformation, preventing the thermal deformation from causing unnecessary stress, and the sliding will be along the bevel, so even if there is thermal deformation, the shaft portion 106b and the assembly hole 10c can be kept, thus avoiding the situation of thermal mismatch.

[0042] Figure 1 It is shown that the front side and the rear side of the CMC member 101 are connected to the metal members 105, 107 through the metal connecting members 104, 106 respectively, wherein the upper end of the metal connecting member 104 is a hook, and the upper end of the metal connecting member 106 needs to be connected by means of a fastener, including but not limited to a pin, a bolt. But as mentioned before, the metal connecting members 104, 106 can be used individually or in combination. When the entire assembly is in the working state, the transmission of force or load between the CMC member 101 and the metal members 105, 107 is carried out through the metal connecting members 104, 106, the force is transmitted between the base portion 106a and the inner side surface of the CMC member 101, then through the shaft portion 106b to the connecting portion 106c, and then to the metal members 105, 107. By observing the stress of the CMC member 101 at the assembly hole 10c, it can be understood that the CMC member mainly bears in-plane stress rather than delamination stress, and the in-plane tensile strength of the CMC material is much larger than the thickness direction tensile strength, which can effectively avoid material damage. If the CMC member is formed by folding to form an assembly surface with the metal member, not only the processing difficulty is large, but also when the CMC member is swung in the -Y direction under the action of aerodynamic load, the delamination stress at the corner position is very large, even exceeding the CMC thickness direction tensile strength, causing material damage.

[0043] Continuing to refer to Figure 4 , the connecting portion 106c of the metal connecting member 106 is provided with a connecting hole 106d, and a fastener not shown in the figure can be connected with the metal members 105, 107 through the connecting hole 106d.

[0044] Figure 6 And Figure 7 Another embodiment of the metal connecting member is shown. It corresponds Figure 1 to the metal connecting member 104 or Figure 8 the metal connecting member on the left side.

[0045] The connecting portion of the metal connecting member 104 has a base portion 104a at the lower end, a connecting portion 104c at the upper end, and a shaft portion 104b between the base portion 104a and the connecting portion 104c. The shaft portion 104b of the metal connecting member 104 passes through the assembly hole 101c of the CMC member, the base portion 104a abuts against the inner side surface 101a of the CMC member 101, and the connecting portion 104c is connected with the metal member 105. The metal connecting member 104 differs from the metal connecting member 106 in that the connecting portion 104c of the metal connecting member 104 comprises a hook 104e.

[0046] Continuing to refer to Figure 7 , the CMC member 101 has an opening 402 at the edge corresponding to the assembly hole 101c, as shown in Figure 6 , the shaft portion 104b of the metal connecting member 104 transitions between the connecting portion 104c and the base portion 104a in a stepped shape, respectively. The connecting portion 104c of the metal connecting member 104 enters the assembly hole 101c through the opening 402, and further allows the shaft portion 104b to be pushed into the assembly hole 101c from the side of the base portion 104a in the direction of the arrow as shown in Figure 7 . The width of the opening 402 is smaller than the width of the assembly hole 101c, so that a protrusion 403 is reserved to limit the movement of the metal connecting member in the Y direction.

[0047] Similarly, as shown in Figure 4 , the connecting portion 106c of the metal connecting member 106 is arranged to allow entering from the inner side of the CMC member 101 into the assembly hole 101c and then passing out of the assembly hole 101c, so as to guide the hole bevel 301 and the shaft bevel 306 into a state of fitting into each other.

[0048] Returning to Figure 5 , the wall surface 303 of the assembly hole 101c on the front and rear sides is also arranged to be inclined in the height direction. The wall surface 304 of the shaft portion of the metal connecting member 104 on the front and rear sides is also arranged to be inclined in the height direction. The wall surfaces 303, 304 are in a contact fit in the section close to the base portion 106a in the height direction, and are in a clearance fit in the section close to the connecting portion 106c. The shaft portion 104b of the metal connecting member 104 and the corresponding assembly hole 101c are also inclined on the respective wall surfaces on the front and rear sides, and have the aforementioned similar contact fit and clearance fit relationship. The bevel / bevel fit relationship can further limit the movement of the metal connecting member in the Y direction.

[0049] As mentioned before, the CMC member is not limited to the shroud provided by the turbine blade, but has obvious advantages when the aforementioned assembly is applied to the connection between the turbine blade and the metal casing:

[0050] (1) CMC blade edge plate is not turned up, but is hung on a specially designed metal part through slotting, thereby avoiding the risk of large delamination stress at the CMC blade turned-up position, simplifying the structure of the CMC blade, avoiding the requirement for a high-precision assembly surface of the CMC blade, and reducing the amount of machining;

[0051] (2) Assembled with front and rear metal parts, the assembly is completed by a metal part, thereby solving the problem that the CMC turbine blade cannot be formed into a complex assembly structure;

[0052] (3) The cooperation of the CMC blade edge plate assembly hole and the metal part solves the problem of thermal mismatch,

[0053] Although the present application is disclosed with the preferred embodiments as above, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the technical solutions of the present application, fall within the protection scope defined by the claims of the present application.

Claims

1. A component for preventing thermal mismatch, characterized in that, include Metal components, CMC components with assembly holes, and A metal connector having a base portion at one end, a connecting portion at the other end, and a shaft portion between the base portion and the connecting portion; The shaft portion of the metal connector passes through the mounting hole of the CMC component, the base portion abuts against one side surface of the CMC component, and the connecting portion is connected to the metal component. The assembly hole has a beveled surface in at least one set of opposing sidewalls that is inclined in the height direction and in a direction perpendicular to the height direction. The shaft portion has at least one inclined plane in each of a set of opposing sidewalls, which is inclined in the height direction and in a direction perpendicular to the height direction. The set of opposing inclined holes and the set of opposing inclined shafts correspond to and fit together, and are in contact fit in the section near the base in the height direction, while having a clearance fit in the section near the connecting part.

2. The component for preventing thermal mismatch as described in claim 1, characterized in that, The connecting part of the metal connector is a hook.

3. The component for preventing thermal mismatch as described in claim 2, characterized in that, The CMC component has an opening at the edge corresponding to the mounting hole. In the metal connector, the shaft portion transitions with the connecting portion and the base portion in a stepped shape; The connecting portion of the metal connector enters the mounting hole through the opening, thereby allowing the shaft portion to be pushed into the mounting hole from one side of the base portion.

4. The component for preventing thermal mismatch as described in claim 1, characterized in that, The connecting portion of the metal connector is connected to the metal component by fasteners.

5. The component for preventing thermal mismatch as described in claim 4, characterized in that, The connecting portion of the metal connector is configured to allow entry into and exit from the mounting hole from one side of the CMC component, so as to guide the hole bevel and the shaft bevel into a mating state.

6. The component for preventing thermal mismatch as described in any one of claims 1 to 5, characterized in that, The CMC component is a flange provided for the CMC turbine blade, the metal component is a metal casing, and the flange has mounting holes on its front and rear edges, so that the metal casing and the flange are connected on their front and rear edges by the metal connectors.

7. The component for preventing thermal mismatch as described in claim 6, characterized in that, One direction perpendicular to the height direction is the front-back direction of the edge plate.

8. The component for preventing thermal mismatch as described in claim 6, characterized in that, The mounting hole and the shaft are respectively inclined in the height direction on the front and rear side walls, and are in contact with the section near the base in the height direction, while they are in clearance fit in the section near the connecting part.

9. A CMC component, characterized in that, The component suitable for preventing thermal mismatch according to any one of claims 1 to 8 includes a mounting hole. The assembly hole has a beveled surface in at least one set of opposing sidewalls that is inclined in the height direction and in a direction perpendicular to the height direction. The set of opposing inclined holes and the set of opposing inclined shafts correspond to and fit together, and are in contact fit in the section near the base in the height direction, while having a clearance fit in the section near the connecting part.

10. A metal connector, characterized in that, The component suitable for preventing thermal mismatch according to any one of claims 1 to 8 has a base portion at one end, a connecting portion at the other end, and a shaft portion between the base portion and the connecting portion. The shaft portion has at least one inclined plane in each of a set of opposing sidewalls, which is inclined in the height direction and in a direction perpendicular to the height direction. The set of opposing inclined holes and the set of opposing inclined shafts correspond to and fit together, and are in contact fit in the section near the base in the height direction, while having a clearance fit in the section near the connecting part.

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