Ceramic matrix composite material flame tube matching design method and system

Abstract

The invention belongs to the field of aero-engines, relates to an engine main combustion chamber design technology, and provides a ceramic matrix composite material flame tube matching design method and system.The method comprises the steps that a flame tube wall temperature interval of a main working state point is obtained; determining the thermal-state radial dimensions of the feature points on the ceramic-based component and the metal component; converting the hot-state radial size into a cold-state radial size; carrying out two-dimensional cold-state flame tube profile design; and the cold-state radial size of the two-dimensional cold-state flame tube molded surface is converted into the hot-state size to obtain a two-dimensional hot-state flame tube molded surface, and a three-dimensional hot-state model is constructed and evaluated and iteratively optimized. According to the method, matching structure characteristic parameters of the ceramic-based component and the metal component are designed, and the molded surface of the flame tube made of the different materials is self-adaptively formed into smooth transition at main working state points, so that a backflow area is actively controlled, and the problems that the stability of a flow field of a main combustion chamber is influenced and pressure is lost due to different and relative displacement changes in the working process are solved.

Description

Technical Field

[0001] The present invention belongs to the field of aviation engines and relates to the design technology of the main combustion chamber of the engine, and in particular to a ceramic-based composite flame tube matching design method and system. Background Art

[0002] Thrust-to-weight ratio is a key performance metric for aircraft engines. Increasing the main combustion chamber outlet temperature and reducing engine weight are the most direct and effective methods for improving this ratio. For high-temperature combustion chambers, maintaining combustion performance requires significantly increasing the proportion of combustion air and reducing the proportion of cooling air. Under such harsh conditions, there is an urgent need to develop a new low-density, high-temperature-resistant material that can meet the performance requirements of the main combustion chamber while reducing weight to improve the engine's thrust-to-weight ratio.

[0003] Ceramic matrix composites have the characteristics of high temperature resistance, oxidation resistance, ablation resistance, high specific strength, low density, etc., and their long-term use temperature is 1350℃, which is about 150~350℃ higher than that of high-temperature alloys. At the same time, the density is 2~2.5g / cm 3 , only 1 / 3 to 1 / 4 of that of high-temperature alloys, and is one of the most promising thermal structural materials. The flame tube, as one of the core components of the main combustion chamber, constitutes the place where fuel and air are mixed for combustion. It directly withstands high temperature, high-pressure gas, as well as high thermal stress and vibration stress. The use of ceramic-based composite materials to manufacture the flame tube has the following main advantages: a) Weight Reduction: Ceramic-based composite flame tubes have a low density, resulting in significant weight reduction compared to similar components made of high-temperature alloys. Furthermore, ceramic-based composites offer higher temperature resistance, simplifying the complex cooling structure, further reducing the weight of the main combustion chamber and improving the engine's thrust-to-weight ratio.

[0004] b) Increase temperature rise: The long-term operating temperature of ceramic-based composite materials can be increased by 150 to 350°C compared to high-temperature alloys. This can fully release the temperature rise capacity of the main combustion chamber, increase the main combustion chamber outlet temperature, and thus improve the engine thrust-to-weight ratio.

[0005] c) Improve combustion performance: Ceramic-based composite materials have higher temperature resistance and can reduce the amount of cooling air in the flame tube. The remaining intake air can be used for head tissue combustion or mixing to improve the outlet temperature field.

[0006] d) Property matching: The flame tube is a thin-walled stator component that is not the main load-bearing component and has a relatively simple structure. It matches well with the properties of ceramic-based composite materials, which have low plasticity and tensile strength.

[0007] When designing flame tubes, ceramic-based composite materials have the characteristics of high hardness, heterogeneity, high hardness and brittleness, which makes the forming process difficult and the load-bearing capacity insufficient. Therefore, the commonly used material selection schemes for ceramic-based flame tubes are: high-temperature alloys are used for vortex finders and fairings with relatively complex structures, high-temperature alloys are used for the transition sections or load-bearing walls of the load-bearing frame, and ceramic-based composite materials are used for the outer ring, inner ring or tile of non-load-bearing components with relatively simple structures.

[0008] However, due to the large difference in linear expansion coefficients between ceramic-based composites and high-temperature alloys, during engine use, there is a continuous radial displacement of metal components relative to ceramic-based components, which can easily lead to turbulent flow separation in the main combustion chamber, large pressure loss, and non-designed air leakage, thereby affecting combustion performance. Summary of the Invention

[0009] In order to solve the technical problem that flame tubes made of ceramic matrix composite materials and high-temperature alloy materials have continuously changing radial displacement due to large differences in linear expansion coefficients, resulting in turbulent flow separation in the main combustion chamber, large pressure loss, and undesigned air leakage, which in turn affects combustion performance, the present invention discloses a matching design method for ceramic matrix composite flame tubes, the method comprising the following steps: S1. Within the engine envelope, select at least one typical operating state point as a main operating state point according to engine design requirements, and perform a two-dimensional simulation to obtain the flame tube wall temperature range for each of the main operating state points; S2. Obtaining the hot radial dimensions of characteristic points on the ceramic-based component and the metal component, respectively, based on the overall structural constraints of the engine and the overall layout of the main combustion chamber, as well as the main combustion chamber inlet and outlet parameters at the main operating state points; S3. Converting the hot radial dimension of each characteristic point into a cold radial dimension according to the flame tube wall temperature range and the material linear expansion coefficient; S4. Designing a two-dimensional cold flame tube profile based on the flame tube wall temperature range and all the cold radial dimensions, and calculating matching structural characteristic parameters of the ceramic-based component and the metal component to obtain a two-dimensional cold flame tube profile; S5. Converting the cold radial dimensions of the ceramic-based component and the metal component in the two-dimensional cold flame tube profile into hot dimensions based on the flame tube wall temperature range and the material linear expansion coefficient to obtain a two-dimensional hot flame tube profile, and circumferentially rotating the two-dimensional hot flame tube profile to form a three-dimensional hot model; S6. At each of the main working state points, the three-dimensional hot model is simulated and analyzed by a simulation method to obtain the flow field quality, and the two-dimensional cold flame tube profile is iteratively optimized according to the flow field quality until a three-dimensional hot model and a two-dimensional cold model that meet the flow field quality requirements are obtained.

[0010] Furthermore, in step S1, the typical operating state points include the maximum aerodynamic load state, the cruising state, the idling state and the design state, and the engine design requirements include the engine mission profile and the time proportion of each typical operating state point.

[0011] Furthermore, in step S1, a two-dimensional simulation calculation is performed to obtain the flame tube wall temperature range of each of the main working state points, including: S11, extracting the main combustion chamber performance parameters at each of the main operating state points, the main combustion chamber performance parameters including the main combustion chamber inlet air total temperature, inlet air total pressure, inlet air flow rate, and fuel supply; S12. Simulate the flow field distribution and temperature field distribution by numerical fluid mechanics methods to obtain the flame tube flow distribution result. Based on the main combustion chamber performance parameters and the flame tube flow distribution result, carry out two-dimensional simulation calculation and analysis to obtain the flame tube wall temperature range of each main working state point.

[0012] Furthermore, in step S2, based on the overall structural limitations of the engine and the overall layout of the main combustion chamber, as well as the main combustion chamber inlet and outlet parameters at the main working state points, the hot radial dimensions of the characteristic points on the ceramic-based component and the metal component are obtained respectively, including: S21. Determine the overall dimensions of the main combustion chamber and the volume of the flame tube based on the overall structural limitations of the engine and the overall layout of the main combustion chamber; S22. According to the overall size of the main combustion chamber, the volume of the flame tube and the inlet and outlet parameters of the main combustion chamber at the main working state point, the hot radial dimensions of the characteristic points on the ceramic-based component and the metal component are obtained respectively. The characteristic points on the ceramic-based component include the main combustion hole, mixing hole and outlet of the flame tube, and the characteristic points on the metal component include the vortex finder outlet, the outer ring of the splash plate and the inner ring of the splash plate.

[0013] Furthermore, in step S3, by formula: The hot radial size of each feature point is converted into the cold radial size, H 冷 H is the cold radial dimension. 热 is the hot radial dimension, T1 is the hot wall temperature of the characteristic point extracted from the flame tube wall temperature range, T0 is the given flame tube cold wall temperature, is the linear expansion coefficient of the material.

[0014] Furthermore, in step S4, a two-dimensional cold flame tube profile design is performed based on the flame tube wall temperature range and all the cold radial dimensions, and matching structural characteristic parameters of the ceramic-based component and the metal component are calculated, including: S41. Extracting the flame tube inner ring wall temperature, the splash plate wall temperature, and the flame tube outer ring wall temperature from the flame tube wall temperature range, and calculating the difference between the cold radial dimension of the vortex finder outlet and the cold radial dimension of the splash plate inner ring as the cold dimension of the splash plate inner ring; S42, obtaining the thermal expansion amount of the flame tube inner ring according to the flame tube inner ring wall temperature, the flame tube inner ring diameter, the material linear expansion coefficient, and the flame tube cold wall temperature; S43, obtaining a hot cooling gap between the inner ring of the splash plate and the inner ring of the flame tube in a hot state according to the thermal expansion amount of the inner ring of the flame tube, the wall temperature of the splash plate, the cold size of the inner ring of the splash plate, the cooling gap of the inner ring of the splash plate in a cold state, the linear expansion coefficient of the material, and the cold wall temperature of the flame tube; S44, obtaining the matching dimensions between the flame tube outer ring and the flame tube head transition section based on the flame tube outer ring wall temperature, the flame tube outer ring diameter, the flame tube outer ring cylinder wall thickness, the material linear expansion coefficient, and the flame tube cold wall temperature; S45. Obtain the hot cooling gap between the outer ring of the splash plate and the outer ring of the flame tube in the hot state according to the outer ring wall temperature of the flame tube, the outer ring diameter of the flame tube, the linear expansion coefficient of the material, the cold wall temperature of the flame tube, the outer ring size of the splash plate, and the cold cooling gap of the outer ring of the splash plate.

[0015] Furthermore, in the above steps S42 to S45, By formula Calculate the thermal expansion of the flame tube inner ring L1, D1 is the flame tube inner ring diameter, T0 is the given flame tube cold wall temperature, is the linear expansion coefficient of the material; By formula Calculate the hot cooling gap L between the inner ring of the splash plate and the inner ring of the flame tube in the hot state 2热 , L 2冷 is the cooling gap of the inner ring of the splash plate in the cold state, with a value of 0~20mm, L3 is the cold size of the inner ring of the splash plate, T3 is the wall temperature of the splash plate, L 2热 The value range is 0~30mm; By formula Calculate the fitting dimension L5 between the outer ring of the flame tube and the transition section of the flame tube head. H1 is the given outer ring wall thickness of the flame tube, D2 is the outer ring diameter of the flame tube, T4 is the outer ring wall temperature of the flame tube, and L5 ranges from 0 to 50 mm. By formula: Calculate the hot cooling gap L between the outer ring of the splash plate and the outer ring of the flame tube in the hot state 6热 , L 6冷 The cooling gap of the outer ring of the splash plate in the cold state is 0~30mm. L4 is the size of the outer ring of the splash plate. 6热 The value range is 0~20mm.

[0016] An embodiment of the present invention also provides a ceramic-based composite flame tube matching design system, including a flame tube wall temperature range acquisition module, a hot radial dimension calculation module, a hot-cold dimension conversion module, a two-dimensional cold flame tube profile design module, a three-dimensional hot model construction module and an evaluation and optimization module.

[0017] The flame tube wall temperature range acquisition module is used to select at least one typical operating state point as a main operating state point within the engine envelope according to the engine design requirements, and perform a two-dimensional simulation calculation to obtain the flame tube wall temperature range of each main operating state point; The hot radial dimension calculation module is used to obtain the hot radial dimensions of characteristic points on the ceramic-based component and the metal component respectively according to the overall structural limitations of the engine and the overall layout of the main combustion chamber, as well as the inlet and outlet parameters of the main combustion chamber at the main working state points; The hot-cold dimension conversion module is used to convert the hot radial dimension of each characteristic point into the cold radial dimension according to the flame tube wall temperature range and the material linear expansion coefficient, and convert the cold radial dimensions of the ceramic-based component and the metal component in the two-dimensional cold flame tube profile into the hot dimensions respectively; The two-dimensional cold flame tube profile design module is used to perform two-dimensional cold flame tube profile design based on the flame tube wall temperature range and all the cold radial dimensions, calculate the matching structural characteristic parameters of the ceramic-based component and the metal component, and obtain the two-dimensional cold flame tube profile; The three-dimensional thermal model construction module is used to circumferentially rotate the two-dimensional thermal flame tube profile to form a three-dimensional thermal model; The evaluation and optimization module is used to simulate and analyze the three-dimensional hot model at each of the main working state points through a simulation method to obtain the flow field quality, and iteratively optimize the two-dimensional cold flame tube surface according to the flow field quality until a three-dimensional hot model and a two-dimensional cold model that meet the flow field quality requirements are obtained.

[0018] Compared with the prior art, the at least one technical solution adopted in the embodiments of this specification can achieve the following beneficial effects: The ceramic-based composite flame tube matching design method of the present invention determines the characteristic parameters of the dissimilar material transition surface according to the main working state of the flame tube, and adaptively forms a smooth transition of the dissimilar material transition surface (i.e., the transition surface between the ceramic-based component and the metal component) at the preset main working state point, thereby actively controlling the reflow zone to solve the problem of relative displacement changes caused by differences in the linear expansion coefficients of the dissimilar material components during engine operation, thereby affecting the stability of the flow field in the main combustion chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0020] Figure 1 This is a flow chart of the ceramic matrix composite flame tube matching design method of the present invention; Figure 2 A schematic diagram of a cold metal component and a ceramic-based component structure disclosed in an embodiment of the present invention; Figure 3 A schematic diagram of a hot metal component and a ceramic-based component structure disclosed in an embodiment of the present invention; Figure 4 This is a diagram of the architecture of the ceramic matrix composite flame tube matching design system of the present invention; Among them, 1. Fairing; 2. Adapter section; 3. Vortex finder mounting seat; 4. Splash plate; 5. Flame tube outer ring cylinder; 6. Flame tube inner ring cylinder; 401. Flame tube wall temperature range acquisition module; 402. Hot radial dimension calculation module; 403. Hot and cold dimension conversion module; 404. Two-dimensional cold flame tube profile design module; 405. Three-dimensional hot model construction module; 406. Evaluation and optimization module. DETAILED DESCRIPTION

[0021] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0022] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the features of the following embodiments and embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of this application.

[0023] The embodiment of the present invention discloses a ceramic matrix composite flame tube matching design method, see Figure 1 As shown, the method includes the following steps: S1. Within the engine envelope, select at least one typical operating state point as a main operating state point according to engine design requirements, and perform a two-dimensional simulation to obtain the flame tube wall temperature range for each of the main operating state points; S2. Obtaining the hot radial dimensions of characteristic points on the ceramic-based component and the metal component, respectively, based on the overall structural constraints of the engine and the overall layout of the main combustion chamber, as well as the main combustion chamber inlet and outlet parameters at the main operating state points; S3. Converting the hot radial dimension of each characteristic point into a cold radial dimension according to the flame tube wall temperature range and the material linear expansion coefficient; S4. Designing a two-dimensional cold flame tube profile based on the flame tube wall temperature range and all the cold radial dimensions, calculating matching structural characteristic parameters of the ceramic-based component and the metal component, and obtaining a two-dimensional cold flame tube profile; S5. Converting the cold radial dimensions of the ceramic-based component and the metal component in the two-dimensional cold flame tube profile into hot dimensions based on the flame tube wall temperature range and the material linear expansion coefficient to obtain a two-dimensional hot flame tube profile, and circumferentially rotating the two-dimensional hot flame tube profile to form a three-dimensional hot model; S6. At each of the main working state points, the three-dimensional hot model is simulated and analyzed by a simulation method to obtain the flow field quality, and the two-dimensional cold flame tube profile is iteratively optimized according to the flow field quality until a three-dimensional hot model and a two-dimensional cold model that meet the flow field quality requirements are obtained.

[0024] In one possible implementation of step S1, typical operating state points within the engine envelope may be sorted out. The typical operating state points include but are not limited to the maximum aerodynamic load state, the cruising state, the idling state, and the design state. The engine design requirements include the engine mission profile and the time proportion of each typical operating state point.

[0025] In one possible implementation of the above step S1, performing a two-dimensional simulation calculation to obtain the flame tube wall temperature range of each of the main working state points includes: S11, extracting the main combustion chamber performance parameters at each of the main operating state points, the main combustion chamber performance parameters including the main combustion chamber inlet air total temperature, inlet air total pressure, inlet air flow rate, and fuel supply; S12. Simulate the flow field distribution and temperature field distribution by numerical fluid mechanics methods to obtain the flame tube flow distribution result. Based on the main combustion chamber performance parameters and the flame tube flow distribution result, carry out two-dimensional simulation calculation and analysis to obtain the flame tube wall temperature range of each main working state point.

[0026] In one possible implementation of step S2, the hot radial dimensions of characteristic points on the ceramic-based component and the metal component are obtained respectively based on the overall structural limitations of the engine and the overall layout of the main combustion chamber, as well as the inlet and outlet parameters of the main combustion chamber at the main operating state points, including: S21. Determine the overall dimensions of the main combustion chamber and the volume of the flame tube based on the overall structural limitations of the engine and the overall layout of the main combustion chamber. Specifically, the basic dimensions of the combustion chamber can be calculated based on the thrust requirements of the engine. Determine the volume of the combustion chamber based on the compressor outlet flow rate and the requirements of the combustion process. Adjust the length, diameter, and shape of the flame tube through optimization algorithms (such as CFD simulation). Adjust the flame tube volume and optimize the design of the cooling channel based on the cooling requirements and heat load calculations.

[0027] S22. According to the overall size of the main combustion chamber, the volume of the flame tube and the inlet and outlet parameters of the main combustion chamber at the main working state point, the hot radial dimensions of the characteristic points on the ceramic-based component and the metal component are obtained respectively. The characteristic points on the ceramic-based component include the main combustion hole, mixing hole and outlet of the flame tube, and the characteristic points on the metal component include the vortex finder outlet, the outer ring of the splash plate and the inner ring of the splash plate.

[0028] In one possible implementation of step S3, based on the flame tube wall temperature range, hot dimensions, and material linear expansion coefficient obtained by the above calculations, the hot radial dimensions of each characteristic point are converted into cold radial dimensions according to the following formula. Specifically, the formula: The hot radial size of each feature point is converted into the cold radial size, H 冷 H is the cold radial dimension. 热 is the hot radial dimension, T1 is the hot wall temperature of the characteristic point extracted from the flame tube wall temperature range, T0 is the cold wall temperature of the flame tube, this value is taken from the standard ambient temperature and is a given value at room temperature. The linear expansion coefficient of the material includes the linear expansion coefficient of metal materials and the linear expansion coefficient of ceramic matrix composite materials. The linear expansion coefficient of ceramic matrix composite materials is used when calculating the cold radial dimensions of ceramic-based components, and the linear expansion coefficient of metal materials is used when calculating the cold radial dimensions of metal components.

[0029] In one possible implementation of step S4, a two-dimensional cold flame tube profile design can be carried out based on the calculated cold radial dimensions of each characteristic point, and the matching structural characteristic parameters of the ceramic-based component and the metal component can be calculated. During the design, the flame tube body profile is mainly composed of one or several straight segments and the transition segments between them. The overall cross-sectional changes should be smooth, wherein the straight segments should be parallel to the main combustion chamber axis or form a fixed angle, and the transition segments should be smoothly connected. This can be understood as: the cold radial dimensions of all characteristic points are connected to form a two-dimensional profile. See Figure 2 and Figure 3 As shown, the metal components (including the guide cover 1, the transition section 2, the vortex finder mounting seat 3 and the splash plate 4 connected as a whole by welding or bolts) and the ceramic-based components (including the flame tube outer ring cylinder 5 and the flame tube inner ring cylinder 6) should be axially limited and radially free to expand to avoid the ceramic-based components from being subjected to additional mechanical loads or thermal stresses.

[0030] For specific implementation, see Figure 2 As shown, the two-dimensional cold flame tube profile design is performed based on the flame tube wall temperature range and all the cold radial dimensions to calculate the matching structural characteristic parameters of the ceramic-based component and the metal component, including: S41. Extract the flame tube inner ring wall temperature, the splash plate wall temperature, and the flame tube outer ring wall temperature from the flame tube wall temperature range, and calculate the difference between the cold radial dimension of the vortex finder outlet and the cold radial dimension of the splash plate inner ring as the cold dimension of the splash plate inner ring.

[0031] S42. Obtain the thermal expansion of the flame tube inner ring according to the flame tube inner ring wall temperature, the flame tube inner ring diameter, the material linear expansion coefficient, and the flame tube cold wall temperature.

[0032] During specific implementation, the metal component should be radially lower than the inner ring cylinder of the ceramic-based component flame tube when in a cold state. The radial height difference is the preset thermal expansion amount L1 of the inner ring of the flame tube. L1 is positively correlated with the inner ring wall temperature T2 of the flame tube and the inner ring diameter D1 of the flame tube (from the two-dimensional surface) at the main working state point, and is calculated and determined by the following formula. In the cold state, a stable and small recirculation zone is formed on the back side of the metal component to avoid separation of the two annular cavity airflows; in the hot state, since the linear expansion coefficient of the metal material is greater than that of the ceramic-based composite material, the metal component expands radially relative to the inner ring of the flame tube. At the preset main working state point, the surfaces of the two adapt to form a smooth transition, thereby avoiding turbulence in the two annular cavity flow fields.

[0033] By formula Calculate the thermal expansion of the flame tube inner ring L1, D1 is the flame tube inner ring diameter, T0 is the given flame tube cold wall temperature, is the linear expansion coefficient of the material.

[0034] S43. Obtain the hot cooling gap between the inner ring of the splash plate and the inner ring of the flame tube in the hot state according to the thermal expansion of the inner ring of the flame tube, the wall temperature of the splash plate, the cold size of the inner ring of the splash plate, the cooling gap of the inner ring of the splash plate in the cold state, the linear expansion coefficient of the material and the cold wall temperature of the flame tube.

[0035] In specific implementation, the cold state cooling gap L of the splash plate inner ring can be designed according to the preset thermal expansion amount L1 of the flame tube inner ring, the cold state dimension L3 of the splash plate inner ring (the difference between the cold state radial dimension of the vortex finder and the cold state radial dimension of the splash plate inner ring) and the splash plate wall temperature T3 (extracted from the temperature range). 2冷 , L 2冷 The value is between 0 and 20 mm to form the first cooling air film in the inner ring of the flame tube to meet the cooling design requirements; at the same time, it must meet the requirements of L 2热 The value ranges from 0 to 30 mm, L 2热 The following formula is used to calculate and determine the cooling channel area formed by the inner ring of the splash plate and the inner ring of the flame tube. This ensures that the cooling channel area formed by the inner ring of the splash plate and the inner ring of the flame tube is controlled when the engine is running, does not affect the flow field and cooling flow distribution at the head of the flame tube, and avoids interference and friction between the splash plate and the inner ring of the flame tube, blocking the air flow channel and affecting the cooling of the inner ring of the flame tube.

[0036] By formula Calculate the hot cooling gap L between the inner ring of the splash plate and the inner ring of the flame tube in the hot state 2热 , L 2热 The value range is 0~30mm, L 2冷 The cooling gap of the inner ring of the splash plate in the cold state is 0~20mm, L3 is the cold size of the inner ring of the splash plate, and T3 is the wall temperature of the splash plate.

[0037] S44. Obtain the matching dimensions between the flame tube outer ring and the flame tube head transition section according to the flame tube outer ring wall temperature, the flame tube outer ring diameter, the flame tube outer ring cylinder wall thickness, the material linear expansion coefficient and the flame tube cold wall temperature.

[0038] In specific implementation, the metal component should be lower than the outer ring of the flame tube when cold. The preset thermal expansion of the flame tube outer ring is determined using the same calculation method. In the cold and low-temperature states, a stable and small recirculation zone will form on the back of the metal component, reducing the impact on the flow field of the two annular cavities. In the hot state, the metal component expands radially relative to the outer ring of the flame tube. At the preset key operating state point, the two surfaces adapt to form a smooth transition, thus ensuring the stability of the main combustion chamber flow. The mating surface dimension L5 is designed based on the outer ring wall temperature T4 of the flame tube, the outer ring diameter D2 of the flame tube (derived from the two-dimensional surface), and the outer ring wall thickness H1 of the flame tube (given during design). L5 is determined by a formula and ranges from 0 to 50 mm to prevent undesigned air leakage caused by the mating surface disengagement during operation.

[0039] By formula Calculate the fitting dimension L5 between the outer ring of the flame tube and the transition section of the flame tube head. H1 is the given wall thickness of the outer ring of the flame tube, D2 is the diameter of the outer ring of the flame tube, T4 is the wall temperature of the outer ring of the flame tube, and L5 is 0~50mm.

[0040] S45. Obtain the hot cooling gap between the outer ring of the splash plate and the outer ring of the flame tube in the hot state according to the outer ring wall temperature of the flame tube, the outer ring diameter of the flame tube, the linear expansion coefficient of the material, the cold wall temperature of the flame tube, the outer ring size of the splash plate, and the cold cooling gap of the outer ring of the splash plate.

[0041] In specific implementation, the cooling gap L of the cold splash plate outer ring can be designed according to the thermal expansion of the flame tube outer ring and the size L4 of the splash plate outer ring. 6冷 , L 6冷 The value is between 0 and 30 mm to ensure that the cooling effect of the first section of the outer ring of the flame tube meets the design requirements; at the same time, the splash plate cooling gap L in the hot state must be met. 6热 The value ranges from 0 to 20 mm, L 6热 It is determined by calculation using a formula to ensure that the cooling channel area formed by the outer ring of the splash plate and the outer ring of the flame tube is controlled when the engine is working, without affecting the flow field and cooling flow distribution at the head of the flame tube, and avoiding interference and friction between the splash plate and the outer ring of the flame tube, blocking the air flow channel and affecting the local cooling of the outer ring of the flame tube.

[0042] Calculate the hot cooling gap L between the outer ring of the splash plate and the outer ring of the flame tube in the hot state 6热 , L 6热 The value range is 0~20mm, L 6冷 L4 is the cooling gap of the outer ring of the splash plate in the cold state, with a value of 0~30mm. L4 is the size of the outer ring of the splash plate.

[0043] In one possible implementation of the above step S5, see Figure 3 As shown, the cold dimensions of the ceramic-based components and the metal components (including L 2冷 , L3, D1, D2, L 6冷 , L4, etc.) to hot size calculation. In specific implementation, based on the flame tube wall temperature range, hot size and linear expansion coefficient of metal materials / ceramic matrix composite materials, the cold size of the two-dimensional cold flame tube profile is converted into the hot size to obtain a two-dimensional hot flame tube profile, and then the two-dimensional hot flame tube profile is circumferentially rotated to form a three-dimensional hot model.

[0044] In one possible implementation of the above step S6, the three-dimensional thermal model of the flame tube can be used to simulate and calculate the main working state points to obtain the flow field quality, and the flow field quality (including parameters such as pressure loss, airflow velocity, and airflow stability) can be analyzed and evaluated (it is necessary to ensure that the airflow velocity in the two-stream channel annular cavity is appropriate, and at the same time, there is no airflow separation at the connection between the cap and the two-stream annular cavity, and the airflow in the annular cavity is smooth and there is no separation phenomenon). When there is a local airflow separation phenomenon, it is necessary to modify the two-dimensional cold flame tube profile in a targeted manner (for example, the L can be modified). 2热 The value range is 0~30mm, L 6冷 The value range is 0~30mm, L 6热The cold size conversion to hot size calculation and three-dimensional flow field simulation calculation are iteratively performed until a three-dimensional hot model that meets the flow field quality requirements is obtained.

[0045] The ceramic-based composite flame tube matching design method of the present invention determines the characteristic parameters of the dissimilar material transition surface according to the main working state of the flame tube, and adaptively forms a smooth transition of the dissimilar material transition surface (i.e., the transition surface between the ceramic-based component and the metal component) at the preset main working state point, thereby actively controlling the reflow zone to solve the problem of relative displacement changes caused by differences in the linear expansion coefficients of the dissimilar material components during engine operation, thereby affecting the stability of the flow field in the main combustion chamber.

[0046] Based on the same inventive concept, an embodiment of the present invention further provides a ceramic matrix composite flame tube matching design system, as described in the following embodiments. Since the principle of solving the problem by the ceramic matrix composite flame tube matching design system is similar to that of the ceramic matrix composite flame tube matching design method, the implementation of the ceramic matrix composite flame tube matching design system can refer to the implementation of the ceramic matrix composite flame tube matching design method disclosed in the above embodiments, and the repeated parts will not be repeated. As used below, the term "unit" or "module" can be a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, implementation in hardware, or a combination of software and hardware, is also possible and conceivable.

[0047] Figure 4 This is a structural block diagram of a ceramic matrix composite flame tube matching design system disclosed in an embodiment of the present invention, such as Figure 4 As shown, the system includes a flame tube wall temperature range acquisition module 401, a hot radial dimension calculation module 402, a hot and cold dimension conversion module 403, a two-dimensional cold flame tube profile design module 404, a three-dimensional hot model construction module 405 and an evaluation and optimization module 406. The structure is described below.

[0048] The flame tube wall temperature range acquisition module 401 is used to select at least one typical operating state point as a main operating state point within the engine envelope according to engine design requirements, and perform a two-dimensional simulation calculation to obtain the flame tube wall temperature range of each main operating state point; The hot radial dimension calculation module 402 is used to obtain the hot radial dimensions of characteristic points on the ceramic-based component and the metal component respectively based on the overall structural limitations of the engine and the overall layout of the main combustion chamber, as well as the main combustion chamber inlet and outlet parameters at the main operating state points; The hot-cold dimension conversion module 403 is used to convert the hot radial dimension of each feature point into the cold radial dimension according to the flame tube wall temperature range and the material linear expansion coefficient, and convert the cold radial dimensions of the ceramic-based component and the metal component in the two-dimensional cold flame tube profile into the hot dimensions respectively; The two-dimensional cold flame tube profile design module 404 is used to perform two-dimensional cold flame tube profile design based on the flame tube wall temperature range and all the cold radial dimensions, calculate the matching structural characteristic parameters of the ceramic-based component and the metal component, and obtain the two-dimensional cold flame tube profile; The three-dimensional thermal model building module 405 is used to circumferentially rotate the two-dimensional thermal flame tube profile to form a three-dimensional thermal model; The evaluation and optimization module 406 is used to simulate and analyze the three-dimensional hot model at each of the main working state points through a simulation method to obtain the flow field quality, and iteratively optimize the two-dimensional cold flame tube surface according to the flow field quality until a three-dimensional hot model and a two-dimensional cold model that meet the flow field quality requirements are obtained.

[0049] Obviously, those skilled in the art will understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations are possible in the embodiments of the present invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A ceramic matrix composite flame tube matching design method, characterized in that: include: Within the engine envelope, at least one typical operating state point is selected as the main operating state point according to the engine design requirements, and a two-dimensional simulation calculation is performed to obtain the flame tube wall temperature range of each of the main operating state points; According to the overall structural limitations of the engine and the overall layout of the main combustion chamber, as well as the main combustion chamber inlet and outlet parameters at the main working state points, the hot radial dimensions of the characteristic points on the ceramic-based component and the metal component are respectively obtained; Converting the hot radial dimension of each characteristic point into a cold radial dimension according to the flame tube wall temperature range and the material linear expansion coefficient; Based on the flame tube wall temperature range and all the cold radial dimensions, a two-dimensional cold flame tube profile is designed, and matching structural characteristic parameters of the ceramic-based component and the metal component are calculated to obtain a two-dimensional cold flame tube profile; According to the flame tube wall temperature range and the material linear expansion coefficient, the cold radial dimensions of the ceramic-based component and the metal component in the two-dimensional cold flame tube profile are converted into hot dimensions to obtain a two-dimensional hot flame tube profile, and the two-dimensional hot flame tube profile is circumferentially rotated to form a three-dimensional hot model; At each of the main working state points, the three-dimensional hot model is simulated and analyzed by a simulation method to obtain the flow field quality, and the two-dimensional cold flame tube surface is iteratively optimized according to the flow field quality until a three-dimensional hot model and a two-dimensional cold model that meet the flow field quality requirements are obtained.

2. The ceramic matrix composite flame tube matching design method according to claim 1, characterized in that: The typical operating state points include the maximum aerodynamic load state, the cruising state, the slow-speed state and the design state, and the engine design requirements include the engine mission profile and the time proportion of each typical operating state point.

3. The ceramic matrix composite flame tube matching design method according to claim 1, characterized in that: Two-dimensional simulation calculations are carried out to obtain the flame tube wall temperature range for each of the main working state points, including: Extracting the main combustion chamber performance parameters at each of the main operating state points, the main combustion chamber performance parameters including the main combustion chamber inlet air total temperature, inlet air total pressure, inlet air flow rate, and fuel supply; The flow field distribution and temperature field distribution are simulated by numerical fluid mechanics methods to obtain the flame tube flow distribution results. Based on the main combustion chamber performance parameters and the flame tube flow distribution results, two-dimensional simulation calculation and analysis are carried out to obtain the flame tube wall temperature range of each main working state point.

4. The ceramic matrix composite flame tube matching design method according to claim 1, characterized in that: Based on the overall structural limitations of the engine and the overall layout of the main combustion chamber, as well as the main combustion chamber inlet and outlet parameters at the main operating state points, the hot radial dimensions of the characteristic points on the ceramic-based component and the metal component are obtained respectively, including: Determine the overall dimensions of the main combustion chamber and the volume of the flame tube based on the overall structural limitations of the engine and the overall layout of the main combustion chamber; According to the overall size of the main combustion chamber, the volume of the flame tube and the inlet and outlet parameters of the main combustion chamber at the main working state point, the hot radial dimensions of the characteristic points on the ceramic-based component and the metal component are obtained respectively. The characteristic points on the ceramic-based component include the main combustion hole, mixing hole and outlet of the flame tube, and the characteristic points on the metal component include the vortex finder outlet, the outer ring of the splash plate and the inner ring of the splash plate.

5. The ceramic matrix composite flame tube matching design method according to claim 1, characterized in that: By formula The hot radial size of each feature point is converted into the cold radial size, H 冷 H is the cold radial dimension. 热 is the hot radial dimension, T1 is the hot wall temperature of the characteristic point extracted from the flame tube wall temperature range, T0 is the given flame tube cold wall temperature, is the linear expansion coefficient of the material.

6. The ceramic matrix composite flame tube matching design method according to claim 1, characterized in that: Based on the flame tube wall temperature range and all the cold radial dimensions, a two-dimensional cold flame tube profile design is performed, and matching structural characteristic parameters of the ceramic-based component and the metal component are calculated, including: Extract the flame tube inner ring wall temperature, splash plate wall temperature, and flame tube outer ring wall temperature from the flame tube wall temperature range, and calculate the difference between the cold radial dimension of the vortex finder outlet and the cold radial dimension of the splash plate inner ring as the cold dimension of the splash plate inner ring; Obtaining the thermal expansion of the flame tube inner ring according to the flame tube inner ring wall temperature, the flame tube inner ring diameter, the material linear expansion coefficient and the flame tube cold wall temperature; Obtaining a hot cooling gap between the inner ring of the splash plate and the inner ring of the flame tube in a hot state according to the thermal expansion amount of the inner ring of the flame tube, the wall temperature of the splash plate, the cold size of the inner ring of the splash plate, the cooling gap of the inner ring of the splash plate in a cold state, the linear expansion coefficient of the material and the cold wall temperature of the flame tube; Obtaining the matching dimensions between the flame tube outer ring and the flame tube head transition section according to the flame tube outer ring wall temperature, the flame tube outer ring diameter, the flame tube outer ring cylinder wall thickness, the material linear expansion coefficient and the flame tube cold wall temperature; According to the flame tube outer ring wall temperature, flame tube outer ring diameter, material linear expansion coefficient, flame tube cold wall temperature, splash plate outer ring size and cold splash plate outer ring cooling gap, the hot cooling gap between the splash plate outer ring and the flame tube outer ring in the hot state is obtained.

7. The ceramic matrix composite flame tube matching design method according to claim 6, characterized in that: By formula Calculate the thermal expansion of the flame tube inner ring L1, D1 is the flame tube inner ring diameter, T0 is the given flame tube cold wall temperature, is the linear expansion coefficient of the material; By formula Calculate the hot cooling gap L between the inner ring of the splash plate and the inner ring of the flame tube in the hot state 2热 , L 2冷 is the cooling gap of the inner ring of the splash plate in the cold state, with a value of 0~20mm, L3 is the cold size of the inner ring of the splash plate, T3 is the wall temperature of the splash plate, L 2热 The value range is 0~30mm; By formula Calculate the fitting dimension L5 between the outer ring of the flame tube and the transition section of the flame tube head. H1 is the given outer ring wall thickness of the flame tube, D2 is the outer ring diameter of the flame tube, T4 is the outer ring wall temperature of the flame tube, and L5 ranges from 0 to 50 mm. By formula: Calculate the hot cooling gap L between the outer ring of the splash plate and the outer ring of the flame tube in the hot state 6热 , L 6冷 The cooling gap of the outer ring of the splash plate in the cold state is 0~30mm. L4 is the size of the outer ring of the splash plate. 6热 The value range is 0~20mm.

8. A ceramic matrix composite flame tube matching design system, characterized in that: include: a duct wall temperature range acquisition module, the duct wall temperature range acquisition module being configured to select at least one typical operating state point as a main operating state point within the engine envelope according to engine design requirements, and perform a two-dimensional simulation calculation to obtain the duct wall temperature range of each main operating state point; a hot radial dimension calculation module, the hot radial dimension calculation module being used to obtain the hot radial dimensions of characteristic points on the ceramic-based component and the metal component respectively based on the overall structural constraints of the engine and the overall layout of the main combustion chamber, as well as the main combustion chamber inlet and outlet parameters at the main operating state points; a hot-cold dimension conversion module, the hot-cold dimension conversion module being used to convert the hot radial dimension of each of the characteristic points into the cold radial dimension according to the flame tube wall temperature range and the material linear expansion coefficient, and to convert the cold radial dimensions of the ceramic-based component and the metal component in the two-dimensional cold flame tube profile into the hot dimensions; a two-dimensional cold flame tube profile design module, the two-dimensional cold flame tube profile design module being used to perform a two-dimensional cold flame tube profile design based on the flame tube wall temperature range and all the cold radial dimensions, and to calculate matching structural characteristic parameters of the ceramic-based component and the metal component to obtain a two-dimensional cold flame tube profile; A three-dimensional thermal model construction module, wherein the three-dimensional thermal model construction module is used to circumferentially rotate the two-dimensional thermal flame tube profile to form a three-dimensional thermal model; An evaluation and optimization module is used to simulate and analyze the three-dimensional hot model at each of the main working state points through a simulation method to obtain the flow field quality, and iteratively optimize the two-dimensional cold flame tube surface according to the flow field quality until a three-dimensional hot model and a two-dimensional cold model that meet the flow field quality requirements are obtained.

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