CMC air-cooled turbine outer ring and design method thereof

Abstract

The invention provides a CMC air-cooled turbine outer ring and a design method thereof, and belongs to the technical field of aero-engines, and the method comprises the steps that the physical environment where the CMC air-cooled turbine outer ring is located and design requirements are determined; determining the type selection of the fiber material according to the design requirement of the outer ring of the CMC air-cooled turbine and the temperature bearing capacity of the fiber material; according to the design requirements of the outer ring of the CMC air-cooled turbine, different preform processes, densification processes and surface treatment processes are selected; constructing a simulation part based on the fiber material, a preform process, a densification process and a surface treatment process; carrying out multi-physics field simulation based on the simulation piece, and optimizing a preliminary structure scheme of the outer ring of the CMC air-cooled turbine; a simulation part is built, and a CMC air-cooled turbine outer ring simulation part level assessment test is carried out; if the structural scheme is reasonable, the detailed design of the outer ring of the CMC air-cooled turbine is carried out; and a turbine outer ring test piece is constructed, and a CMC air-cooled turbine outer ring component level assessment test is carried out.

Description

Technical Field

[0001] This application belongs to the field of aero-engine technology, and specifically relates to a CMC air-cooled turbine outer ring and its design method. Background Technology

[0002] like Figure 1 The diagram shows a typical turbine outer ring mounting structure 10. The turbine outer ring 11 is part of the engine's gas flow path. It cooperates with the tip of the turbine rotor blade 12 to form a tip clearance G1. By controlling the tip clearance G1, the amount of gas leakage during engine operation can be minimized to improve working efficiency. The turbine outer ring 11 is fixed by the outer ring fixing ring 14. There is generally an interstage clearance G2 between the turbine outer ring 11 and the guide vane 13 on the front side.

[0003] Because the turbine outer ring operates at very high temperatures, methods such as film cooling are typically used to reduce its temperature. To ensure coordinated thermal deformation between the turbine outer ring and the turbine casing, the turbine outer ring is usually composed of several circumferential sector-shaped blocks joined together, with sealing plates connecting the sector-shaped blocks to prevent airflow leakage. To avoid damage to the turbine blades caused by friction between the turbine outer ring and the blade tips due to changes in engine conditions, a wear-resistant coating of moderate hardness is generally sprayed onto the surface of the turbine outer ring. Since the coating on the turbine outer ring is in direct contact with the combustion gases, the coating material must be impact-resistant, corrosion-resistant, and possess a certain bonding strength.

[0004] Existing metal-based turbine outer rings are generally made of single-crystal or high-temperature alloy materials, and their design methods are as follows: Figure 2 As shown, the process begins with a requirements analysis of the turbine outer ring to determine its physical environment and stakeholder requirements, thereby determining the materials to be used. Next, based on the requirements list and technical foundation, the structural design of the turbine outer ring is carried out, and a thermal analysis is performed on the structural design. If the engine requirements are met, the detailed design of the turbine outer ring (engineering drawings) is completed. If the engine requirements are not met, the requirements analysis is repeated, and stakeholders are coordinated to adjust the operating environment or improve the structural design until the engine requirements are met.

[0005] However, with the shift from metal-based materials to CMC (Ceramic Matrix Composites) materials for turbine outer rings, the existing design process for metal-based turbine outer rings cannot meet the design requirements for CMC material turbine outer rings. Summary of the Invention

[0006] The purpose of this application is to provide a CMC air-cooled turbine outer ring and its design method to solve or mitigate at least one problem in the prior art.

[0007] The technical solution of this application is: a CMC air-cooled turbine outer ring design method, including:

[0008] Determine the physical environment and design requirements of the outer ring of the CMC air-cooled turbine;

[0009] The selection of fiber material is determined based on the design requirements of the CMC air-cooled turbine outer ring and the temperature and load-bearing capacity of the fiber material.

[0010] Based on the design requirements of the CMC air-cooled turbine outer ring, different preform processes, densification processes, and surface treatment processes are selected.

[0011] A simulated part was constructed based on the aforementioned fiber material and preform process, densification process, and surface treatment process;

[0012] Multiphysics simulations were conducted based on the aforementioned simulation components to optimize the preliminary structural scheme of the outer ring of the CMC air-cooled turbine.

[0013] Based on the preliminary structural design of the optimized CMC air-cooled turbine outer ring, a simulation component was constructed, and a simulation component-level evaluation test of the CMC air-cooled turbine outer ring was conducted to verify the feasibility of the structural design.

[0014] If the structural design is reasonable, then carry out detailed design of the outer ring of the CMC air-cooled turbine and draw up engineering drawings;

[0015] Based on the engineering drawings, a turbine outer ring test piece was fabricated, and a component-level assessment test of the CMC air-cooled turbine outer ring was carried out. If the assessment is passed, it indicates that the CMC air-cooled turbine outer ring obtained in the detailed design stage has the conditions for whole-machine verification and use.

[0016] In a preferred embodiment of this application, in conducting multiphysics simulation, a solid domain is established for the guide vane, rotor blade, and outer ring fixed ring, while a fluid domain is established for the interstage clearance and blade tip clearance. The interstage clearance includes the interstage axial clearance formed by the guide vane and the outer ring of the CMC air-cooled turbine, and the interstage radial clearance formed by the lower surface of the guide vane and the bottom surface of the outer ring of the CMC air-cooled turbine.

[0017] In a preferred embodiment of this application, the top surface of the rotor blade and the bottom surface of the outer ring of the CMC air-cooled turbine form a flow area for the gas blade tip gap. This flow area is divided into two regions at equal distances. The region near the bottom surface of the outer ring of the CMC air-cooled turbine is set as a fluid static region, and the region on the top surface of the rotor blade is a fluid flow region. A flow-flow boundary is set at the interface between the two regions.

[0018] In a preferred embodiment of this application, the CMC air-cooled turbine outer ring simulation component-level assessment tests include structural process tests, heat transfer tests, strength tests, and EBC performance tests or TBC performance tests.

[0019] In a preferred embodiment of this application, the evaluation tests at the CMC air-cooled turbine outer ring component level include cooling effect test, thermal erosion test, thermal shock test, wearable coating scraping and adhesion characteristic test.

[0020] On the other hand, the technical solution provided in this application is: a CMC air-cooled turbine outer ring, wherein the CMC air-cooled turbine outer ring is obtained by any of the CMC air-cooled turbine outer ring design methods described above.

[0021] The CMC air-cooled turbine outer ring design method provided in this application divides the design process of the CMC air-cooled turbine outer ring into two stages: schematic design and detailed design. The schematic design stage determines the outer ring configuration and fixes the process route; the detailed design stage allows for local optimization of assembly and manufacturing details, forming the final production plan. Through this two-stage design process, the operational risks of the ceramic matrix composite turbine outer ring in the overall machine state can be reduced step by step, minimizing trial and error costs. By defining the key technical activities and their specific connotations in each stage, the design process of the CMC air-cooled turbine outer ring is covered with strong logic and complete technical activities, identifying and avoiding risks, and supporting the integrated verification of the entire machine platform. Attached Figure Description

[0022] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.

[0023] Figure 1 This is a typical schematic diagram of the turbine outer ring and its installation location.

[0024] Figure 2 This is a schematic diagram of the design process for metal-based turbine outer rings in the prior art.

[0025] Figure 3 This is a schematic diagram of the design process for the outer ring of the CMC air-cooled turbine in this application.

[0026] Figure 4 This is a schematic diagram of the simulation region analysis in this application.

[0027] Figure 5 This is a schematic diagram of the mesh division of the dynamic-static interface in this application. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings.

[0029] There is currently no complete design process for Ceramic Matrix Composite (CMC) air-cooled turbine outer rings. If the existing design process for metal-based turbine outer rings is used, the following problems will occur:

[0030] 1) Compared with the relatively mature design and application system of metal outer rings, ceramic matrix composite air-cooled turbine outer rings are difficult to design and meet the requirements of use by relying on only one design stage due to the complexity of the process.

[0031] 2) In the design process of metal-based turbine outer rings, the design requirements can be met by material selection technology activities alone. However, ceramic-based composite turbine outer rings are components with strong coupling between materials and manufacturing processes. Material selection alone is insufficient to support the component design and cannot support the subsequent multiphysics simulation parameter input requirements.

[0032] 3) Thermal load ablation failure mode of metal-based turbine outer ring is relatively common, so its temperature resistance can be determined by thermal analysis alone. However, the comprehensive load-bearing characteristics of ceramic matrix composite turbine outer ring are still unclear, and multi-physics analysis is required to accurately determine whether its load-bearing capacity meets the requirements.

[0033] 4) The technology of ceramic matrix composite air-cooled turbine outer ring has low maturity. It is geared towards the needs of the whole machine. If the technical activities of test verification are not set up in the scheme and technical design stage, the simulation design results cannot be effectively verified, and it is difficult to support the reliability and safety of ceramic matrix composite turbine outer ring in the whole machine use stage.

[0034] Therefore, this application provides a design method for the outer ring (or simply outer ring) of a CMC air-cooled turbine, such as... Figure 3 As shown, the CMC airflow turbine outer ring design method of this application divides the design process of the CMC air-cooled turbine outer ring into two main stages—namely, the outer ring structure scheme design stage and the outer ring structure detailed design stage, specifically including:

[0035] Phase 1: Outer ring structure design, specifically including:

[0036] S11, Outer Ring Demand Analysis: Determine the physical environment of the outer ring of the CMC air-cooled turbine and the requirements of stakeholders for the outer ring.

[0037] The outer ring of a CMC air-cooled turbine is usually fixed to the turbine casing. It surrounds the high-speed rotating turbine rotor blades, thus forming a gas flow channel. The physical environment of the outer ring of a CMC air-cooled turbine is high temperature, high pressure, high stress, and complex vibration and aerodynamic environment.

[0038] S12, Fiber material selection: Based on the design requirements of the CMC air-cooled turbine outer ring, select suitable fiber materials, taking into account the temperature and load-bearing capacity of the fiber materials.

[0039] For example, the fiber materials that can be selected include carbon fiber, ceramic fiber, etc. The type of fiber material that can withstand the temperature and load of the environment in which the CMC air-cooled turbine outer ring is selected according to the physical environment of the CMC air-cooled turbine outer ring.

[0040] S13, Manufacturing process selection: Based on the design requirements of the CMC air-cooled turbine outer ring, different preform processes, densification processes, and surface treatment processes are selected.

[0041] Preform manufacturing refers to the controlled arrangement of fibers into a preform with a predetermined shape, orientation, and structure, reserving space and channels for the introduction of the matrix (resin, metal, ceramic). For ceramic matrix composites and carbon-based composites, preform manufacturing typically includes steps such as needle punching, chemical vapor infiltration, and three-dimensional weaving.

[0042] Densification refers to the process of combining porous fiber preforms with matrix materials to fill their internal pores, thereby forming a dense and robust composite material. For carbon-based composites, densification processes typically include chemical vapor infiltration and liquid-phase impregnation carbonization, while for ceramic matrix composites, densification processes typically include chemical vapor infiltration, polymer impregnation pyrolysis, and melt infiltration.

[0043] Surface treatment processes refer to the processes that alter the microstructure, chemical properties, and energy state of a composite material surface through physical or chemical methods, thereby significantly improving its adhesion, paintability, and compatibility with other materials. Surface treatment methods typically include mechanical treatment, chemical treatment, and plasma treatment.

[0044] The selection of composite materials and manufacturing processes has a significant impact on the design of the outer ring of a CMC air-cooled turbine. Based on the manufacturing characteristics of the CMC air-cooled turbine outer ring, this application adds two technical activities during the design phase: fiber material selection and manufacturing process selection, focusing on analyzing the impact of the manufacturing process on the design results. To this end, a sub-process for manufacturing process selection was outlined, and the feasibility of braided preform processes, densification processes, machining processes, and special processes was verified through process experiments.

[0045] S14, Outer Ring Structure Design: Based on the design requirements of the CMC air-cooled turbine outer ring and the selected process route, structural schemes for different process levels are designed to obtain the preliminary structural scheme of the CMC air-cooled turbine outer ring.

[0046] S15, Multiphysics Simulation of Outer Ring: Based on the intake fit structure of the CMC air-cooled turbine outer ring and turbine casing, the influence of guide vanes and rotor blades on the flow field, and the leakage of seals between turbine outer rings, multiphysics coupling simulation of multiple components is carried out to optimize the preliminary structural scheme of the CMC air-cooled turbine outer ring.

[0047] The high-pressure turbine outer ring is subjected to complex loads. This application employs multiphysics simulation to fully identify and analyze interactive loads—primarily including the cooling effect of leaking cold air from the guide vane and turbine casing clearance on the outer ring front end, the scouring heat transfer from the narrow clearance at the rotor blade tip and the guide vane outlet flow field on the outer ring gas side, the impact heat transfer from the gas collector shroud on the turbine outer ring cold air side, and the strength and mechanical loads generated by the pressure difference and assembly relationship between the two sides. To address the issue that a single physics field cannot accurately identify these loads, this application establishes a multiphysics simulation technology activity sub-process. Based on the turbine outer ring's operating environment, simulation regions are established for fixed rings, pins, rotor blades, etc., which form assembly and influence relationships with the outer ring. Further mesh generation and boundary condition loading are then performed to obtain results such as flow field, temperature field, and stress field. The rationality of the structural design is then determined based on the applicable standards.

[0048] In the simulation region analysis technology activities, establish Figure 4 The solid domains of the guide vanes, rotor blades, and outer ring fixed ring shown are combined with the fluid domains of the interstage clearance and blade tip clearance to form a complete computational domain. Specifically, the interstage axial clearance formed by the guide vanes and the outer ring requires the establishment of a fluid domain to allow cool air to flow out from this region. The interstage radial clearance formed by the lower surface of the guide vanes and the bottom surface of the outer ring must be considered during the design process, ensuring that the lower surface of the guide vanes is lower than the bottom surface of the outer ring to prevent the risk of ablation caused by the vertical impact of the combustion gases on the outer ring.

[0049] like Figure 5 As shown, the top surface of the rotor blades and the bottom surface of the CMC air-cooled turbine outer ring form a flow region for the gas tip clearance. Due to the influence of film jet cooling in the turbine outer ring, this region is divided into two regions at equal intervals in this application. The region near the bottom surface of the CMC air-cooled turbine outer ring is set as a fluid static region, mainly considering film jet cooling of the CMC outer ring; the region on the top surface of the rotor blades is a fluid flow region, mainly considering the influence of blade tip rotation on the gas. A flow-flow interface is set at the interface between the two regions to transfer calculation data.

[0050] S16, Outer Ring Simulation Test: By constructing a turbine outer ring simulation test piece, conduct simulation-level structural process tests, heat transfer tests, strength tests, and EBC (Environmental Barrier Coating) / TBC (Thermal Barrier Coating) performance tests to verify the feasibility of the structural scheme.

[0051] After verifying the feasibility of the multiphysics simulation scheme, a turbine outer ring simulation test piece is manufactured according to the selected process route to conduct turbine outer ring tests and verify the feasibility of the structural scheme. The turbine outer ring simulation piece is usually a simplified component; for example, its overall structure can be set as a plate structure rather than a ring structure.

[0052] Phase Two: Detailed Design of the Outer Ring Structure

[0053] S21, Detailed design of outer ring: If the multiphysics simulation and simulation test verification in the first stage are passed, the detailed design of the outer ring of the CMC air-cooled turbine will be carried out and engineering drawings will be drawn; if not, the selection of fiber materials, preform process, densification process and surface treatment process will be adjusted.

[0054] S22, Outer Ring Component Test: Based on the engineering drawings from the detailed design stage of the outer ring structure, the turbine outer ring test piece is fabricated. Component-level assessment tests are conducted, including CMC air-cooled turbine outer ring cooling effect test, thermal erosion test, thermal shock test, wearable coating scraping and adhesion characteristic test. If the assessment is passed, it indicates that the CMC air-cooled turbine outer ring obtained in the detailed design stage can meet the conditions for whole-machine verification and use, and the design process ends.

[0055] The CMC air-cooled turbine outer ring design method provided in this application divides the design process of the CMC air-cooled turbine outer ring into two stages: schematic design and detailed design. The schematic design stage determines the outer ring configuration and fixes the process route; the detailed design stage allows for local optimization of assembly and manufacturing details, forming the final production plan. Through this two-stage design process, the operational risks of the ceramic matrix composite turbine outer ring in the overall machine state can be reduced step by step, minimizing trial and error costs. By defining the key technical activities and their specific connotations in each stage, the design process of the CMC air-cooled turbine outer ring is covered with strong logic and complete technical activities, identifying and avoiding risks, and supporting the integrated verification of the entire machine platform.

[0056] Furthermore, based on the manufacturing, analysis, and usage characteristics of ceramic-based components, the method of this application incorporates relevant technical activities in the process, such as material and process selection, multiphysics simulation, and testing of simulated parts and components. These activities can effectively avoid failure modes such as outer ring misalignment, ablation, and coating peeling, thereby improving the overall performance of the outer ring.

[0057] Finally, the method of this application plans for simulation-level and component-level test verification to verify the reliability and performance of the outer ring design results in stages. The test categories mainly include static load test, cooling effect and flow characteristic test, gas thermal erosion and corrosion test, thermal shock test and coating scraping test.

[0058] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A design method for the outer ring of a CMC air-cooled turbine, characterized in that, include: Determine the physical environment and design requirements of the outer ring of the CMC air-cooled turbine; The selection of fiber material is determined based on the design requirements of the CMC air-cooled turbine outer ring and the temperature and load-bearing capacity of the fiber material. Based on the design requirements of the CMC air-cooled turbine outer ring, different preform processes, densification processes, and surface treatment processes are selected. A simulated part was constructed based on the aforementioned fiber material and preform process, densification process, and surface treatment process; Multiphysics simulations were conducted based on the aforementioned simulation components to optimize the preliminary structural scheme of the outer ring of the CMC air-cooled turbine. Based on the preliminary structural design of the optimized CMC air-cooled turbine outer ring, a simulation component was constructed, and a simulation component-level evaluation test of the CMC air-cooled turbine outer ring was conducted to verify the feasibility of the structural design. If the structural design is reasonable, then carry out detailed design of the outer ring of the CMC air-cooled turbine and draw up engineering drawings; Based on the engineering drawings, a turbine outer ring test piece was fabricated, and a component-level assessment test of the CMC air-cooled turbine outer ring was carried out. If the assessment is passed, it indicates that the CMC air-cooled turbine outer ring obtained in the detailed design stage has the conditions for whole-machine verification and use.

2. The CMC air-cooled turbine outer ring design method as described in claim 1, characterized in that, In conducting multiphysics simulations, a solid domain is established for the guide vane, rotor blade, and outer ring fixed ring, while a fluid domain is established for the interstage clearance and blade tip clearance. The interstage clearance includes the interstage axial clearance formed by the guide vane and the outer ring of the CMC air-cooled turbine, and the interstage radial clearance formed by the lower surface of the guide vane and the bottom surface of the outer ring of the CMC air-cooled turbine.

3. The CMC air-cooled turbine outer ring design method as described in claim 2, characterized in that, The top surface of the rotor blades and the bottom surface of the outer ring of the CMC air-cooled turbine form a flow area for the gas blade tip gap. This flow area is divided into two regions at equal distances. The region near the bottom surface of the outer ring of the CMC air-cooled turbine is set as the fluid static region, and the region on the top surface of the rotor blades is the fluid flow region. The interface between the two regions is set as a flow-flow boundary.

4. The CMC air-cooled turbine outer ring design method as described in claim 1, characterized in that, The evaluation tests for the CMC air-cooled turbine outer ring simulator include structural process tests, heat transfer tests, strength tests, and EBC performance tests or TBC performance tests.

5. The CMC air-cooled turbine outer ring design method as described in claim 1, characterized in that, The evaluation tests for the outer ring component of the CMC air-cooled turbine include cold effect test, thermal erosion test, thermal shock test, wearable coating scraping and adhesion characteristic test.

6. A CMC air-cooled turbine outer ring, characterized in that, The CMC air-cooled turbine outer ring is obtained using the CMC air-cooled turbine outer ring design method as described in any one of claims 1 to 5.

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