Method and apparatus for determining a takeoff characteristic velocity of a conveyor

Abstract

The application belongs to the technical field of take-off field performance design, and particularly relates to a method and device for determining take-off characteristic velocity of a transport aircraft, and is applied to a lower surface air-blowing flap powered lift transport aircraft. The method comprises the following steps: S1, determining a take-off ground speed in a non-powered lift state and a use angle of attack; S2, selecting a plurality of ground speeds near the take-off ground speed in the non-powered lift state, determining corresponding residual lift, and interpolating and calculating a take-off ground speed V L0 when the residual lift is 0; S3, taking the take-off ground speed V L0 as a take-off ground speed in a lift state, and calculating a lift coefficient in the lift state; and S4, calculating a take-off ground speed in a cycle output according to the lift coefficient in the lift state, returning to step S3 until the take-off ground speed converges, and calculating a corresponding take-off characteristic velocity. The application can quickly and accurately calculate the take-off characteristic velocity of the lower surface air-blowing flap powered lift transport aircraft.

Description

Technical Field

[0001] This application belongs to the field of takeoff field performance design technology, and specifically relates to a method and apparatus for determining the takeoff characteristic speed of a transport aircraft. Background Technology

[0002] Stall speed, nose wheel lift-off speed, ground clearance speed, and safe altitude speed are key factors affecting the takeoff performance of transport aircraft. The maximum lift coefficient of a conventional transport aircraft takeoff configuration is fixed, but the maximum lift coefficient of a blown-flap powered transport aircraft varies with thrust and speed. Since takeoff thrust is closely related to speed, engine jet efficiency, and jet deflection angle, calculating the takeoff characteristic speed of blown-flap powered transport aircraft is far more complex than that of conventional aircraft, and conventional algorithms cannot be applied to the calculation of the takeoff characteristic speed of blown-flap powered transport aircraft. Summary of the Invention

[0003] To address the aforementioned issues, this application provides a method and apparatus for determining the takeoff characteristic velocity of a transport aircraft, offering technical support for calculating the takeoff field performance of a transport aircraft with lower-surface blown flaps and enhanced lift.

[0004] The first aspect of this application provides a method for determining the takeoff characteristic velocity of a transport aircraft, applied to a transport aircraft with lower surface blown flaps and enhanced lift, the method comprising:

[0005] Step S1: Determine the takeoff speed and angle of attack for non-powered lift conditions;

[0006] Step S2: Select multiple takeoff velocities near the takeoff speed in the non-powered lift state, determine the corresponding remaining lift, and interpolate to calculate the takeoff speed V when the remaining lift is 0. L0 ;

[0007] Step S3: Set the takeoff speed V L0 The takeoff speed, which is used as the cyclic input for the lift-enhancing state, is used to calculate the lift coefficient for the lift-enhancing state.

[0008] Step S4: Calculate the takeoff takeoff speed output in the cyclic output based on the lift coefficient in the lift-enhanced state, return to step S3, and continue until the difference between the calculated cyclic input takeoff takeoff speed and the cyclic output takeoff takeoff speed is less than the set value. Calculate the lift-enhanced stall speed, takeoff nose wheel lift speed and safe altitude speed corresponding to the cyclic output takeoff takeoff speed at this time.

[0009] Preferably, in step S1, the takeoff speed V in the non-powered lift state is determined by the following formula. lof :

[0010]

[0011] Among them, CLmax W represents the maximum lift coefficient for takeoff configuration in non-powered lift enhancement mode. to Where ρ is the takeoff weight, ρ is the atmospheric density of the takeoff airport, and S is the air density of the airport. ref This is the reference wing area of ​​the aircraft.

[0012] Preferably, in step S1, the angle of attack for non-powered lift is determined using the following formula:

[0013]

[0014] α lof =interp1(CLsz,alphasz,C Llof );

[0015] Where interp1 is the interpolation function, which is used to interpolate the lift coefficient C from the correspondence table constructed between the angle of attack array alphasz and the lift coefficient array CLsz for the takeoff configuration in the non-powered lift augmentation state. Llof The corresponding angle of attack α lof .

[0016] Preferably, in step S2, at least four takeoff speeds are selected in steps of 5-10 m / s near the takeoff speed in the non-powered lift state.

[0017] Preferably, in step S2, the remaining lift ΔZ is determined using the following formula:

[0018] ΔZ=L+Z p -W to g;

[0019] Where L=qS ref C Llof-on Z p =P xz η j sin(α lof +θ j ); P xz =n e P emax (1-K s )K v K h ;n e Where L is the number of engines, Z is the lift force when the engine is lifted off the ground, and L is the lift force when the engine is lifted off the ground. p P is the component of thrust in the lift direction. emax For the engine's maximum thrust, K s K is the system power extraction factor. v K is the speed correction factor for takeoff thrust. h As a high correction factor, P xzFor the takeoff thrust corrected for power and speed, η j θ is the engine jet efficiency factor. j α is the downward deflection angle of the jet stream affected by the flaps relative to the fuselage axis, and α is the calculated or selected angle of attack.

[0020] Preferably, in step S4, the takeoff speed V output cyclically is calculated using the following formula. lof-on :

[0021]

[0022] Among them, C Lmax-on To increase the lift coefficient at ground level, V s-on To increase the stall speed, V R-on For takeoff nose wheel lift speed under increased lift conditions, V 2-on The safe altitude speed under elevated conditions.

[0023] A second aspect of this application provides a transport aircraft takeoff characteristic velocity determination device, applied to a transport aircraft with lower surface blown flaps and enhanced lift, the device comprising:

[0024] The non-powered lift enhancement state parameter determination module is used to determine the takeoff speed and angle of attack in the non-powered lift enhancement state.

[0025] The lift augmentation state initial value determination module is used to select multiple takeoff velocities near the takeoff takeoff speed in the non-powered lift augmentation state, determine the corresponding remaining lift, and interpolate to calculate the takeoff takeoff speed V when the remaining lift is 0. L0 ;

[0026] The lift coefficient calculation module is used to calculate the takeoff lift velocity V. L0 The takeoff speed, which is used as the cyclic input for the lift-enhancing state, is used to calculate the lift coefficient for the lift-enhancing state.

[0027] The cyclic control module is used to calculate the cyclic output takeoff speed based on the lift coefficient in the lift-enhanced state. It calls the lift coefficient calculation module until the difference between the calculated cyclic input takeoff speed and the cyclic output takeoff speed is less than a set value. Then, it calculates the corresponding lift-enhanced state stall speed, takeoff nose wheel lift speed, and safe altitude speed at the cyclic output takeoff speed.

[0028] Preferably, in the non-powered lift state parameter determination module, the takeoff speed V in the non-powered lift state is determined by the following formula. lof :

[0029]

[0030] Among them, C LmaxW represents the maximum lift coefficient for takeoff configuration in non-powered lift enhancement mode. to Where ρ is the takeoff weight, ρ is the atmospheric density of the takeoff airport, and S is the air density of the airport. ref This is the reference wing area of ​​the aircraft.

[0031] Preferably, in the non-powered lift state parameter determination module, the operating angle of attack for the non-powered lift state is determined using the following formula:

[0032]

[0033] α lof =interp1(CLsz,alphasz,C Llof );

[0034] Where interp1 is the interpolation function, which is used to interpolate the lift coefficient C from the correspondence table constructed between the angle of attack array alphasz and the lift coefficient array CLsz for the takeoff configuration in the non-powered lift augmentation state. Llof The corresponding angle of attack α lof .

[0035] Preferably, in the lift-enhancing state initial value determination module, at least four takeoff speeds are selected in steps of 5-10 m / s near the takeoff speed in the non-powered lift-enhancing state.

[0036] Preferably, in the initial value determination module for the increased lift state, the remaining lift ΔZ is determined using the following formula:

[0037] ΔZ=L+Z p -W to g;

[0038] Where L=qS ref C Llof-on Z p =P xz η j sin(α lof +θ j ); P xz =n e P emax (1-K s )K v K h ;n e Where L is the number of engines, Z is the lift force when the engine is lifted off the ground, and L is the lift force when the engine is lifted off the ground. p P is the component of thrust in the lift direction. emax For the engine's maximum thrust, K s K is the system power extraction factor. v K is the speed correction factor for takeoff thrust. h As a high correction factor, Pxz For the takeoff thrust corrected for power and speed, η j θ is the engine jet efficiency factor. j α is the downward deflection angle of the jet stream affected by the flaps relative to the fuselage axis, and α is the calculated or selected angle of attack.

[0039] Preferably, in the cycle control module, the takeoff speed V output in the cycle is calculated using the following formula. lof-on :

[0040]

[0041] Among them, C Lmax-on To increase the lift coefficient at ground level, V s-on To increase the stall speed, V R-on For takeoff nose wheel lift speed under increased lift conditions, V 2-on The safe altitude speed under elevated conditions.

[0042] A third aspect of this application provides a computer device including a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method for determining the takeoff characteristic speed of a transport aircraft as described above.

[0043] A fourth aspect of this application provides a readable storage medium storing a computer program that, when executed by a processor, is used to implement the method for determining the takeoff characteristic speed of a transport aircraft as described above.

[0044] This application enables the rapid and accurate calculation of the characteristic velocity of takeoff for a power-assisted transport aircraft with lower surface blowing flaps. Attached Figure Description

[0045] Figure 1 This is a flowchart of a preferred embodiment of the method for determining the takeoff characteristic speed of a transport aircraft according to this application.

[0046] Figure 2 This is a schematic diagram of the structure of a computer device suitable for implementing the embodiments of this application. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0048] The first aspect of this application provides a method for determining the takeoff characteristic velocity of a transport aircraft, applicable to a transport aircraft with lower-surface blown flaps and enhanced lift, such as... Figure 1 As shown, the method mainly includes:

[0049] Step S1: Determine the takeoff speed and angle of attack for non-powered lift conditions;

[0050] Step S2: Select multiple takeoff velocities near the takeoff speed in the non-powered lift state, determine the corresponding remaining lift, and interpolate to calculate the takeoff speed V when the remaining lift is 0. L0 ;

[0051] Step S3: Set the takeoff speed V L0 The takeoff speed, which is used as the cyclic input for the lift-enhancing state, is used to calculate the lift coefficient for the lift-enhancing state.

[0052] Step S4: Calculate the takeoff takeoff speed output in the cyclic output based on the lift coefficient in the lift-enhanced state, return to step S3, and continue until the difference between the calculated cyclic input takeoff takeoff speed and the cyclic output takeoff takeoff speed is less than the set value. Calculate the lift-enhanced stall speed, takeoff nose wheel lift speed and safe altitude speed corresponding to the cyclic output takeoff takeoff speed at this time.

[0053] This application first determines the takeoff speed V when the remaining lift in the non-powered lift state is 0 through steps S1 and S2. L0 This serves as the initial input for the cyclic calculation of the lift-off speed in steps S3 and S4.

[0054] In some alternative implementations, in step S1, the takeoff speed V in the non-powered lift state is determined by the following formula. lof :

[0055]

[0056] Among them, CLmax W represents the maximum lift coefficient for takeoff configuration in non-powered lift enhancement mode. to Where ρ is the takeoff weight, ρ is the atmospheric density of the takeoff airport, and S is the air density of the airport. ref This is the reference wing area of ​​the aircraft.

[0057] In some alternative implementations, in step S1, the angle of attack for the non-powered lift state is determined using the following formula:

[0058]

[0059] α lof =interp1(CLsz,alphasz,C Llof );

[0060] Where interp1 is the interpolation function, which is used to interpolate the lift coefficient C from the correspondence table constructed between the angle of attack array alphasz and the lift coefficient array CLsz for the takeoff configuration in the non-powered lift augmentation state. Llof The corresponding angle of attack α lof .

[0061] In some alternative implementations, in step S2, at least four takeoff velocities are selected in increments of 5-10 m / s near the takeoff speed in the non-powered lift state. For example, the takeoff speed V in the non-powered lift state calculated in step S1. lof If the speed is 85m / s, then four takeoff speeds of 60m / s, 70m / s, 80m / s, and 90m / s can be selected.

[0062] In some alternative implementations, in step S2, the remaining lift ΔZ is determined using the following formula:

[0063] ΔZ=L+Z p -W to g;

[0064] Where L=qS ref C Llof-on Z p =P xz η j sin(α lof +θ j ); P xz =n e P emax (1-K s )K v K h ;n e Where L is the number of engines, Z is the lift force when the engine is lifted off the ground, and L is the lift force when the engine is lifted off the ground. p P is the component of thrust in the lift direction. emax For the engine's maximum thrust, Ks K is the system power extraction factor. v K is the speed correction factor for takeoff thrust. h As a high correction factor, P xz For the takeoff thrust corrected for power and speed, η j θ is the engine jet efficiency factor. j α is the downward deflection angle of the jet stream affected by the flaps relative to the fuselage axis, and α is the calculated or selected angle of attack.

[0065] For example, the reference wing area of ​​an aircraft is 353m². 2 The aircraft has a wingspan of 50.6m, an aspect ratio of 7.25, a quarter-chord sweep angle of 21°, and a tip-to-root ratio of 0.24. It is powered by four high-bypass turbofan engines, each with a thrust of 185.5 kN, mounted under the wings. The engine thrust axis is deflected by -5° relative to the local wing chord. The inner engine is mounted at 29.6% of half the span, with a wing section angle of 3°, while the outer engine is mounted at 55% of half the span, with a wing section angle of 2.5°. The aircraft's tail strike angle is 11.5°.

[0066] The aircraft has a maximum takeoff weight of 265 tons, an engine takeoff thrust of 185.5 kN, and a takeoff thrust loss factor of 0.07. Takeoff configuration: leading edge slat deflection angle of 15°, trailing edge flap deflection angle of 25°, and a downward slope angle of the upper surface of the flap trailing edge of 8°. The depth of the flap portion immersed in the engine exhaust is 2.4 m, and the diameter of the exhaust jet at the trailing edge of the flap is 5.21 m. The engine exhaust efficiency factor is 0.907, and the exhaust deflection angle is 12.28°. Takeoff thrust velocity correction model: K v =1 - 0.167V / 80, with a high correction factor K h Set to 1, the system power extraction factor K for takeoff s Take 0.036.

[0067] In step S1, the maximum lift coefficient C of the given non-powered lift-enhancing takeoff configuration is... Lmax Given a value of 2.2, calculate the takeoff speed V. lof The speed is 85.03 m / s, and the angle of attack α is used in the calculation. lof It is 9.21°.

[0068] The tail strike angle of the example aircraft is 11.5°. To ensure takeoff safety, the takeoff angle of attack in the lift-enhanced state is taken as 9° to 10°.

[0069] At takeoff speed V lof Using 85.03 m / s as the reference point, a calculation velocity array [60 70 80 90] was established, with a ground-flying angle of attack of 9°. The remaining lift at the point of takeoff in the lift-enhancing state at the four velocity points was calculated, and the calculation data are shown in Table 1.

[0070] Table 1. Residual lift calculation data at four velocity points

[0071]

[0072]

[0073] Based on the data in Table 2, the calculation speed for calculating gravity balance using the interpolation algorithm is 77.98 m / s.

[0074] Steps S3 and S4 are iterative calculation steps. The speed calculated in step S2, 77.98 m / s, will be used as the initial input for step S3. Step S3 calculates the lift coefficient for the enhanced lift state, and then step S4 recalculates the takeoff speed based on the lift coefficient. After three rounds of iterative calculation, the difference between the cyclically input takeoff speed and the cyclically output takeoff speed is less than 0.15%. The maximum usable lift coefficient for takeoff of the example aircraft is 2.666. The data from the calculation process are shown in Table 2 below.

[0075] Table 2. Calculation data for maximum lift coefficient available for takeoff.

[0076]

[0077] In the table above, the angle of attack α lof-on The lift coefficient C under the increased lift condition Lmax The relationship with the angle of attack is obtained through interpolation calculation.

[0078] In some alternative implementations, in step S4, the takeoff speed V output cyclically is calculated using the following formula. lof-on :

[0079]

[0080] Among them, C Lmax-on To increase the lift coefficient at ground level, V s-on To increase the stall speed, V R-on For takeoff nose wheel lift speed under increased lift conditions, V 2-on The safe altitude speed under elevated conditions.

[0081] The calculation results of this embodiment are shown in Table 3 below.

[0082] Table 3. Parameters related to the calculation of takeoff characteristic velocity in lift-enhanced state

[0083]

[0084]

[0085] A second aspect of this application provides a transport aircraft takeoff characteristic velocity determination device corresponding to the above method, applied to a transport aircraft with lower surface blown flaps and enhanced lift, the device comprising:

[0086] The non-powered lift enhancement state parameter determination module is used to determine the takeoff speed and angle of attack in the non-powered lift enhancement state.

[0087] The lift augmentation state initial value determination module is used to select multiple takeoff velocities near the takeoff takeoff speed in the non-powered lift augmentation state, determine the corresponding remaining lift, and interpolate to calculate the takeoff takeoff speed V when the remaining lift is 0. L0 ;

[0088] The lift coefficient calculation module is used to calculate the takeoff lift velocity V. L0 The takeoff speed, which is used as the cyclic input for the lift-enhancing state, is used to calculate the lift coefficient for the lift-enhancing state.

[0089] The cyclic control module is used to calculate the cyclic output takeoff speed based on the lift coefficient in the lift-enhanced state. It calls the lift coefficient calculation module until the difference between the calculated cyclic input takeoff speed and the cyclic output takeoff speed is less than a set value. Then, it calculates the corresponding lift-enhanced state stall speed, takeoff nose wheel lift speed, and safe altitude speed at the cyclic output takeoff speed.

[0090] In some optional embodiments, in the non-powered lift state parameter determination module, the takeoff speed V in the non-powered lift state is determined by the following formula. lof :

[0091]

[0092] Among them, C Lmax W represents the maximum lift coefficient for takeoff configuration in non-powered lift enhancement mode. to Where ρ is the takeoff weight, ρ is the atmospheric density of the takeoff airport, and S is the air density of the airport. ref This is the reference wing area of ​​the aircraft.

[0093] In some alternative implementations, the angle of attack for the non-powered lift state is determined in the non-powered lift state parameter determination module using the following formula:

[0094]

[0095] α lof =interp1(CLsz,alphasz,C Llof );

[0096] Where interp1 is the interpolation function, which is used to interpolate the lift coefficient C from the correspondence table constructed between the angle of attack array alphasz and the lift coefficient array CLsz for the takeoff configuration in the non-powered lift augmentation state. Llof The corresponding angle of attack α lof .

[0097] In some alternative implementations, in the lift state initial value determination module, at least four takeoff speeds are selected in steps of 5-10 m / s near the takeoff speed in the non-powered lift state.

[0098] In some optional implementations, the remaining lift ΔZ is determined in the initial lift state determination module using the following formula:

[0099] ΔZ=L+Z p -W to g;

[0100] Where L=qS ref C Llof-on Z p =P xz η j sin(α lof +θ j ); P xz =n e P emax (1-K s )K v K h ;n e Where L is the number of engines, Z is the lift force when the engine is lifted off the ground, and L is the lift force when the engine is lifted off the ground. p P is the component of thrust in the lift direction. emax For the engine's maximum thrust, K s K is the system power extraction factor. v K is the speed correction factor for takeoff thrust. h As a high correction factor, P xz For the takeoff thrust corrected for power and speed, η j θ is the engine jet efficiency factor. j α is the downward deflection angle of the jet stream affected by the flaps relative to the fuselage axis, and α is the calculated or selected angle of attack.

[0101] In some alternative implementations, the takeoff speed V of the cyclic output is calculated in the cyclic control module using the following formula. lof-on :

[0102]

[0103] Among them, C Lmax-on To increase the lift coefficient at ground level, Vs-on To increase the stall speed, V R-on For takeoff nose wheel lift speed under increased lift conditions, V 2-on The safe altitude speed under elevated conditions.

[0104] In a third aspect of this application, a computer device is provided, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement a method for determining the takeoff characteristic speed of a transport aircraft.

[0105] In a fourth aspect, this application provides a readable storage medium storing a computer program that, when executed by a processor, implements the method for determining the takeoff characteristic speed of a transport aircraft as described above. This computer-readable storage medium may be included in the apparatus described in the above embodiments; or it may exist independently and not be incorporated into the apparatus. The aforementioned computer-readable storage medium carries one or more programs that, when executed by the apparatus, process data according to the method described above.

[0106] The following is for reference. Figure 2 It shows a schematic diagram of the structure of a computer device 400 suitable for implementing the embodiments of this application. Figure 2 The computer device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments described in this application.

[0107] like Figure 2 As shown, the computer device 400 includes a central processing unit (CPU) 401, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 402 or a program loaded from a storage section 408 into a random access memory (RAM) 403. The RAM 403 also stores various programs and data required for the operation of the device 400. The CPU 401, ROM 402, and RAM 403 are interconnected via a bus 404. An input / output (I / O) interface 405 is also connected to the bus 404.

[0108] The following components are connected to I / O interface 405: an input section 406 including a keyboard, mouse, etc.; an output section 407 including a cathode ray tube (CRT), liquid crystal display (LCD), etc., and speakers, etc.; a storage section 408 including a hard disk, etc.; and a communication section 409 including a network interface card such as a LAN card, modem, etc. The communication section 409 performs communication processing via a network such as the Internet. A drive 410 is also connected to I / O interface 405 as needed. A removable medium 411, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on drive 410 as needed so that computer programs read from it can be installed into storage section 408 as needed.

[0109] Specifically, according to embodiments of this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication section 409, and / or installed from removable medium 411. When the computer program is executed by central processing unit (CPU) 401, it performs the functions defined in the methods of this application. It should be noted that the computer storage medium of this application can be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. A computer-readable storage medium can be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this application, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in connection with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on a computer-readable medium can be transmitted using any suitable medium, including but not limited to: wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0110] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0111] The modules or units described in the embodiments of this application can be implemented in software or hardware. The described modules or units can also be located in a processor, and the names of these modules or units do not necessarily constitute a limitation on the module or unit itself.

[0112] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for determining the takeoff characteristic velocity of a transport aircraft, applied to a transport aircraft with lower-surface blown flaps and enhanced lift, characterized in that, The method includes: Step S1: Determine the takeoff speed and angle of attack for non-powered lift conditions; Step S2: Select multiple takeoff velocities near the takeoff speed in the non-powered lift state, determine the corresponding remaining lift, and interpolate to calculate the takeoff speed V when the remaining lift is 0. L0 ; Step S3: Set the takeoff speed V L0 The takeoff speed, which is used as the cyclic input for the lift-enhancing state, is used to calculate the lift coefficient for the lift-enhancing state. Step S4: Calculate the takeoff takeoff speed output in the cyclic output based on the lift coefficient in the lift-enhanced state, return to step S3, and continue until the difference between the calculated cyclic input takeoff takeoff speed and the cyclic output takeoff takeoff speed is less than the set value. Calculate the lift-enhanced stall speed, takeoff nose wheel lift speed and safe altitude speed corresponding to the cyclic output takeoff takeoff speed at this time.

2. The method for determining the takeoff characteristic speed of a transport aircraft as described in claim 1, characterized in that, In step S1, the takeoff speed V in the non-powered lift state is determined using the following formula. lof : Among them, C Lmax W represents the maximum lift coefficient for takeoff configuration in non-powered lift enhancement mode. to Where ρ is the takeoff weight, ρ is the atmospheric density of the takeoff airport, and S is the atmospheric density of the airport. ref This is the reference wing area of ​​the aircraft.

3. The method for determining the takeoff characteristic speed of a transport aircraft as described in claim 1, characterized in that, In step S1, the angle of attack for non-powered lift is determined using the following formula: α lof =interp1(CLsz,alphasz,C Llof ); Where interp1 is the interpolation function, which is used to interpolate the lift coefficient C from the correspondence table constructed between the angle of attack array alphasz and the lift coefficient array CLsz for the takeoff configuration in the non-powered lift augmentation state. Llof The corresponding angle of attack α lof .

4. The method for determining the takeoff characteristic speed of a transport aircraft as described in claim 1, characterized in that, In step S2, at least four takeoff speeds are selected in steps of 5-10 m / s near the takeoff speed in the non-powered lift state.

5. The method for determining the takeoff characteristic speed of a transport aircraft as described in claim 2, characterized in that, In step S2, the remaining lift ΔZ is determined using the following formula: △Z=L+Z p -W to g; Where L=qS ref C Llof-on Z p =P xz η j sin(α lof +θ j ); P xz =n e P emax (1-K s )K v K h ;n e Where L is the number of engines, Z is the lift force when the engine is lifted off the ground, and L is the lift force when the engine is lifted off the ground. p P is the component of thrust in the lift direction. emax For the engine's maximum thrust, K s K is the system power extraction factor. v K is the speed correction factor for takeoff thrust. h As a high correction factor, P xz For the takeoff thrust corrected for power and speed, η j θ is the engine jet efficiency factor. j For the downward deflection angle of the jet stream relative to the fuselage axis due to flap interference, C Llof-on α is the lift coefficient of the aircraft during takeoff in a lift-enhanced state. lof The angle of attack used for calculation or selection.

6. The method for determining the takeoff characteristic speed of a transport aircraft as described in claim 2, characterized in that, In step S4, the takeoff speed V output by the cycle is calculated using the following formula. lof-on : Among them, C Lmax-on To increase the lift coefficient at ground level, V s-on To increase the stall speed, V R-on For takeoff nose wheel lift speed under increased lift conditions, V 2-on Let g be the safe altitude velocity under the rising state, and g be the acceleration due to gravity.

7. A device for determining the takeoff characteristic speed of a transport aircraft, applied to a transport aircraft with lower surface blown flaps and enhanced lift, characterized in that, The device includes: The non-powered lift enhancement state parameter determination module is used to determine the takeoff speed and angle of attack in the non-powered lift enhancement state. The lift augmentation state initial value determination module is used to select multiple takeoff velocities near the takeoff takeoff speed in the non-powered lift augmentation state, determine the corresponding remaining lift, and interpolate to calculate the takeoff takeoff speed V when the remaining lift is 0. L0 ; The lift coefficient calculation module is used to calculate the takeoff lift velocity V. L0 The takeoff speed, which is used as the cyclic input for the lift-enhancing state, is used to calculate the lift coefficient for the lift-enhancing state. The cyclic control module is used to calculate the cyclic output takeoff speed based on the lift coefficient in the lift-enhanced state. It calls the lift coefficient calculation module until the difference between the calculated cyclic input takeoff speed and the cyclic output takeoff speed is less than a set value. Then, it calculates the corresponding lift-enhanced state stall speed, takeoff nose wheel lift speed, and safe altitude speed at the cyclic output takeoff speed.

8. The transport aircraft takeoff characteristic speed determination device as described in claim 7, characterized in that, In the non-powered lift state parameter determination module, the takeoff speed V in the non-powered lift state is determined by the following formula. lof : Among them, C Lmax W represents the maximum lift coefficient for takeoff configuration in non-powered lift enhancement mode. to Where ρ is the takeoff weight, ρ is the atmospheric density of the takeoff airport, and S is the atmospheric density of the airport. ref This is the reference wing area of ​​the aircraft.

9. The transport aircraft takeoff characteristic speed determination device as described in claim 7, characterized in that, In the non-powered lift enhancement state parameter determination module, the operating angle of attack for the non-powered lift enhancement state is determined using the following formula: α lof =interp1(CLsz,alphasz,C Llof ); Where interp1 is the interpolation function, which is used to interpolate the lift coefficient C from the correspondence table constructed between the angle of attack array alphasz and the lift coefficient array CLsz for the takeoff configuration in the non-powered lift augmentation state. Llof The corresponding angle of attack α lof .

10. The transport aircraft takeoff characteristic speed determination device as described in claim 7, characterized in that, In the lift-enhancing state initial value determination module, at least four takeoff speeds are selected in step sizes of 5-10 m / s near the takeoff speed in the non-powered lift-enhancing state.

11. The transport aircraft takeoff characteristic speed determination device as described in claim 8, characterized in that, In the initial value determination module for the increased lift state, the remaining lift ΔZ is determined using the following formula: △Z=L+Z p -W to g; Where L=qS ref C Llof-on Z p =P xz η j sin(α lof +θ j ); P xz =n e P emax (1-K s )K v K h ;n e Where L is the number of engines, Z is the lift force when the engine is lifted off the ground, and L is the lift force when the engine is lifted off the ground. p P is the component of thrust in the lift direction. emax For the engine's maximum thrust, K s K is the system power extraction factor. v K is the speed correction factor for takeoff thrust. h As a high correction factor, P xz For the takeoff thrust corrected for power and speed, η j θ is the engine jet efficiency factor. j For the downward deflection angle of the jet stream relative to the fuselage axis due to flap interference, C Llof-on α is the lift coefficient of the aircraft during takeoff in a lift-enhanced state. lof For the calculation or selection of the angle of attack, α lof The angle of attack used for calculation or selection.

12. The transport aircraft takeoff characteristic speed determination device as described in claim 8, characterized in that, In the cycle control module, the takeoff speed V output in the cycle is calculated using the following formula. lof-on : Among them, C Lmax-on To increase the lift coefficient at ground level, V s-on To increase the stall speed, V R-on For takeoff nose wheel lift speed under increased lift conditions, V 2-on Let g be the safe altitude velocity under the rising state, and g be the acceleration due to gravity.

13. A computer device, characterized in that, It includes a processor, a memory, and a computer program stored in the memory and executable on the processor, the processor executing the computer program to implement the method for determining the takeoff characteristic speed of a transport aircraft as described in any one of claims 1-6.

14. A readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it is used to implement the method for determining the takeoff characteristic speed of a transport aircraft as described in any one of claims 1-6.

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