A design method of high-load low reynolds number low pressure turbine cascade

Abstract

This invention belongs to the field of aero-engine aerodynamic design and provides a design method for a high-load, low-Reynolds-number, low-pressure turbine blade cascade, applicable to high-bypass-ratio aero-engines operating under high-altitude cruise conditions. The method first constructs a reference blade cascade with a Zweifel coefficient of 0.7–1.1 and verifies its performance at a Reynolds number of 1 × 10⁻⁶. 4 ~5×10 4 The initial flow exhibits non-separated flow characteristics. Subsequently, while maintaining key geometric angles, an initial high-load blade cascade is generated by reducing the axial chord length or increasing the cascade pitch. Then, by reducing the installation angle and reconstructing the leading-edge blade back profile, the isentropic Mach number distribution of the accelerated section of the optimized blade cascade is matched with the reference blade cascade, ultimately obtaining a high-load blade cascade with a Zweifel coefficient of 1.2–1.44. This is achieved at a Reynolds number of 1 × 10⁻⁶. 4 Under operating conditions, its total pressure loss coefficient is ≤0.045 and its outlet flow angle deviation is ≤±1°, taking into account both high load and low Reynolds number aerodynamic performance.

Description

Technical Field

[0001] This invention belongs to the field of aerodynamic design technology for aero-engines, and relates to a design method for a high-load, low-Reynolds-number, low-pressure turbine blade cascade. Background Technology

[0002] The design of modern aero engines has always revolved around core objectives such as low fuel consumption, light weight, high thrust-to-weight ratio, and low cost. Achieving these performance targets highly depends on the meticulous design of key components. In high-bypass turbofan engines, the low-pressure turbine, as the core power unit driving the fan, not only has a decisive influence on the overall fuel consumption rate but is also one of the aerodynamic components with the lowest Reynolds number in the engine, especially under typical operating conditions such as high-altitude cruise, where its Reynolds number can be as low as 1×10⁻⁶. 4 5×10 4 Magnitude.

[0003] Under such low Reynolds number conditions, the flow is easily dominated by viscous effects, and the boundary layer is more prone to separation, resulting in a significant increase in total pressure loss of the blade cascade and a sharp decrease in aerodynamic efficiency. Therefore, effectively suppressing the performance degradation caused by low Reynolds number and achieving efficient operation is a key challenge in low-pressure turbine design.

[0004] Meanwhile, the low-pressure turbine is typically one of the heaviest hot-end components in an engine. To reduce overall engine weight and control costs, engineers often employ methods such as reducing the number of blades or shortening the axial chord length. However, both of these measures reduce cascade density (i.e., the pitch-to-chord ratio), directly increasing the aerodynamic load borne by a single blade. While increasing cascade load helps reduce turbine stage radial dimensions, structural weight, and manufacturing costs, it often comes at the cost of aerodynamic efficiency, especially at low Reynolds numbers where the conflict between high load and high efficiency is more acute. Increased load can induce stronger flow separation and secondary flow losses, further exacerbating performance degradation.

[0005] In summary, achieving synergistic optimization of high load and high aerodynamic performance under low Reynolds number conditions has become a critical technical bottleneck that urgently needs to be overcome in the design of low-pressure turbines for advanced aero-engines. Existing design methods are mostly based on empirical extrapolation of conventional load cascades, making it difficult to simultaneously meet the multiple requirements of weight reduction, cost reduction, and high-efficiency operation at high altitudes. Summary of the Invention

[0006] To address the technical problem of severely deteriorated aerodynamic performance of high-load, low-pressure turbine blade cascades under low Reynolds number conditions in existing technologies, making it difficult to balance weight reduction and efficiency, this invention discloses a design method for high-load, low-Reynolds number, low-pressure turbine blade cascades. This method involves systematically adjusting key geometric parameters of the blade cascade, such as axial chord length, cascade pitch, blade mounting angle, and leading edge profile, thereby increasing the Zweifel coefficient of the blade cascade to 1.2. While maintaining a high load level of 1.44, it can still maintain a total pressure loss level and outlet airflow angle matching characteristics comparable to those of conventional load blades. This effectively overcomes the flow instability and efficiency reduction problems caused by high loads under low Reynolds number environments, providing a practical technical path for the development of lightweight, efficient, and low-cost aero engines for high-altitude cruise conditions.

[0007] Specifically, the method is used for the design of low-pressure turbines for high-bypass ratio aero-engines under high-altitude cruise conditions, and includes the following steps:

[0008] S1: Construct a benchmark low-pressure turbine blade cascade and verify its performance at Reynolds number Re=1×10⁻⁶ using numerical simulation. 4 5×10 4 Under certain operating conditions, the uncovered section on the back of the blade exhibits non-separated flow characteristics, wherein the Zweifel coefficient of the reference low-pressure turbine blade cascade is 0.7 to 1.1. S2: While keeping the effective exhaust angle, inlet structure angle, trailing edge bend angle, trailing edge diameter, leading edge wedge angle, and trailing edge wedge angle of the reference low-pressure turbine blade cascade unchanged, an initial high-load blade cascade with a Zweifel coefficient of 1.2 to 1.44 is generated by reducing the axial chord length or increasing the cascade pitch, wherein the installation angle of the initial high-load blade cascade is the same as that of the reference low-pressure turbine blade cascade. S3: The initial high-load blade cascade is geometrically adjusted to optimize its aerodynamic performance, and its aerodynamic performance is verified by numerical simulation. A high-load, low-Reynolds-number, low-pressure turbine blade cascade with a Zweifel coefficient of 1.2 to 1.44 and non-separation flow characteristics in the uncovered section on the blade back is obtained.

[0009] Furthermore, in step S3, the aerodynamic performance is optimized by adjusting the initial high-load cascade geometry, including: S31: Calculate the blade back isentropic Mach number distribution curve of the reference low-pressure turbine blade cascade in the range of 5% to 30% of the axial chord length, and extract the first average slope of the curve. S32: Reduce the installation angle of the initial high-load blade cascade, so that the leading edge stagnation point moves backward along the pressure surface to compensate for the loss of acceleration capability caused by the reduction in consistency; S33: Based on the adjusted installation angle, reconstruct the leading edge blade profile of the initial high-load blade cascade within the range of 5% to 30% of the axial chord length, and calculate the second average slope of the new blade back isentropic Mach number distribution curve, so that the relative deviation between the first average slope and the second average slope does not exceed 5%; S34: Verify whether the uncovered section on the back of the reconstructed high-load low-pressure turbine blade cascade meets the design requirements, including having non-separated flow characteristics and whether it meets the requirements at a Reynolds number Re=1×10⁻⁶ compared to the reference low-pressure turbine blade cascade.4 5×10 4 Under the operating conditions, the total pressure loss coefficient increases by ≤5%, and the outlet flow angle deviation is ≤±1°; S35: If the verification fails, the installation angle and the leading edge blade profile are adjusted collaboratively for iterative optimization until a high-load, low-Reynolds-number, low-pressure turbine blade cascade that meets the design requirements is obtained.

[0010] Furthermore, in step S33, the leading edge back profile is reconstructed using a cubic B-spline curve, constrained by the curvature of the leading edge profile being continuous and without inflection points.

[0011] Further, in step S2, the axial chord length is reduced by 15% to 70% of the axial chord length of the reference low-pressure turbine blade cascade, and the cascade pitch is increased by 15% to 70% of the cascade pitch of the reference low-pressure turbine blade cascade.

[0012] Furthermore, in step S1, the trailing edge bend angle of the reference low-pressure turbine blade cascade is no greater than 15° to ensure that the reverse pressure gradient is gentle in the uncovered section on the back of the blade.

[0013] Furthermore, in steps S1 and S3, the numerical simulation employs a three-dimensional steady-state method based on the Reynolds-averaged Navier-Stokes equations. The turbulence model is the SST k-ω model, and the transition model is the Gamma-Theta model. The mesh near the blade wall is refined so that the dimensionless wall distance y corresponding to the first layer of mesh cells adjacent to the wall is... + Less than 1.

[0014] Compared with the prior art, the beneficial effects that at least one technical solution adopted in the embodiments of this specification can achieve include at least: 1. The designed high-load, low-Reynolds-number, low-pressure turbine blade cascade has excellent aerodynamic performance and lightweight structure. Compared with the reference blade cascade, the number of blades is reduced by about 40% (the number of blades can be reduced by increasing the cascade pitch) and the weight is reduced by about 30%, which significantly reduces manufacturing costs and rotor mechanical load, and can effectively support the engineering application of high-performance, low-cost low-pressure turbines; 2. The method of this invention is efficient and reproducible. By maintaining key geometric angles and synergistically optimizing the mounting angle and leading edge profile, a high-load blade cascade with a Zweifel coefficient of 1.44 can be rapidly constructed based on a conventionally loaded blade cascade with good low Reynolds number performance. This is achieved by keeping key geometric angles constant and adjusting only the axial chord length or pitch, while simultaneously optimizing the mounting angle and leading edge profile. Furthermore, its aerodynamic performance is comparable to the original reference blade cascade. This method overcomes the limitations of traditional methods that rely on qualitative experience, achieving rapid synergistic optimization of high-load and low Reynolds number performance.

[0015] 3. This method is particularly suitable for meeting the urgent needs of low-pressure turbine weight reduction, cost reduction and blade number adjustment in scenarios such as aero-engines, and provides a reliable technical path for the efficient optimization design of low-pressure turbines. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating the design method for a high-load, low-Reynolds-number, low-pressure turbine blade cascade disclosed in an embodiment of the present invention. Figure 2 A schematic diagram of a baseline low-pressure turbine blade cascade and a high-load low-pressure turbine blade cascade; Figure 3 A schematic diagram of the dimensions of a baseline low-pressure turbine blade cascade; Figure 4 A schematic diagram of the mounting angle of a reference low-pressure turbine blade cascade; Figure 5 The diagram shows the isentropic Mach number of the low-pressure turbine cascade surface under different Zweifel coefficients, where the horizontal axis represents the relative axial chord length and the vertical axis represents the isentropic Mach number. Among them, 1. Reference low-pressure turbine blade cascade; 2. High-load low Reynolds number low-pressure turbine blade cascade; 3. Uncovered section on the back of the reference low-pressure turbine blade cascade; 4. Uncovered section on the back of the high-load low-pressure turbine blade cascade; 5. Axial chord length of the reference low-pressure turbine blade cascade; 6. Blade pitch of the reference low-pressure turbine blade cascade; 7. Blade pitch of the high-load low-pressure turbine blade cascade; 8. Throat line; 9. Mounting angle of the reference low-pressure turbine blade cascade; 10. Mounting angle of the high-load low-pressure turbine blade cascade. Detailed Implementation

[0018] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0019] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features of the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] like Figures 1 to 5 As shown in the figure, this invention discloses a design method for a high-load, low-Reynolds-number, low-pressure turbine blade cascade. This method is used for the design of low-pressure turbines for high-bypass ratio aero-engines under high-altitude cruise conditions, and includes the following steps: S1: Construct a benchmark low-pressure turbine blade cascade and verify its performance at Reynolds number Re=1×10⁻⁶ using numerical simulation. 4 5×10 4 Under certain operating conditions, the uncovered section on the back of the blade exhibits non-separated flow characteristics, wherein the Zweifel coefficient of the reference low-pressure turbine blade cascade is 0.7 to 1.1.

[0021] In addition, such as Figure 3 As shown, the trailing edge bend angle of the constructed reference low-pressure turbine blade cascade 1 is no greater than 15° to ensure that the reverse pressure gradient of the uncovered section 3 on the back of the reference low-pressure turbine blade cascade is gentle.

[0022] In practical implementation, the design benchmark low-pressure turbine blade cascade 1 not only requires its Zweifel coefficient (which can be abbreviated as Zw coefficient) to be 0.7 to 1.1, but also needs to have good low Reynolds number aerodynamic performance. The specific construction steps are as follows: S11: Construct a reference low-pressure turbine blade cascade 1 with a Zweifel coefficient of 1.01. Control the reverse pressure gradient of the uncovered section 3 on the back of the reference low-pressure turbine blade cascade to obtain the optimal mounting angle 9 of the reference low-pressure turbine blade cascade. Ensure that under the target Reynolds number condition, as verified by steady viscous CFD simulation, there is no flow separation in this region. S12: Disconnect the blade back profile at the throat position to enhance the independence of the adjustment of the uncovered section 3 profile of the reference low-pressure turbine blade cascade. During the optimization of the blade back profile, the curvature of the profile before and after the throat should be continuous. S13: Adjust the reverse pressure gradient of the uncovered section 3 on the back of the reference low-pressure turbine blade cascade by adjusting the aerodynamic loading distribution of the blade cascade, and control the trailing edge turning angle to no more than 15°. If the CFD results show that there is separation, further reduce the trailing edge turning angle. S14: The trailing edge turning angle is not necessarily better the smaller it is. The optimal aerodynamic performance obtained from steady viscous CFD simulation should be taken as the final optimization goal.

[0023] S2: While keeping the effective exhaust angle, inlet structure angle, trailing edge turning angle, trailing edge diameter, leading edge wedge angle, and trailing edge wedge angle of the reference low-pressure turbine blade cascade unchanged, an initial high-load blade cascade with a Zweifel coefficient of 1.2 to 1.44 is generated by reducing the axial chord length 5 or the cascade pitch 6 of the reference low-pressure turbine blade cascade. The initial high-load low-pressure turbine blade cascade mounting angle 10 is the same as the reference low-pressure turbine blade cascade mounting angle 9, and the length of the uncovered section 4 on the back of the high-load low-pressure turbine blade cascade and the width of the throat line 8 are significantly increased.

[0024] In specific implementation, the axial chord length is reduced by 15% to 70% of the axial chord length 5 of the reference low-pressure turbine blade cascade, and the high-load low-pressure turbine cascade pitch 7 is increased by 15% to 70% of the pitch 6 of the reference low-pressure turbine blade cascade.

[0025] S3: The initial high-load blade cascade was geometrically adjusted to optimize its aerodynamic performance, and its aerodynamic performance was verified through numerical simulation, resulting in a high-load, low-Reynolds-number, low-pressure turbine blade cascade 2 with a Zweifel coefficient of 1.2–1.44 and non-separated flow characteristics in the uncovered section on the blade back. Furthermore, compared to the reference low-pressure turbine blade cascade 1, it exhibits better performance at a Reynolds number Re=1×10⁻⁶. 4 Under the operating conditions, the total pressure loss coefficient increases by ≤5%, the outlet flow angle deviation is ≤±1°, and the high-load low-pressure turbine blade installation angle 10 is the same as the reference low-pressure turbine blade installation angle 9.

[0026] In one embodiment of step S3 above, the aerodynamic performance is optimized by geometrically adjusting the initial high-load blade cascade, including the following steps: S31: Calculate the blade back isentropic Mach number distribution curve of the reference low-pressure turbine blade cascade in the range of 5% to 30% of the axial chord length, and extract the first average slope of the curve.

[0027] S32: Reduce the initial high-load blade angle to move the leading edge stagnation point back along the pressure surface to compensate for the loss of acceleration capability caused by reduced consistency.

[0028] S33: Based on the adjusted installation angle, reconstruct the leading edge back profile of the initial high-load blade cascade within the range of 5% to 30% of the axial chord length, and calculate the second average slope of the new blade back isentropic Mach number distribution curve, ensuring that the relative deviation between the first average slope and the second average slope does not exceed 5%. When reconstructing the leading edge back profile, the curvature of the leading edge back profile can be continuous and without inflection points, and a cubic B-spline curve can be used for reconstruction.

[0029] S34: Verify whether the uncovered section on the back of the reconstructed high-load low-pressure turbine blade cascade meets the design requirements, including having non-separated flow characteristics and whether it meets the requirements at a Reynolds number Re=1×10⁻⁶ compared to the reference low-pressure turbine blade cascade. 4 5×10 4 Under the operating conditions, the total pressure loss coefficient increases by ≤5%, and the outlet flow angle deviation is ≤±1°. S35: If the verification fails, the installation angle and the leading edge blade profile are adjusted collaboratively for iterative optimization until a high-load, low-Reynolds-number, low-pressure turbine blade cascade that meets the design requirements is obtained.

[0030] In one embodiment, in steps S1 and S3, the numerical simulation employs a three-dimensional steady-state method based on the Reynolds-averaged Navier-Stokes equations, wherein the turbulence model is the SST k-ω model, the transition model is the Gamma-Theta model, and the mesh near the blade wall is refined so that the dimensionless wall distance y corresponding to the first layer of mesh cells adjacent to the wall is... + Less than 1.

[0031] The core design of this invention lies in decoupling high-load design from low Reynolds number aerodynamic performance: First, a high-performance reference blade cascade with no separation flow at low Reynolds number is constructed based on a conventional load (Zweifel coefficient 0.7–1.1), ensuring that its uncovered back section has a gentle adverse pressure gradient and good acceleration capability; then, while keeping the key geometric angles of the reference blade cascade (such as the exhaust angle and trailing edge turning angle) unchanged, the load is increased to a Zweifel coefficient of 1.2–1.44 by reducing the axial chord length or increasing the cascade pitch, and the leading edge stagnation point is moved backward by reducing the installation angle. At the same time, the leading edge profile is reconstructed to match the slope of the isentropic Mach number distribution of the reference blade cascade in the 5%–30% chord length range. Thus, under the unfavorable conditions of reduced consistency and increased channel expansion, the leading edge acceleration characteristics of the reference blade cascade are reproduced, effectively suppressing boundary layer separation at low Reynolds number, and ultimately achieving a synergistic effect of high load and excellent aerodynamic performance at low Reynolds number.

[0032] The embodiments of the present invention achieve the following technical effects: 1. The designed high-load, low-Reynolds-number, low-pressure turbine blade cascade has excellent aerodynamic performance and lightweight structure. Compared with the standard blade cascade, the number of blades is reduced by about 40% (the number of blades can be reduced by increasing the cascade pitch) and the weight is reduced by about 30%, which significantly reduces manufacturing costs and rotor load, and can effectively support the engineering application of high-performance, low-cost low-pressure turbines. 2. The method of this invention is efficient and reproducible. By maintaining key geometric angles and synergistically optimizing the mounting angle and leading edge profile, a high-load blade cascade with a Zweifel coefficient of 1.2–1.44 can be rapidly constructed based on a conventionally loaded blade cascade with good low Reynolds number performance. This is achieved by keeping key geometric angles constant and adjusting only the axial chord length or cascade pitch, while simultaneously optimizing the mounting angle and leading edge profile. Furthermore, its aerodynamic performance is comparable to the original reference blade cascade. This method overcomes the limitations of traditional methods that rely on qualitative experience, achieving synergistic optimization of high-load and low Reynolds number performance.

[0033] 3. This method is particularly suitable for meeting the urgent needs of low-pressure turbine weight reduction, cost reduction and blade number adjustment in scenarios such as aero-engines, and provides a reliable technical path for the efficient optimization design of low-pressure turbines.

[0034] In this embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the above-described design method for any high-load, low-Reynolds-number, low-pressure turbine blade cascade.

[0035] Specifically, the computer device can be a computer terminal, a server, or a similar computing device.

[0036] In this embodiment, a computer-readable storage medium is provided, which stores a computer program that executes the design method of any of the above-described high-load, low-Reynolds-number, low-pressure turbine blade cascades.

[0037] Specifically, computer-readable storage media, including both permanent and non-permanent, removable and non-removable media, can store information using any method or technology. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer-readable storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable storage media does not include transient media, such as modulated data signals and carrier waves.

[0038] Obviously, those skilled in the art should understand that the modules or steps of the above-described embodiments of the present invention can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. Optionally, they can be implemented using computer-executable program code, thereby storing them in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those presented here, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the embodiments of the present invention are not limited to any particular hardware and software combination.

[0039] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the embodiments of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A design method for a high-load, low-Reynolds-number, low-pressure turbine blade cascade, characterized in that, The method for designing a low-pressure turbine for a high-bypass ratio aero-engines under high-altitude cruise conditions includes: A benchmark low-pressure turbine blade cascade is constructed, and its performance at Reynolds number Re=1×10⁻⁶ is verified through numerical simulation. 4 5×10 4 Under certain operating conditions, the uncovered section on the back of the blade exhibits non-separated flow characteristics, wherein the Zweifel coefficient of the reference low-pressure turbine blade cascade is 0.7 to 1.

1. While keeping the effective exhaust angle, inlet structure angle, trailing edge bend angle, trailing edge diameter, leading edge wedge angle, and trailing edge wedge angle of the reference low-pressure turbine blade cascade unchanged, an initial high-load blade cascade with a Zweifel coefficient of 1.2 to 1.44 is generated by reducing the axial chord length or increasing the cascade pitch, wherein the installation angle of the initial high-load blade cascade is the same as that of the reference low-pressure turbine blade cascade. The aerodynamic performance of the initial high-load blade cascade was optimized by geometric adjustment, and its aerodynamic performance was verified by numerical simulation. A high-load low Reynolds number low-pressure turbine blade cascade with a Zweifel coefficient of 1.2 to 1.44 and non-separation flow characteristics in the uncovered section on the back of the blade was obtained. Among them, the aerodynamic performance optimization is achieved by geometrically adjusting the initial high-load blade cascade, including: Calculate the blade back isentropic Mach number distribution curve of the reference low-pressure turbine blade cascade in the range of 5% to 30% of the axial chord length, and extract the first average slope of the curve. Reduce the installation angle of the initial high-load blade cascade, so that the leading edge stagnation point moves backward along the pressure surface to compensate for the loss of acceleration capability caused by the reduction in consistency; Based on the adjusted installation angle, the leading edge blade profile of the initial high-load blade cascade within the range of 5% to 30% of the axial chord length is reconstructed, and the second average slope of the new blade back isentropic Mach number distribution curve is calculated, so that the relative deviation between the first average slope and the second average slope does not exceed 5%; Verify whether the uncovered section on the back of the reconstructed high-load low-pressure turbine blade cascade meets the design requirements, including having non-separated flow characteristics and whether it meets the requirements at a Reynolds number Re=1×10⁻⁶ compared to the reference low-pressure turbine blade cascade. 4 5×10 4 Under the operating conditions, the total pressure loss coefficient increases by ≤5%, and the outlet flow angle deviation is ≤±1°; If the verification fails, the installation angle and the leading edge blade profile are adjusted collaboratively for iterative optimization until a high-load, low-Reynolds-number, low-pressure turbine blade cascade that meets the design requirements is obtained.

2. The design method for high-load, low-Reynolds-number, low-pressure turbine blade cascade according to claim 1, characterized in that, With the constraint that the curvature of the leading edge profile is continuous and without inflection points, the leading edge back profile is reconstructed using a cubic B-spline curve.

3. The design method for high-load, low-Reynolds-number, low-pressure turbine blade cascade according to claim 1, characterized in that, The axial chord length is reduced by 15% to 70% of the axial chord length of the reference low-pressure turbine blade cascade, and the cascade pitch is increased by 15% to 70% of the cascade pitch of the reference low-pressure turbine blade cascade.

4. The design method for high-load, low-Reynolds-number, low-pressure turbine blade cascade according to claim 1, characterized in that, The trailing edge bend angle of the reference low-pressure turbine blade cascade is no greater than 15° to ensure a gentle reverse pressure gradient in the uncovered section on the blade back.

5. The design method for high-load, low-Reynolds-number, low-pressure turbine blade cascade according to claim 1, characterized in that, The numerical simulation adopts a three-dimensional steady method based on the Reynolds-averaged Navier-Stokes equation, wherein a SST k-omega model is selected as the turbulence model, a Gamma-Theta model is selected as the transition model, and the grid near the blade wall is encrypted, so that the dimensionless wall distance y + is less than 1.

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