A method for matching high and low pressure turbines of a cross-generation low bypass ratio turbofan engine

Abstract

The application belongs to the field of aero-engine design, and is a high-low pressure turbine matching design method for a cross-generation small-bypass-ratio turbofan engine. The method comprises the following steps: firstly, determining the initial constraint conditions of the low-pressure turbine matching design of a high-performance advanced engine; then, determining the constraint conditions of the high-pressure turbine matching design of the high-performance advanced engine through the high-low pressure turbine matching design; after the matching is completed, carrying out component processing and assembly; after the assembly is completed, carrying out high-low pressure turbine component tests and whole-process engine tests to obtain whole-process engine measurement test results; according to the whole-process engine measurement results, evaluating the high-low pressure turbine matching work, determining the problems existing in the high-low pressure turbine matching, and carrying out targeted structural improvement on the high-low pressure turbine and whole-process tests again; through repeated correction, the design requirements are met. The method can quickly and accurately realize good matching work of the high-low pressure turbine, reduce the exhaust temperature, and solve the problem of ablation of high-temperature components.

Description

A design method for matching high and low pressure turbines in a next-generation low-bypass turbofan engine Technical Field

[0001] This application belongs to the field of aero-engine design, and specifically relates to a high- and low-pressure turbine matching design method for a next-generation low-bypass turbofan engine. Background Technology

[0002] With the development of aviation weaponry, the requirements for the overall performance of engines are becoming increasingly stringent, mainly reflected in high specific thrust, compact structure, and the ability to achieve high-maneuverability flight while meeting the requirements for long-duration loiter time. To achieve high specific thrust, turbofan engines need to select smaller bypass ratios and higher turbine inlet temperatures, which poses a significant challenge to the matching of high- and low-pressure turbines.

[0003] 1) Large Turbine Cooling Air Volume: To improve the heat resistance of high-temperature components, the airflow for turbine cooling is typically increased. In high-performance advanced engines, the cooling air volume for high-temperature components reaches more than 1 / 4 of the compressor inlet flow rate, resulting in a large turbine cooling air volume. A large cooling air volume can easily deviate from the design specifications, and it significantly impacts turbine flow capacity and efficiency, as well as the matching of high- and low-pressure turbines.

[0004] 2) Complex turbine cooling flow path: In order to improve the turbine cooling effect and balance other factors, the turbine cooling flow path is becoming more and more complex, which can easily lead to ineffective air use such as leakage, which has a significant impact on the matching of high and low pressure turbines.

[0005] 3) Compact structure and large turbine stage load: In order to improve the thrust-to-weight ratio, the structure is usually very compact and the turbine load is very large. The flow between turbine components and the turbine outlet flow field are complex and have a large degree of non-uniformity, which brings great difficulties to the matching of high and low pressure turbines.

[0006] Due to the aforementioned technical characteristics, existing traditional high- and low-pressure turbine matching design methods are difficult to apply to the matching design of high- and low-pressure turbines in next-generation high-performance low-bypass turbofan engines. Therefore, using existing traditional high- and low-pressure turbine matching design methods usually results in problems such as a small expansion ratio of the high-pressure turbine, a small equivalent flow rate of the low-pressure turbine, and the operating points of the high- and low-pressure turbines deviating from the design state, leading to low efficiency of the high- and low-pressure turbines, a large engine bypass ratio, high turbine inlet temperature, and high-temperature component ablation.

[0007] Therefore, it is necessary to develop a method for the matching and optimization design of high and low pressure turbines suitable for high-performance low-bypass turbofan engines. Summary of the Invention

[0008] The purpose of this application is to provide a cross-generational low-bypass turbofan engine high- and low-pressure turbine matching design method to solve problems such as low high-pressure turbine efficiency, large engine bypass ratio, high turbine inlet temperature, and high-temperature component ablation caused by the deviation of the operating point of the existing high- and low-pressure turbine from the design state.

[0009] The technical solution of this application is: a high- and low-pressure turbine matching design method for a next-generation low-bypass turbofan engine, comprising:

[0010] The initial constraints for the low-pressure turbine matching design of high-performance advanced engines are determined based on the design and test parameters of engines with the same or similar configurations, including turbine inlet temperature, turbine cooling flow path and cooling flow rate, turbine performance and turbine outlet flow field.

[0011] The high- and low-pressure turbine matching design is carried out. Based on the design and test parameters of engines with the same or similar configurations, the high-pressure turbine matching design constraints of high-performance advanced engines are determined. This includes the overall high- and low-pressure turbine matching scheme design, the aerodynamic scheme design of high-pressure turbine components, the aerodynamic scheme design of low-pressure turbine components, and the joint simulation calculation of high- and low-pressure turbines. It is then determined whether the matching design of the high- and low-pressure turbine design and the simulation results meet the constraints. If the constraints are met, the components are processed and trial-produced according to the process requirements. Otherwise, the constraints or the aerodynamic scheme design of the high- and low-pressure turbine components are modified, and the judgment is made again until the matching degree meets the design requirements.

[0012] After the components are processed and assembled, high- and low-pressure turbine component tests are conducted according to the type of high- and low-pressure turbine. The performance of the high- and low-pressure turbine components is evaluated based on the test results, and the flow and efficiency characteristics of the turbine components are obtained to determine whether the matching degree of the high- and low-pressure turbines meets the design requirements. If yes, a full-process test is carried out. If not, the aerodynamic scheme is modified or the exhaust area of ​​the high- and low-pressure turbine guide vanes is adjusted, and the high- and low-pressure turbine matching is carried out again until the design requirements are met. If yes, a full-process test is carried out.

[0013] The matched high and low pressure turbines are first installed in series on the engine, and the whole engine is tested throughout the entire process. The actual performance of each component under the whole engine conditions is collected to obtain the measurement and test results of the whole engine throughout the entire process.

[0014] Based on the measurement results of the whole machine, an adaptive identification model is established to evaluate the matching operation of high and low pressure turbines. The test parameters of high and low pressure turbines are compared with the design values ​​to identify the problems in the matching of high and low pressure turbines.

[0015] Based on the problems existing in the matching of high and low pressure turbines, targeted structural improvements were made to the high and low pressure turbines.

[0016] The improved high and low pressure turbine and air system hardware are then reinstalled into the engine and a full-process test is conducted to reassess the matching of the high and low pressure turbine and air system hardware. If the constraints are met, the high and low pressure turbine matching optimization is completed; if the constraints are not met, the optimization scheme or the constraints are further modified.

[0017] Preferably, the specific method for the high- and low-pressure turbine matching design is as follows:

[0018] The constraints of the high-pressure turbine and the low-pressure turbine are determined separately. The overall performance calculation software is used to calculate the overall matching scheme of the high-pressure turbine and the low-pressure turbine. After calculating the gas flow rate of the corresponding rotor of the low-pressure turbine and the high-pressure turbine respectively, the gas flow rate of the corresponding rotor is reduced simultaneously and the difference between the initial efficiency of the high-pressure turbine and the efficiency before the rotor of the high-pressure turbine is calculated again. If the difference is within the set range, the equivalent effect of the efficiency of the high-pressure turbine and the low-pressure turbine is completed.

[0019] When designing the aerodynamic scheme of high-pressure turbine components, a step-by-step design scheme from low dimension to high dimension is adopted. First, the meridional channel form of the high-pressure turbine is determined, then the blade shape of the high-pressure turbine at different blade height sections is determined, and finally the high-pressure turbine performance surface and parameter distribution are obtained to carry out the high-pressure turbine scheme design. After the design is completed, the performance of the high-pressure turbine is evaluated by full three-dimensional numerical analysis.

[0020] When designing the aerodynamic scheme for low-pressure turbine components, the load distribution inside the low-pressure turbine stage is adjusted by using the reaction force optimization design of the low-pressure turbine stage. After the design is completed and the work capacity of the low-pressure turbine is confirmed to meet the design requirements, the design is completed.

[0021] A complex flow model based on solid-gas-thermal coupling was established to perform fluid dynamics simulation, simulating the internal flow details of the high and low pressure turbines, obtaining the distribution of interstage parameters inside the high and low pressure turbines, and determining the flow capacity and efficiency level of the high and low pressure turbines under the overall machine condition. Full three-dimensional data simulation was used to determine the temperature field and pressure field distribution at the main combustion chamber outlet, and the influence of high and low pressure turbine in-disk leakage flow, inter-blade leakage, and cooling vents on the mainstream was further calculated, completing the joint simulation calculation of the high and low pressure turbines.

[0022] Preferably, when designing the aerodynamic scheme for high-pressure turbine components, one-dimensional aerodynamic design is first carried out according to the overall design requirements. Dimensionless design parameters are selected to determine the design parameters of the mid-section. Then, the turbine meridional channel form is determined by selecting basic aerodynamic and geometric parameters through low-dimensional design space analysis. When conducting two-dimensional aerodynamic design, the required torsional law is selected to determine the velocity triangles of different blade height sections of the turbine stage. The key aerodynamic parameters of each row of the turbine are obtained through inverse problem calculation. Then, aerodynamic shaping of different blade height sections is designed according to the blade aerodynamic parameters, and the rationality of the blade design is verified using S1 numerical simulation. When conducting three-dimensional aerodynamic design, three-dimensional superposition is first performed on the basis of the two-dimensional design. Then, S2 or quasi-three-dimensional numerical simulation is used to calculate the high-pressure turbine performance and parameter distribution, and flow analysis and diagnosis are performed.

[0023] Preferably, when designing the aerodynamic scheme for the low-pressure turbine components, the airfoil of the guide vane is determined by combining the reaction force optimization design scheme with three-dimensional molding design. The flow capacity of the guide vane is determined by adjusting the width of the guide vane channel at the rear and its variation along the blade height. The flow field changes at the high-pressure turbine outlet are then matched by adjusting the inlet configuration angle and increasing the leading edge radius.

[0024] Preferably, during the testing of high and low pressure turbine components, the ratio of cold air flow rate to main gas flow rate is kept equal, and the ratio of cold air temperature to main gas temperature is kept equal.

[0025] Preferably, the specific evaluation method of the adaptive identification model is as follows: based on the actual performance of each component under the overall machine conditions, obtain the initial guess of the bypass ratio (BPR) and the afterburner fuel flow rate (W). fb Then, based on the bypass ratio (BPR) and afterburner fuel flow rate (W)... fb Calculate the average parameters at the fan outlet. Based on the average parameters at the fan outlet, first evaluate the fan characteristic parameters, and then evaluate the compressor characteristic parameters, combustion chamber parameters, high vortex characteristic parameters, and low vortex characteristic parameters in sequence.

[0026] Determine whether the high-vortex characteristic parameters and low-vortex characteristic parameters meet the residual accuracy requirements. If not, solve for the bypass ratio BPR and afterburner fuel flow rate W again using the Newton-Raphson method. fb And the compressor characteristic parameters, combustion chamber parameters, high vortex characteristic parameters and low vortex characteristic parameters are evaluated again until the residual accuracy requirements are met.

[0027] If the residual accuracy requirements are met, the tail nozzle parameters and performance parameters are evaluated sequentially to obtain the evaluation results.

[0028] Preferably, the structural improvement of the high and low pressure turbines is carried out by adjusting the flow capacity of the high and low pressure turbines, the air intake of the air system, and the exhaust volume, specifically including:

[0029] High and low pressure turbine guide area adjustment: If the compressor operating line is lower than the design operating line, reduce the area of ​​the high pressure turbine guide; if the compressor operating line is higher than the design operating line, increase the area of ​​the high pressure turbine guide.

[0030] Low-pressure turbine guide area adjustment: If the expansion ratio of the high-pressure turbine is too small, then on the basis of meeting the lower limit of the total pressure ratio P16 / P6 between the outer and inner outlets, the area of ​​the low-pressure turbine guide should be increased and the amount of ineffective gas consumption should be reduced.

[0031] Adjustment of air intake and exhaust volume in the air system: Reduce ineffective air consumption by reducing air leakage at the sealing teeth and casing joints.

[0032] This application discloses a high- and low-pressure turbine matching design method for a next-generation low-bypass turbofan engine. The method first determines the initial constraints for the low-pressure turbine matching design of a high-performance advanced engine, then determines the constraints for the high-pressure turbine matching design of the high- and low-pressure turbine. After matching, component processing and assembly are performed. Following assembly, high- and low-pressure turbine component tests and a full-process engine test are conducted to obtain the full-process measurement test results. Based on these results, the matching performance of the high- and low-pressure turbines is evaluated, existing problems are identified, targeted structural improvements are made to the turbines, and another full-process test is conducted until the matching between the high- and low-pressure turbines and related air system hardware meets the design requirements. This method can quickly and accurately achieve good matching of the high- and low-pressure turbines, reducing exhaust temperature while solving the problem of high-temperature component ablation. The feasibility and effectiveness of this patent are verified using a high-performance engine high- and low-pressure turbine matching design and optimization design. Attached Figure Description

[0033] 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.

[0034] Figure 1 is a schematic diagram of the overall process of this application;

[0035] Figure 2 is a schematic diagram of the design process of the high-pressure turbine component in this application;

[0036] Figure 3 is a schematic diagram of the joint simulation calculation of high and low pressure turbines in this application;

[0037] Figure 4 is a flowchart of the evaluation of the working conditions of various components of the turbine engine in this application. Detailed Implementation

[0038] 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.

[0039] A design method for matching high and low pressure turbines in a next-generation low-bypass turbofan engine, as shown in Figure 1, includes the following steps:

[0040] Step S100: Determine the design constraints for matching high and low pressure turbines.

[0041] Based on the design and testing experience of engines with similar or identical configurations both domestically and internationally, the initial constraints for the high- and low-pressure turbine matching design of high-performance advanced engines are preliminarily determined, including:

[0042] Turbine inlet temperature: Directly affects engine thrust level, high-pressure turbine temperature resistance, etc. The turbine inlet temperature is determined by fully considering turbine materials, cooling level and service life requirements.

[0043] Turbine cooling flow path and cooling flow rate: Based on the turbine inlet temperature and the material's temperature resistance, determine the turbine cooling flow path and cooling air to achieve a balance between engine thrust, cooling air volume, combustion gas temperature, and component wall temperature;

[0044] Turbine performance includes performance parameters such as turbine equivalent flow rate, equivalent speed, expansion ratio, and efficiency;

[0045] Turbine outlet flow field: The outlet airflow angle of the high-pressure turbine directly affects the operation of the low-pressure turbine, and the outlet flow field of the low-pressure turbine directly affects the operation of the afterburner. Therefore, the constraints on the outlet airflow angles of the high-pressure and low-pressure turbines are determined in the early stage of the design. Usually, the axial angle of the turbine outlet airflow is no greater than 5°.

[0046] Based on the initially provided parameters such as turbine inlet temperature and flow rate, a preliminary mathematical model is established to meet the basic operating requirements of high and low pressure turbines, and the corresponding relationship between flow rate and temperature before and after the high and low pressure turbines is obtained. Since the turbine inlet temperature, turbine cooling flow path and cooling flow rate, turbine performance, and turbine outlet flow field are only given empirically, the parameters before and after the turbine will be modified accordingly when determining specific temperature, flow rate, and other parameters.

[0047] Step S200, High and Low Pressure Turbine Matching Design

[0048] Based on the design and test parameters of engines with the same or similar configurations at home and abroad, the high-pressure turbine matching design constraints of high-performance advanced engines are determined. This includes the overall design of the high-pressure and low-pressure turbine matching scheme, the aerodynamic scheme design of the high-pressure turbine components, the aerodynamic scheme design of the low-pressure turbine components, and the joint simulation calculation of the high-pressure and low-pressure turbines. It is then determined whether the matching design of the high-pressure and low-pressure turbine design and simulation results meets the constraints. That is, it is compared with the design parameters in step S100 to determine whether the design parameters obtained from the design and simulation can be well matched with the constraints given in step S100.

[0049] Specific design methods include:

[0050] a) Overall design of high- and low-pressure turbine matching scheme

[0051] Considering the various constraints initially set, the overall performance calculation software is used to calculate the overall matching scheme of the high-pressure and low-pressure turbines. Due to the high turbine inlet temperature in advanced engines, turbine blades typically employ a fully slotted guide vane structure. Cooling gas is usually present after the turbine guide vane throat and before the turbine rotor blades, causing a discrepancy between the initial efficiency used in the turbine component design and the turbine rotor inlet efficiency used in the overall calculation. This affects the determination of low-pressure turbine conductivity and high-pressure turbine expansion ratio. To address this issue, the gas flow rate of the corresponding rotor is typically reduced. The reduction amount is given empirically, and the difference between the initial efficiency of the high-pressure and low-pressure turbines and the rotor inlet efficiency is recalculated. If the difference is within a set range, the equivalence of the high-pressure and low-pressure turbine efficiencies is achieved.

[0052] b) Aerodynamic design of high-pressure turbine components

[0053] As shown in Figure 2, the aerodynamic design of high-pressure turbine components is a process of gradual design and optimization from low-dimensional to high-dimensional. The design results in low-dimensional space are the basis for working in high-dimensional space. Figure 3 illustrates the aerodynamic design process for high-pressure turbine components. Generally, the first step in high-pressure turbine aerodynamic design is to conduct one-dimensional aerodynamic design based on the overall design requirements. The main tasks involve rationally selecting dimensionless design parameters to determine parameters such as the velocity triangle of the mid-section, thereby generating the turbine meridional flow channel form. During this process, basic aerodynamic and geometric parameters can be rationally selected and optimized in the low-dimensional design space as needed. Then, starting from the two-dimensional level, a reasonable torsional law is selected to obtain the velocity triangle of different blade height sections of the turbine stage. The key aerodynamic parameters of each row of the turbine are obtained through inverse problem calculations. Then, the blade profile design of different blade height sections is carried out according to parameters such as the inlet and outlet airflow angles of the blades. The rationality of the blade design is verified by S1 numerical simulation. On this basis, three-dimensional stacking of the blades is carried out. The flow channels in the channel are rationally organized by making full use of stacking methods such as bending, twisting, and sweeping. The performance and parameter distribution of the high-pressure turbine are calculated by S2 or quasi-three-dimensional numerical simulation, and flow analysis and diagnosis are performed. If the design results meet the design requirements, full three-dimensional numerical simulation is used to conduct a more detailed analysis of the internal flow field of the turbine and comprehensively evaluate the performance of the high-pressure turbine.

[0054] c) Aerodynamic design of low-pressure turbine components

[0055] Aerodynamic design schemes for low-pressure turbine components were carried out. Through optimized design of the low-pressure turbine stage reaction force, the load distribution within the turbine stage was rationally adjusted to reduce or avoid local supersonic regions within the blade channel, thereby reducing shock wave losses. Combined with the reaction force optimization scheme, the guide vanes adopted an advanced three-dimensional forming design. Furthermore, by adjusting the throat width of the guide vane channel and its variation along the blade height, the flow capacity of the guide vane was improved. Adjusting the inlet configuration angle and appropriately increasing the leading edge radius better matched the changes in the high-pressure turbine outlet flow field. The rotor blades were adaptively adjusted to match the optimized guide vanes, such as adjusting the inlet configuration angle to reduce angle-of-attack losses and adjusting the radial distribution of the high-performance region, ensuring that the work capacity of the optimized low-pressure turbine is no less than that of the original scheme.

[0056] Through two-dimensional and three-dimensional flow field simulation analysis and analogy analysis, the design results were verified to ensure they met the overall design requirements. Furthermore, joint simulation with a high-pressure turbine was conducted to further confirm the rationality and feasibility of the proposed scheme.

[0057] d) Joint simulation calculation of high and low pressure turbines

[0058] Determining the actual flow capacity and efficiency of the guide vane for matching high and low pressure turbines under complex flow conditions is more difficult than for previous engines. Therefore, it is necessary to conduct joint simulation calculations of high and low pressure turbines to obtain relatively accurate flow capacity and efficiency of high and low pressure turbines.

[0059] 1) Establish a complex flow model that considers solid-gas-thermal coupling, perform fluid dynamics simulation, quickly and accurately simulate the internal flow details of high and low pressure turbines, obtain the distribution of interstage parameters inside the turbine, and understand the turbine flow capacity and efficiency level under the overall machine condition.

[0060] 2) The temperature and pressure field distribution at the main combustion chamber outlet is considered in three dimensions, taking into account the effects of in-disc leakage flow, inter-blade leakage, and cooling vents on the main flow.

[0061] If the constraints are met, the components are processed and trial-produced according to the process requirements. Otherwise, the constraints or the aerodynamic design of the high and low pressure turbine components are modified, and the judgment is made again until the matching degree meets the design requirements.

[0062] This step completed the preliminary matching design under the constraints of the high- and low-pressure turbine aerodynamic scheme design, providing a foundation for further verification.

[0063] Step S300, High and Low Pressure Turbine Component Testing

[0064] Aero gas turbines operate under extremely harsh conditions, including high temperature, high pressure, and high speed, and are subjected to significant aerodynamic forces, thermal stress, inertial forces, and vibrations. The flow of gas within the turbine is a complex, unsteady, viscous, three-dimensional flow, exhibiting significant unsteady, viscous, and three-dimensional effects. Turbines designed based on theoretical calculations and design experience typically require aerodynamic performance testing on a turbine testing facility. For smaller turbines, full-scale turbine tests can be performed; however, for larger turbines, only plastic molding tests, i.e., model turbine tests, are possible. Regardless of the type of turbine test, due to limitations in gas source conditions and hydraulic dynamometer power, full-scale, full-pressure tests are not feasible; only aerodynamic simulation tests are possible. Aerodynamic simulation tests are based on the principle of similarity and must also consider the influence of the inlet flow field. Furthermore, for high-temperature gas-cooled turbines, in addition to ensuring the above conditions, the following two conditions must also be met: the ratio of cold gas flow rate to main gas flow rate must be equal; and the ratio of cold gas temperature to main gas temperature must be equal.

[0065] The performance of the turbine components is evaluated based on the test results, and the flow and efficiency characteristics of the turbine components are obtained to determine whether the matching of the high- and low-pressure turbines meets the design requirements. If not, the aerodynamic design scheme is modified or the exhaust area of ​​the high- and low-pressure turbine guide vanes is adjusted to meet the matching requirements.

[0066] Based on the test results, further determine whether the matching of the high- and low-pressure turbines meets the design constraints. If the constraints are not met, modify the constraints or modify the aerodynamic design. If the constraints are modified, return to step S100; if the aerodynamic design is modified, return to step S200. The choice can be made according to requirements.

[0067] This step enables the production of high- and low-pressure turbine components that simultaneously meet the constraints and undergo experimental verification.

[0068] Step S400: Conduct a full-process test.

[0069] The test process adopts a "one set of hardware, step-by-step implementation" approach and a "comprehensive and precise measurement" method (i.e., each component uses the same set of hardware and the same test plan, and the test is carried out in stages at the component test, core engine test, and whole engine test). The matched high and low pressure turbines are first connected in series to the whole engine for a full-process test to obtain the actual performance of each component under the whole engine conditions, including the compressor outlet total pressure P3, the pressure drop of the main combustion chamber diffuser and flame tube, the high pressure turbine outlet total pressure P43, the low pressure turbine outlet total pressure P5, the external internal pressure ratio P16 / P6, the exhaust temperature T6, the engine thrust, the main fuel flow rate, and parameters such as the cavity temperature and cavity pressure related to the air system.

[0070] Step S500: Identify problems in the matching of high and low pressure turbines.

[0071] As shown in Figure 3, an adaptive identification model is established based on the measurement results of the entire machine process to evaluate the matching operation of the high and low pressure turbines, including parameters such as the flow capacity, expansion ratio, and efficiency of the high and low pressure turbine guides under complex working conditions of the entire machine. The test parameters of the high and low pressure turbines are compared with the design values ​​to determine the problems in the matching of the high and low pressure turbines.

[0072] Preferably, the specific evaluation method for the adaptive identification model is as follows: based on the actual performance of each component under the overall machine conditions, obtain the initial guess of the bypass ratio (BPR) and the afterburner fuel flow rate (W). fb Then, based on the bypass ratio (BPR) and afterburner fuel flow rate (W)... fb Calculate the average parameters at the fan outlet. Based on the average parameters at the fan outlet, first evaluate the fan characteristic parameters, and then evaluate the compressor characteristic parameters, combustion chamber parameters, high vortex characteristic parameters, and low vortex characteristic parameters in sequence.

[0073] As shown in Figure 4, the specific evaluation method using the adaptive identification model is as follows: It is determined whether the high-vortex characteristic parameters and low-vortex characteristic parameters meet the residual accuracy requirements. The high-vortex characteristic parameter evaluation calculates the residual value using the high-vortex converted flow parameter equation, and the low-vortex characteristic parameter evaluation calculates the residual value using the T6 residual equation. If not, the bypass ratio BPR and afterburner fuel flow W are solved again using the Newton-Raphson method. fb And the compressor characteristic parameters, combustion chamber parameters, high vortex characteristic parameters and low vortex characteristic parameters are evaluated again until the residual accuracy requirements are met.

[0074] If the residual accuracy requirements are met, the tail nozzle parameters and performance parameters are evaluated sequentially to obtain the evaluation results.

[0075] When matching issues arise, structural improvements to the high and low pressure turbines are made by adjusting the flow capacity of the high and low pressure turbines, the air intake of the air system, and the exhaust volume. Specifically, these improvements include:

[0076] a) The expansion ratio of the high-pressure turbine is too small: The main reasons for the expansion ratio of the high-pressure turbine are that the area of ​​the low-pressure turbine guide vane is too small, the area of ​​the high-pressure turbine guide vane is too large (whether it is appropriate is judged according to the compressor working line), and the air intake of the air system is too large.

[0077] b) Low-pressure turbine expansion ratio is too small: low-pressure turbine guide area is too large, nozzle throat area is too small, air intake of air system is too large, etc.

[0078] The aforementioned influencing factors are coupled and mutually influential. Therefore, in order to accurately determine which factor causes the poor matching of high and low pressure turbines, it is necessary to carry out joint simulation calculations of high and low pressure turbines. The calculations should focus on the actual bleed air volume and exhaust volume of the engine's air system measured under the whole machine environment.

[0079] Step S600: High and low pressure turbine matching optimization design

[0080] Based on the problems with the matching of high and low pressure turbines, it is necessary to adjust the flow capacity of high and low pressure turbines, the bleed air volume of the air system, and the exhaust volume.

[0081] 1) High-pressure turbine guide vane area adjustment: When adjusting the high-pressure turbine guide vane area, pay close attention to changes in the compressor operating line. If the compressor operating line is lower than the design operating line, the high-pressure turbine guide vane area needs to be reduced; if the compressor operating line is higher than the design operating line, the high-pressure turbine guide vane area needs to be increased. This can be achieved by cascading different groups of blades, or by grinding the trailing edges of the guide vanes to enlarge the high-pressure turbine guide vane area.

[0082] 2) Low-pressure turbine guide vane area adjustment: When adjusting the low-pressure turbine guide vane, the key points to focus on are the high-pressure turbine expansion ratio, the low-pressure turbine expansion ratio, and the total pressure ratio of the outer bypass tunnel outlet (P16 / P6). If the high-pressure turbine expansion ratio is too small, the low-pressure turbine guide vane area needs to be increased and the ineffective gas consumption reduced. However, the increase in the low-pressure turbine guide vane area is limited by the lower limit of P16 / P6 (if P16 / P6 is too low, the outer bypass tunnel outlet area (A16) also needs to be reduced). In terms of implementation, the low-pressure turbine guide vane area can be adjusted by cascading different groups of blades, or by grinding the trailing edges of the guide vanes.

[0083] 3) Adjustment of air system bleed and exhaust volume: The air system bleed and exhaust volume have a significant impact on the matching of high and low pressure turbines with complex cooling. Therefore, when optimizing the matching design of high and low pressure turbines, we should minimize the amount of ineffective air consumption, such as air leakage at the sealing wall teeth and air leakage at the casing joint.

[0084] This step optimized the matching degree between component-level tests and overall process tests to meet design requirements, until a high- and low-pressure turbine component that can be practically designed was basically completed.

[0085] Step S700: Improve the overall verification of component serial assembly.

[0086] The improved high and low pressure turbines and related air system hardware are reinstalled on the engine and a full-process test is carried out. As shown in step S400, the matching status of the high and low pressure turbines and related air system hardware is judged again. If the constraint conditions are met, the high and low pressure turbine matching optimization is completed. If the matching of the high and low pressure turbines does not meet the constraint conditions or the design target is not achieved during operation, or if high-temperature component burning occurs, further modification of the optimization scheme or modification of the constraint conditions is required.

[0087] The above work establishes a generational design criterion for matching high and low pressure turbines under complex flow conditions with low bypass ratio, as well as related flow fields, for use in subsequent engines with the same configuration.

[0088] After adopting the high-low pressure turbine matching design and optimization design method in this application, the matching optimization adjustment of the high-low pressure turbine was successfully completed in one go. The matching condition of each component is good, and each component basically works in the high efficiency range. At the same time, the engine bypass ratio is close to the predetermined value, P16 / P6 is within a reasonable range, and the exhaust temperature is reduced by about 7 to 10°C under the same thrust conditions.

[0089] This application first determines the initial constraints for the low-pressure turbine matching design of a high-performance advanced engine, then determines the constraints for the high-pressure turbine matching design of the high-pressure turbine. After matching, component processing and assembly are carried out. After assembly, high- and low-pressure turbine component tests and a full-process test of the entire engine are conducted to obtain the full-process measurement test results. Based on the full-process measurement results, the matching performance of the high- and low-pressure turbines is evaluated, existing problems are identified, targeted structural improvements are made to the high- and low-pressure turbines, and another full-process test is conducted until the matching between the high- and low-pressure turbines and related air system hardware meets the design requirements. This approach can quickly and accurately achieve good matching of the high- and low-pressure turbines, reducing exhaust temperature while solving the problem of high-temperature component ablation. The feasibility and effectiveness of this patent are verified using a high-performance engine high- and low-pressure turbine matching design and optimization design.

[0090] 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 method for matching high and low pressure turbines in a next-generation low-bypass turbofan engine, characterized in that, include: Based on the design and test parameters of engines with the same or similar configurations, the initial constraints for the matching design of high-pressure and low-pressure turbines in high-performance advanced engines are determined, including turbine inlet temperature, turbine cooling flow path and flow rate, turbine performance, and turbine outlet flow field. High-pressure and low-pressure turbine matching design is then carried out, with constraints determined based on the same or similar configurations. This includes the overall high-pressure and low-pressure turbine matching scheme design, aerodynamic scheme design for high-pressure turbine components, aerodynamic scheme design for low-pressure turbine components, and joint simulation calculations of the high-pressure and low-pressure turbines. The matching design between the high-pressure and low-pressure turbine design and simulation results is then assessed to determine if it meets the constraints. If it does, component processing and trial production are carried out according to process requirements. Otherwise, the constraints or the aerodynamic scheme design of the high-pressure and low-pressure turbine components are modified, and the assessment is repeated until the matching degree meets the design requirements. After the components are processed and assembled, high-pressure and low-pressure turbine component tests are conducted according to the type of high-pressure and low-pressure turbine. The performance of the high-pressure and low-pressure turbine components is evaluated based on the test results, obtaining the turbine component flow rate and efficiency characteristics, and determining the high-pressure and low-pressure turbine matching performance. If the turbine matching meets the design requirements, a full-process test is conducted. If not, the aerodynamic scheme is modified or the exhaust area of ​​the high- and low-pressure turbine guide vanes is adjusted, and the high- and low-pressure turbine matching is performed again until the design requirements are met. If the matching is met, a full-process test is conducted. The matched high- and low-pressure turbines are then connected in series to the engine, and a full-process test is conducted. The actual performance of each component under full-process conditions is collected to obtain the full-process measurement test results. Based on the full-process measurement results, an adaptive identification model is established to evaluate the matching operation of the high- and low-pressure turbines. The test parameters of the high- and low-pressure turbines are compared with the design values ​​to identify any problems in the matching. Based on the problems in the matching, targeted structural improvements are made to the high- and low-pressure turbines. The improved high- and low-pressure turbines and related air system hardware are then connected in series to the engine again, and a full-process test is conducted. The matching of the high- and low-pressure turbines and related air system hardware is judged again. If the constraints are met, the high- and low-pressure turbine matching optimization is completed. If the constraints are not met, the optimization scheme or constraints are further modified.

2. The high- and low-pressure turbine matching design method for a next-generation low-bypass turbofan engine as described in claim 1, characterized in that, The specific method for the high- and low-pressure turbine matching design is as follows: The constraints of the high-pressure turbine and the low-pressure turbine are determined separately. Overall performance calculation software is used to calculate the overall matching scheme for the high- and low-pressure turbines. After calculating the gas flow rates of the corresponding rotors of the low-pressure turbine and the high-pressure turbine, the gas flow rates of the corresponding rotors are simultaneously reduced, and the difference between the initial efficiency of the high- and low-pressure turbines and the efficiency before the rotors is calculated again. If the difference is within a set range, the equivalent effect on the efficiency of the high- and low-pressure turbines is achieved. When designing the aerodynamic scheme for the high-pressure turbine components, a step-by-step design scheme from low-dimensional to high-dimensional is adopted. First, the meridional channel form of the high-pressure turbine is determined, then the blade profiles for different blade height sections of the high-pressure turbine are determined, and finally, the high-pressure turbine performance surface and parameter distribution are obtained to design the high-pressure turbine scheme. After the design is completed... After completion, the performance of the high-pressure turbine was evaluated using full three-dimensional numerical analysis. When designing the aerodynamic scheme for the low-pressure turbine components, the load distribution inside the low-pressure turbine stage was adjusted using the reaction force optimization design. After the design was completed and the work capacity of the low-pressure turbine was confirmed to meet the design requirements, the design was completed. A complex flow model based on solid-gas-thermal coupling was established to perform fluid dynamics simulation, simulate the internal flow details of the high and low pressure turbines, obtain the distribution of inter-stage parameters inside the high and low pressure turbines, and determine the flow capacity and efficiency level of the high and low pressure turbines under the overall machine condition. Full three-dimensional data simulation was used to determine the temperature and pressure field distribution at the main combustion chamber outlet, and the influence of the high and low pressure turbine in-disk leakage flow, inter-blade leakage, and cooling vents on the mainstream was further calculated, completing the joint simulation calculation of the high and low pressure turbines.

3. The high- and low-pressure turbine matching design method for a next-generation low-bypass turbofan engine as described in claim 2, characterized in that: When designing aerodynamic schemes for high-pressure turbine components, one-dimensional aerodynamic design is first carried out according to the overall design requirements. Dimensionless design parameters are selected to determine the design parameters of the mid-section. Then, the turbine meridional flow path form is determined by selecting basic aerodynamic and geometric parameters through a low-dimensional design space. For two-dimensional aerodynamic design, the required torsional law is selected to determine the velocity triangles for different blade height sections of the turbine stage. Key aerodynamic parameters for each row of the turbine are obtained through inverse problem calculations. Then, aerodynamic profiles for different blade height sections are designed according to the blade aerodynamic parameters, and the rationality of the blade design is verified using two-dimensional numerical simulation. For three-dimensional aerodynamic design, three-dimensional stacking is first performed on the basis of the two-dimensional design. Then, quasi-three-dimensional numerical simulation is used to calculate the performance and parameter distribution of the high-pressure turbine, and flow analysis and diagnosis are performed.

4. The high- and low-pressure turbine matching design method for a next-generation low-bypass turbofan engine as described in claim 2, characterized in that: When designing the aerodynamic scheme for low-pressure turbine components, the airfoil of the guide vane is determined by combining the reaction force optimization design scheme with three-dimensional molding design. The flow capacity of the guide vane is determined by adjusting the width of the guide vane channel at the rear and its variation along the blade height. The flow field changes at the high-pressure turbine outlet are matched by adjusting the inlet configuration angle and increasing the leading edge radius.

5. The high- and low-pressure turbine matching design method for a next-generation low-bypass turbofan engine as described in claim 1, characterized in that: When conducting tests on high and low pressure turbine components, ensure that the ratio of cold air flow rate to main gas flow rate is equal, and that the ratio of cold air temperature to main gas temperature is equal.

6. The high- and low-pressure turbine matching design method for a next-generation low-bypass turbofan engine as described in claim 1, characterized in that, The specific evaluation method for the adaptive identification model is as follows: based on the actual performance of each component under the overall engine conditions, the bypass ratio (BPR) and afterburner fuel flow rate (W) are obtained. fb Then, based on the bypass ratio (BPR) and afterburner fuel flow rate (W)... fb Calculate the average parameters at the fan outlet. Based on these parameters, first evaluate the fan characteristic parameters, then sequentially evaluate the compressor characteristic parameters, combustion chamber parameters, high-vortex characteristic parameters, and low-vortex characteristic parameters. Determine whether the high-vortex and low-vortex characteristic parameters meet the residual accuracy requirements. If not, use the Newton-Lafferson method to solve again for the bypass ratio (BPR) and afterburner fuel flow rate (W). fb Then, the compressor characteristic parameters, combustion chamber parameters, high vortex characteristic parameters, and low vortex characteristic parameters are evaluated again until the residual accuracy requirements are met. If the residual accuracy requirements are met, the tail nozzle parameters and performance parameters are evaluated in sequence to obtain the evaluation results.

7. The high- and low-pressure turbine matching design method for a next-generation low-bypass turbofan engine as described in claim 1, characterized in that, Structural improvements to the high and low pressure turbines are made by adjusting the flow capacity of the high and low pressure turbines, the intake air volume, and the exhaust air volume. Specifically, this includes: adjusting the area of ​​the high and low pressure turbine guide vanes: if the compressor operating line is lower than the design operating line, the area of ​​the high pressure turbine guide vane is reduced; if the compressor operating line is higher than the design operating line, the area of ​​the high pressure turbine guide vane is increased; adjusting the area of ​​the low pressure turbine guide vane: if the expansion ratio of the high pressure turbine is too small, the area of ​​the low pressure turbine guide vane is increased and the ineffective air consumption is reduced, while meeting the lower limit of the total pressure ratio between the inner and outer casings; adjusting the intake air volume and exhaust air volume of the air system: reducing ineffective air consumption by reducing leakage at the sealing wall teeth and the casing joint.

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