Method and device for determining length of takeoff field of transport plane

Abstract

The invention belongs to the technical field of take-off field domain performance design, and particularly relates to a method and device for determining the length of a transport plane take-off field, which are applied to a lower surface blowing flap power lift augmentation transport plane. The method comprises the following steps: S1, determining the takeoff thrust of the transport plane; s2, determining the accelerated speed of the transport plane and the track angle of constant-speed climbing according to the take-off thrust; and S3, calculating the take-off field length of the transport plane according to an integral formula. The method can accurately simulate the influence of system power extraction, speed, height, jet efficiency and jet direction deflection on takeoff thrust, and can quickly and accurately calculate the length of the single-shot failure takeoff field of the lower surface blowing type flap power high lift transport plane.

Description

Technical Field

[0001] The present application belongs to the technical field of take-off field performance design, and in particular relates to a method and device for determining the take-off field length of a transport aircraft. Background Art

[0002] Compared with conventional aircraft, the thrust model, lift and drag model of the takeoff of the powered lift-enhancing aircraft with air flaps are much more complicated. The takeoff thrust is closely related to the speed, engine jet efficiency and jet deflection angle; the lift is composed of two parts: aerodynamic lift and jet flap interference lift. The aerodynamic lift coefficient is only related to the angle of attack and does not change with speed, while the jet flap interference lift coefficient is very sensitive to speed but not to the angle of attack. The jet flap interference lift has nothing to do with the speed-pressure relationship. The drag of the powered lift-enhancing aircraft with air flaps has the same characteristics. The dynamic model for calculating the takeoff field length of conventional aircraft cannot be applied to the powered lift-enhancing aircraft with air flaps. Summary of the invention

[0003] In order to solve the above problems, the present application provides a method and device for determining the take-off field length of a transport aircraft, providing technical support for determining the take-off field length of a lower surface blown flap powered lift transport aircraft.

[0004] In a first aspect, the present application provides a method for determining the take-off field length of a transport aircraft, which is applied to a power-assisted lift transport aircraft with lower surface blown flaps. The method comprises:

[0005] Step S1: Determine the takeoff thrust P of the transport aircraft xzon ;

[0006] Step S2: According to the take-off thrust P xzon Determine the acceleration a of the transport aircraft and the flight path angle θ of the constant speed climb;

[0007] Step S3: Calculate the take-off field length L of the transport aircraft according to the following integral formula:

[0008]

[0009] Among them, L R L is the ground rolling distance before lifting the front wheel for takeoff. L-R L is the rolling distance between the front wheel lift and the departure point, C is the flight distance to climb to a safe altitude, V is the speed, V S is the stall speed in takeoff configuration, V R is the front wheel speed, V lof is the ground speed.

[0010] Preferably, in step S1, the takeoff thrust P is determined by the following formula: xzon :

[0011]

[0012] Among them, n e is the number of engines, P emax is the maximum takeoff thrust of the engine, K s is the takeoff system power extraction factor, K v is the speed correction factor for takeoff thrust, K h is the altitude correction factor for takeoff thrust, P xz is the available thrust for takeoff corrected for power and speed, η j is the engine jet efficiency factor, θ j is the downward deflection angle of the jet disturbed by the flap relative to the fuselage axis, and α is the fuselage angle of attack.

[0013] Preferably, step S2 further comprises:

[0014] Step S21: Determine the takeoff lift coefficient C in the increased lift state L ;

[0015] Step S22: Determine the takeoff drag coefficient C in the increased lift state D ;

[0016] Step S23, determine the acceleration a of the conveyor by the following formula:

[0017]

[0018] Where W is the takeoff weight of the aircraft, D is the takeoff aerodynamic drag, L is the takeoff aerodynamic lift, F is the friction force of the taxiing, f is the rolling friction coefficient of the taxiing, and Z p is the component of thrust in the lift direction, S ref is the reference area of ​​the wing, ρ is the air density, and q is the velocity pressure;

[0019] Step S24: determine the track angle θ of the constant speed climb by the following formula:

[0020]

[0021] Preferably, step S21 further comprises:

[0022] Step S211: Determine the lift coefficient correction value ΔC of the jet flap flow Lb ;

[0023] Step S212: Determine the lift coefficient correction value ΔC of the jet vector effect Lp ;

[0024] Step S213: Determine the takeoff lift coefficient C in the increased lift state by the following formula: L :

[0025] C L =C Loff +ΔC Lb +ΔC Lp ;

[0026] Among them, C Loff It is the takeoff lift coefficient in the non-powered lift state.

[0027] Preferably, in step S211, the lift coefficient correction value ΔC of the jet flap flow is determined by the following formula: Lb :

[0028] ΔC Lb =ΔC Lθ +ΔC Lα ;

[0029] Where, ΔC Lθ is the reference value of the dynamic effect correction of the lift coefficient; ΔC Lα is the correction amount of the lift coefficient increment corresponding to the angle of attack α.

[0030] Preferably, in step S212, the lift coefficient correction value ΔC of the jet vector effect is determined by the following formula: Lp :

[0031]

[0032] Among them, C T is the aircraft takeoff thrust coefficient.

[0033] Preferably, in step S22, the takeoff drag coefficient C in the increased lift state is determined by the following formula: D :

[0034] C D =C Doff +ΔC D ;

[0035] Among them, C Doff is the drag coefficient in the non-powered lift state, ΔC D is the dynamic effect correction of the drag coefficient.

[0036] Preferably, in step S23, when the takeoff thrust coefficient of the aircraft exceeds 5.6, the takeoff aerodynamic drag D and the takeoff aerodynamic lift L of the aircraft are determined by the following steps:

[0037] Step S231, determining the lift correction amount and the drag correction amount at multiple speed points with a thrust coefficient between 0.26 and 5.6, and fitting the quadratic function of the lift correction amount and the speed, and the quadratic function of the drag correction amount and the speed respectively;

[0038] Step S232: determine the lift correction amount and the drag correction amount according to the current speed of the transport aircraft, and then determine the takeoff aerodynamic drag D and the takeoff aerodynamic lift L of the aircraft.

[0039] A second aspect of the present application provides a transport aircraft takeoff field length determination device, which is applied to a lower surface blown flap powered lift transport aircraft, and the device comprises:

[0040] Take-off thrust determination module, used to determine the take-off thrust P of the transport aircraft xzon ;

[0041] The acceleration and track angle determination module is used to determine the takeoff thrust P xzon Determine the acceleration a of the transport aircraft and the flight path angle θ of the constant speed climb;

[0042] The take-off field length determination module is used to calculate the take-off field length L of the transport aircraft according to the following integral formula:

[0043]

[0044] Among them, L R L is the ground rolling distance before lifting the front wheel for takeoff. L-R L is the rolling distance between the front wheel lift and the departure point, C is the flight distance to climb to a safe altitude, V is the speed, V S is the stall speed in takeoff configuration, V R is the front wheel speed, V lof is the ground speed.

[0045] Preferably, in the takeoff thrust determination module, the takeoff thrust P is determined by the following formula: xzon :

[0046]

[0047] Among them, n e is the number of engines, P emax is the maximum takeoff thrust of the engine, K s is the takeoff system power extraction factor, K v is the speed correction factor for takeoff thrust, K h is the altitude correction factor for takeoff thrust, P xz is the available thrust for takeoff corrected for power and speed, η j is the engine jet efficiency factor, θ j is the downward deflection angle of the jet disturbed by the flap relative to the fuselage axis, and α is the fuselage angle of attack.

[0048] Preferably, the acceleration and track angle determination module includes:

[0049] The take-off lift coefficient determination unit is used to determine the take-off lift coefficient C in the increased lift state. L ;

[0050] Takeoff drag coefficient determination unit, used to determine the takeoff drag coefficient C in the increased lift state D ;

[0051] The acceleration determination unit is used to determine the acceleration a of the conveyor by the following formula:

[0052]

[0053] Where W is the takeoff weight of the aircraft, D is the takeoff aerodynamic drag, L is the takeoff aerodynamic lift, F is the friction force of the taxiing, f is the rolling friction coefficient of the taxiing, and Z p is the component of thrust in the lift direction, S ref is the wing reference area, ρ is the air density, q is the velocity pressure;

[0054] The track angle determination unit is used to determine the track angle θ of the constant speed climb by the following formula:

[0055]

[0056] Preferably, the take-off lift coefficient determination unit comprises:

[0057] The first lift coefficient correction determination subunit is used to determine the lift coefficient correction ΔC of the jet flap flow. Lb ;

[0058] The second lift coefficient correction determination subunit is used to determine the lift coefficient correction ΔC of the jet vector effect. Lp ;

[0059] The takeoff lift coefficient calculation subunit is used to determine the takeoff lift coefficient C in the increased lift state by the following formula L :

[0060] C L =C Loff +ΔC Lb +ΔC Lp ;

[0061] Among them, C Loff It is the takeoff lift coefficient in the non-powered lift state.

[0062] Preferably, in the first lift coefficient correction amount determination subunit, the lift coefficient correction amount ΔC of the jet flap flow is determined by the following formula: Lb :

[0063] ΔC Lb =ΔC Lθ +ΔCLα ;

[0064] Where, ΔC Lθ is the reference value of the dynamic effect correction of the lift coefficient; ΔC Lα is the correction amount of the lift coefficient increment corresponding to the angle of attack α.

[0065] Preferably, in the second lift coefficient correction amount determination subunit, the lift coefficient correction amount ΔC of the jet vector effect is determined by the following formula: Lp :

[0066]

[0067] Among them, C T is the aircraft takeoff thrust coefficient.

[0068] Preferably, in the takeoff drag coefficient determination unit, the takeoff drag coefficient C in the increased lift state is determined by the following formula: D :

[0069] C D =C Doff +ΔC D ;

[0070] Among them, C Doff is the drag coefficient in the non-powered lift state, ΔC D is the dynamic effect correction of the drag coefficient.

[0071] Preferably, in the acceleration determination unit, when the takeoff thrust coefficient of the aircraft exceeds 5.6, the takeoff aerodynamic drag D and the takeoff aerodynamic lift L of the aircraft are reconstructed by the following modules:

[0072] The quadratic function construction subunit is used to determine the lift correction and drag correction at multiple speed points with thrust coefficients between 0.26 and 5.6, and to fit the quadratic function of lift correction and speed, and the quadratic function of drag correction and speed respectively;

[0073] The lift-drag reconstruction subunit is used to determine the lift correction amount and the drag correction amount according to the current speed of the transport aircraft, and then determine the takeoff aerodynamic drag D and takeoff aerodynamic lift L of the aircraft.

[0074] 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 determining the length of a transport aircraft takeoff field as described above.

[0075] A fourth aspect of the present application provides a readable storage medium, wherein the readable storage medium stores a computer program, and when the computer program is executed by a processor, it is used to implement the method for determining the length of a transport aircraft takeoff field as described above.

[0076] The application can accurately simulate the influence of system power extraction, speed, altitude, jet efficiency, and jet direction deflection on takeoff thrust, and can quickly and accurately calculate the length of the single-engine failure takeoff field of a lower surface blown flap powered lift transport aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Figure 1 It is a flow chart of a preferred embodiment of the method for determining the length of the transport aircraft takeoff field of the present application.

[0078] Figure 2 It is a schematic diagram of the structure of a computer device suitable for implementing the embodiments of the present application. DETAILED DESCRIPTION

[0079] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the implementation of this application will be described in more detail in combination with the drawings in the implementation of this application. In the drawings, the same or similar reference numerals 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 cannot 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 combination with the drawings.

[0080] In a first aspect, the present application provides a method for determining the take-off field length of a transport aircraft, which is applied to a power-assisted lift transport aircraft with blown flaps on the lower surface, such as Figure 1 As shown, the method mainly includes:

[0081] Step S1: Determine the takeoff thrust P of the transport aircraft xzon ;

[0082] Step S2: According to the take-off thrust P xzon Determine the acceleration a of the transport aircraft and the flight path angle θ of the constant speed climb;

[0083] Step S3: Calculate the take-off field length L of the transport aircraft according to the following integral formula:

[0084]

[0085] Among them, L RL is the ground rolling distance before lifting the front wheel for takeoff. L-R L is the rolling distance between the front wheel lift and the departure point, C is the flight distance to climb to a safe altitude, V is the speed, V S is the stall speed in takeoff configuration, V R is the front wheel speed, V lof is the ground speed.

[0086] The present application first calculates the takeoff thrust in step S1, based on which the acceleration a of the transport aircraft and the track angle θ of the constant speed climb can be calculated in step S2. Finally, in step S3, the velocity V can be integrated based on the acceleration a of the transport aircraft to obtain the moving distance of the transport aircraft on the ground, that is, the first part of the runway length. Based on the track angle, the flight altitude can be integrated to determine the second part of the runway length required within the safe altitude range. The two parts of the runway length are superimposed to form the minimum length of the required takeoff field. This length can guide the design of the takeoff field, and can also optimize the aircraft parameters based on the existing takeoff field.

[0087] In some optional embodiments, in step S1, the takeoff thrust P is determined by the following formula: xzon :

[0088]

[0089] Among them, n e is the number of engines, P emax is the maximum takeoff thrust of the engine, K s is the takeoff system power extraction factor, K v is the speed correction factor for takeoff thrust, K h is the altitude correction factor for takeoff thrust, P xz is the available thrust for takeoff corrected for power and speed, η j is the engine jet efficiency factor, θ j is the downward deflection angle of the jet disturbed by the flap relative to the fuselage axis, and α is the fuselage angle of attack.

[0090] In this embodiment, the engine jet efficiency factor η j The calculation model is:

[0091]

[0092] Among them, θ jc is the theoretical deflection angle of the engine jet caused by flap interference, and the calculation model is as follows:

[0093] (1) When λ1=1 and θ d =0, θ jc =0;

[0094] (2) When λ1=1, θ jc =θ d ;

[0095] (3) In other cases,

[0096] Among them, when F<1.0, When F ≥ 1.0, λ1 = 1;

[0097] in, Y=1-2F;λ2=interp1(θ m sz,λ2sz,θ m );

[0098]

[0099] Where F is the jet immersion factor of the flap, H f is the jet immersion depth of the flap, θ m is the downward deflection angle of the flap relative to the engine axis, θ d is the deflection angle of the engine jet disturbed by the flap, λ2 is θ m function, interp1 is the interpolation function.

[0100] The deflection angle θ of the engine jet disturbed by the flap d and the downward deflection angle θ of the jet disturbed by the flap relative to the fuselage axis j The calculation model is as follows:

[0101]

[0102] Where δ f is the flap downward deflection angle, θ fte is the angle between the upper surface of the flap trailing edge and the flap chord, θ ew is the downward deflection angle of the engine axis relative to the wing chord line, θ m is the downward deflection angle of the flap relative to the engine axis, θ d is the deflection angle of the jet disturbed by the flap, θ jw is the downward deflection angle of the engine jet relative to the wing chord line, θ wi The installation angle of the wing section at the engine installation position.

[0103] In some optional implementations, step S2 further includes:

[0104] Step S21: Determine the takeoff lift coefficient C in the increased lift state L ;

[0105] Step S22: Determine the takeoff drag coefficient C in the increased lift state D ;

[0106] Step S23, determine the acceleration a of the conveyor by the following formula:

[0107]

[0108] Where W is the takeoff weight of the aircraft, D is the takeoff aerodynamic drag, L is the takeoff aerodynamic lift, F is the friction force of the taxiing, f is the rolling friction coefficient of the taxiing, and Z p is the component of thrust in the lift direction, S ref is the reference area of ​​the wing, ρ is the air density, and q is the velocity pressure;

[0109] Step S24: determine the track angle θ of the constant speed climb by the following formula:

[0110]

[0111] In some optional implementations, step S21 further includes:

[0112] Step S211: Determine the lift coefficient correction value ΔC of the jet flap flow Lb ;

[0113] Step S212: Determine the lift coefficient correction value ΔC of the jet vector effect Lp ;

[0114] Step S213: Determine the takeoff lift coefficient C in the increased lift state by the following formula: L :

[0115] C L =C Loff +ΔC Lb +ΔC Lp ;

[0116] Among them, C Loff It is the takeoff lift coefficient in the non-powered lift state.

[0117] In some optional embodiments, in step S211, the lift coefficient correction value ΔC of the jet flap flow is determined by the following formula: Lb :

[0118] ΔC Lb =ΔC Lθ +ΔC Lα ;

[0119] Where, ΔC Lθ is the reference value of the dynamic effect correction of the lift coefficient; ΔC Lα is the correction amount of the lift coefficient increment corresponding to the angle of attack α.

[0120] In this embodiment, the reference value ΔC of the lift coefficient dynamic influence correction amount isLθ The calculation model is:

[0121]

[0122] Among them, C μ is the engine tail jet momentum coefficient, φ is the wingspan factor affected by the jet, K1 is a function of the momentum coefficient, G is a function of the wing aspect ratio AR and parameter K2, K2 is the ratio of the flap extended chord length to the original chord length; θ f is the downward deflection angle of the upper surface of the trailing edge of the second flap relative to the chord, θ faux c is the downward deflection angle of the second flap chord relative to the front flap chord; f is the sum of the chord lengths of the two flaps, c faux is the chord length of the second flap, c' is the chord length of the wing after the flap is extended, and c is the chord length of the wing when the flap is not extended. K 3aux and K3 are functions of the momentum coefficient and the relative chord length of the flap.

[0123] In this embodiment, the correction amount ΔC of the lift coefficient increment corresponding to the angle of attack α is Lα The calculation model is:

[0124]

[0125] Among them, θ wi is the installation angle of the engine axis corresponding to the wing section relative to the fuselage axis, The relative thickness of the wing with flaps extended.

[0126] In some optional embodiments, in step S212, the lift coefficient correction value ΔC of the jet vector effect is determined by the following formula: Lp :

[0127]

[0128] Among them, C T is the aircraft takeoff thrust coefficient.

[0129] In some optional implementations, in step S22, the takeoff drag coefficient C in the increased lift state is determined by the following formula: D :

[0130] C D =C Doff +ΔC D ;

[0131] Among them, C Doff is the drag coefficient in the non-powered lift state, ΔC D is the dynamic effect correction of the drag coefficient.

[0132] In this embodiment, the dynamic influence correction amount ΔC of the drag coefficient is D The calculation model is:

[0133]

[0134] In some optional implementations, in step S23, when the takeoff thrust coefficient of the aircraft exceeds 5.6, the takeoff aerodynamic drag D and the takeoff aerodynamic lift L of the aircraft are determined by the following steps:

[0135] Step S231, determining the lift correction amount and the drag correction amount at multiple speed points with a thrust coefficient between 0.26 and 5.6, and fitting the quadratic function of the lift correction amount and the speed, and the quadratic function of the drag correction amount and the speed respectively;

[0136] Step S232: determine the lift correction amount and the drag correction amount according to the current speed of the transport aircraft, and then determine the takeoff aerodynamic drag D and the takeoff aerodynamic lift L of the aircraft.

[0137] In this embodiment, the calculation model of the dynamic influence correction amount of the lift coefficient and the drag coefficient can only be used in the speed region where the thrust coefficient is less than 5.6. Since the speed in the initial stage of takeoff is low and the thrust coefficient is large, the present application reconstructs the calculation method of the takeoff aerodynamic drag D and the takeoff aerodynamic lift L when the takeoff thrust coefficient exceeds 5.6 through the above method.

[0138] In this embodiment, the lift and drag correction values ​​in the low speed region are calculated by data fitting. In step S231, the correction values ​​of lift and drag dynamic effects at multiple speed points with thrust coefficients between 0.26 and 5.6 are first determined. The calculation model is shown in the formula:

[0139]

[0140] Afterwards, a fitting algorithm is used to construct the quadratic function of the lift and drag dynamic effect correction with respect to speed:

[0141]

[0142] Finally, in step S232, new takeoff aerodynamic drag D and takeoff aerodynamic lift L are calculated.

[0143] The example aircraft uses the lower surface blowing flap power lift technology, and the aircraft reference wing area is 353m 2, wingspan 50.6m, aspect ratio 7.25, wing 1 / 4 chord sweep angle 21°, tip-to-root ratio 0.24. Four high-bypass turbofan engines are hung under the aircraft wing, each with a thrust of 185KN. The engine thrust axis is -5° relative to the local wing chord. The span-wise installation position of the inner engine is 29.6% of the half span, where the wing section installation angle is 3°, and the span-wise installation position of the outer engine is 55% of the half span, where the wing section installation angle is 2.5°.

[0144] Aircraft takeoff configuration: leading edge slat deflection angle 15°, trailing edge double slot Fuller flap deflection angle 15°+10°, flap trailing edge upper surface downward inclination angle 8°. After the flap is released, the chord length of the wing is 1.2 times the original chord length, the flap chord length is 32% of the wing chord length, of which the chord length of the second section of the flap is 7% of the wing chord length. The depth of the inner flap part immersed in the engine jet is 2.33m, the diameter of the jet at the trailing edge of the flap is 5.43m, and the local wing chord length is 8.73m. The depth of the outer flap part immersed in the engine jet is 2.1m, the diameter of the jet at the trailing edge of the flap is 4.89m, and the local wing chord length is 6.48m.

[0145] Calculation status: take-off weight 265t, system power extraction factor Ks 3.6%, calculation model of speed correction factor Speed ​​correction factor K h Take 1; the takeoff front wheel speed is 76.27m / s, the ground speed and safety altitude speed are 82.08m / s, and the ground attack angle is 8°. The dynamic simulation calculation process of the example aircraft takeoff is as follows:

[0146] (1) Engine jet downward deflection angle θ relative to the fuselage axis j Calculated to be 12.25°;

[0147] (2) Theoretical deflection angle θ of the engine jet caused by flap interference jc Calculated to be 38.1°;

[0148] (3) Engine jet efficiency factor η j Calculated as 0.907;

[0149] (4) The quadratic function of the takeoff aerodynamic drag D determined in step S231 with respect to speed is:

[0150] ΔD=-0.0073319V2+0.68819V;

[0151] The quadratic function of the determined takeoff aerodynamic lift L with respect to speed is:

[0152] ΔL=-0.057942V2+7.0166V.

[0153] Finally, simulation calculations are performed, as shown in Table 1 below. The calculation data show that the takeoff field length of the target aircraft is 2364m, the climb track angle is 4.97°, the acceleration is shown in the 5th column, the takeoff thrust is shown in the 6th column, the lift in the non-powered lift increase state is shown in the 7th column, the dynamic correction of the lift is shown in the 8th column, the lift direction component of the thrust is shown in the 9th column, the drag in the non-powered lift increase state is shown in the 10th column, the dynamic correction of the drag is shown in the 11th column, and the friction drag is shown in the 12th column.

[0154] Table 1. Calculation data of takeoff dynamics simulation of the target aircraft

[0155]

[0156] In Table 1 above, a lot of data is omitted between the third and fourth rows.

[0157] In a second aspect, the present application provides a transport aircraft takeoff field length determination device corresponding to the above method, which is applied to a lower surface blown flap powered lift transport aircraft, and the device comprises:

[0158] Take-off thrust determination module, used to determine the take-off thrust P of the transport aircraft xzon ;

[0159] The acceleration and track angle determination module is used to determine the takeoff thrust P xzon Determine the acceleration a of the transport aircraft and the flight path angle θ of the constant speed climb;

[0160] The take-off field length determination module is used to calculate the take-off field length L of the transport aircraft according to the following integral formula:

[0161]

[0162] Among them, L R L is the ground rolling distance before lifting the front wheel for takeoff. L-R L is the rolling distance between the front wheel lift and the departure point, C is the flight distance to climb to a safe altitude, V is the speed, V S is the stall speed in takeoff configuration, V R is the front wheel speed, V lof is the ground speed.

[0163] In some optional embodiments, in the takeoff thrust determination module, the takeoff thrust P is determined by the following formula: xzon :

[0164]

[0165] Among them, n e is the number of engines, P emax is the maximum takeoff thrust of the engine, K sis the takeoff system power extraction factor, K v is the speed correction factor for takeoff thrust, K h is the altitude correction factor for takeoff thrust, P xz is the available thrust for takeoff corrected for power and speed, η j is the engine jet efficiency factor, θ j is the downward deflection angle of the jet disturbed by the flap relative to the fuselage axis, and α is the fuselage angle of attack.

[0166] In some optional implementations, the acceleration and track angle determination module includes:

[0167] The take-off lift coefficient determination unit is used to determine the take-off lift coefficient C in the increased lift state. L ;

[0168] Takeoff drag coefficient determination unit, used to determine the takeoff drag coefficient C in the increased lift state D ;

[0169] The acceleration determination unit is used to determine the acceleration a of the conveyor by the following formula:

[0170]

[0171] Where W is the takeoff weight of the aircraft, D is the takeoff aerodynamic drag, L is the takeoff aerodynamic lift, F is the friction force of the taxiing, f is the rolling friction coefficient of the taxiing, and Z p is the component of thrust in the lift direction, S ref is the wing reference area, ρ is the air density, q is the velocity pressure;

[0172] The track angle determination unit is used to determine the track angle θ of the constant speed climb by the following formula:

[0173]

[0174] In some optional implementations, the takeoff lift coefficient determination unit includes:

[0175] The first lift coefficient correction determination subunit is used to determine the lift coefficient correction ΔC of the jet flap flow. Lb ;

[0176] The second lift coefficient correction determination subunit is used to determine the lift coefficient correction ΔC of the jet vector effect. Lp ;

[0177] The takeoff lift coefficient calculation subunit is used to determine the takeoff lift coefficient C in the increased lift state by the following formula L :

[0178] C L =CLoff +ΔC Lb +ΔC Lp ;

[0179] Among them, C Loff It is the takeoff lift coefficient in the non-powered lift state.

[0180] In some optional embodiments, in the first lift coefficient correction amount determination subunit, the lift coefficient correction amount ΔC of the jet flap flow is determined by the following formula: Lb :

[0181] ΔC Lb =ΔC Lθ +ΔC Lα ;

[0182] Where, ΔC Lθ is the reference value of the dynamic effect correction of the lift coefficient; ΔC Lα is the correction amount of the lift coefficient increment corresponding to the angle of attack α.

[0183] In some optional embodiments, in the second lift coefficient correction amount determination subunit, the lift coefficient correction amount ΔC of the jet vector effect is determined by the following formula: Lp :

[0184]

[0185] Among them, C T is the aircraft takeoff thrust coefficient.

[0186] In some optional embodiments, in the takeoff drag coefficient determination unit, the takeoff drag coefficient C in the increased lift state is determined by the following formula: D :

[0187] C D =C Doff +ΔC D ;

[0188] Among them, C Doff is the drag coefficient in the non-powered lift state, ΔC D is the dynamic effect correction of the drag coefficient.

[0189] In some optional implementations, in the acceleration determination unit, when the takeoff thrust coefficient of the aircraft exceeds 5.6, the takeoff aerodynamic drag D and the takeoff aerodynamic lift L of the aircraft are reconstructed by the following modules:

[0190] The quadratic function construction subunit is used to determine the lift correction and drag correction at multiple speed points with thrust coefficients between 0.26 and 5.6, and to fit the quadratic function of lift correction and speed, and the quadratic function of drag correction and speed respectively;

[0191] The lift-drag reconstruction subunit is used to determine the lift correction amount and the drag correction amount according to the current speed of the transport aircraft, and then determine the takeoff aerodynamic drag D and takeoff aerodynamic lift L of the aircraft.

[0192] 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 determining the length of a transport aircraft takeoff field.

[0193] In a fourth aspect of the present application, a readable storage medium stores a computer program, and when the computer program is executed by a processor, it is used to implement the method for determining the length of the transport aircraft takeoff field as described above. The computer-readable storage medium may be included in the device described in the above embodiment; or it may exist independently without being assembled into the device. The computer-readable storage medium carries one or more programs, and when the one or more programs are executed by the device, the data is processed according to the above method.

[0194] Reference below Figure 2 , which shows a schematic 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 bring any limitation to the functions and scope of use of the embodiments of the present application.

[0195] 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 part 408 into a random access memory (RAM) 403. In the RAM 403, various programs and data required for the operation of the device 400 are also stored. The CPU 401, the ROM 402, and the RAM 403 are connected to each other via a bus 404. An input / output (I / O) interface 405 is also connected to the bus 404.

[0196] The following components are connected to the I / O interface 405: an input section 406 including a keyboard, a mouse, etc.; an output section 407 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, 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, a modem, etc. 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. A removable medium 411, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 410 as needed, so that a computer program read therefrom is installed into the storage section 408 as needed.

[0197] 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 device 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 with one or more conductors, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, an apparatus or a device. In the present application, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable program code. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium, which may send, propagate, or transmit a program for use by or in combination with an instruction execution system, an apparatus or a device. The program code contained on the computer-readable medium may be transmitted using any appropriate medium, including but not limited to: wireless, wire, optical cable, RF, etc., or any suitable combination of the above.

[0198] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some implementations as replacements, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square 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 square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0199] The modules or units involved in the embodiments described in this application may be implemented by software or hardware. The modules or units described may also be set in a processor, and the names of these modules or units do not constitute limitations on the modules or units themselves in some cases.

[0200] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for determining the take-off field length of a transport aircraft, applied to a powered lift transport aircraft with lower surface blown flaps, characterized in that: The method includes: Step S1: Determine the takeoff thrust P of the transport aircraft xzon ; Step S2: According to the takeoff thrust P xzon Determine the acceleration a of the transport aircraft and the flight path angle θ of the constant speed climb; Step S3: Calculate the take-off field length L of the transport aircraft according to the following integral formula: Among them, L R L is the ground rolling distance before lifting the front wheel for takeoff. L-R L is the rolling distance between the front wheel lift and the departure point, C is the flight distance to climb to a safe altitude, V is the speed, V S is the stall speed in takeoff configuration, V R is the front wheel speed, V lof is the ground speed.

2. The method for determining the length of a transport aircraft takeoff field according to claim 1, characterized in that: In step S1, the takeoff thrust P is determined by the following formula: xzon : Among them, n e is the number of engines, P emax is the maximum takeoff thrust of the engine, K s is the takeoff system power extraction factor, K v is the speed correction factor for takeoff thrust, K h is the altitude correction factor for takeoff thrust, P xz is the available thrust for takeoff corrected for power and speed, η j is the engine jet efficiency factor, θ j is the downward deflection angle of the jet disturbed by the flap relative to the fuselage axis, and α is the fuselage angle of attack.

3. The method for determining the length of a transport aircraft takeoff field according to claim 1, characterized in that: Step S2 further comprises: Step S21: Determine the takeoff lift coefficient C in the increased lift state L ; Step S22: Determine the takeoff drag coefficient C in the increased lift state D ; Step S23, determine the acceleration a of the conveyor by the following formula: Where W is the takeoff weight of the aircraft, D is the takeoff aerodynamic drag, L is the takeoff aerodynamic lift, F is the friction force of the taxiing, f is the rolling friction coefficient of the taxiing, and Z p is the component of thrust in the lift direction, S ref is the reference area of ​​the wing, ρ is the air density, and q is the velocity pressure; Step S24: determine the track angle θ of the constant speed climb by the following formula:

4. The method for determining the length of a transport aircraft takeoff field according to claim 3, characterized in that: Step S21 further includes: Step S211: Determine the lift coefficient correction value ΔC of the jet flap flow Lb ; Step S212: Determine the lift coefficient correction value ΔC of the jet vector effect Lp ; Step S213: Determine the takeoff lift coefficient C in the increased lift state by the following formula: L : C L =C Loff +ΔC Lb +ΔC Lp ; Among them, C Loff It is the takeoff lift coefficient in the non-powered lift state.

5. The method for determining the length of a transport aircraft takeoff field according to claim 4, characterized in that: In step S211, the lift coefficient correction value ΔC of the jet flap flow is determined by the following formula: Lb : ΔC Lb =ΔC Lθ +ΔC Lα ; Where, ΔC Lθ is the reference value of the dynamic effect correction of the lift coefficient; ΔC Lα is the correction amount of the lift coefficient increment corresponding to the angle of attack α.

6. The method for determining the length of a transport aircraft takeoff field according to claim 4, characterized in that: In step S212, the lift coefficient correction value ΔC of the jet vector effect is determined by the following formula: Lp : Among them, C T is the aircraft takeoff thrust coefficient.

7. The method for determining the length of a transport aircraft takeoff field according to claim 3, characterized in that: In step S22, the takeoff drag coefficient C in the increased lift state is determined by the following formula: D : C D =C Doff +ΔC D ; Among them, C Doff is the drag coefficient in the non-powered lift state, ΔC D is the dynamic effect correction of the drag coefficient.

8. The method for determining the length of a transport aircraft takeoff field according to claim 3, characterized in that: In step S23, when the takeoff thrust coefficient of the aircraft exceeds 5.6, the takeoff aerodynamic drag D and the takeoff aerodynamic lift L of the aircraft are determined by the following steps: Step S231, determining the lift correction amount and the drag correction amount at multiple speed points with a thrust coefficient between 0.26 and 5.6, and fitting the quadratic function of the lift correction amount and the speed, and the quadratic function of the drag correction amount and the speed respectively; Step S232: determine the lift correction amount and the drag correction amount according to the current speed of the transport aircraft, and then determine the takeoff aerodynamic drag D and the takeoff aerodynamic lift L of the aircraft.

9. A transport aircraft takeoff field length determination device, applied to a lower surface blown flap powered lift transport aircraft, characterized in that: The device includes: Takeoff thrust determination module, used to determine the takeoff thrust P of the transport aircraft xzon ; The acceleration and track angle determination module is used to determine the takeoff thrust P xzon Determine the acceleration a of the transport aircraft and the flight path angle θ of the constant speed climb; The take-off field length determination module is used to calculate the take-off field length L of the transport aircraft according to the following integral formula: Among them, L R L is the ground rolling distance before lifting the front wheel for takeoff. L-R L is the rolling distance between the front wheel lift and the departure point, C is the flight distance to climb to a safe altitude, V is the speed, V S is the stall speed in takeoff configuration, V R is the front wheel speed, V lof is the ground speed.

10. The device for determining the length of a transport aircraft takeoff field according to claim 9, characterized in that: In the takeoff thrust determination module, the takeoff thrust P is determined by the following formula: xzon : Among them, n e is the number of engines, P emax is the maximum takeoff thrust of the engine, K s is the takeoff system power extraction factor, K v is the speed correction factor for takeoff thrust, K h is the altitude correction factor for takeoff thrust, P xz is the available thrust for takeoff corrected for power and speed, η j is the engine jet efficiency factor, θ j is the downward deflection angle of the jet disturbed by the flap relative to the fuselage axis, and α is the fuselage angle of attack.

11. The device for determining the length of a transport aircraft takeoff field according to claim 9, characterized in that: The acceleration and track angle determination module includes: The take-off lift coefficient determination unit is used to determine the take-off lift coefficient C in the increased lift state. L ; Takeoff drag coefficient determination unit, used to determine the takeoff drag coefficient C in the increased lift state D ; The acceleration determination unit is used to determine the acceleration a of the conveyor by the following formula: Where W is the takeoff weight of the aircraft, D is the takeoff aerodynamic drag, L is the takeoff aerodynamic lift, F is the friction force of the taxiing, f is the rolling friction coefficient of the taxiing, and Z p is the component of thrust in the lift direction, S ref is the wing reference area, ρ is the air density, q is the velocity pressure; The track angle determination unit is used to determine the track angle θ of the constant speed climb by the following formula:

12. The device for determining the length of a transport aircraft takeoff field according to claim 11, characterized in that: The take-off lift coefficient determination unit comprises: The first lift coefficient correction determination subunit is used to determine the lift coefficient correction ΔC of the jet flap flow. Lb ; The second lift coefficient correction determination subunit is used to determine the lift coefficient correction ΔC of the jet vector effect. Lp ; The takeoff lift coefficient calculation subunit is used to determine the takeoff lift coefficient C in the increased lift state by the following formula L : C L =C Loff +ΔC Lb +ΔC Lp ; Among them, C Loff It is the takeoff lift coefficient in the non-powered lift state.

13. The device for determining the length of a transport aircraft takeoff field according to claim 12, characterized in that: In the first lift coefficient correction determination subunit, the lift coefficient correction ΔC of the jet flap flow is determined by the following formula: Lb : ΔC Lb =ΔC Lθ +ΔC Lα ; Where, ΔC Lθ is the reference value of the dynamic effect correction of the lift coefficient; ΔC Lα is the correction amount of the lift coefficient increment corresponding to the angle of attack α.

14. The device for determining the length of a transport aircraft takeoff field according to claim 12, characterized in that: In the second lift coefficient correction amount determination subunit, the lift coefficient correction amount ΔC of the jet vector effect is determined by the following formula: Lp : Among them, C T is the aircraft takeoff thrust coefficient.

15. The device for determining the length of a transport aircraft takeoff field according to claim 11, characterized in that: In the takeoff drag coefficient determination unit, the takeoff drag coefficient C in the increased lift state is determined by the following formula: D : C D =C Doff +ΔC D ; Among them, C Doff is the drag coefficient in the non-powered lift state, ΔC D is the dynamic effect correction of the drag coefficient.

16. The device for determining the length of a transport aircraft takeoff field according to claim 11, characterized in that: In the acceleration determination unit, when the takeoff thrust coefficient of the aircraft exceeds 5.6, the takeoff aerodynamic drag D and the takeoff aerodynamic lift L of the aircraft are reconstructed through the following modules: The quadratic function construction subunit is used to determine the lift correction and drag correction at multiple speed points with thrust coefficients between 0.26 and 5.6, and to fit the quadratic function of lift correction and speed, and the quadratic function of drag correction and speed respectively; The lift-drag reconstruction subunit is used to determine the lift correction amount and the drag correction amount according to the current speed of the transport aircraft, and then determine the takeoff aerodynamic drag D and takeoff aerodynamic lift L of the aircraft.

17. 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 determining the length of the take-off field of a transport aircraft according to any one of claims 1 to 8.

18. 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 determining the length of the transport aircraft takeoff field as described in any one of claims 1-8.

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