Method and device for evaluating take-off and climb performance of a transport aircraft in case of single engine failure

Abstract

The application belongs to the technical field of aircraft design, and particularly relates to a method and device for evaluating take-off and climbing performance of a transport aircraft with single-engine failure, and is applied to a lower surface air-blowing flap powered lift transport aircraft. The method comprises the following steps: S1, determining a drag coefficient generated by single-engine failure roll moment trim; S2, determining a drag coefficient generated by single-engine failure pitch moment trim; S3, determining a drag coefficient generated by single-engine failure yaw moment trim; and S4, calculating a single-engine failure take-off maximum climbing gradient. The application can quickly and accurately calculate the climbing gradient of the air-blowing flap powered lift transport aircraft with single-engine failure, and improves the aircraft design efficiency.

Description

Technical Field

[0001] The present application belongs to the field of aircraft design technology, and in particular relates to a method and device for evaluating the takeoff and climbing performance of a transport aircraft with a single engine failure. Background Art

[0002] The climb gradient with a single engine failure is a crucial parameter for evaluating takeoff performance in transport aircraft. The aerodynamic forces in a takeoff configuration for a powered-lift aircraft with blown flaps are significantly affected by the power. An engine failure generates rolling and yawing moments, while the trim moment creates additional drag. The flap disturbance deflects the engine jet downward, resulting in thrust loss. Conventional algorithms for calculating the climb gradient with a single engine failure are inapplicable to powered-lift aircraft with blown flaps. Summary of the Invention

[0003] In order to solve the above problems, the present application provides a method and device for evaluating the takeoff and climbing performance of a transport aircraft with a single engine failure, providing technical support for the evaluation of the takeoff and climbing performance of a transport aircraft with a single engine failure using a blown flap powered lift system.

[0004] In a first aspect, the present application provides a method for evaluating the takeoff and climb performance of a transport aircraft with a single engine failure, which is applied to a powered high-lift transport aircraft with blown flaps on the lower surface. The method comprises:

[0005] Step S1: Determine the drag coefficient C generated by the rolling moment trim due to a single engine failure. Da ;

[0006] Step S2: Determine the drag coefficient C generated by the pitching moment trim due to a single engine failure. De ;

[0007] Step S3: Determine the drag coefficient C generated by the yaw moment trim due to single engine failure. Dr ;

[0008] Step S4: Calculate the maximum climb gradient tanθ for takeoff with a single engine failure based on the following formula: max :

[0009]

[0010] Among them, θ max is the maximum flight path angle for takeoff climb, n e is the number of engines, P max is the maximum thrust of the engine, P xz is the engine thrust corrected for system power extraction, speed, and altitude, K S is the system power extraction factor in takeoff state, K V is the speed correction factor of thrust, K h is the altitude correction factor, α is the fuselage angle of attack, η j is the jet efficiency factor of the engine in the lift-increasing state, θj is the downward deflection angle of the jet flow disturbed by the flap relative to the fuselage axis, q is the velocity pressure, ρ is the air density, V is the airspeed, S ref is the wing reference area, W is the aircraft weight, C Don is the lift coefficient in the lift-increasing state, C Doff is the drag coefficient for takeoff in non-powered lift mode, C Db is the power effect correction value of the full-engine takeoff drag coefficient, C DLG is the drag coefficient of the landing gear.

[0011] Preferably, in step S1, the drag coefficient C generated by the single engine failure rolling moment trim is determined according to the following formula: Da :

[0012]

[0013] Among them, δ a Aileron deflection angle for rolling moment balancing, C Dδa is the increase in drag coefficient caused by aileron unit deflection angle, C l is the rolling moment coefficient caused by single engine failure, C lδa is the aileron control efficiency, ΔC L is the loss of lift coefficient of the wing on the side of the failed engine, L ye is the span length between the axis of the failed engine and the axis of the fuselage, C Lb is the lift coefficient increment generated by the full-engine takeoff jet flow around the flap, b w The wing span.

[0014] Preferably, step S2 further comprises:

[0015] Step S21: Determine the pitch moment coefficient increment C generated by the jet vector effect mp ;

[0016] Step S22: Determine the pitching moment coefficient increment C generated by the jet flap flow mb ;

[0017] Step S23: Determine the pitching moment coefficient C for takeoff and climb using the following formula: m :

[0018] C m =C moff +C mp +C mb Among them, C moff The pitching moment for takeoff climb in non-powered-up state;

[0019] Step S24: Determine the drag coefficient C generated by the single engine failure pitching moment trim using the following formula: De :

[0020] C De =C Dδe δ e ;

[0021]

[0022] Among them, δ e Elevator deflection angle to balance the pitch moment, C Dδe is the drag coefficient generated by the unit deflection angle of the elevator, C mδe The control efficiency of the elevator.

[0023] Preferably, in step S21, the pitch moment coefficient increment C generated by the jet vector effect is determined by the following formula: mp :

[0024]

[0025] Among them, C T is the thrust coefficient for takeoff of an aircraft with one engine failure, θ e is the downward deflection angle of the engine axis relative to the fuselage axis, h cf L is the vertical distance of the flap aerodynamic pressure center below the center of gravity, f The axial distance behind the center of gravity of the flap's aerodynamic pressure center, h e is the vertical distance of the engine nozzle below the center of gravity, L e is the axial distance of the engine nozzle behind the center of gravity, c a is the average aerodynamic chord length of the wing.

[0026] Preferably, in step S22, the pitching moment coefficient increment C generated by the jet flap flow is determined by the following formula: mb :

[0027]

[0028] Among them, L0 is the axial distance between the leading edge of the wing and the center of gravity of the fuselage at the engine installation position. It is positive if it is located behind the center of gravity. L c is the axial distance behind the center of gravity of the wing's aerodynamic pressure center after the flaps are placed, and c' is the axial projection length of the wing's chord length at the engine installation position.

[0029] Preferably, in step S3, the drag coefficient C generated by the yaw moment trim due to single engine failure is determined according to the following formula: Dr :

[0030]

[0031] Among them, δ rThe rudder deflection angle to balance the yaw moment, C Dδr is the drag coefficient generated by the rudder unit deflection angle, C n is the yaw moment coefficient caused by single engine failure, C nδr The control efficiency of the rudder.

[0032] Preferably, step S4 further includes determining the drag coefficient dynamic influence correction value C by the following formula: Db :

[0033]

[0034] Among them, C Lb is the lift coefficient increment generated by the jet flap flow, C La C Lb The incremental correction part of the lift coefficient at medium angle of attack, AR is the aspect ratio, and K is the correction coefficient.

[0035] A second aspect of the present application provides a transport aircraft single-engine failure takeoff and climb performance evaluation device, which is applied to a powered high-lift transport aircraft with blown flaps on the lower surface. The device comprises:

[0036] Roll moment trim drag coefficient determination module, used to determine the drag coefficient C generated by single engine failure roll moment trim Da ;

[0037] Pitch moment trim drag coefficient determination module, used to determine the drag coefficient C generated by pitch moment trim when a single engine fails De ;

[0038] Yaw moment trim drag coefficient determination module, used to determine the drag coefficient C generated by yaw moment trim in case of single engine failure Dr ;

[0039] The maximum climb gradient determination module is used to calculate the maximum climb gradient tanθ for single-engine failure takeoff based on the following formula max :

[0040]

[0041] Among them, θ max is the maximum flight path angle for takeoff climb, n e is the number of engines, P max is the maximum thrust of the engine, P xz is the engine thrust corrected for system power extraction, speed, and altitude, K S is the system power extraction factor in takeoff state, K V is the speed correction factor of thrust, K h is the altitude correction factor, α is the fuselage angle of attack, η jis the jet efficiency factor of the engine in the lift-increasing state, θ j is the downward deflection angle of the jet flow disturbed by the flap relative to the fuselage axis, q is the velocity pressure, ρ is the air density, V is the airspeed, S ref is the wing reference area, W is the aircraft weight, C Don is the lift coefficient in the lift-increasing state, C Doff is the drag coefficient for takeoff in non-powered lift mode, C Db is the power effect correction value of the full-engine takeoff drag coefficient, C DLG is the drag coefficient of the landing gear.

[0042] Preferably, in the roll moment trim drag coefficient determination module, the drag coefficient C generated by the roll moment trim due to a single engine failure is determined according to the following formula: Da :

[0043]

[0044] Among them, δ a Aileron deflection angle for rolling moment balancing, C Dδa is the increase in drag coefficient caused by aileron unit deflection angle, C l is the rolling moment coefficient caused by single engine failure, C lδa is the aileron control efficiency, ΔC L is the loss of lift coefficient of the wing on the side of the failed engine, L ye is the span length between the axis of the failed engine and the axis of the fuselage, C Lb is the lift coefficient increment generated by the full-engine takeoff jet flow around the flap, b w The wing span.

[0045] Preferably, the pitching moment trim drag coefficient determination module includes:

[0046] The first pitch moment coefficient increment determining unit is used to determine the pitch moment coefficient increment C generated by the jet vector effect. mp ;

[0047] The second pitch moment coefficient increment determination unit is used to determine the pitch moment coefficient increment C generated by the jet flap flow mb ;

[0048] The pitch moment coefficient determination unit is used to determine the pitch moment coefficient C for takeoff and climb using the following formula m :

[0049] C m =C moff +C mp +C mb Among them, C moff The pitching moment for takeoff climb in non-powered-up state;

[0050] The pitch moment trim drag coefficient determination unit is used to determine the drag coefficient C generated by the pitch moment trim of a single engine failure using the following formula De :

[0051] C De =C Dδe δ e ;

[0052]

[0053] Among them, δ e Elevator deflection angle to balance the pitch moment, C Dδe is the drag coefficient generated by the unit deflection angle of the elevator, C mδe The control efficiency of the elevator.

[0054] Preferably, in the first pitching moment coefficient increment determining unit, the pitching moment coefficient increment C generated by the jet vector effect is determined by the following formula: mp :

[0055]

[0056] Among them, C T is the thrust coefficient for takeoff of an aircraft with one engine failure, θ e is the downward deflection angle of the engine axis relative to the fuselage axis, h cf L is the vertical distance of the flap aerodynamic pressure center below the center of gravity, f The axial distance behind the center of gravity of the flap's aerodynamic pressure center, h e is the vertical distance of the engine nozzle below the center of gravity, L e is the axial distance of the engine nozzle behind the center of gravity, c a is the average aerodynamic chord length of the wing.

[0057] Preferably, in the second pitching moment coefficient increment determining unit, the pitching moment coefficient increment C generated by the jet flap flow is determined by the following formula: mb :

[0058]

[0059] Among them, L0 is the axial distance between the leading edge of the wing and the center of gravity of the fuselage at the engine installation position. It is positive if it is located behind the center of gravity. L c is the axial distance behind the center of gravity of the wing's aerodynamic pressure center after the flaps are placed, and c' is the axial projection length of the wing's chord length at the engine installation position.

[0060] Preferably, in the yaw moment trim drag coefficient determination module, the drag coefficient C generated by the yaw moment trim of a single engine failure is determined according to the following formula: Dr :

[0061]

[0062] Among them, δ r The rudder deflection angle to balance the yaw moment, C Dδr is the drag coefficient generated by the rudder unit deflection angle, C n is the yaw moment coefficient caused by single engine failure, C nδr The control efficiency of the rudder.

[0063] Preferably, the maximum climb gradient determination module further includes a drag coefficient dynamic influence correction value calculation unit for determining the drag coefficient dynamic influence correction value C by the following formula: Db :

[0064]

[0065] Among them, C Lb is the lift coefficient increment generated by the jet flap flow, C La C Lb The incremental correction part of the lift coefficient at medium angle of attack, AR is the aspect ratio, and K is the correction coefficient.

[0066] A third aspect of the present application provides a computer device, 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 the method for evaluating the takeoff and climb performance of a transport aircraft with a single engine failure as described above.

[0067] A fourth aspect of the present application provides a readable storage medium, which stores a computer program. When the computer program is executed by a processor, it is used to implement the method for evaluating the takeoff and climb performance of a transport aircraft with a single engine failure as described above.

[0068] The present application can quickly and accurately calculate the climb gradient of a blown flap powered lift transport aircraft taking off with a single engine failure, thereby improving the efficiency of aircraft design. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 This is a flow chart of a preferred embodiment of the method for evaluating the takeoff and climb performance of a transport aircraft with a single engine failure of the present application.

[0070] Figure 2 It is a structural diagram of a computer device suitable for implementing the embodiments of the present application. DETAILED DESCRIPTION

[0071] In order to make the purpose, technical solutions and advantages of the implementation of this application clearer, the technical solutions in the implementation of this application will be described in more detail below in conjunction with the drawings in the implementation of this application. In the drawings, the same or similar numbers throughout represent the same or similar elements or elements with the same or similar functions. The described implementation is a part of the implementation of this application, not all of the implementations. The implementation described below with reference to the drawings is exemplary and is intended to be used to explain this application, and should not be understood as a limitation on this application. Based on the implementation in this application, all other implementations obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The implementation of this application is described in detail below in conjunction with the drawings.

[0072] The first aspect of the present application provides a method for evaluating the takeoff and climbing performance of a transport aircraft with a single engine failure, which is applied to a transport aircraft with a powered lift booster with blown flaps on the lower surface, such as Figure 1 As shown, the method mainly includes:

[0073] Step S1: Determine the drag coefficient C generated by the rolling moment trim due to a single engine failure. Da ;

[0074] Step S2: Determine the drag coefficient C generated by the pitching moment trim due to a single engine failure. De ;

[0075] Step S3: Determine the drag coefficient C generated by the yaw moment trim due to single engine failure. Dr ;

[0076] Step S4: Calculate the maximum climb gradient tanθ for takeoff with a single engine failure based on the following formula: max :

[0077]

[0078] Among them, θ max is the maximum flight path angle for takeoff climb, n e is the number of engines, P max is the maximum thrust of the engine, P xz is the engine thrust corrected for system power extraction, speed, and altitude, K S is the system power extraction factor in takeoff state, K V is the speed correction factor of thrust, K h is the altitude correction factor, α is the fuselage angle of attack, η j is the jet efficiency factor of the engine in the lift-increasing state, θ j is the downward deflection angle of the jet flow disturbed by the flap relative to the fuselage axis, q is the velocity pressure, ρ is the air density, V is the airspeed, S ref is the wing reference area, W is the aircraft weight, CDon is the lift coefficient in the lift-increasing state, C Doff is the drag coefficient for takeoff in the non-powered lift state (untrim), C Db is the power effect correction value of the full-engine takeoff drag coefficient, C DLG is the drag coefficient of the landing gear.

[0079] In some optional embodiments, in step S1, the drag coefficient C generated by the single engine failure rolling moment trim is determined according to the following formula: Da :

[0080]

[0081] Among them, δ a Aileron deflection angle for rolling moment balancing, C Dδa is the increase in drag coefficient caused by aileron unit deflection angle, C l is the rolling moment coefficient caused by single engine failure, C lδa is the aileron control efficiency, ΔC L is the loss of lift coefficient of the wing on the side of the failed engine, L ye is the span length between the axis of the failed engine and the axis of the fuselage, C Lb is the lift coefficient increment generated by the full-engine takeoff jet flow around the flap, b w The wing span.

[0082] In some optional embodiments, step S2 further includes:

[0083] Step S21: Determine the pitch moment coefficient increment C generated by the jet vector effect mp ;

[0084] Step S22: Determine the pitching moment coefficient increment C generated by the jet flap flow mb ;

[0085] Step S23: Determine the pitching moment coefficient C for takeoff and climb using the following formula: m :

[0086] C m =C moff +C mp +C mb Among them, C moff The pitching moment for takeoff climb in non-powered-up state;

[0087] Step S24: Determine the drag coefficient C generated by the single engine failure pitching moment trim using the following formula: De :

[0088] C De =C Dδe δe ;

[0089]

[0090] Among them, δ e Elevator deflection angle to balance the pitch moment, C Dδe is the drag coefficient generated by the unit deflection angle of the elevator, C mδe The control efficiency of the elevator.

[0091] In some optional embodiments, in step S21, the pitch moment coefficient increment C generated by the jet vector effect is determined by the following formula: mp :

[0092]

[0093] Among them, C T is the thrust coefficient for takeoff of an aircraft with one engine failure, θ e is the downward deflection angle of the engine axis relative to the fuselage axis, h cf L is the vertical distance of the flap aerodynamic pressure center below the center of gravity, f The axial distance behind the center of gravity of the flap's aerodynamic pressure center, h e is the vertical distance of the engine nozzle below the center of gravity, L e is the axial distance of the engine nozzle behind the center of gravity, c a is the average aerodynamic chord length of the wing.

[0094] In some optional embodiments, in step S22, the pitching moment coefficient increment C generated by the jet flap flow is determined by the following formula: mb :

[0095]

[0096] Among them, L0 is the axial distance between the leading edge of the wing and the center of gravity of the fuselage at the engine installation position. It is positive if it is located behind the center of gravity. L c is the axial distance behind the center of gravity of the wing's aerodynamic pressure center after the flaps are extended, and c' is the axial projection length of the wing's chord length (flaps extended) at the engine installation position.

[0097] In some optional embodiments, in step S3, the drag coefficient C generated by the single engine failure yaw moment trim is determined according to the following formula: Dr :

[0098]

[0099] Among them, δ r The rudder deflection angle to balance the yaw moment, C Dδris the drag coefficient generated by the rudder unit deflection angle, C n is the yaw moment coefficient caused by single engine failure, C nδr The control efficiency of the rudder.

[0100] In some optional embodiments, step S4 further includes determining the drag coefficient dynamic influence correction value C by the following formula: Db :

[0101]

[0102] Among them, C Lb is the lift coefficient increment generated by the jet flap flow, C La C Lb The incremental correction part of the lift coefficient at medium angle of attack, AR is the aspect ratio, and K is the correction coefficient.

[0103] In this step, K is a function of K4 and is obtained by interpolation operation. The required interpolation data is shown in Table 1 below.

[0104] Table 1 Data required for parameter K interpolation

[0105] <![CDATA[(K4) 2 ]]> 0 0.02 0.04 0.06 0.07 0.08 0.09 0.1 0.11 0.12 0.13 0.14 K 0 0.001 0.003 0.012 0.02 0.027 0.037 0.05 0.058 0.07 0.85 0.1

[0106] In the above table, the value of K4 can be calculated by the following formula:

[0107]

[0108] Among them, interp1 is a one-dimensional interpolation function.

[0109] This application can determine whether the aircraft design meets the requirements based on the final calculated maximum climb gradient for aircraft takeoff. If it does not meet the requirements, the parameters involved in the above calculation process can be redesigned and assigned, thereby accelerating the efficiency of aircraft design.

[0110] The example aircraft uses the lower surface blown flap power lift technology, and the aircraft reference wing area is 353m 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. Four high-bypass turbofan engines, each with a thrust of 185 kN, are suspended from the wings. The engine thrust axes are angled -5° relative to the local wing chord. The inboard engines are mounted at 29.6% of half-span, with a 3° wing section angle. The outboard engines are mounted at 55% of half-span, with a 2.5° wing section angle.

[0111] The aircraft's takeoff configuration includes leading-edge slats with a 15° deflection angle, double-slotted Fuller-type flaps with a 15° + 10° deflection angle, and an 8° downward inclination on the upper surface of the flap trailing edge. The chord length of the wing after flap extension is 1.2 times its original chord length, with the flap chord length being 32% of the wing chord length, of which the chord length of the second flap section is 7% of the wing chord length. The depth of the inboard flap portion immersed in the engine jet is 2.33 m, the diameter of the jet at the flap's trailing edge is 5.43 m, and the local wing chord length is 8.73 m. The depth of the outboard flap portion immersed in the engine jet is 2.1 m, the diameter of the jet at the flap's trailing edge is 4.89 m, and the local wing chord length is 6.48 m. The engine jet efficiency factor is 0.907, and the jet downward inclination angle is 12.25°.

[0112] Calculation conditions: Climb with one engine inoperative, airspeed 90 m / s, altitude 20 m, and angle of attack 5°. Input data: The drag coefficient of the example aircraft in the power-off takeoff configuration at a 5° angle of attack is 0.1263, the landing gear drag coefficient is 0.015, and the pitching moment coefficient is -0.207. The system power extraction factor is 0.035, the thrust velocity correction factor is 0.763, the altitude correction factor is 0.995, and the lift coefficient increment generated by the full-engine takeoff jet flow flaps is 0.1302, and the drag coefficient increment is 0.0145.

[0113] First, in step S1, the drag coefficient C generated by the rolling moment trim due to single engine failure is calculated. Da is 0.0151. Then, in step S2, the drag coefficient C generated by the pitching moment trim due to single engine failure is calculated. De is 0.0085, and then in step S3 the drag coefficient C generated by the yaw moment trim due to single engine failure is calculated. Dr is 0.0072. Finally, the maximum climb gradient tanθ for single-engine failure takeoff is calculated according to the formula in step S4. max The maximum climb gradient for the example aircraft during a missed approach is 4.04%, which meets the 3% climb gradient requirement for a single-engine-failure takeoff on a transport aircraft.

[0114] In a second aspect, the present application provides a transport aircraft single-engine failure takeoff and climb performance evaluation device corresponding to the above method, which is applied to a powered high-lift transport aircraft with blown flaps on the lower surface. The device comprises:

[0115] Roll moment trim drag coefficient determination module, used to determine the drag coefficient C generated by single engine failure roll moment trim Da ;

[0116] Pitch moment trim drag coefficient determination module, used to determine the drag coefficient C generated by pitch moment trim when a single engine fails De ;

[0117] Yaw moment trim drag coefficient determination module, used to determine the drag coefficient C generated by yaw moment trim in case of single engine failure Dr ;

[0118] The maximum climb gradient determination module is used to calculate the maximum climb gradient tanθ for single-engine failure takeoff based on the following formula max :

[0119]

[0120] Among them, θ max is the maximum flight path angle for takeoff climb, n e is the number of engines, P max is the maximum thrust of the engine, P xz is the engine thrust corrected for system power extraction, speed, and altitude, K S is the system power extraction factor in takeoff state, K V is the speed correction factor of thrust, K h is the altitude correction factor, α is the fuselage angle of attack, η j is the jet efficiency factor of the engine in the lift-increasing state, θ j is the downward deflection angle of the jet flow disturbed by the flap relative to the fuselage axis, q is the velocity pressure, ρ is the air density, V is the airspeed, S ref is the wing reference area, W is the aircraft weight, C Don is the lift coefficient in the lift-increasing state, C Doff is the drag coefficient for takeoff in the non-powered lift state (untrim), C Db is the power effect correction value of the full-engine takeoff drag coefficient, C DLG is the drag coefficient of the landing gear.

[0121] In some optional embodiments, in the roll moment trim drag coefficient determination module, the drag coefficient C generated by the roll moment trim due to a single engine failure is determined according to the following formula: Da :

[0122]

[0123] Among them, δ a Aileron deflection angle for rolling moment balancing, C Dδa is the increase in drag coefficient caused by aileron unit deflection angle, C l is the rolling moment coefficient caused by single engine failure, C lδa is the aileron control efficiency, ΔC L is the loss of lift coefficient of the wing on the side of the failed engine, L ye is the span length between the axis of the failed engine and the axis of the fuselage, C Lbis the lift coefficient increment generated by the full-engine takeoff jet flow around the flap, b w The wing span.

[0124] In some optional implementations, the pitching moment trim drag coefficient determination module includes:

[0125] The first pitch moment coefficient increment determining unit is used to determine the pitch moment coefficient increment C generated by the jet vector effect. mp ;

[0126] The second pitch moment coefficient increment determination unit is used to determine the pitch moment coefficient increment C generated by the jet flap flow mb ;

[0127] The pitch moment coefficient determination unit is used to determine the pitch moment coefficient C for takeoff and climb using the following formula m :

[0128] C m =C moff +C mp +C mb Among them, C moff The pitching moment for takeoff climb in non-powered-up state;

[0129] The pitch moment trim drag coefficient determination unit is used to determine the drag coefficient C generated by the pitch moment trim of a single engine failure using the following formula De :

[0130] C De =C Dδe δ e ;

[0131]

[0132] Among them, δ e Elevator deflection angle to balance the pitch moment, C Dδe is the drag coefficient generated by the unit deflection angle of the elevator, C mδe The control efficiency of the elevator.

[0133] In some optional embodiments, in the first pitching moment coefficient increment determining unit, the pitching moment coefficient increment C generated by the jet vector effect is determined by the following formula: mp :

[0134]

[0135] Among them, C T is the thrust coefficient for takeoff of an aircraft with one engine failure, θ e is the downward deflection angle of the engine axis relative to the fuselage axis, h cfL is the vertical distance of the flap aerodynamic pressure center below the center of gravity, f The axial distance behind the center of gravity of the flap's aerodynamic pressure center, h e is the vertical distance of the engine nozzle below the center of gravity, L e is the axial distance of the engine nozzle behind the center of gravity, c a is the average aerodynamic chord length of the wing.

[0136] In some optional embodiments, in the second pitching moment coefficient increment determining unit, the pitching moment coefficient increment C generated by the jet flap flow is determined by the following formula: mb :

[0137]

[0138] Among them, L0 is the axial distance between the leading edge of the wing and the center of gravity of the fuselage at the engine installation position. It is positive if it is located behind the center of gravity. L c is the axial distance behind the center of gravity of the wing's aerodynamic pressure center after the flaps are placed, and c' is the axial projection length of the wing's chord length at the engine installation position.

[0139] In some optional embodiments, in the yaw moment trim drag coefficient determination module, the drag coefficient C generated by single engine failure yaw moment trim is determined according to the following formula: Dr :

[0140]

[0141] Among them, δ r The rudder deflection angle to balance the yaw moment, C Dδr is the drag coefficient generated by the rudder unit deflection angle, C n is the yaw moment coefficient caused by single engine failure, C nδr The control efficiency of the rudder.

[0142] In some optional embodiments, the maximum climb gradient determination module further includes a drag coefficient power influence correction value calculation unit, which is used to determine the drag coefficient power influence correction value C by the following formula: Db :

[0143]

[0144] Among them, C Lb is the lift coefficient increment generated by the jet flap flow, C La C Lb The incremental correction part of the lift coefficient at medium angle of attack, AR is the aspect ratio, and K is the correction coefficient.

[0145] In a third aspect of the present application, a computer device includes 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 evaluating the takeoff and climb performance of a transport aircraft with a single engine failure.

[0146] In a fourth aspect, the present application provides a readable storage medium storing a computer program that, when executed by a processor, implements the aforementioned method for evaluating the takeoff and climb performance of a transport aircraft with a single engine failure. The computer-readable storage medium may be included in the apparatus described in the aforementioned embodiments, or it may exist independently and not be incorporated into the apparatus. The computer-readable storage medium carries one or more programs, and when executed by the apparatus, the one or more programs process data according to the aforementioned method.

[0147] Reference below Figure 2 , which shows a structural diagram of a computer device 400 suitable for implementing the embodiments of the present application. Figure 2 The computer device shown is only an example and should not limit the functions and scope of use of the embodiments of the present application.

[0148] like Figure 2 As shown, 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 portion 408 into a random access memory (RAM) 403. Various programs and data required for the operation of device 400 are also stored in RAM 403. CPU 401, ROM 402, and RAM 403 are connected to each other via a bus 404. An input / output (I / O) interface 405 is also connected to bus 404.

[0149] The following components are connected to the I / O interface 405: an input section 406 including a keyboard, a mouse, and the like; an output section 407 including devices such as a cathode ray tube (CRT), a liquid crystal display (LCD), and a speaker; a storage section 408 including a hard disk; and a communication section 409 including a network interface card such as a LAN card or a modem. The communication section 409 performs communication processing via a network such as the Internet. A drive 410 is also connected to the I / O interface 405 as needed. Removable media 411, such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory, is installed in the drive 410 as needed, so that computer programs read therefrom can be installed into the storage section 408 as needed.

[0150] In particular, according to the embodiment of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiment of the present application includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication part 409, and / or installed from the removable medium 411. When the computer program is executed by the central processing unit (CPU) 401, the above functions defined in the method of the present application are executed. It should be noted that the computer storage medium of the present application can be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium can be, for example, but not limited to, a system, device or component of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to, an electrical connection having one or more conductors, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In this application, a computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction 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, which carries computer-readable program code. Such a propagated data signal may take a variety of forms, including, but not limited to, electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium that can transmit, propagate, or transfer a program for use by or in conjunction with an instruction execution system, apparatus, or device. The program code embodied on a computer-readable medium may be transmitted using any suitable medium, including, but not limited to, wireless, wire, optical cable, RF, etc., or any suitable combination thereof.

[0151] The flow charts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present application. In this regard, each box in the flow chart or block diagram can represent a module, program segment or a part of code, and the module, program segment or a part of code includes one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a sequence different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented by a dedicated hardware-based system that performs the specified function or operation, or can be implemented by a combination of dedicated hardware and computer instructions.

[0152] The modules or units described in the embodiments of this application may be implemented in software or hardware. The modules or units described may also be provided in a processor, and the names of these modules or units do not, in certain circumstances, limit the modules or units themselves.

[0153] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for evaluating the takeoff and climb performance of a transport aircraft with a single engine failure, applied to a powered lift transport aircraft with blown flaps on the lower surface, characterized in that: The method includes: Step S1: Determine the drag coefficient C generated by the rolling moment trim due to a single engine failure. Da ; Step S2: Determine the drag coefficient C generated by the pitching moment trim due to a single engine failure. De ; Step S3: Determine the drag coefficient C generated by the yaw moment trim due to single engine failure. Dr ; Step S4: Calculate the maximum climb gradient tanθ for takeoff with a single engine failure based on the following formula: max : Among them, θ max is the maximum flight path angle for takeoff climb, n e is the number of engines, P max is the maximum thrust of the engine, P xz is the engine thrust corrected for system power extraction, speed, and altitude, K S is the system power extraction factor in takeoff state, K V is the speed correction factor of thrust, K h is the altitude correction factor, α is the fuselage angle of attack, η j is the jet efficiency factor of the engine in the lift-increasing state, θ j is the downward deflection angle of the jet flow disturbed by the flap relative to the fuselage axis, q is the velocity pressure, ρ is the air density, V is the airspeed, S ref is the wing reference area, W is the aircraft weight, C Don is the lift coefficient in the lift-increasing state, C Doff is the drag coefficient for takeoff in non-powered lift mode, C Db is the power effect correction value of the full-engine takeoff drag coefficient, C DLG is the drag coefficient of the landing gear.

2. The method for evaluating the takeoff and climb performance of a transport aircraft with a single engine failure according to claim 1, wherein: In step S1, the drag coefficient C generated by the single engine failure rolling moment trim is determined according to the following formula: Da : Among them, δ a Aileron deflection angle for rolling moment balancing, C Dδa is the increase in drag coefficient caused by aileron unit deflection angle, C l is the rolling moment coefficient caused by single engine failure, C lδa is the aileron control efficiency, ΔC L is the loss of lift coefficient of the wing on the side of the failed engine, L ye is the span length between the axis of the failed engine and the axis of the fuselage, C Lb is the lift coefficient increment generated by the full-engine takeoff jet flow around the flap, b w The wing span.

3. The method for evaluating the takeoff and climb performance of a transport aircraft with a single engine failure according to claim 1, wherein: Step S2 further comprises: Step S21: Determine the pitch moment coefficient increment C generated by the jet vector effect mp ; Step S22: Determine the pitching moment coefficient increment C generated by the jet flap flow mb ; Step S23: Determine the pitching moment coefficient C for takeoff and climb using the following formula: m : C m =C moff +C mp +C mb Among them, C moff The pitching moment for takeoff climb in non-powered-up state; Step S24: Determine the drag coefficient C generated by the single engine failure pitching moment trim using the following formula: De : C De =C Dδe d e ; Among them, δ e Elevator deflection angle to balance the pitch moment, C Dδe is the drag coefficient generated by the unit deflection angle of the elevator, C mδe The control efficiency of the elevator.

4. The method for evaluating the takeoff and climb performance of a transport aircraft with a single engine failure according to claim 3, wherein: In step S21, the pitch moment coefficient increment C generated by the jet vector effect is determined by the following formula: mp : Among them, C T is the thrust coefficient for takeoff of an aircraft with one engine failure, θ e is the downward deflection angle of the engine axis relative to the fuselage axis, h cf L is the vertical distance of the flap aerodynamic pressure center below the center of gravity, f The axial distance behind the center of gravity of the flap's aerodynamic pressure center, h e is the vertical distance of the engine nozzle below the center of gravity, L e is the axial distance of the engine nozzle behind the center of gravity, c a is the average aerodynamic chord length of the wing.

5. The method for evaluating takeoff and climb performance of a transport aircraft with a single engine failure according to claim 3, wherein: In step S22, the pitching moment coefficient increment C generated by the jet flap flow is determined by the following formula: mb : Among them, L0 is the axial distance between the leading edge of the wing and the center of gravity of the fuselage at the engine installation position. It is positive if it is located behind the center of gravity. L c is the axial distance behind the center of gravity of the wing's aerodynamic pressure center after the flaps are placed, and c' is the axial projection length of the wing's chord length at the engine installation position.

6. The method for evaluating the takeoff and climb performance of a transport aircraft with a single engine failure according to claim 1, wherein: In step S3, the drag coefficient C generated by the yaw moment trim due to single engine failure is determined according to the following formula: Dr : Among them, δ r The rudder deflection angle to balance the yaw moment, C Dδr is the drag coefficient generated by the rudder unit deflection angle, C n is the yaw moment coefficient caused by single engine failure, C nδr The control efficiency of the rudder.

7. The method for evaluating takeoff and climb performance of a transport aircraft with a single engine failure according to claim 1, wherein: Step S4 further includes determining the drag coefficient dynamic influence correction value C by the following formula: Db : Among them, C Lb is the lift coefficient increment generated by the jet flap flow, C La C Lb The incremental correction part of the lift coefficient at medium angle of attack, AR is the aspect ratio, and K is the correction coefficient.

8. A transport aircraft single engine failure takeoff and climb performance evaluation device, applied to a transport aircraft with a powered lift booster with blown flaps on the lower surface, characterized in that: The device includes: Roll moment trim drag coefficient determination module, used to determine the drag coefficient C generated by single engine failure roll moment trim Da ; Pitch moment trim drag coefficient determination module, used to determine the drag coefficient C generated by pitch moment trim when a single engine fails De ; Yaw moment trim drag coefficient determination module, used to determine the drag coefficient C generated by yaw moment trim in case of single engine failure Dr ; The maximum climb gradient determination module is used to calculate the maximum climb gradient tanθ for single-engine failure takeoff based on the following formula max : Among them, θ max is the maximum flight path angle for takeoff climb, n e is the number of engines, P max is the maximum thrust of the engine, P xz is the engine thrust corrected for system power extraction, speed, and altitude, K S is the system power extraction factor in takeoff state, K V is the speed correction factor of thrust, K h is the altitude correction factor, α is the fuselage angle of attack, η j is the jet efficiency factor of the engine in the lift-increasing state, θ j is the downward deflection angle of the jet flow disturbed by the flap relative to the fuselage axis, q is the velocity pressure, ρ is the air density, V is the airspeed, S ref is the wing reference area, W is the aircraft weight, C Don is the lift coefficient in the lift-increasing state, C Doff is the drag coefficient for takeoff in non-powered lift mode, C Db is the power effect correction value of the full-engine takeoff drag coefficient, C DLG is the drag coefficient of the landing gear.

9. The transport aircraft single engine failure takeoff and climb performance evaluation device according to claim 8, characterized in that: In the roll moment trim drag coefficient determination module, the drag coefficient C generated by the roll moment trim of a single engine failure is determined according to the following formula: Da : Among them, δ a Aileron deflection angle for rolling moment balancing, C Dδa is the increase in drag coefficient caused by aileron unit deflection angle, C l is the rolling moment coefficient caused by single engine failure, C lδa is the aileron control efficiency, ΔC L is the loss of lift coefficient of the wing on the side of the failed engine, L ye is the span length between the axis of the failed engine and the axis of the fuselage, C Lb is the lift coefficient increment generated by the full-engine takeoff jet flow around the flap, b w The wing span.

10. The transport aircraft single engine failure takeoff and climb performance evaluation device according to claim 8, characterized in that: The pitching moment trim drag coefficient determination module includes: The first pitch moment coefficient increment determining unit is used to determine the pitch moment coefficient increment C generated by the jet vector effect. mp ; The second pitch moment coefficient increment determination unit is used to determine the pitch moment coefficient increment C generated by the jet flap flow mb ; The pitch moment coefficient determination unit is used to determine the pitch moment coefficient C for takeoff and climb using the following formula m : C m =C moff +C mp +C mb Among them, C moff The pitching moment for takeoff climb in non-powered-up state; The pitch moment trim drag coefficient determination unit is used to determine the drag coefficient C generated by the pitch moment trim of a single engine failure using the following formula De : C De =C Dδe d e ; Among them, δ e Elevator deflection angle to balance the pitch moment, C Dδe is the drag coefficient generated by the unit deflection angle of the elevator, C mδe The control efficiency of the elevator.

11. The transport aircraft single engine failure takeoff and climb performance evaluation device according to claim 10, characterized in that: In the first pitching moment coefficient increment determining unit, the pitching moment coefficient increment C generated by the jet vector effect is determined by the following formula: mp : Among them, C T is the thrust coefficient for takeoff of an aircraft with one engine failure, θ e is the downward deflection angle of the engine axis relative to the fuselage axis, h cf L is the vertical distance of the flap aerodynamic pressure center below the center of gravity, f The axial distance behind the center of gravity of the flap's aerodynamic pressure center, h e is the vertical distance of the engine nozzle below the center of gravity, L e is the axial distance of the engine nozzle behind the center of gravity, c a is the average aerodynamic chord length of the wing.

12. The transport aircraft single engine failure takeoff and climb performance evaluation device according to claim 10, characterized in that: In the second pitching moment coefficient increment determining unit, the pitching moment coefficient increment C generated by the jet flap flow is determined by the following formula: mb : Among them, L0 is the axial distance between the leading edge of the wing and the center of gravity of the fuselage at the engine installation position. It is positive if it is located behind the center of gravity. L c is the axial distance behind the center of gravity of the wing's aerodynamic pressure center after the flaps are placed, and c' is the axial projection length of the wing's chord length at the engine installation position.

13. The transport aircraft single engine failure takeoff and climb performance evaluation device according to claim 8, characterized in that: In the yaw moment trim drag coefficient determination module, the drag coefficient C generated by single engine failure yaw moment trim is determined according to the following formula: Dr : Among them, δ r The rudder deflection angle to balance the yaw moment, C Dδr is the drag coefficient generated by the rudder unit deflection angle, C n is the yaw moment coefficient caused by single engine failure, C nδr The control efficiency of the rudder.

14. The transport aircraft single engine failure takeoff and climb performance evaluation device according to claim 8, characterized in that: The maximum climb gradient determination module further includes a drag coefficient power influence correction value calculation unit for determining the drag coefficient power influence correction value C by the following formula: Db : Among them, C Lb is the lift coefficient increment generated by the jet flap flow, C La C Lb The incremental correction part of the lift coefficient at medium angle of attack, AR is the aspect ratio, and K is the correction coefficient.

15. A computer device, characterized in that: The method comprises 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 evaluating the takeoff and climb performance of a transport aircraft with a single engine failure as described in any one of claims 1 to 7.

16. A readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, it is used to implement the method for evaluating the takeoff and climb performance of a transport aircraft with a single engine failure as described in any one of claims 1 to 7.

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