A turbine blade with a hook-secured ceramic armor

Abstract

The present application belongs to the technical field of aero-engine and gas turbine, and relates to a turbine blade with a hook fixing type ceramic armor. The present application improves the temperature bearing capacity of the turbine blade and the thrust or power of the engine, and the temperature bearing capacity of the combined turbine blade with the ceramic armor is significantly improved. The combined turbine blade replaces most of the blade surface high-temperature alloy with ceramic matrix composite material, so that it has the same blade shape as the original blade, and thus can also complete the guiding action of the gas. At the same time, compared with the high-temperature alloy, the ceramic matrix composite material has higher temperature resistance, and the effective cooling of the cold gas is not lost, so that the combined turbine blade can work in a higher gas temperature environment while still having the original function. According to the characteristics of the Brayton cycle used by the turbine engine, increasing the gas temperature can effectively improve the cycle power, that is, the thrust or power of the engine can be increased.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine and gas turbine technology, and relates to a turbine blade with a hook-fixed ceramic armor. Background Technology

[0002] For aero-engines and gas turbines, increasing the inlet gas temperature of turbine blades can effectively increase engine thrust or power. According to calculations, with the engine volume remaining constant, an increase of 55°C in inlet gas temperature can increase engine thrust by 10%. However, the long-term operating temperature of the high-temperature alloys used in turbine blades is difficult to exceed 1200°C, while predictions indicate that the inlet gas temperature of future aero-engines is very likely to exceed 2000°C, surpassing the known temperature resistance limit of high-temperature alloys. To address this issue, film cooling technology is commonly used to cool turbine blades. Figure 1 shows the structure of a twin-turbine guide vane. The turbine blade 1 is hollow, with film cooling holes 2 machined into the blade body, and impact holes 4 constructed using cooling gas ducts 3. The cooling gas jet impacts the target surface, enhancing convective heat transfer, and the film cooling effect is improved by the cooling gas covering the exhaust gas through the film cooling holes 2, thus isolating the heated gas. However, as the gas temperature increases, this type of turbine blade architecture based on high-temperature alloy materials and convection cooling begins to show problems such as low cooling efficiency, high cold air consumption, and limited temperature resistance, which restricts the improvement of gas temperature level and engine performance.

[0003] Ceramic matrix composites, composed of a ceramic matrix and fibers, possess the following characteristics: ① low density, with a density only 1 / 4 to 1 / 3 that of high-temperature alloys; ② high temperature resistance, capable of withstanding temperatures up to 1500℃; ③ chemical stability and corrosion resistance. These characteristics indicate that using ceramic matrix composites to replace high-temperature alloys in turbine blade manufacturing offers numerous advantages. While ceramic matrix composites can solve the problem of high-temperature resistance to combustion gases in turbine blades, their relatively low strength and brittleness, coupled with the significant aerodynamic and centrifugal loads they withstand during operation, make it difficult to directly fabricate turbine blades from this material. Therefore, this patent proposes a solution using a combination of ceramic armor and a metal blade assembly. Summary of the Invention

[0004] To solve the above-mentioned problems and realize the application of ceramic matrix composites on turbine blades, a turbine blade with hook-fixed ceramic armor is invented. The present invention enables the assembly and connection of ceramic matrix composite to the metal blade, such that metal, as the substrate, bears the main mechanical load applied to the blade, while the armor formed by the ceramic matrix composite insulates the internal structure from ablation by high-temperature gas, i.e., bears the main thermal load. Through this method where components of two materials each exert their respective advantages and combine with each other, the problems of insufficient temperature resistance of blades and poor engine performance can be effectively solved.

[0005] The technical solution of the present invention is as follows:

[0006] A turbine blade with hook-fixed ceramic armor, characterized in that it comprises ceramic armor, a turbine blade metal matrix, and a spring; the ceramic armor is disposed on the turbine blade metal matrix.

[0007] The ceramic armor comprises a ceramic matrix composite leading edge armor, a ceramic matrix composite blade back armor, a ceramic matrix composite blade basin armor, a ceramic matrix composite upper shroud armor, and a ceramic matrix composite lower shroud armor.

[0008] In order to protect the turbine blade metal matrix in a larger area, the ceramic armor is installed on the leading edge, the front half of the blade basin and blade back, and the front half of the upper / lower shroud of the turbine blade metal matrix, and the ceramic armor accounts for more than 50% of the contact area between the blade and gas. There are no less than two pieces of ceramic armor, which adopt an array layout on the surface of the blade body. The number of rows and columns of the ceramic armor distribution is adjusted according to the size of the blade and the armor, and the number of ceramic armors in adjacent rows or columns can be different. The ceramic armor is arranged in a staggered "grid" pattern or "triple-staggered" pattern in appearance.

[0009] The ceramic armor on a typical blade body can be arranged in a 4-row and 4-column structure, totaling 16 pieces. Among them, there are 2 columns of ceramic matrix composite blade basin armor, located on the basin side of the blade; 1 column of ceramic matrix composite leading edge armor, located at the leading edge of the blade; 1 column of ceramic matrix composite blade back armor, located on the blade back of the blade.

[0010] Because the trailing edge area of the blade is relatively thin and it is difficult to assemble ceramic armor thereon, the airfoil in these areas is completely made of metal, and a conventional cooling method is adopted;

[0011] Ceramic armor is arranged on the surface of the blade body and the upper and lower shrouds of the blade, which are the ceramic matrix composite upper shroud armor and the ceramic matrix composite lower shroud armor respectively.

[0012] Because the shape of the shroud flow path surface is complex after being cut by the airfoil, the armor distribution is arranged along the airfoil curve, so it is not strictly in rows and columns. The thermal load at the position of the shroud near the trailing edge is small, so it may not be covered with ceramic armor, and simple cooling or no cooling is adopted.

[0013] Springs are used to connect adjacent ceramic armor plates to prevent them from detaching from the turbine blade's metal substrate. To ensure that cool air can flow over the blades and ceramic armor plates and provide cooling, an armor gap width W1 is designed between adjacent ceramic armor plates, typically ranging from 0.1 to 0.5 mm. To allow for smoother airflow and to form an air film to enhance cooling, the angle ∠θ1 between the armor gap and the gas flow direction is designed by controlling the shape of the ceramic armor plates, typically ranging from -30° to 30°.

[0014] Taking the ceramic matrix composite leading-edge armor as an example, its typical structure is shown in Figure 3. It consists of a sheet-like armor and a hook perpendicularly connected to its center. To complete the installation of the ceramic armor on the blade and to ensure that the spring does not detach from the hook, the hook is designed to consist of two segments: a vertical segment that is directly connected to and perpendicular to the armor, responsible for passing through the metal matrix wall of the turbine blade; and an inclined segment connected to the vertical segment, the angle between its axis and the vertical segment being an obtuse angle. The typical range of the angle ∠θ2 between the vertical and inclined segments is 110° to 150°. Other types of armor, as shown in Figures 4 and 5, also have the same type of vertical and inclined hook segments, and the two also have an angle ∠θ2 between them.

[0015] To ensure the aerodynamic performance of the turbine blade, after the ceramic armor is assembled onto the metal substrate of the turbine blade, the outer surface of the composite turbine blade must form a complete blade profile. Therefore, the center lines of each center surface and cross section of the ceramic armor, the center line of the cross section of the blade back or lower edge plate armor, and the center line of the cross section of the blade basin or upper edge plate armor should have curvatures that match the turbine blade profile.

[0016] For example, Figure 3 shows a ceramic matrix composite leading-edge armor. In the CC section, the centerline of the leading-edge armor cross-section bends towards the hook side with a large curvature to match the relatively narrow area of ​​the blade's leading edge. Figure 4 shows a ceramic matrix composite blade back armor or lower edge plate armor. In the EE section, the centerline of the blade back or lower edge plate armor cross-section bends towards the hook side, but the curvature is smaller than that of the leading-edge armor to match the convex flow channel surface in the blade. Figure 5 shows a ceramic matrix composite blade basin armor or upper edge plate armor. In the GG section, the centerline of the blade basin or upper edge plate armor cross-section bends towards the other side of the hook, with a curvature smaller than that of the leading-edge armor, comparable to that of the back side or lower edge plate, to match the concave flow channel surface in the blade. To facilitate the installation of the armor with the hook, special armor mounting holes are designed, such as... Figure 6As shown, the turbine blade metal substrate is provided with armor mounting holes. The entire armor mounting hole includes inclined holes and vertical holes. Both types of holes penetrate the wall surface and partially overlap in the middle, making the cross-section of the armor mounting hole approximately "X" shaped. The angle ∠θ4 between the axis of the inclined hole and the axis of the vertical hole typically ranges from 30° to 70°, and is complementary to the angle ∠θ2 between the vertical and inclined sections of the hook.

[0017] like Figure 7 The diagram illustrates the installation process of hooks passing through mounting holes in single-piece ceramic matrix composite (CMC) leading-edge armor, CMC blade back armor, CMC blade basin armor, CMC upper edge armor, and CMC lower edge armor. This process can be divided into two steps: First, the armor moves along an inclined direction, and the inclined holes constrain the inclined sections of the hooks, causing them to move along the axis of the inclined holes until the vertical section of the hook reaches the position of the vertical hole. Second, the armor moves along the normal direction of the blade wall, and the vertical holes constrain the vertical sections of the hooks, causing them to move along the axis of the vertical holes until the armor is in contact with the turbine blade metal matrix or the gap is small, thus completing the installation of the single-piece ceramic armor.

[0018] Figure 8 illustrates the assembly process of the ceramic matrix composite (CMC) leading-edge armor, CMC blade back armor, CMC blade head armor, CMC upper edge armor, and CMC lower edge armor on the turbine blade metal matrix: the CMC blade head armor is assembled along the armor mounting holes corresponding to the blade head portion of the turbine blade. Figure 7 The installation process is shown until the armor contacts the turbine blade metal substrate, then the above process is repeated to install all the ceramic matrix composite blade head armor into place; the ceramic matrix composite blade back armor is installed along the armor mounting holes corresponding to the back of the turbine blade. Figure 7 The installation process is shown until the armor contacts the turbine blade metal substrate, and then the above process is repeated to install all the ceramic matrix composite blade back armor in place; the ceramic matrix composite leading edge armor is installed along the armor mounting holes corresponding to the leading edge of the turbine blade. Figure 7 The installation process is shown until the armor contacts the turbine blade metal substrate. Then, the above process is repeated to install all the ceramic matrix composite leading-edge armor in place. The ceramic matrix composite upper-edge armor is installed along the corresponding armor mounting holes on the turbine blade upper-edge plate. Figure 7 The installation process is shown below, continuing until the armor contacts the turbine blade metal substrate. Then, the above process is repeated to install all the ceramic matrix composite upper edge armor plates in place; the ceramic matrix composite lower edge armor plates are installed along the corresponding armor mounting holes on the turbine blade lower edge plate. Figure 7The installation process is shown until the armor contacts the metal substrate of the turbine blade. Then, repeat the process to install all the ceramic matrix composite lower edge armor plates in place. To ensure the armor can be secured to the blade with the spring, the tilting directions of the hook sections of adjacent armor plates should be opposite, and the tilting directions of the corresponding tilting holes in the armor mounting holes should also be opposite.

[0019] The spring is made of a high-temperature alloy with elasticity and mainly serves to fix the ceramic matrix composite leading-edge armor, ceramic matrix composite blade back armor, ceramic matrix composite blade basin armor, ceramic matrix composite upper edge plate armor, and ceramic matrix composite lower edge plate armor. Furthermore, its elasticity can suppress the generation of thermal stress due to the mismatch in thermal deformation between the high-temperature alloy and the ceramic matrix composite material. Two typical shapes of the spring are shown below. Figure 9a As shown in Figure 9c, the springs are divided into two types: convex and concave. When the distance between two adjacent hooks is less than 10mm, a convex spring is used; when the distance between two adjacent hooks is greater than 10mm, a concave spring is used. The number of concave ripples can be dynamically adjusted according to this distance. To ensure sufficient tension, the typical range for the spring diameter D is 0.5mm-2mm. Additionally, the width W6 of the spring hook section should ensure that the hook passes through it, and its typical range is 1.7mm-4.5mm.

[0020] Figure 8 illustrates the installation method of the spring. For the installation of a series of armor plates on the leading edge of the blade, the spring is inserted through the air inlet of the blade's leading cavity and then installed onto two adjacent hooks with opposite tilt directions on the hook's inclined section. For the installation of a series of armor plates near the middle of the blade, the spring is inserted through the air inlet of the blade's trailing cavity and then installed onto two adjacent hooks with opposite tilt directions on the hook's inclined section. For a series of armor plates on the edge plate, the spring can be directly hooked onto the hook on the outside of the edge plate, thus omitting the step of inserting the spring into the blade's inner cavity.

[0021] Taking the ceramic matrix composite leading edge armor shown in Figure 10 as an example, the installation of the armor and spring with the turbine blade metal matrix is ​​further explained. The main structures and their functions are as follows: The hook back side boss is cuboid in shape. During operation, it fits tightly with the vertical section of the hook and is tangentially positioned to it. To ensure that it provides sufficient support for the hook structure, the typical value range of the hook back side boss height W4 is 1.5 to 3 mm, which can cover the vertical section of the hook; the typical value range of the hook back side boss width W3 is 0.4 mm to 2.0 mm, so as to ensure that the boss has sufficient strength to resist the pull of the spring; a certain distance should be maintained between two adjacent hook back side bosses for the elastic deformation of the spring and the generation of tension force. The type of spring can be determined by the spacing W5 between the hook's back-side bosses. When W5 is less than 3.5mm, an outwardly convex type with elastic bending is used; otherwise, an inwardly concave type is used. The spring support boss is located at the inner opening of the armor mounting hole. Its top surface, which contacts the spring, is flat and smooth, and there is a spring support boss height W2 between it and the inner wall of the blade. The typical value range is 0.2mm to 1.5mm. Through this top surface design, the spring can be lifted first and then the hook can be held in place to prevent the hook from coming out of the hole. At the same time, the gap W8 between the armor and the turbine blade metal substrate can be precisely controlled, and the instability caused by direct contact between the spring and the inner curved surface of the blade can be avoided. In addition, the spring can slide in the wedge-shaped gap formed between the inclined section of the hook and the top surface of the spring support boss, thereby allowing the vertical section of the hook to move slightly within the armor mounting hole, that is, allowing the gap W8 to change slightly, to balance the aerodynamic load on the blade during operation and coordinate the thermal deformation between the metal and the CMC material. The armor mounting of other parts also relies on the above structure and follows the same principle.

[0022] As shown in Figure 11, to further enhance the heat resistance of this type of composite turbine blade, a series of gaps for cooling air flow are designed between the ceramic matrix composite leading-edge armor, ceramic matrix composite blade back armor, ceramic matrix composite blade basin armor, ceramic matrix composite upper edge armor, ceramic matrix composite lower edge armor, and the turbine blade metal matrix. These gaps include the gap between the vertical section of the hook and the armor mounting hole, and the gap between the turbine blade metal matrix and the armor, forming a gap W8 between the armor and the turbine blade metal matrix. A typical value range is 0.1 mm to 0.5 mm. During turbine blade operation, because the pressure of the cooling air is slightly greater than that of the combustion gas, the cooling air can flow along these gaps from the cooling air side inside the blade to the combustion gas side outside, simultaneously cooling the armor and the blade. Furthermore, during the final merging with the combustion gas, a gas film can form on the outer surface of the armor, further isolating the armor from heating by the combustion gas.

[0023] Beneficial effects of this invention:

[0024] 1. Improved the temperature resistance of turbine blades and the thrust or power of the engine.

[0025] Compared to existing turbine blades using high-temperature alloys and convection cooling, the invented composite turbine blade with ceramic armor significantly improves its temperature resistance. This composite turbine blade replaces most of the high-temperature alloy on its surface with ceramic matrix composite material, giving it the same airfoil as the original blade and allowing it to guide the combustion gas. Simultaneously, compared to high-temperature alloys, ceramic matrix composite material has higher temperature resistance while maintaining effective cooling from the airflow. This allows the composite turbine blade to operate in higher combustion gas temperature environments while retaining its original functions. As the Brayton cycle characteristic of turbine engines shows, increasing the combustion gas temperature effectively increases cycle work, resulting in increased engine thrust or power. Furthermore, the improved temperature resistance of the blades reduces the demand for cooling air, lessening the engine's workload and also contributing to improved cycle efficiency, thrust, and power.

[0026] 2. Further enhance its heat resistance through a composite cooling system for the armor and metal blades.

[0027] Because of the significant differences in the properties of CMC materials and the structure of CMC turbine blades compared to traditional high-temperature alloy turbine blades, conventional cooling systems are no longer suitable for CMC turbine blades. This invention designs a combined turbine blade composite cooling system, further improving the temperature resistance of turbine blades. This composite cooling system incorporates a series of gaps between the ceramic armor and the turbine blade metal substrate to allow for the flow of cool air. These gaps include the gap between the vertical section of the hook and the armor mounting hole, and the gap between the turbine blade metal substrate and the armor. Cool air can flow along these gaps from the cool air side inside the blade to the combustion gas side outside, simultaneously cooling both the armor and the blade. To ensure smoother flow of cool air to the combustion gas side and to simultaneously form an air film to enhance cooling, the angle between the armor gaps and the combustion gas flow direction is designed by controlling the shape of the armor, thus increasing the area of ​​the air film covering the armor surface.

[0028] 3. Higher strength compared to all-ceramic matrix composites.

[0029] Turbine blades are subjected to aerodynamic loads from the combustion gas, vibration loads, and support loads on the casing, turbine rotor, and other structures during operation. These loads collectively create a significant mechanical load on the turbine blades. Traditional turbine blades utilize high-strength high-temperature alloys to bear these mechanical loads and prevent damage. However, turbine blades made entirely of ceramic matrix composites are prone to failure under impact or stress concentration due to the high brittleness of ceramic matrix composites. In this invention, a connecting structure transfers the aerodynamic loads on the ceramic armor to the metal matrix of the blade, while the mechanical loads remain borne by the metal matrix. This avoids excessive mechanical loads on the armor itself and the resulting failure.

[0030] 4. Reduce engine maintenance costs

[0031] Turbine blades are the hottest and most impact-stressed parts of an engine, but due to the insufficient temperature resistance of high-temperature alloys and the limited cooling effect of the blades, they are highly susceptible to ablation. When turbine blades are damaged by ablation, the entire blade often needs to be replaced. However, the high cost of high-temperature alloys and the complex manufacturing process of turbine blades result in high maintenance costs. In this invention, after the ceramic armor sacrifices its lifespan to protect the internal metal substrate, a detachable hook connection method allows the damaged armor to be removed and replaced without affecting the integrity of the turbine blade's metal substrate. This extends the blade's lifespan and allows it to be put back into service, thereby reducing engine maintenance costs. Furthermore, the hook uses spring tension as a constraint, which is more flexible and convenient for installation and disassembly compared to connections using screws, pins, rivets, or welding.

[0032] 5. Reduce stress at the connection between the hook and the armor.

[0033] Because the coefficient of thermal expansion of the turbine blade's metal matrix is ​​more than 10% greater than that of the ceramic matrix composite material, the mismatch in thermal deformation between the two under the impact of high-temperature combustion gases can generate additional thermal stress at the connection between the armor and the hook, easily leading to damage. This solution uses a spring to partially constrain the hook, allowing the ceramic armor to extend, contract, and move on the blade via spring deformation. This alleviates the additional stress caused by deformation at the connection between the hook and the armor, thereby increasing the lifespan of the armor structure.

[0034] 6. Less damage to the strength of turbine blades.

[0035] To attach the armor plates to the blades, numerous mounting holes need to be drilled in the blade's metal substrate for the hooks to pass through, which inevitably causes significant damage to the blade's strength. This invention employs inclined hooks and mounting holes with an "X"-shaped cross-section, resulting in a smaller opening area than conventional straight holes, thus reducing damage to the blade. The meaning is illustrated in Figure 12, where Figure a shows a conventional straight mounting hole 33. To ensure the hook can be inserted into this hole without obstruction along the wall's normal direction, the projected width of the inclined section 18 of the hook should be equal to the width W of the straight mounting hole. 11 36 is the same as or less than this value; however, as shown in Figure b, the present invention adopts a method of inserting the hook obliquely first and then vertically, that is, the armor mounting hole 20 is designed to be formed by two nested holes, one oblique and one vertical, which reduces the opening area without affecting the armor installation effect. In a typical design, the inner wall width W934 and the outer wall width W of the armor mounting hole are... 10 35 is greater than the width of the straight mounting hole W 11 The value of 36 was reduced by more than 25%, thereby reducing the damage to the strength of the turbine blades. Attached Figure Description

[0036] Figure 1(a) shows the structure of a turbine blade using film cooling.

[0037] Figure 1(b) shows the AA cross-section of a turbine blade using film cooling.

[0038] Figure 2(a) Front view of the combined turbine blade.

[0039] Figure 2(b) shows a partial enlarged view of the combined turbine blade.

[0040] Figure 2(c) Top view of the combined turbine blade.

[0041] Figure 2(d) Side view of the combined turbine blade.

[0042] Figure 3(a) shows the leading edge armor structure of the ceramic matrix composite material.

[0043] Figure 3(b) Cross-sectional view of the leading edge armor BB of ceramic matrix composite material.

[0044] Figure 3(c) Cross-sectional view of the leading edge armor of ceramic matrix composite material.

[0045] Figure 4(a) shows the structure of the blade back or lower edge plate armor of ceramic matrix composite material.

[0046] Figure 4(b) Cross-sectional view of the blade back or lower edge plate armor of ceramic matrix composite material.

[0047] Figure 4(c) Cross-sectional view of the ceramic matrix composite blade back or lower edge plate armor EE.

[0048] Figure 5(a) shows the structure of the ceramic matrix composite blade basin or upper edge plate armor.

[0049] Figure 5(b) Cross-sectional view of ceramic matrix composite blade basin or upper edge plate armor FF.

[0050] Figure 5(c) Cross-sectional view of ceramic matrix composite blade basin or upper edge plate armor GG.

[0051] Figure 6 Sectional view of the armor mounting holes.

[0052] Figure 7 Diagram showing the installation process of a single ceramic armor piece.

[0053] Figure 8(a) Front view of the assembly process of ceramic armor in different parts on the combined turbine blade.

[0054] Figure 8(b) shows a side view of the assembly process of ceramic armor in different parts on a combined turbine blade.

[0055] Figure 9(a) shows the structure of an elastic bending convex spring.

[0056] Figure 9(b) Cross-sectional view of the elastic bending convex spring KK.

[0057] Figure 9(c) shows the structure of an elastic bending concave spring.

[0058] Figure 10(a) Partial perspective view of the assembled turbine blade after the ceramic matrix composite leading edge armor is assembled. Figure 10(b) Partial enlarged view of the assembled ceramic matrix composite leading edge armor.

[0059] Figure 10(c) HH cross-section view after the ceramic matrix composite leading edge armor is assembled.

[0060] Figure 10(d) JJ cross-section after the ceramic matrix composite leading edge armor is assembled.

[0061] Figure 11(a) shows the structure of the combined turbine blade under working conditions.

[0062] Figure 11(b) shows a partial enlarged view of the combined turbine blade.

[0063] Figure 11(c) shows a schematic diagram of the cooling process of cold air on the ceramic armor and blades.

[0064] Figure 12(a) shows the structure of the straight hole.

[0065] Figure 12(b) shows the structure of the “X”-shaped hole.

[0066] Figure 13(a) shows a combined turbine blade assembled with a ceramic armor and a single hook back side boss.

[0067] Figure 13(b) is a partial enlarged view of the assembly and connection between the ceramic armor and the single hook back side boss.

[0068] Figure 13(c) MM cross-sectional view of the assembly connection between the ceramic armor and the single hook back side boss.

[0069] Figure 14(a) shows the structure of the guide ribs in the gap between the blade matrix and the ceramic matrix composite leading edge armor.

[0070] Figure 14(b) is a magnified view of the guide ribs in the gap between the blade matrix and the ceramic matrix composite leading edge armor.

[0071] Figure 14(c) shows the flow guide ribs in the gap between the blade matrix and the ceramic matrix composite blade back or blade basin armor.

[0072] Figure 14(d) is a magnified view of a portion of the guide ribs in the gap between the blade matrix and the ceramic matrix composite blade back or blade basin armor.

[0073] Figure 14(e) shows a cross-sectional view of the guide rib NN in the gap between the blade substrate and the ceramic armor.

[0074] In the diagram: 1. Turbine blade; 2. Film cooling vent; 3. Cooling gas duct; 4. Impingement vent; 5. Ceramic matrix composite leading edge armor; 6. Ceramic matrix composite blade back armor; 7. Ceramic matrix composite blade base armor; 8. Ceramic matrix composite upper edge plate armor; 9. Ceramic matrix composite lower edge plate armor; 10. Angle ∠θ1 between armor clearance and gas flow direction; 11. Turbine blade metal matrix; 12. Spring; 13. Armor clearance width W1; 14. Centerline of leading edge armor cross-section; 15. Centerline of blade back or lower edge plate armor cross-section; 16. Centerline of blade base or upper edge plate armor cross-section; 17. Hook vertical section; 18. Hook. 19. Angle ∠θ2 between the vertical and inclined sections of the hook; 20. Armor mounting hole; 21. Hook back side boss; 22. Blade front cavity; 23. Blade rear cavity; 24. Spring support boss; 25. Spring support boss height W2; 26. Hook back side boss width W3; 27. Hook back side boss height W4; 28. Hook back side boss spacing W5; 29. ​​Spring hook section width W6; 30. Spring length W7; 31. Spring diameter D; 32. Clearance between the armor and the turbine blade metal substrate W8; 33. Straight mounting hole; 34. Armor mounting hole inner wall width W9; 35. Armor mounting hole outer wall width W 10 36. Width of straight mounting hole W 11 37. Single hook back side boss; 38. Length W of single hook back side boss 12 39. Wedge angle ∠θ3 of the back boss of the single hook; 40. Inclined hole; 41. Vertical hole; 42. Angle ∠θ4 between the axis of the inclined hole and the axis of the vertical hole; 43. Guide rib. Detailed Implementation

[0075] To make the content of this invention easier to understand, the implementation of this invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0076] Example 1

[0077] As shown in Figure 13, this embodiment is a special case of the invention, in which a single piece of armor is directly connected to the single hook back side protrusion 37. Unlike the case where two pieces of armor are connected, where the spring 12 is installed on two adjacent hooks with opposite inclination directions on the hook tilt section 18, in this embodiment, one end of the spring 12 is installed to the hook of the armor, and the other end is installed to the single hook back side protrusion 37, which is in close contact with the hook vertical section 17. The cross-sectional shape of the single hook back side protrusion 37 is a right-angled trapezoid. The plane containing its right-angled side is in close contact with the hook vertical section 17 during operation and is tangentially positioned to it. The plane containing its hypotenuse forms a wedge angle ∠θ339 between the single hook back side protrusion and the surface of the spring support protrusion 24, with a typical value range of 42° to 48°, which can lock and prevent the spring 12 from falling out of the single hook back side protrusion 37. The length W of the single hook back side protrusion... 12 The typical value range of 38 is 3.5mm to 5.5mm. This is mainly to ensure that the spring 12 can generate sufficient elastic deformation and tension, while ensuring that the single hook back side boss 35 has sufficient strength to resist the pull of the spring 12. Since the boss and hook occupy the space in the middle of the spring, the spring 12 should be selected as elastically bent and convex in this case. In this design, the spring 12 can still slide in the wedge gap at both ends, thereby allowing the vertical section 17 of the hook to move slightly within the armor mounting hole 20, and the gap 32 between the armor and the turbine blade metal substrate to change slightly, so as to balance the aerodynamic load during operation and coordinate the thermal deformation between the metal and the CMC material.

[0078] Example 2

[0079] For the gap W832 between the armor and the turbine blade metal substrate, in addition to the smooth surface solution mentioned above, a special embodiment can be adopted by adding guide ribs to the outer surface of the metal substrate or the inner surface of the ceramic armor. The specific meaning and scheme are shown in Figure 14. To avoid damage to the turbine blade metal substrate 11 and the ceramic armor 5-9 due to insufficient cooling, it is necessary to distribute the cold air as evenly as possible. One solution is to design guide ribs 43 on the turbine blade metal substrate 11, located in the gap between the armor and the turbine blade metal substrate. The height of the ribs protruding from the wall is the same as W8, and the top surface of the ribs is in close contact with the inner wall of the ceramic armor to prevent cold air leakage. By utilizing the guiding effect of these ribs, the flow of cold air in the gap is more controlled. Guide ribs 43 can be distributed on composite turbine blades between various ceramic armors and the blade substrate, typically such as ceramic matrix composite leading edge armor 5, ceramic matrix composite blade back armor 6, and ceramic matrix composite blade base armor 7. Their shape can be straight or curved following the blade profile. A key feature is that the starting end is located at the outlet of the armor mounting hole 20, and multiple guide ribs divide it into multiple exhaust ports. The width of the exhaust ports controls the distribution ratio of the discharged cool air (the specific value depends on actual design requirements). Due to this restriction, the discharged cool air flows in the space formed between adjacent guide ribs, simultaneously cooling both the armor and the metal substrate, and then flows out from the gaps between the armors, forming a film cooling effect. The spacing and angle between the guide ribs 43 should be adjusted according to the cooling requirements and the pressure of the incoming gas flow to ensure sufficient cool air outflow without gas intrusion. Generally, a feasible solution is as follows: for the leading edge of the blade, the guide rib 43 should be straight and extend radially along the blade; for both sides of the blade back, the guide rib 43 should be radial and extend outward from the mounting hole 20.

Claims

1. A turbine blade employing a hook-fixed ceramic armor, characterized in that: comprising a ceramic armor, a turbine blade metal matrix (11), and a spring (12); the ceramic armor is located on the turbine blade metal matrix (11); said ceramic armor comprises a ceramic matrix composite leading edge armor (5), a ceramic matrix composite blade back armor (6), a ceramic matrix composite blade basin armor (7), a ceramic matrix composite upper shroud armor (8), and a ceramic matrix composite lower shroud armor (9); the ceramic armor is mounted on the leading edge of the turbine blade metal matrix (11), the front half of the blade basin and blade back, and the front half of the upper / lower shroud; the ceramic armor accounts for more than 50% of the contact area between the blade and fuel gas; there are no less than two pieces of said ceramic armor, which adopt an array layout on the surface of the blade airfoil; the ceramic armor is interlaced and arranged in a "grid" shape or a "triangular-staggered" shape in appearance; ceramic armors are arranged on the surfaces of the blade airfoil, the upper shroud and the lower shroud of the blade, which are the ceramic matrix composite upper shroud armor (8) and the ceramic matrix composite lower shroud armor (9) respectively; the spring (12) connects two adjacent pieces of ceramic armor, and an armor gap width W1 (13) designed between two adjacent pieces of ceramic armor is 0.1mm~0.5mm; through controlling the shape of the ceramic armor, an included angle ∠θ1 (10) between the armor gap and the fuel gas flow direction is set to be -30°~30°; said ceramic armor consists of a sheet-shaped armor body and a hanging hook vertically connected to the center of the armor body; the hanging hook consists of two segments: one segment is a hanging hook vertical segment (17) directly connected to the armor body and perpendicular thereto, which is responsible for passing through the wall surface of the turbine blade metal matrix (11); connected to the vertical segment is a hanging hook inclined segment (18), and an included angle ∠θ2 (19) between the axis of the inclined segment and the vertical segment is an obtuse angle.

2. A turbine blade with a hook-fixed ceramic armor as described in claim 1, characterized in that: said ceramic armor is arranged in a 4-row and 4-column structure, with a total of 16 pieces; wherein the ceramic matrix composite blade basin armor (7) has 2 columns, located on the basin side of the blade; the ceramic matrix composite leading edge armor (5) has 1 column, located on the leading edge of the blade; the ceramic matrix composite blade back armor (6) has 1 column, located on the blade back of the blade.

3. A turbine blade with a hook-fixed ceramic armor as described in claim 1, characterized in that: said turbine blade metal matrix (11) is provided with armor mounting holes (20), the entire armor mounting hole (20) comprises an inclined hole (40) and a vertical hole (41), both types of holes penetrate through the wall surface and partially overlap in the middle, so that the cross section of the armor mounting hole (20) is in an "X" shape; an included angle ∠θ4 (42) between the axes of the inclined hole and the vertical hole is complementary to the included angle ∠θ2 (19) between the vertical segment and the inclined segment of the hanging hook.

4. A turbine blade with hook-fixed ceramic armor as described in claim 3, characterized in that: said included angle ∠θ4 (42) between the axes of the inclined hole and the vertical hole is 30°~70°; said included angle ∠θ2 (19) is 110°~150°.

5. A turbine blade with a hook-fixed ceramic armor as described in claim 1, characterized in that: said springs (12) are divided into two types: elastic outward-protruding type and elastic inward-concave type; when the distance between two adjacent hanging hooks is less than 10mm, the elastic outward-protruding spring (12) is used; when the distance between two adjacent hanging hooks is more than 10mm, the elastic inward-concave spring (12) is used.

6. A turbine blade with hook-fixed ceramic armor as described in claim 5, characterized in that: a spring diameter D (31) of said spring (12) is 0.5mm-2mm; a width W6 (29) of the spring hook segment is 1.7mm-4.5mm.

7. A turbine blade with hook-fixed ceramic armor as described in claim 1, characterized in that: The turbine blade metal substrate (11) is provided with a hook back side boss (21). The hook back side boss (21) is a cuboid. The hook back side boss height W4 (27) is 1.5mm~3mm, which can cover the hook vertical section (17). The hook back side boss width W3 (26) is 0.4mm~2.0mm.

8. A turbine blade with a hook-fixed ceramic armor as described in claim 1, characterized in that: The turbine blade metal substrate (11) is provided with a spring support boss (24). The spring support boss (24) is located in the inner hole of the armor mounting hole (20). Its top surface that contacts the spring (12) is flat and smooth. The height W2 (25) of the spring support boss is 0.2mm~1.5mm.

9. A turbine blade with a hook-fixed ceramic armor as described in claim 1, characterized in that: The installation process of the ceramic armor hook passing through the armor mounting hole (20) is divided into two steps: First, the armor moves along the inclined direction, and the inclined hole (40) applies a constraint to the inclined section (18) of the hook, so that it moves along the axial direction of the inclined hole (40) until the vertical section (17) of the hook moves to the position of the vertical hole (41) and stops; Second, the armor moves along the normal direction of the blade wall, and the vertical hole (41) applies a constraint to the vertical section (17) of the hook, so that it moves along the axial direction of the vertical hole (41) until the armor is in contact with the metal substrate (11) of the turbine blade or the gap is small, thus completing the installation of a single piece of ceramic armor.

10. A turbine blade with a hook-fixed ceramic armor as described in claim 1, characterized in that: The ceramic matrix composite leading edge armor (5), ceramic matrix composite blade back armor (6), ceramic matrix composite blade basin armor (7), ceramic matrix composite upper edge plate armor (8), ceramic matrix composite lower edge plate armor (9) and turbine blade metal matrix (11) are provided with gaps for the flow of cold air, including between the vertical section of the hook (17) and the armor mounting hole (20), and between the turbine blade metal matrix (11) and the armor, where the gap W8 (32) between the armor and the turbine blade metal matrix is ​​0.1mm~0.5mm.

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