Design method for optimizing structural parameters of pre-cooling wide-area turbine engine based on flight path

Abstract

The invention discloses a design method for optimizing structural parameters of a pre-cooling wide-area turbine engine based on a flight path. The design method comprises the following steps: constructing a flight propelling model of the pre-cooling wide-area turbine engine; establishing a point mass motion model of the aircraft or the propulsion system; embedding the flight promotion model into the point mass motion model to form an aviation motion model; defining state parameters, control variables and constraint conditions of the aviation motion model, and performing flight motion simulation on the aviation motion model; adjusting state parameters and control variables of the aviation motion model by using a Gaussian pseudo-spectrum method, and determining an optimal track of the aviation motion model; and outputting the state parameters, the control variables and the optimal track information under the optimal track condition. By comprehensively considering various state parameters and control variables and combining a Gaussian pseudo-spectrum method, structural design parameters of the pre-cooling wide-area turbine engine under the optimal track condition are determined; and the optimal thrust and fuel economy of the engine can be realized in different flight states.

Description

Technical Field

[0001] The invention relates to the field of aircraft trajectory optimization design, in particular to a design method for structural parameters of a precooling wide-range turbine engine based on trajectory optimization. Background Art

[0002] As the flight Mach number increases, the total inlet temperature of conventional turbine engines rises in a quadratic curve trend. Limited by the temperature resistance of the compression system and the strength of the rotor, the converted speed and flow of the engine drop significantly, resulting in a decrease in thrust of conventional turbine engines at high Mach numbers. In contrast, the performance of precooled wide-range turbine engines is affected by the combined effects of flight conditions, precooling systems, and fuel control laws. The precooling system effectively improves the thermal efficiency of the turbine engine at high Mach numbers and slows down the increase in heat load by lowering the inlet temperature. This cooling effect enables the engine to operate at higher Mach numbers without losing thrust, thereby maintaining an efficient working state.

[0003] In terms of fuel control, the precooling system allows for a more flexible fuel injection strategy, by monitoring the engine's operating status in real time and dynamically adjusting the fuel flow to adapt to different flight conditions. This efficient control can optimize the combustion process, improve fuel economy, reduce emissions, and ensure the stability and reliability of the engine in high temperature and high pressure environments. Overall, the combination of the precooling system and efficient fuel control enables the precooled high-speed turbine engine to maintain excellent thrust performance under various flight conditions, which has obvious advantages over conventional turbine engines.

[0004] However, although the precooled wide-range turbine engine has shown significant advantages in improving thrust performance and fuel economy, there is still a lack of sufficient research on the determination of its structural parameters under the optimal track conditions (such as the relative length of the central cone of the inlet, the oil-gas ratio of the main combustion chamber, the oil-gas ratio of the afterburner, the nozzle throat area and the outlet area), and it has failed to fully consider the characteristics of the precooling system and its performance under various complex working conditions. For example, the application number is 202411121570.6, which discloses a simulation analysis method for aircraft mission profile planning based on pseudo-spectral method. The application document realizes the optimal overall performance analysis of the aircraft by coupling the aircraft track with the wing variable curvature control strategy. However, the engine object studied in the application document is a conventional turbine engine, and the model and some algorithms therein are not applicable to the precooled wide-range turbine engine. In addition, in the application document, the structural parameters of the turbine engine are fixed values, that is, the component-level structure of the turbine engine is a predetermined structure, not a variable structure; while the components and structures of the precooled wide-range turbine engine of the present invention are variable structures, and the final results of its structural parameters are determined by the optimal track.

[0005] Therefore, the existing models and algorithms are not suitable for the structural parameter optimization of the pre-cooled wide-range turbine engine. There is an urgent need for a new method to optimize the characteristics of the pre-cooled wide-range turbine engine so as to achieve the optimal design of its structural parameters under the optimal track conditions. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a design method for structural parameters of a pre-cooling wide-range turbine engine based on trajectory optimization.

[0007] The purpose of the present invention is mainly achieved through the following technical solutions:

[0008] The embodiment of the present application provides a design method for structural parameters of a pre-cooling wide-range turbine engine based on trajectory optimization, including:

[0009] S1: Construct a flight propulsion model of a precooled wide-range turbine engine;

[0010] S2: Establish a point mass motion model for an aircraft or propulsion system;

[0011] S3: embed the flight propulsion model into the point mass motion model to form an aviation motion model;

[0012] S4: define the state parameters, control variables and constraints of the aviation motion model, and perform flight motion simulation on the aviation motion model;

[0013] Among them, the state parameters include flight altitude, flight speed, climb angle, flight angle of attack, rate of change of angle of attack, thrust, drag, lift, specific impulse, mass, distance from the center of the earth and gravity acceleration; the control variables include the relative length of the central cone of the inlet of the flight propulsion model, the oil-gas ratio of the main combustion chamber, the oil-gas ratio of the afterburner, the nozzle throat area and the outlet area; the constraints include the flight dynamics restrictions of the aviation motion model and the mechanical performance restrictions of the flight propulsion model;

[0014] S5: Use the Gaussian pseudospectral method to adjust the state parameters and control variables of the aviation motion model and determine the optimal trajectory of the aviation motion model;

[0015] S6: Output state parameters, control variables and optimal track information under the optimal track conditions.

[0016] When this embodiment is implemented, the aircraft of the present invention is an unmanned transport aircraft. In actual application, the starting point and end point of its flight are fixed values, while its flight trajectory is a variable; therefore, when the starting point and end point are fixed, its flight trajectory is easier to determine; in addition, the structural design of most pre-cooled wide-range turbine engines is based on the forward derivation of fuel consumption rate and flight time based on the determined trajectory; however, this type of design often ignores the fact that the working state of the pre-cooled wide-range turbine engine is affected by the flight conditions and the pre-cooling system, resulting in a large discrepancy between the performance parameters of the designed pre-cooled wide-range turbine engine and the performance under actual conditions. The inventor of the present application combines the flight state data of the aircraft with the control variables of the pre-cooled wide-range turbojet engine to convert the structural design problem of the pre-cooled wide-range turbine engine into a multivariable optimal trajectory solution problem for a specific aircraft. The control variables under the optimal trajectory are the optimal structural parameters of the pre-cooled wide-range turbojet engine. In this way, many design difficulties such as complex power and nonlinear parameter changes can be overcome, and an overall analysis and design of the pre-cooled wide-range turbine engine at the level of flight and engine integration can be achieved.

[0017] In this embodiment, the inventors of the present application found that existing models and algorithms are often unable to effectively capture the dynamic characteristics and complexity of a pre-cooled wide-range turbine engine under high Mach number conditions when dealing with the trajectory optimization of the pre-cooled wide-range turbine engine, and thus are unable to determine the structural parameters of the pre-cooled wide-range turbine engine under optimal trajectory conditions.

[0018] There are many factors that affect the determination of the structural parameters of the pre-cooled wide-range turbine engine under the optimal flight path conditions. For example, the flight altitude will affect the aerodynamic characteristics and engine performance. A higher flight altitude will cause the air to be thinner, thus affecting the lift and drag of the aircraft. The flight speed is directly related to the aerodynamic load and thrust output. Changes in flight speed will affect the working state and overall performance of the engine. The climb angle will affect the vertical speed of the aircraft, and the angle of attack is an important factor affecting lift. Excessive angles of attack may cause stalling. The speed of change in the angle of attack will also have a significant impact on the stability and controllability of the aircraft. Too fast a change may cause the aerodynamic parameters of the aircraft to change. Unstable; thrust is the force provided by the engine, drag is the hindrance of air flow to the aircraft when the aircraft moves forward, and lift is a necessary condition for the aircraft to overcome gravity. The balance between these three directly determines the flight state of the aircraft; the relative length of the central cone of the pre-cooling engine's inlet duct will affect the inflow speed of the airflow and the engine's intake efficiency; the oil-gas ratio of the main combustion chamber and the afterburner combustion chamber is directly related to the combustion efficiency of the fuel, and an appropriate oil-gas ratio helps to achieve optimal thrust and fuel economy; the nozzle throat area and outlet area affect the gas discharge speed and thrust generation, and the optimization of the nozzle design is an important link in achieving efficient propulsion.

[0019] Therefore, based on many influencing factors and under high Mach number conditions, existing models and algorithms often cannot fully capture their dynamic characteristics and complexity. In order to overcome these shortcomings, the inventors of this application comprehensively considered multiple influencing factors, such as flight altitude, flight speed, climb angle, angle of attack, thrust, drag, etc., and introduced a more accurate component-level model to construct a precooling turbine engine gas generator model. Combined with the Gaussian pseudo-spectrum-based trajectory optimization method, the precooling engine control law optimization design is achieved by solving the parameter change state under the optimal trajectory. By establishing a combination of a flight propulsion model and a point mass motion model, an aviation motion model is formed, thereby achieving accurate simulation of the flight state and determination of the relevant precooling turbine engine structural parameters under the optimal trajectory.

[0020] The setting of state parameters, control variables and constraints ensures the reliability and effectiveness of the model under actual flight conditions. When using the Gaussian pseudo-spectral method for adjustment, the state parameters and control variables can be effectively optimized, and the structural parameters of the aviation motion model can be derived. First, a flight propulsion model of a precooled wide-range turbine engine is constructed to accurately describe its aerodynamic performance under various working conditions; secondly, a point mass motion model of an aircraft or propulsion system is established, and the flight propulsion model is embedded in the point mass motion model, so that the mutual influence between the aerodynamic performance of the flight propulsion model and the motion characteristics of the aircraft under different working conditions can be considered in the same framework during motion simulation; the state parameters, control variables and constraints of the aviation motion model are defined to ensure the authenticity and reliability of the aviation motion model when simulating actual flight; the Gaussian pseudo-spectral method is used to adjust the aviation motion model, optimize the state parameters and control variables, and determine the structural parameters under the optimal trajectory. This process can effectively capture the dynamic characteristics under high Mach number conditions and significantly improve the accuracy and efficiency of structural parameter design.

[0021] In one possible implementation, the structure of the flight propulsion model includes an adjustable air inlet, a jet and / or a strong pre-cooling device, a single-rotor turbine engine, an afterburner and an adjustable nozzle, wherein the throat and outlet area of ​​the adjustable nozzle are adjustable.

[0022] In one possible implementation, the mathematical expression defining the state parameters of the aviation motion model is:

[0023] h=V sinγ

[0024]

[0025] L=qSC L (α,M α )

[0026] L=qSS D (α,M α )

[0027] In the formula, h, V, γ, α, T, I sp ,m,r,g,q,S,C L , C D and M α They respectively represent flight altitude, flight speed, climb angle, flight angle of attack, thrust, drag, lift, specific impulse, aircraft mass, distance of aircraft from the center of the earth, gravitational acceleration, flight dynamic pressure, reference wing area, lift coefficient, drag coefficient and Mach number.

[0028] In one possible implementation, the control variables of the aviation motion model are defined as:

[0029]

[0030] Where, L in,r 、F b 、f ab , A8, A9 and They are the relative length of the center cone of the inlet duct, the oil-gas ratio of the main combustion chamber, the oil-gas ratio of the afterburner, the nozzle throat area and the outlet area.

[0031] In a possible implementation, the specific steps of using the Gaussian pseudospectral method to determine the optimal trajectory of the aviation motion model include:

[0032] S51: Loading state parameters and control variables of the aviation motion model;

[0033] S52: constructing the initial state of the aviation motion model according to the state parameters, and setting the initial structural state of the flight propulsion model according to the control variables;

[0034] S53: Setting parameters of the Gaussian pseudo-spectrum method, including the number of pseudo-spectrum points and the time step, and performing flight motion trajectory optimization on the aviation motion model;

[0035] S54: The trajectory optimization problem is expressed as a corresponding cost function, and the performance indicator of the cost function is the shortest flight acceleration time and the minimum fuel consumption;

[0036] S55: Continuously adjust the state parameters and control variables through the performance indicators set by the cost function until the optimal trajectory is analyzed and simulated;

[0037] S56: Calculate and check whether the state parameters under the optimal track meet the constraint conditions. If they do, the track optimization analysis ends.

[0038] In one possible implementation, the mathematical expression of the cost function is:

[0039] J min,time =t f

[0040] J min,fuel =-m(t f )

[0041] In the formula, J min,time , J min,fuel ,t f 、m(t f ) represent the shortest flight acceleration time, the minimum fuel consumption, the terminal time and the terminal aircraft weight respectively.

[0042] In a possible implementation, the states of the adjustable nozzle include a fully expanded state, an under-expanded state, and an over-expanded state.

[0043] In a possible implementation, the air intake passage includes a subcritical state and a supercritical state.

[0044] In a possible implementation, a system for optimizing structural parameters of a precooling wide-range turbine engine based on a trajectory is also included, the system comprising:

[0045] a model building unit configured to build a flight propulsion model of a precooled wide-range turbine engine, establish a point mass motion model of an aircraft or a propulsion system, and build an aviation motion model based on the flight propulsion model and the point mass motion model;

[0046] A data setting unit is configured to set structural parameters of the flight propulsion model and state parameters of the aviation motion model;

[0047] a flight dynamics simulation unit configured to perform flight motion simulation on the aviation motion model;

[0048] The trajectory optimization unit is configured to optimize the trajectory of the aviation motion model and determine the optimal trajectory; the data output unit is configured to output state parameters, control variables and optimal trajectory information under the optimal trajectory conditions.

[0049] In summary, the present invention has the following beneficial effects compared with the prior art:

[0050] The present invention determines the optimal flight path of a precooled wide-range turbine engine by comprehensively considering multiple state parameters and control variables and combining the Gaussian pseudo-spectral method, and then establishes the structural design parameters of the precooled wide-range turbine engine under the optimal flight path conditions. This method can effectively capture the complex dynamic characteristics under high Mach number conditions, and significantly improves the accuracy and reliability of the structural design parameters of the precooled wide-range turbine engine compared to conventional models and algorithms. The final structural design parameters, including the relative length of the central cone of the inlet, the oil-to-gas ratio of the main combustion chamber, the oil-to-gas ratio of the afterburner, the nozzle throat area and the outlet area, enable the engine to achieve optimal thrust and fuel economy under different flight conditions, reduce the risks in the research and development process, and improve the overall performance to meet the technical requirements and market competitiveness in the field of modern aviation. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0052] Figure 1 A flow chart of a method for designing structural parameters of a precooling wide-range turbine engine according to an example of this application;

[0053] Figure 2 This is a flowchart for determining the optimal trajectory of an aviation motion model using the Gaussian pseudospectral method in this application example. DETAILED DESCRIPTION

[0054] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0055] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0056] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0058] In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of the present invention.

[0059] In the following description, suffixes such as "module", "component", "assembly" or "unit" are used only to facilitate the description of the present invention and have no specific meanings. Therefore, they can be used in combination.

[0060] The present invention will be further described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0061] Please refer to Figure 1 , which is a flow chart of the method for designing structural parameters of a pre-cooling wide-range turbine engine provided in an embodiment of the present invention. Furthermore, the method for designing structural parameters of a pre-cooling wide-range turbine engine based on track optimization may specifically include the contents described in the following steps S1 to S6.

[0062] S1: Construct a flight propulsion model of a precooled wide-range turbine engine;

[0063] S2: Establish a point mass motion model for an aircraft or propulsion system;

[0064] S3: embedding the flight propulsion model into the point mass motion model to form an aviation motion model;

[0065] S4: defining state parameters, control variables and constraint conditions of the aviation motion model, and performing flight motion simulation on the aviation motion model;

[0066] The state parameters include flight altitude, flight speed, climb angle, flight angle of attack, rate of change of angle of attack, thrust, drag, lift, specific impulse, mass, distance from the center of the earth and gravitational acceleration; the control variables include the relative length of the central cone of the inlet of the flight propulsion model, the oil-gas ratio of the main combustion chamber, the oil-gas ratio of the afterburner combustion chamber, the nozzle throat area and the outlet area; the constraint conditions include the flight dynamics restrictions of the aviation motion model and the mechanical performance restrictions of the flight propulsion model;

[0067] S5: using a Gaussian pseudospectral method to adjust the state parameters and control variables of the aviation motion model, and determine the optimal trajectory of the aviation motion model;

[0068] S6: Output state parameters, control variables and optimal track information under the optimal track conditions.

[0069] When implementing this embodiment, the inventors found that existing models and algorithms are often unable to effectively capture the dynamic characteristics and complexity of the pre-cooled wide-range turbine engine under high Mach number conditions when dealing with the trajectory optimization of the pre-cooled wide-range turbine engine, and thus are unable to determine the structural parameters of the pre-cooled wide-range turbine engine under the optimal trajectory conditions.

[0070] There are many factors that affect the determination of the structural parameters of the pre-cooled wide-range turbine engine under the optimal flight path conditions. For example, the flight altitude will affect the aerodynamic characteristics and engine performance. A higher flight altitude will cause the air to be thinner, thus affecting the lift and drag of the aircraft. The flight speed is directly related to the aerodynamic load and thrust output. Changes in flight speed will affect the working state and overall performance of the engine. The climb angle will affect the vertical speed of the aircraft, and the angle of attack is an important factor affecting lift. Excessive angles of attack may cause stalling. The speed of change in the angle of attack will also have a significant impact on the stability and controllability of the aircraft. Too fast a change may cause the aerodynamic parameters of the aircraft to change. Unstable; thrust is the force provided by the engine, drag is the hindrance of air flow to the aircraft when the aircraft moves forward, and lift is a necessary condition for the aircraft to overcome gravity. The balance between these three directly determines the flight state of the aircraft; the relative length of the central cone of the pre-cooling engine's inlet duct will affect the inflow speed of the airflow and the engine's intake efficiency; the oil-gas ratio of the main combustion chamber and the afterburner combustion chamber is directly related to the combustion efficiency of the fuel, and an appropriate oil-gas ratio helps to achieve optimal thrust and fuel economy; the nozzle throat area and outlet area affect the gas discharge speed and thrust generation, and the optimization of the nozzle design is an important link in achieving efficient propulsion.

[0071] Therefore, based on many influencing factors and under high Mach number conditions, existing models and algorithms often cannot fully capture their dynamic characteristics and complexity. In order to overcome these shortcomings, the inventors of this application comprehensively considered multiple influencing factors, such as flight altitude, flight speed, climb angle, angle of attack, thrust, drag, etc., and introduced a more accurate component-level model to construct a precooling turbine engine gas generator model. Combined with the Gaussian pseudo-spectrum-based trajectory optimization method, the precooling engine control law optimization design is achieved by solving the parameter change state under the optimal trajectory. By establishing a combination of a flight propulsion model and a point mass motion model, an aviation motion model is formed, thereby achieving accurate simulation of the flight state and determination of the relevant precooling turbine engine structural parameters under the optimal trajectory.

[0072] The setting of state parameters, control variables and constraints ensures the reliability and effectiveness of the model under actual flight conditions. When using the Gaussian pseudo-spectral method for adjustment, the state parameters and control variables can be effectively optimized, and the structural parameters of the aviation motion model can be derived. First, a flight propulsion model of a precooled wide-range turbine engine is constructed to accurately describe its aerodynamic performance under various working conditions; secondly, a point mass motion model of an aircraft or propulsion system is established, and the flight propulsion model is embedded in the point mass motion model, so that the mutual influence between the aerodynamic performance of the flight propulsion model and the motion characteristics of the aircraft under different working conditions can be considered in the same framework during motion simulation; the state parameters, control variables and constraints of the aviation motion model are defined to ensure the authenticity and reliability of the aviation motion model when simulating actual flight; the Gaussian pseudo-spectral method is used to adjust the aviation motion model, optimize the state parameters and control variables, and determine the structural parameters under the optimal trajectory. This process can effectively capture the dynamic characteristics under high Mach number conditions and significantly improve the accuracy and efficiency of structural parameter design.

[0073] In one possible implementation, the structure of the flight propulsion model includes an adjustable air inlet, a jet and / or a strong pre-cooling device, a single-rotor turbine engine, an afterburner and an adjustable nozzle, wherein the throat and outlet area of ​​the adjustable nozzle are adjustable.

[0074] In the implementation of this embodiment, the flight propulsion model includes an adjustable air inlet, a jet and / or a strong precooling device, a single-rotor turbine engine, an afterburner and an adjustable nozzle. The advantage of these precise component-level models is that they can flexibly adapt to different flight conditions and mission requirements to optimize engine performance; the adjustable parameters of the adjustable air inlet include the position of the adjustable air inlet center cone, the angle of the air inlet wedge and the bleed air flow rate in the air inlet; the adjustable parameters of the jet include the spray volume of the jet precooling; the adjustable parameters of the strong precooling device are the selection of the precoolant and the flow rate of the precoolant; the adjustable parameters of the single-rotor turbine engine include the oil-gas ratio and the flow path form of the main combustion chamber; the adjustable parameters of the afterburner include the oil-gas ratio of the combustion chamber; the adjustable parameters of the adjustable nozzle are the throat and outlet cross-sectional areas; the setting of the adjustable air inlet enables the intake flow and airflow characteristics to be adjusted according to the flight state Adjustments can be made to improve the thrust efficiency of the engine; the combination of the jet and strong pre-cooling device can effectively reduce the operating temperature of the engine and increase the overall thermal efficiency; the design of the single-spool turbine engine simplifies the turbine system and improves the reliability of power output; the afterburner improves the thrust output by adjusting the oil-gas ratio during the combustion process; and the design of the adjustable nozzle can optimize the characteristics of the jet flow according to changes in flight speed and altitude to enhance the maneuverability of the aircraft; the adjustable parameters of each precise component are adjusted through the optimization algorithm in the Gaussian pseudospectrum, so that the flight propulsion model can be dynamically adjusted under different missions or environmental conditions, providing the engine with higher adaptability and flexibility; by determining the optimal trajectory of the pre-cooled wide-range turbine engine, the engine structure design parameters under the optimal trajectory conditions are further established, and the effective combination of trajectory optimization and engine performance improvement is achieved.

[0075] In a possible implementation, the mathematical expression defining the state parameters of the aviation motion model is:

[0076] h=V sinγ

[0077]

[0078] L=qSC L (α,M α )

[0079] L=qSC D (α,M α )

[0080] In the formula, h, V, γ, α, T, I sp ,m,r,g,q,S,C L , C D and M αThey respectively represent flight altitude, flight speed, climb angle, flight angle of attack, thrust, drag, lift, specific impulse, aircraft mass, distance of aircraft from the center of the earth, gravitational acceleration, flight dynamic pressure, reference wing area, lift coefficient, drag coefficient and Mach number.

[0081] In a possible implementation, the control variable of the aviation motion model is defined as:

[0082]

[0083] Where, L in,r 、f b 、f ab , A8, A9 and They are the relative length of the center cone of the inlet duct, the oil-gas ratio of the main combustion chamber, the oil-gas ratio of the afterburner, the nozzle throat area and the outlet area.

[0084] In one possible implementation, please refer to Figure 2 The specific steps of using the Gaussian pseudospectral method to determine the optimal trajectory of the aviation motion model include:

[0085] S51: Loading state parameters and control variables of the aviation motion model;

[0086] S52: constructing the initial state of the aviation motion model according to the state parameters, and setting the initial structural state of the flight propulsion model according to the control variables;

[0087] S53: Setting parameters of the Gaussian pseudo-spectrum method, including the number of pseudo-spectrum points and the time step, and performing flight motion track optimization on the aviation motion model;

[0088] S54: expressing the trajectory optimization problem as a corresponding cost function, wherein the performance indicator of the cost function is the shortest flight acceleration time and the minimum fuel consumption;

[0089] S55: Continuously adjusting the state parameters and control variables through the performance indicators set by the cost function until the optimal trajectory is analyzed and simulated;

[0090] S56: Calculate and check whether the state parameters under the optimal track meet the constraint conditions. If they do, the track optimization analysis ends.

[0091] When implementing this embodiment, all relevant state parameters and control variables of the aviation motion model are loaded to ensure the integrity and accuracy of the data, and then the data is converted into a matrix form to ensure the unit consistency of the data; the state data and control variables are then assigned to the aviation motion model by splitting and combining, so that the state data is converted into an initial state vector, and the control variables are converted into a control variable vector, and a suitable number of pseudo-spectrum points (usually 10 to 50 points) and a time step (such as 0.1 second to 1 second) are selected for trajectory optimization. In this embodiment, when setting pseudo-spectrum points, pseudo-spectrum points are generated by Chebyshev polynomials, and the generated pseudo-spectrum points can be used to construct a discretization of state parameters in the time domain to form a time series matrix; a set target is constructed based on a cost function, and according to the set target, the state parameters and control variables are continuously adjusted to run the Gaussian pseudo-spectrum optimization algorithm to simulate and obtain the optimal trajectory; after obtaining the optimization result, the state parameters under the optimal trajectory need to be verified for constraint conditions to ensure that all output parameters are within the established flight dynamics and mechanical performance limits.

[0092] In a possible implementation, the states of the adjustable nozzle include a fully expanded state, an under-expanded state, and an over-expanded state.

[0093] In a possible implementation, the air intake passage includes a subcritical state and a supercritical state.

[0094] In a possible implementation, the mathematical expression of the cost function is:

[0095] J min,time =t f

[0096] J min,fuel =-m(t f )

[0097] In the formula, J min,time , J min,fuel ,t f 、m(t f ) represent the shortest flight acceleration time, the minimum fuel consumption, the terminal time and the terminal aircraft weight respectively.

[0098] In a possible implementation, a system for optimizing structural parameters of a precooling wide-range turbine engine based on a trajectory is also included, the system comprising:

[0099] a model building unit configured to build a flight propulsion model of a precooled wide-range turbine engine, establish a point mass motion model of an aircraft or a propulsion system, and build an aviation motion model based on the flight propulsion model and the point mass motion model;

[0100] A data setting unit, configured to set structural parameters of the flight propulsion model and state parameters of the aviation motion model;

[0101] a flight dynamics simulation unit, configured to perform flight motion simulation on the aviation motion model;

[0102] A track optimization unit, configured to optimize the track of the aviation motion model to determine an optimal track;

[0103] The data output unit is configured to output state parameters, control variables and optimal track information under optimal track conditions.

[0104] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A design method for structural parameters of a precooling wide-range turbine engine based on trajectory optimization, characterized in that: The following steps are involved: S1: Construct a flight propulsion model of a precooled wide-range turbine engine; S2: Establish a point mass motion model for an aircraft or propulsion system; S3: embedding the flight propulsion model into the point mass motion model to form an aviation motion model; S4: defining state parameters, control variables and constraint conditions of the aviation motion model, and performing flight motion simulation on the aviation motion model; The state parameters include flight altitude, flight speed, climb angle, flight angle of attack, rate of change of angle of attack, thrust, drag, lift, specific impulse, mass, distance from the center of the earth and gravitational acceleration; the control variables include the relative length of the central cone of the inlet of the flight propulsion model, the oil-gas ratio of the main combustion chamber, the oil-gas ratio of the afterburner combustion chamber, the nozzle throat area and the outlet area; the constraint conditions include the flight dynamics restrictions of the aviation motion model and the mechanical performance restrictions of the flight propulsion model; S5: using a Gaussian pseudospectral method to adjust the state parameters and control variables of the aviation motion model, and determine the optimal trajectory of the aviation motion model; S6: Output state parameters, control variables and optimal track information under the optimal track conditions.

2. The design method of structural parameters of a precooling wide-range turbine engine based on trajectory optimization according to claim 1 is characterized in that: The structure of the flight propulsion model includes an adjustable air inlet, a jet and / or a strong precooling device, a single-rotor turbine engine, an afterburner and an adjustable nozzle, wherein the throat and outlet area of ​​the adjustable nozzle are adjustable.

3. The design method of structural parameters of a precooling wide-range turbine engine based on trajectory optimization according to claim 1 is characterized in that: The mathematical expressions defining the state parameters of the aerodynamic motion model are: h=V sinγ L=qSC L (α,M α ) L=qSC D (α,M α ) In the formula, h, V, γ, α, T, I sp ,m,r,g,q,S,C L , C D and M α They respectively represent flight altitude, flight speed, climb angle, flight angle of attack, thrust, drag, lift, specific impulse, aircraft mass, distance of aircraft from the center of the earth, gravitational acceleration, flight dynamic pressure, reference wing area, lift coefficient, drag coefficient and Mach number.

4. The design method of structural parameters of a precooling wide-range turbine engine based on trajectory optimization according to claim 1 is characterized in that: The control variables of the aviation motion model are defined as: Where, L in,r 、f b 、f ab , A8, A9 and They are the relative length of the center cone of the inlet duct, the oil-gas ratio of the main combustion chamber, the oil-gas ratio of the afterburner, the nozzle throat area and the outlet area.

5. The design method of structural parameters of a precooling wide-range turbine engine based on trajectory optimization according to claim 1 is characterized in that: The specific steps of using the Gaussian pseudospectral method to determine the optimal trajectory of the aviation motion model include: S51: Loading state parameters and control variables of the aviation motion model; S52: constructing the initial state of the aviation motion model according to the state parameters, and setting the initial structural state of the flight propulsion model according to the control variables; S53: Setting parameters of the Gaussian pseudo-spectrum method, including the number of pseudo-spectrum points and the time step, and performing flight motion track optimization on the aviation motion model; S54: expressing the trajectory optimization problem as a corresponding cost function, wherein the performance indicator of the cost function is the shortest flight acceleration time and the minimum fuel consumption; S55: Continuously adjusting the state parameters and control variables through the performance indicators set by the cost function until the optimal trajectory is analyzed and simulated; S56: Calculate and check whether the state parameters under the optimal track meet the constraint conditions. If they do, the track optimization analysis ends.

6. The design method of structural parameters of a precooling wide-range turbine engine based on trajectory optimization according to claim 5 is characterized in that: The mathematical expression of the cost function is: J min,time =t f J min,fuel =-M(t f ) In the formula, J min,time , J min,fuel ,t f 、m(t f ) represent the shortest flight acceleration time, the minimum fuel consumption, the terminal time and the terminal aircraft weight respectively.

7. The design method of structural parameters of a precooling wide-range turbine engine based on trajectory optimization according to claim 2 is characterized in that: The states of the adjustable nozzle include a fully expanded state, an under-expanded state and an over-expanded state.

8. According to the design method of structural parameters of a pre-cooling wide-range turbine engine based on trajectory optimization in claim 2, the air inlet includes a subcritical state and a supercritical state.

9. A system for optimizing structural parameters of a precooling wide-range turbine engine based on flight path, the system comprising: a model building unit configured to build a flight propulsion model of a precooled wide-range turbine engine, establish a point mass motion model of an aircraft or a propulsion system, and build an aviation motion model based on the flight propulsion model and the point mass motion model; A data setting unit, configured to set structural parameters of the flight propulsion model and state parameters of the aviation motion model; a flight dynamics simulation unit, configured to perform flight motion simulation on the aviation motion model; A track optimization unit, configured to optimize the track of the aviation motion model to determine an optimal track; The data output unit is configured to output state parameters, control variables and optimal track information under optimal track conditions.

Images