An MBSE-based aero-engine gas path system digital prototype development method

Abstract

A method of developing aero-engine gas path system digital prototype based on MBSE is proposed to solve the problems of long development cycle, low efficiency and high cost in traditional text-based research and development, and to promote digital transformation and forward design. The core of the method is to realize the deep connection between "static design constraints" and "dynamic performance simulation" through the conversion of SysML parameter constraints to Modelica performance model, to build a closed-loop MBSE system with thrust estimation as the target, and to achieve "demand-model-performance" full-link traceability and verification. SysML and Enterprise Architect are used to complete demand and architecture modeling, 11 types of core component mechanism models are built based on Modelica, and digital prototype is built through MWORKS and verified by full flight cycle data. The method can shorten the development cycle and reduce the design error, and can be used for aero-engine gas path system design optimization, state monitoring and fault diagnosis.

Description

Technical Field

[0001] This invention relates to the field of digital R&D technology for aero-engines, and in particular to a digital prototype development method for aero-engine air path systems based on MBSE. Background Technology

[0002] With the increasing complexity of aero-engine structures and the upgrading of mission requirements, the traditional "design-test-optimize-retest" aero-engine aero-engine gas path system development method has significant limitations. Its core problems include lengthy development cycles, low efficiency of interdisciplinary collaboration, a disconnect between requirements and performance verification, and high costs due to high dependence on physical prototypes. Existing digital modeling methods mostly focus on single-stage simulation, lacking a complete traceability and closed-loop verification mechanism from top-level requirements to performance output. This makes it difficult to identify system-level design defects in advance and fails to meet the demands of efficient and precise development for the digital transformation of aero-engines. Furthermore, existing technologies such as SysML architecture modeling and Modelica performance simulation have tool barriers and lack a mature mechanism for transferring requirement parameters to simulation models, leading to delayed design iterations and high verification costs, ultimately hindering the efficient construction and full-process verification of digital prototypes for the gas path system. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing aero-engine gas path system development methods and provide a digital prototype development method based on MBSE. Through systematic modeling, mechanism derivation and closed-loop verification, it achieves full traceability of "requirements-architecture-performance", shortens the R&D cycle and reduces R&D costs.

[0004] The technical solution of this invention is as follows: A digital prototype development method for an aero-engine air path system based on MBSE, comprising the following steps: Step 1) Based on the Harmony-SE method, the requirements definition, behavior analysis, structural composition and parameter constraint modeling of the aero-engine gas path system are completed using the system modeling language SysML, forming a complete gas path system model; Step 2) Analyze the properties and behaviors of the 11 core components of the aero-engine air path system (atmosphere, intake, fan, bypass duct, low-pressure compressor, high-pressure compressor, combustion chamber, high-pressure turbine, low-pressure turbine, inner nozzle, and outer bypass nozzle) and derive the thermodynamic mechanism equations. Step 3) Based on the MWORDS simulation platform, the SysML parameter constraints are mapped to the Modelica equation, a multiphysics modeling language. The constructed air path system performance model is compared and verified with the JT9D performance model. The virtual digital prototype of the aero-engine air path system after the comparison and verification is passed shortens the development cycle and reduces the development cost of the aero-engine air path system.

[0005] In step 1), the demand definition includes decomposing the top-level thrust demand into secondary demands, including the inlet total pressure recovery coefficient, compressor pressure ratio, turbine pressure ratio, bypass pressure ratio, combustion chamber total pressure recovery coefficient, and nozzle total pressure recovery coefficient, thus establishing a demand hierarchy structure. The behavioral analysis described involves dividing the system into five core modules: flight control system, auxiliary power unit, aero-engine, atmospheric environment, and fuel system. It clarifies the interaction sequence between components and analyzes the behavioral logic between airflow compression, combustion, expansion, and work in the air path system.

[0006] The structure consists of: constructing a hierarchical structure tree of the core components, including the intake duct, fan, compressor, combustion chamber, turbine, and nozzle, through a demand diagram, and defining the mechanical interfaces, air passage interfaces, and fuel interfaces between the components.

[0007] The parameter constraint modeling involves establishing thermodynamic constraint relationships between components and clarifying the association rules between the design parameters of each component as follows: "Intake duct to fan", total pressure at the intake duct outlet and total temperature at the intake and outlet The total pressure loss is directly transmitted to the fan inlet and is determined by the total pressure recovery coefficient. and intake manifold total pressure The following corrections have been made, and the relationships are as follows: in, Indicates the total temperature at the intake of the air intake; "Fan to Bypass / Low-Pressure Compressor": The fan outlet splits into two airflows, which are delivered to the bypass duct and the low-pressure compressor respectively; the total pressure at the bypass duct outlet... By bypass ratio pressure ratio Correction, connotation of total temperature at the inlet The power is directly transmitted to the low-pressure compressor, as follows: in, The total temperature at the outlet of the outer duct. For the total temperature of the outlet, for ; From low-pressure compressor to high-pressure compressor, low-pressure compressor outlet pressure By pressure ratio Calculate the outlet temperature of the low-pressure compressor. With the compression work of the low-pressure compressor The relationship is as follows: in, Let be the specific heat capacity of air at constant pressure, and k be the specific heat ratio of air. This refers to the isentropic efficiency of low-pressure compressors. The association rule for "high-pressure compressor to combustion chamber": total pressure at the high-pressure compressor outlet. and the total temperature at the outlet of the high-pressure compressor Transmitted to the combustion chamber, , As the compression process increases, the relationship is as follows: in, The compression work of the high-pressure compressor. This refers to the pressure ratio of the high-pressure compressor. This refers to the isentropic efficiency of the high-pressure compressor. "Combustion chamber to high-pressure turbine", total pressure at combustion chamber outlet From the total pressure recovery coefficient Correction, combustion chamber outlet temperature Based on the heat released during combustion, the relationship is as follows: in, The fuel flow rate in the combustion chamber. The calorific value of the fuel in the combustion chamber. For combustion efficiency in the combustion chamber, This refers to the mass flow rate of the air at the combustion chamber inlet. The specific heat capacity of the gas at constant pressure; From high-pressure turbine to low-pressure turbine, the high-pressure turbine expands and performs work, resulting in the high-pressure turbine outlet pressure. With high pressure turbine outlet temperature The parameters are directly passed to the low-pressure turbine as follows: in, For the expansion work of the high-pressure turbine, The pressure ratio of the high-pressure turbine. This refers to the isentropic efficiency of a high-pressure turbine. "Low-pressure turbine to inner nozzle", low-pressure turbine outlet temperature and low-pressure turbine outlet pressure Pressure is transmitted to the inner nozzle. Due to turbine pressure ratio The decision is as follows: in, For low-pressure turbine expansion work, For low-pressure turbine pressure ratio, For low-pressure turbine isentropic efficiency; "From the outer duct to the outer duct nozzle", total pressure at the outer duct outlet and the outlet temperature of the outer duct The total pressure at the outlet of the bypass duct is transmitted to the bypass nozzle. Recovery coefficient of total pressure from outer bypass nozzle The relationship is corrected as follows: The parameter definitions and quantitative relationships of each component in the 11 core components of the aero-engine air path system in step 2) are as follows: Atmospheric component parameters include flight altitude H (m), atmospheric static temperature T0 (K), and atmospheric static pressure P0 (Pa). T0 and P0 are determined solely by flight altitude H and provide inlet environmental parameters for the air intake.

[0008] Thermodynamic equation: The inlet duct assembly parameters include inlet total temperature T1 (K), inlet total pressure P1 (Pa), outlet total temperature T2 (K), outlet total pressure P2 (Pa), and total pressure recovery coefficient σ1 = 0.97. Inlet parameters are determined by the atmospheric environment and Mach number, while outlet parameters are directly transmitted to the fan assembly. , .

[0009] Thermodynamic equation: Import total temperature: Total inlet pressure: Total temperature at the exit: Total outlet pressure: Fan component parameters include bypass ratio m=5 (fixed for JT9D engine), total inlet flow rate G2 (kg / s), and outer bypass outlet flow rate G. 13 (kg / s), internal channel outlet flow rate G 21 (kg / s). Among them + The bypass flow rate is 5 times that of the inner flow rate, and the total temperature of the airflow at the bypass outlet is... = = Total pressure , = .

[0010] Thermodynamic equation: Total import flow: External duct flow rate: The essence of traffic: in, For fan thrust, For dynamic pressure, It is the gas constant; External bypass duct component parameters include outlet total temperature T 13 (K), Total outlet pressure P 13 (Pa), duct pressure ratio The inlet parameters are the airflow parameters of the fan outlet bypass, and the outlet parameters are directly transmitted to the bypass nozzle. Consistent with the total temperature at the fan inlet. It is twice the total pressure at the fan outlet.

[0011] Thermodynamic equation: Outlet temperature: Total outlet pressure: Low-pressure compressor component parameters include pressure ratio isentropic efficiency Compression power L 25 Outlet temperature T 25 Total export pressure P 25 The inlet parameters are the fan's internal outlet parameters ( The outlet parameters are transmitted to the high-pressure compressor, T 25 As compression work increases, P 25 It is three times the total pressure of the import.

[0012] Thermodynamic equation: Compression work: Outlet temperature: Total outlet pressure: High-pressure compressor component parameters include pressure ratio isentropic efficiency Compression work L3 (J / kg), outlet total temperature T3 (K), and outlet total pressure P3 (Pa). The inlet parameters are the outlet parameters of the low-pressure compressor (T). 25 P 25 The outlet parameters are transmitted to the combustion chamber, P3 is 14 times the total inlet pressure, and T3 increases significantly with compression work.

[0013] Thermodynamic equation: Compression work: Total temperature at the exit: Total outlet pressure: Combustion chamber component parameters include fuel flow rate G f (kg / s), fuel oil calorific value H f =43000×10 3 (J / kg), combustion efficiency η2=0.98, total pressure recovery coefficient σ2=0.95, outlet total temperature T4 (K), outlet total pressure P4 (Pa). Among them, the inlet parameters are the outlet parameters of the high-pressure compressor (T3, P3, G3), and the outlet parameters are transmitted to the high-pressure turbine. T4 is determined by the heat released from fuel combustion, and P4 is 95% of P3.

[0014] Thermodynamic equation: Total temperature at the exit: Total outlet pressure: High-pressure turbine component parameters include pressure ratio isentropic efficiency Expansion work L 42 (J / kg), Total outlet temperature T 42 (K), Total outlet pressure P 42 (Pa). The inlet parameters are the combustion chamber outlet parameters (T4, P4), and the expansion work L... 42 Balanced with the compression work L3 of the high-pressure compressor, the outlet parameters are transmitted to the low-pressure turbine, P 42 It is 1 / 2 of the total inlet pressure.

[0015] Thermodynamic equation: Expansion work: Total temperature at the exit: Total outlet pressure: Low-pressure turbine component parameters include pressure ratio isentropic effect Expansion work L5 (J / kg), total outlet temperature T5 (K), and total outlet pressure P5 (Pa). The inlet parameters are the high-pressure turbine outlet parameters (T...). 42 P 42 ), expansion work L5 and low-pressure compressor compression work L 25 Balance, the exit parameters are transmitted to the inner nozzle.

[0016] Thermodynamic equation: Expansion work: Total temperature at the exit: Total outlet pressure: The parameters of the internal nozzle assembly include the total pressure recovery coefficient σ3, the total outlet temperature T9 (K), the total outlet pressure P9 (Pa), and the static outlet pressure P. s9 (Pa), outlet velocity V9 (m / s), thrust F9 (N). The inlet parameters are the low-pressure turbine outlet parameters (T5, P5). The thrust is determined by the change in momentum and the pressure difference, and is superimposed with the outer bypass nozzle thrust to form the total engine thrust.

[0017] Thermodynamic equation: Outlet temperature: Total outlet pressure: Critical pressure ratio: Operating Condition 1: Operating Condition 2: thrust: in, The total pressure recovery coefficient of the inner nozzle. For the internal nozzle pressure ratio, This is the nozzle critical pressure ratio. The mass flow rate of the combustion gas at the nozzle outlet is [value missing]. This refers to the cross-sectional area of ​​the nozzle exit. The parameters of the outer bypass nozzle assembly include the total pressure recovery coefficient σ4 and the total outlet temperature T. 19 (K), Total outlet pressure P 19 (Pa), outlet static pressure P s19 (Pa), outlet velocity V 19 (m / s), thrust F 19 (N). The inlet parameters are the same as the outlet parameters of the bypass duct (T). 13 P 13 The thrust calculation logic is consistent with that of the internal nozzle; the total thrust F = F9 + F 19 .

[0018] Thermodynamic equation: Total temperature at the exit: Total outlet pressure: thrust: in, This refers to the mass flow rate of the air at the outlet of the outer bypass nozzle. This refers to the cross-sectional area of ​​the nozzle outlet. In step 3), based on the thermodynamic mechanism equations derived above, and relying on the toolchain integration of Enterprise Architect (EA) and MWORDS, the accurate conversion of SysML parameter constraints to Modelica equations and the construction of system performance models are achieved. From the SysML model constructed by EA, focusing on the parameter diagram, structural block diagram, and constraint blocks, the core constraint information of the aero-engine air path system is extracted. The SysML constraint blocks correspond to the Modelica class (component class), the SysML parameter attributes correspond to the Modelica parameter (parameter) or variable (state variable), the SysML "equality constraint" corresponds to the Modelica equation, and the physical interface between SysML components (air path, energy transfer) corresponds to the Modelica connector, ensuring the consistency of parameter transfer during component integration.

[0019] In the MWORKS platform, following the Modelica 3.2.3 standard, each core component is encapsulated as an independent Modelica component class, realizing a closed loop of "parameter-equation-interface". The thermodynamic mechanism equations corresponding to SysML constraints are written into the equation section of the Modelica component class, and a physical interface is defined for each component class to clarify the direction of transmission of inlet and outlet parameters.

[0020] Based on the actual physical flow of the aero-engine air path system, the 11 encapsulated Modelica components are arranged sequentially by dragging and dropping components in the graphical interface of MWORKS. The connection between components is completed through the Modelica connector interface. The top-level design parameters extracted from SysML are batch assigned to the parameter attributes of the corresponding components to complete the parameter initialization of the model. Finally, syntax and equation verification is performed in MWORKS to ensure that all SysML constraints have been correctly converted into solvable Modelica equations, thus forming a Modelica model of the aero-engine air path system that can be directly used for performance simulation.

[0021] Meanwhile, using publicly available data from the JT9D engine as a comparison, a full flight cycle simulation and verification were completed. By comparing core performance data such as thrust (F), fuel consumption rate (SFC), and total pressure at the high-pressure compressor outlet (P3), the feasibility and accuracy of the model were verified, and closed-loop verification of the top-level thrust requirements was achieved.

[0022] This concludes the description of the MBSE-based digital prototype development method for aero-engine airflow systems proposed in this invention. Through the deep integration of SysML architecture modeling and Modelica performance simulation, and the systematic derivation of thermodynamic mechanism equations, and through full flight cycle simulation verification, the core performance of the airflow system, including thrust and fuel consumption rate, has been described with quantitative data. This provides a guarantee for subsequent verification of the design rationality and performance optimization of the aero-engine airflow system by analyzing the consistency between simulation results and publicly available data, and for achieving a closed loop for top-level thrust requirements.

[0023] Compared with existing development methods, this invention has the following significant advantages: 1) Full traceability of requirements-model-performance process, solving the problem of requirement disconnect in traditional methods. In existing development, requirements lack direct correlation with design and performance models, and verification relies on later physical testing. This invention establishes a direct traceability chain from top-level thrust requirements to component parameters and simulation performance through precise mapping of SysML parameter diagrams and Modelica equations, ensuring that requirements are executable and verifiable, and realizing a closed loop of the entire process of "requirement definition-model construction-performance verification". 2) Forward design avoids risks in advance, breaking through the limitations of the traditional "build first, verify later" approach. Performance simulation is embedded in the conceptual design stage, and core indicators such as thrust and fuel consumption rate are predicted in advance through virtual prototypes. Design defects are identified before physical integration, significantly reducing the risk of major redesign and promoting positive optimization of the system architecture. 3) Using virtual prototypes to replace physical testing, which is reusable and has significant cost-saving and efficiency-enhancing effects. Existing methods rely on the production and testing of a large number of physical prototypes, which is not only time-consuming but also has high material and testing costs. The digital prototype generated by this invention can fully simulate the operating conditions of the entire flight cycle, can be reused and modified flexibly, greatly reducing dependence on physical prototypes, while reducing test energy consumption and design change costs. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the "V" model and a digital prototype design based on MBSE.

[0025] Figure 2 This is a requirements diagram for the development of a digital prototype of an aero-engine air path system based on MBSE.

[0026] Figure 3 This is a flowchart of the model conversion process from SysML parameter constraints to the Modelica performance model.

[0027] Figure 4 These are thrust-time comparison curves of the model of this invention and the JT9D model, where (a) is the thrust-time comparison curve of the model of this invention and (b) is the thrust-time comparison curve of the JT9D model. Detailed Implementation

[0028] To achieve the above objectives, this invention proposes a digital prototype development method for an aero-engine air path system based on MBSE, comprising the following steps: S1: MBSE Method Framework Construction S1.1: Based on the development requirements of aero-engine air path systems, the following core elements are defined: The Harmony-SE modeling methodology is adopted, dividing the development process into three core phases to form a closed loop of "analysis-design-verification." SysML is used for architectural modeling, and requirement diagrams are used to fully describe system requirements, structure, behavior, and parameter constraints. Modelica is used for performance modeling, and Enterprise Architect (EA) is employed, supporting full-process SysML modeling, including use case analysis, state analysis, and parameter constraint definition. The MWORKS performance simulation tool, compatible with the Modelica 3.2.3 standard, is used to support thermodynamic and dynamic simulations and result visualization of complex systems.

[0029] S1.2: Development Process Design Follow the "V" model for reference Figure 1 The system constructs a complete process of "top-level design - bottom-level verification - closed-loop feedback". In the top-level design, the requirements are defined and functions are analyzed first, followed by architecture design and parameter constraints, and finally the model is built. In the bottom-level verification, system integration simulation is completed in component simulation, performance verification is completed, requirements are traced, and finally the parameters are optimized according to the requirements.

[0030] S2: Requirements and Architecture Modeling Implementation S2.1: Definition of Requirement Hierarchy refer to Figure 2 The requirement diagram breaks down the top-level requirement "provide rated thrust under different flight conditions" into nine secondary parameter requirements, described using a requirement quadruple: Vreq=(ID,Type,Param,Constraint). Figure 2 It clearly presents the relationship between top-level requirements and secondary parameters, providing a visual basis for requirement tracing and verification, and ensuring that each design parameter originates from the core thrust requirements.

[0031] Where: ID is the requirement number, Type is the parameter type (pressure ratio, total pressure recovery coefficient), Param is the parameter value (σ1=0.97, πlpc=3), and Constraint is the constraint condition (flight altitude 0-11km, Mach number 0-0.8). The demand definition includes decomposing the top-level thrust demand into secondary demands, including the inlet total pressure recovery coefficient, compressor pressure ratio, turbine pressure ratio, bypass duct pressure ratio, combustion chamber total pressure recovery coefficient, and nozzle total pressure recovery coefficient, establishing a demand hierarchy structure. A hierarchical structure tree of the core components—inlet, fan, compressor, combustion chamber, turbine, and nozzle—is constructed using a demand diagram, defining the mechanical interfaces, air passage interfaces, and fuel interfaces between components. Finally, thermodynamic constraints between components are established, clarifying the association rules between the design parameters of each component as follows: "Intake duct to fan", total pressure at the intake duct outlet and total temperature at the intake and outlet The total pressure loss is directly transmitted to the fan inlet and is determined by the total pressure recovery coefficient. and intake manifold total pressure The following corrections have been made, and the relationships are as follows: in, Indicates the total temperature at the intake of the air intake; "Fan to Bypass / Low-Pressure Compressor": The fan outlet splits into two airflows, which are delivered to the bypass duct and the low-pressure compressor respectively; the total pressure at the bypass duct outlet... By bypass ratio pressure ratio Correction, connotation of total temperature at the inlet The power is directly transmitted to the low-pressure compressor, as follows: in, The total temperature at the outlet of the outer duct. For the total temperature of the outlet, for ; From low-pressure compressor to high-pressure compressor, low-pressure compressor outlet pressure By pressure ratio Calculate the outlet temperature of the low-pressure compressor. With the compression work of the low-pressure compressor The relationship is as follows: in, Let be the specific heat capacity of air at constant pressure, and k be the specific heat ratio of air. This refers to the isentropic efficiency of low-pressure compressors. The association rule for "high-pressure compressor to combustion chamber": total pressure at the high-pressure compressor outlet. and the total temperature at the outlet of the high-pressure compressor Transmitted to the combustion chamber, , As the compression process increases, the relationship is as follows: in, The compression work of the high-pressure compressor. This refers to the pressure ratio of the high-pressure compressor. This refers to the isentropic efficiency of the high-pressure compressor. "Combustion chamber to high-pressure turbine", total pressure at combustion chamber outlet From the total pressure recovery coefficient Correction, combustion chamber outlet temperature Based on the heat released during combustion, the relationship is as follows: in, The fuel flow rate in the combustion chamber. The calorific value of the fuel in the combustion chamber. For combustion efficiency in the combustion chamber, This refers to the mass flow rate of the air at the combustion chamber inlet. The specific heat capacity of the gas at constant pressure; From high-pressure turbine to low-pressure turbine, the high-pressure turbine expands and performs work, resulting in the high-pressure turbine outlet pressure. With high pressure turbine outlet temperature The parameters are directly passed to the low-pressure turbine as follows: in, For the expansion work of the high-pressure turbine, The pressure ratio of the high-pressure turbine. This refers to the isentropic efficiency of a high-pressure turbine. "Low-pressure turbine to inner nozzle", low-pressure turbine outlet temperature and low-pressure turbine outlet pressure Pressure is transmitted to the inner nozzle. Due to turbine pressure ratio The decision is as follows: in, For low-pressure turbine expansion work, For low-pressure turbine pressure ratio, For low-pressure turbine isentropic efficiency; "From the outer duct to the outer duct nozzle", total pressure at the outer duct outlet and the outlet temperature of the outer duct The total pressure at the outlet of the bypass duct is transmitted to the bypass nozzle. Recovery coefficient of total pressure from outer bypass nozzle The relationship is corrected as follows: S2.2: Architecture Modeling An EA (Experimental Architecture) model was used to construct a hierarchical structure of the aero-engine's airflow system components (11 core components). Component interfaces (mechanical, airflow, and fuel interfaces) were defined. For each of the 11 core components of the aero-engine's airflow system (atmosphere, intake, fan, bypass duct, low-pressure compressor, high-pressure compressor, combustion chamber, high-pressure turbine, low-pressure turbine, inner nozzle, and outer nozzle), a systematic analysis of the properties and behaviors of each component was conducted. Thermodynamic mechanism equations were derived. Based on SysML parameter diagrams, secondary parameters were used as component constraints to establish a "component parameter-constraint equation" relationship, ensuring clear design consistency. The parameter definitions and quantitative relationships of each component are as follows: Atmospheric component parameters include flight altitude H (m), atmospheric static temperature T0 (K), and atmospheric static pressure P0 (Pa). T0 and P0 are determined solely by flight altitude H and provide inlet environmental parameters for the air intake.

[0032] Thermodynamic equation: The inlet duct assembly parameters include inlet total temperature T1 (K), inlet total pressure P1 (Pa), outlet total temperature T2 (K), outlet total pressure P2 (Pa), and total pressure recovery coefficient σ1 = 0.97. Inlet parameters are determined by the atmospheric environment and Mach number, while outlet parameters are directly transmitted to the fan assembly. , .

[0033] Thermodynamic equation: Import total temperature: Total inlet pressure: Total temperature at the exit: Total outlet pressure: Fan component parameters include bypass ratio m=5 (fixed for JT9D engine), total inlet flow rate G2 (kg / s), and outer bypass outlet flow rate G. 13 (kg / s), internal channel outlet flow rate G 21 (kg / s). Among them + The external bypass flow rate is 5 times the internal bypass flow rate, and the total temperature of the outlet airflow is... = = Total pressure , = .

[0034] Thermodynamic equation: Total import flow: External duct flow rate: The essence of traffic: External bypass duct component parameters include outlet total temperature T 13 (K), Total outlet pressure P 13 (Pa), duct pressure ratio The inlet parameters are the airflow parameters of the fan outlet bypass, and the outlet parameters are directly transmitted to the bypass nozzle. Consistent with the total temperature at the fan inlet. It is twice the total pressure at the fan outlet.

[0035] Thermodynamic equation: Outlet temperature: Total outlet pressure: Low-pressure compressor component parameters include pressure ratio isentropic efficiency Compression power L 25 Outlet temperature T 25 Total export pressure P 25 The inlet parameters are the fan's internal outlet parameters ( The outlet parameters are transmitted to the high-pressure compressor, T 25 As compression work increases, P 25 It is three times the total pressure of the import.

[0036] Thermodynamic equation: Compression work: Outlet temperature: Total outlet pressure: High-pressure compressor component parameters include pressure ratio isentropic efficiency Compression work L3 (J / kg), outlet total temperature T3 (K), and outlet total pressure P3 (Pa). The inlet parameters are the outlet parameters of the low-pressure compressor (T). 25 P 25 The outlet parameters are transmitted to the combustion chamber, P3 is 14 times the total inlet pressure, and T3 increases significantly with compression work.

[0037] Thermodynamic equation: Compression work: Total temperature at the exit: Total outlet pressure: Combustion chamber component parameters include fuel flow rate G f (kg / s), fuel oil calorific value H f =43000×10 3 (J / kg), combustion efficiency η2=0.98, total pressure recovery coefficient σ2=0.95, outlet total temperature T4 (K), outlet total pressure P4 (Pa). Among them, the inlet parameters are the outlet parameters of the high-pressure compressor (T3, P3, G3), and the outlet parameters are transmitted to the high-pressure turbine. T4 is determined by the heat released from fuel combustion, and P4 is 95% of P3.

[0038] Thermodynamic equation: Total temperature at the exit: Total outlet pressure: High-pressure turbine component parameters include pressure ratio isentropic efficiency Expansion work L 42 (J / kg), Total outlet temperature T 42 (K), Total outlet pressure P 42 (Pa). The inlet parameters are the combustion chamber outlet parameters (T4, P4), and the expansion work L... 42 Balanced with the compression work L3 of the high-pressure compressor, the outlet parameters are transmitted to the low-pressure turbine, P 42 It is 1 / 2 of the total inlet pressure.

[0039] Thermodynamic equation: Expansion work: Total temperature at the exit: Total outlet pressure: Low-pressure turbine component parameters include pressure ratio isentropic effect Expansion work L5 (J / kg), total outlet temperature T5 (K), and total outlet pressure P5 (Pa). The inlet parameters are the high-pressure turbine outlet parameters (T...). 42 P 42 ), expansion work L5 and low-pressure compressor compression work L 25 Balance, the exit parameters are transmitted to the inner nozzle.

[0040] Thermodynamic equation: Expansion work: Total temperature at the exit: Total outlet pressure: The parameters of the internal nozzle assembly include the total pressure recovery coefficient σ3, the total outlet temperature T9 (K), the total outlet pressure P9 (Pa), and the static outlet pressure P.s9 (Pa), outlet velocity V9 (m / s), thrust F9 (N). The inlet parameters are the low-pressure turbine outlet parameters (T5, P5). The thrust is determined by the change in momentum and the pressure difference, and is superimposed with the outer bypass nozzle thrust to form the total engine thrust.

[0041] Thermodynamic equation: Outlet temperature: Total outlet pressure: Critical pressure ratio: Operating Condition 1: Operating Condition 2: thrust: The parameters of the outer bypass nozzle assembly include the total pressure recovery coefficient σ4 and the total outlet temperature T. 19 (K), Total outlet pressure P 19 (Pa), outlet static pressure P s19 (Pa), outlet velocity V 19 (m / s), thrust F 19 (N). The inlet parameters are the same as the outlet parameters of the bypass duct (T). 13 P 13 The thrust calculation logic is consistent with that of the internal nozzle; the total thrust F = F9 + F 19 .

[0042] Thermodynamic equation: Total temperature at the exit: Total outlet pressure: thrust: .

[0043] S3: Digital Prototype Building and Validation Based on the derived thermodynamic mechanism equations, and leveraging the toolchain integration of Enterprise Architect (EA) and MWORKS, the accurate conversion of SysML parameter constraints to Modelica equations and the construction of system performance models are achieved. Figure 3As shown, from the SysML model constructed by EA, focusing on the parameter diagram, structure block diagram and constraint block, the core constraint information of the aero-engine air path system is extracted. The SysML constraint block corresponds to the Modelica class (component class), the SysML parameter attribute corresponds to the Modelica parameter (parameter) or variable (state variable), the SysML "equality constraint" corresponds to the Modelica equation, and the physical interface between SysML components (air path, energy transfer) corresponds to the Modelica connector, ensuring the consistency of parameter transfer during component integration.

[0044] In the MWORKS platform, following the Modelica 3.2.3 standard, each core component is encapsulated as an independent Modelica component class, realizing a closed loop of "parameter-equation-interface". The thermodynamic mechanism equations corresponding to SysML constraints are written into the equation section of the Modelica component class, and a physical interface is defined for each component class to clarify the direction of transmission of inlet and outlet parameters.

[0045] Based on the actual physical flow of the aero-engine air path system, the 11 encapsulated Modelica components are arranged sequentially by dragging and dropping components in the graphical interface of MWORKS. The connection between components is completed through the Modelica connector interface. The top-level design parameters extracted from SysML are batch assigned to the parameter attributes of the corresponding components to complete the parameter initialization of the model. Finally, syntax and equation verification is performed in MWORKS to ensure that all SysML constraints have been correctly converted into solvable Modelica equations, thus forming a Modelica model of the aero-engine air path system that can be directly used for performance simulation.

[0046] Meanwhile, using publicly available data from the JT9D engine as a comparison... Figure 4 The simulation and verification of the entire flight cycle were completed. By comparing the core performance data of thrust (F), the feasibility and accuracy of the development method were verified.

[0047] The digital prototype can replace part of the physical entity verification process. By saving multiple versions of the empirically validated digital prototype, it can be used as needed for subsequent production or design optimization, reducing reliance on physical prototypes, lowering R&D costs, shortening the R&D cycle, and improving the speed and accuracy of design optimization and verification.

Claims

1. A digital prototype development method for an aero-engine air path system based on MBSE, characterized in that, Includes the following steps: Step 1) Based on the Harmony-SE method, the requirements definition, behavior analysis, structural composition and parameter constraint modeling of the aero-engine gas path system are completed using the system modeling language SysML, forming a complete gas path system model; Step 2) Analyze the properties and behaviors of the 11 core components of the aero-engine air path system and derive the thermodynamic mechanism equations. The 11 core components include the atmosphere, air intake, fan, bypass duct, low-pressure compressor, high-pressure compressor, combustion chamber, high-pressure turbine, low-pressure turbine, inner nozzle, and outer bypass nozzle. Step 3) Based on the MWORKS simulation platform, the SysML parameter constraints are mapped to the Modelica equations of the multiphysics modeling language. The constructed gas path system performance model is compared and verified with the JT9D performance model to generate a virtual digital prototype of the aero-engine gas path system.

2. The method for developing a digital prototype of an aero-engine airflow system based on MBSE according to claim 1, characterized in that, In step 1), the demand definition includes decomposing the top-level thrust demand into secondary demands, including the inlet total pressure recovery coefficient, compressor pressure ratio, turbine pressure ratio, bypass pressure ratio, combustion chamber total pressure recovery coefficient, and nozzle total pressure recovery coefficient, thus establishing a demand hierarchy structure. The behavioral analysis described above involves dividing the system into five core modules: flight control system, auxiliary power unit, aero-engine, atmospheric environment, and fuel system; clarifying the interaction sequence between components; and analyzing the behavioral logic between airflow compression, combustion, expansion, and work in the air path system. The structure consists of: constructing a hierarchical structure tree of the core components, including the intake duct, fan, compressor, combustion chamber, turbine, and nozzle, through a demand diagram, and defining the mechanical interfaces, air passage interfaces, and fuel interfaces between the components.

3. The method for developing a digital prototype of an aero-engine air path system based on MBSE according to claim 1, characterized in that, The parameter constraint modeling involves establishing thermodynamic constraint relationships between components and clarifying the association rules between the design parameters of each component as follows: "Intake duct to fan", total pressure at the intake duct outlet and total temperature at the intake and exhaust outlet The total pressure loss is directly transmitted to the fan inlet and is determined by the total pressure recovery coefficient. and intake manifold total pressure The following corrections have been made, and the relationships are as follows: in, Indicates the total temperature at the intake of the air intake; "Fan to Bypass Duct / Low-Pressure Compressor": The fan outlet splits into two airflows, which are delivered to the bypass duct and the low-pressure compressor respectively; the total pressure at the bypass duct outlet... By bypass ratio pressure ratio Correction, connotation of total temperature at the inlet The power is directly transmitted to the low-pressure compressor, as follows: in, The total temperature at the outlet of the outer duct. For the total temperature of the outlet, for ; "From low-pressure compressor to high-pressure compressor", low-pressure compressor outlet pressure By pressure ratio Calculate the low-pressure compressor outlet temperature. With the compression work of the low-pressure compressor The relationship is as follows: in, Let be the specific heat capacity of air at constant pressure, and k be the specific heat ratio of air. For low-pressure compressors, the isentropic efficiency is required. The association rule for "high-pressure compressor to combustion chamber": total pressure at the high-pressure compressor outlet. and the total temperature at the outlet of the high-pressure compressor Transmitted to the combustion chamber, , As the compression process increases, the relationship is as follows: in, The compression work of the high-pressure compressor. This refers to the pressure ratio of the high-pressure compressor. This refers to the isentropic efficiency of the high-pressure compressor. "Combustion chamber to high-pressure turbine", total pressure at combustion chamber outlet From the total pressure recovery coefficient Correction, combustion chamber outlet temperature Based on the heat released during combustion, the relationship is as follows: in, The fuel flow rate in the combustion chamber. The calorific value of the fuel in the combustion chamber. For combustion efficiency in the combustion chamber, This refers to the mass flow rate of the air at the combustion chamber inlet. The specific heat capacity of the gas at constant pressure; "High-pressure turbine to low-pressure turbine", high-pressure turbine expands and performs work, high-pressure turbine outlet pressure With high pressure turbine outlet temperature The parameters are directly passed to the low-pressure turbine as follows: in, For the expansion work of the high-pressure turbine, The pressure ratio of the high-pressure turbine. This refers to the isentropic efficiency of a high-pressure turbine. "Low-pressure turbine to inner nozzle", low-pressure turbine outlet temperature and low-pressure turbine outlet pressure Pressure is transmitted to the inner nozzle. Due to turbine pressure ratio The decision is as follows: in, For low-pressure turbine expansion work, For low-pressure turbine pressure ratio, For low-pressure turbine isentropic efficiency; "From duct to duct nozzle", total pressure at duct outlet and the outlet temperature of the outer duct The total pressure at the outlet of the bypass duct is transmitted to the bypass nozzle. Recovery coefficient of total pressure from outer bypass nozzle The relationship is corrected as follows: 。 4. The method for developing a digital prototype of an aero-engine airflow system based on MBSE according to claim 1, characterized in that, The parameter definitions and quantitative relationships of each component in the 11 core components of the aero-engine air circuit system in step 2) are as follows: Atmospheric component parameters include flight altitude H, atmospheric static temperature T0, and atmospheric static pressure P0; T0 and P0 are determined solely by flight altitude H, providing inlet environmental parameters for the air intake. Thermodynamic equation: The parameters of the intake duct assembly include inlet total temperature T1, inlet total pressure P1, outlet total temperature T2, outlet total pressure P2, and total pressure recovery coefficient σ1 = 0.97; the inlet parameters are determined by the atmospheric environment and Mach number, while the outlet parameters are directly transmitted to the fan assembly. , ; Thermodynamic equation: Import total temperature: Total inlet pressure: Total temperature at the exit: Total pressure at the outlet: Fan component parameters include bypass ratio m=5, total inlet flow rate G2, and external bypass outlet flow rate G. 13 , Inner channel outlet flow G 21 ;in + The bypass flow rate is 5 times that of the inner flow rate, and the total temperature of the airflow at the bypass outlet is... = = Total pressure , = ; Thermodynamic equation: Total import flow: External duct flow rate: Internal Traffic: in, For fan thrust, For dynamic pressure, It is the gas constant; External bypass duct component parameters include outlet total temperature T 13 Total export pressure P 13 duct pressure ratio The inlet parameters are the airflow parameters of the fan outlet bypass, and the outlet parameters are directly transmitted to the bypass nozzle. Consistent with the total temperature at the fan inlet. It is twice the total pressure at the fan outlet. Thermodynamic equation: Outlet temperature: Total pressure at the outlet: Low-pressure compressor component parameters include pressure ratio isentropic efficiency Compression power L 25 Outlet temperature T 25 Total export pressure P 25 The inlet parameters are the fan's internal and outlet parameters, i.e. The outlet parameters are transmitted to the high-pressure compressor, T 25 As compression work increases, P 25 Three times the total import pressure; Thermodynamic equation: Compression work: Outlet temperature: Total pressure at the outlet: High-pressure compressor component parameters include pressure ratio isentropic efficiency Compression work L3, total outlet temperature T3, total outlet pressure P3; where the inlet parameters are the low-pressure compressor outlet parameters T. 25 P 25 The outlet parameters are transmitted to the combustion chamber, P3 is 14 times the total inlet pressure, and T3 increases significantly with compression work. Thermodynamic equation: Compression work: Total temperature at the exit: Total pressure at the outlet: Combustion chamber component parameters include fuel flow rate G f Fuel calorific value H f =43000×10 3 Combustion efficiency η2 = 0.98, total pressure recovery coefficient σ2 = 0.95, outlet total temperature T4, and outlet total pressure P4; where the inlet parameters are the high-pressure compressor outlet parameters T3, P3, and G3, and the outlet parameters are transmitted to the high-pressure turbine. T4 is determined by the heat released from fuel combustion, and P4 is 95% of P3. Thermodynamic equation: Total temperature at the exit: Total pressure at the outlet: High-pressure turbine component parameters include pressure ratio isentropic efficiency Expansion work L 42 Total outlet temperature, total outlet pressure P 42 The inlet parameters are the combustion chamber outlet parameters T4 and P4, and the expansion work L. 42 Balanced with the compression work L3 of the high-pressure compressor, the outlet parameters are transmitted to the low-pressure turbine, P 42 It is 1 / 2 of the total inlet pressure; Thermodynamic equation: Expansion work: Total temperature at the exit: Total pressure at the outlet: Low-pressure turbine component parameters include pressure ratio isentropic effect Expansion work L5, total outlet temperature T5, total outlet pressure P5; where the inlet parameters are the high-pressure turbine outlet parameters T. 42 P 42 Expansion work L5 and low-pressure compressor compression work L 25 Balance, the exit parameters are transmitted to the inner nozzle; Thermodynamic equation: Expansion work: Total temperature at the exit: Total pressure at the outlet: The parameters of the internal nozzle assembly include the total pressure recovery coefficient σ3, the total outlet temperature T9, the total outlet pressure P9, and the static outlet pressure P. s9 The inlet parameters are the low-pressure turbine outlet parameters T5 and P5. The thrust is determined by the momentum change and pressure difference, and is superimposed with the outer bypass nozzle thrust to form the total engine thrust. Thermodynamic equation: Outlet temperature: Total pressure at the outlet: Critical pressure ratio: Operating Condition 1: Operating Condition 2: thrust: in, The total pressure recovery coefficient of the inner nozzle. For the internal nozzle pressure ratio, This is the nozzle critical pressure ratio. The mass flow rate of the combustion gas at the nozzle outlet is [value missing]. This refers to the cross-sectional area of ​​the nozzle exit. The parameters of the outer bypass nozzle assembly include the total pressure recovery coefficient σ4 and the total outlet temperature T. 19 Total export pressure P 19 outlet static pressure P s19 Outlet velocity V 19 Thrust F 19 The inlet parameter is the outlet parameter T of the bypass duct. 13 P 13 The thrust calculation logic is consistent with that of the internal nozzle; the total thrust F = F9 + F 19 ; Thermodynamic equation: Total temperature at the exit: Total pressure at the outlet: thrust: in, This refers to the mass flow rate of the air at the outlet of the outer bypass nozzle. This refers to the cross-sectional area of ​​the nozzle outlet.

5. The method for developing a digital prototype of an aero-engine air path system based on MBSE according to claim 1, characterized in that, In step 3), based on the thermodynamic mechanism equations derived above, and relying on the toolchain integration of Enterprise Architect and MWORDS, the accurate conversion of SysML parameter constraints to Modelica equations and the construction of system performance models are achieved. From the SysML model constructed by EA, focusing on the parameter diagram, structural block diagram, and constraint blocks, the core constraint information of the aero-engine gas path system is extracted. SysML constraint blocks correspond to Modelica component classes, SysML parameter attributes correspond to Modelica parameters or state variables, SysML "equality constraints" correspond to Modelica equations, and the physical interfaces between SysML components correspond to Modelica connectors, ensuring the consistency of parameter transmission during component integration.

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