High-fuel-efficiency double-fuselage layout passenger plane and design method

Abstract

The invention provides a high-fuel-efficiency double-fuselage layout passenger plane and a design method. The high-fuel-efficiency double-fuselage layout passenger plane comprises fuselages, wings, empennages and a power device. The machine body comprises a first machine body and a second machine body which are arranged in parallel in bilateral symmetry; the wings are fixedly arranged above the middle parts of the first fuselage and the second fuselage, and the empennage is fixedly arranged above the tail parts of the first fuselage and the second fuselage; the power devices are symmetrically arranged at the front edges of the left side and the right side of the wing in a wing-hung double-sheet bureau mode. The high-fuel-efficiency double-fuselage layout passenger plane and the design method have the characteristics of energy conservation and emission reduction, the design method and the internal layout design method of the corresponding double-fuselage layout passenger plane are provided, and energy conservation and environmental protection are achieved by minimizing the weight of the fuselage structure and fully utilizing the internal space of the fuselage. And the method has the potential of bringing more operating profits to airlines.

Description

Technical Field

[0001] The present invention belongs to the technical field of aircraft design, and in particular relates to a high fuel efficiency twin-fuselage layout passenger aircraft and a design method thereof. Background Art

[0002] The next generation of air transport requires increasing air traffic flow while improving its environmental friendliness, which requires a step-by-step improvement in aircraft performance. To this end, the development and technology upgrade of ultra-high aspect ratio wing layouts is a key enabling strategy. However, compared with traditional aircraft, ultra-high aspect ratio wing structures bear higher loads, which poses challenges to aircraft layout design and related technologies. At present, the twin-fuselage concept description has become one of the most promising layouts for ultra-high aspect ratio wings. For future energy-efficient aircraft technology, existing patent technologies such as the Chinese invention patent "A laminar flow technology verification aircraft" with application number 201911322028.6 and patent technologies such as the Chinese invention patent "A twin-fuselage aircraft" with application number 201811256599.X have designed aircraft with twin-fuselage layouts, but these inventions are all small drones and cannot be used for passenger aircraft. Summary of the invention

[0003] In view of the defects of the prior art, the present invention provides a high fuel efficiency twin-fuselage layout passenger aircraft and a design method, which can effectively solve the above problems.

[0004] The technical solution adopted by the present invention is as follows:

[0005] The present invention provides a high fuel efficiency twin-fuselage passenger aircraft, comprising a fuselage (100), wings (200), a tail wing (300) and a power device (400);

[0006] The fuselage (100) comprises a first fuselage (101) and a second fuselage (102) which are arranged parallel to each other and symmetrically. The wing (200) is fixedly arranged above the middle of the first fuselage (101) and the second fuselage (102). The wing (200) adopts an upper single-wing layout with a symmetrical structure. The middle of the first fuselage (101) and the second fuselage (102) are connected as a whole through the wing (200). The tail wing (300) is fixedly arranged above the tail of the first fuselage (101) and the second fuselage (102). The tail wing (300) adopts an N-shaped layout with a symmetrical structure. The tail of the first fuselage (101) and the second fuselage (102) are connected as a whole through the tail wing (300). The power unit (400) adopts a wing-mounted double-engine layout and is symmetrically arranged at the leading edge positions on the left and right sides of the wing (200).

[0007] Preferably, the first fuselage (101) and the second fuselage (102) have the same shape, and both include a fuselage middle section (A1), a fuselage head section (A2) and a fuselage tail section (A3);

[0008] The fuselage middle section (A1) is cylindrical, and the front end of the fuselage middle section (A1) gradually shrinks forward along the fuselage axis to form the conical fuselage head (A2); the lower surface of the tail end of the fuselage middle section (A1) gradually shrinks upward along the fuselage axis to form the fuselage tail (A3) with a duckbill flat shape, the top surface of which is horizontal and the bottom surface of which is inclined and upturned;

[0009] Wherein: the axial length of the middle section (A1) of the fuselage is longer than the axial length of the tail section (A3) of the fuselage; and the axial length of the tail section (A3) of the fuselage is longer than the axial length of the head section (A2) of the fuselage.

[0010] Preferably, the wing (200) comprises a middle wing (201), a left wing (202) and a right wing (203);

[0011] The left and right sides of the middle wing (201) are respectively fixedly connected to the top center line of the first fuselage (101) and the top center line of the second fuselage (102);

[0012] The left side of the middle wing (201) extends toward the outer side of the first fuselage (101) to form the left wing (202); and the right side of the middle wing (201) extends toward the outer side of the second fuselage (102) to form the right wing (203).

[0013] Preferably, the middle wing (201) is in a horizontally arranged rectangular shape;

[0014] The left wing (202) and the right wing (203) are symmetrical, and the left wing (202) and the right wing (203) are arranged to be inclined upward relative to the middle wing (201); the width of the left wing (202) and the right wing (203) gradually decreases from the wing root to the wing tip, and they are trapezoidal wings.

[0015] Preferably, a left flap (2021) and a left aileron (2022) are provided at the trailing edge of the left wing (202); the left aileron (2022) is located outside the left flap (2021);

[0016] The trailing edge of the right wing (203) is provided with a right flap (2031) and a right aileron (2032); the right aileron (2032) is located outside the right flap (2031).

[0017] Preferably, the power plant (400) comprises a first engine nacelle (401), a first engine pylon (402), a second engine nacelle (403) and a second engine pylon (404);

[0018] The first engine nacelle (401) is suspended below the left wing (202) via the first engine pylon (402);

[0019] The second engine nacelle (403) is suspended below the right wing (203) via the second engine pylon (404).

[0020] Preferably, the tail wing (300) includes a first vertical tail wing (301), a second vertical tail wing (302), a first horizontal tail wing (303) and a second horizontal tail wing (304);

[0021] The first vertical tail wing (301) is fixedly mounted above the tail centerline of the first fuselage (101); the second vertical tail wing (302) is fixedly mounted above the tail centerline of the second fuselage (102); the second vertical tail wing (302) and the first vertical tail wing (301) are bilaterally symmetrical;

[0022] The first horizontal tail wing (303) and the second horizontal tail wing (304) are symmetrical on both sides and are arranged in sequence along the direction from the first vertical tail wing (301) to the second vertical tail wing (302); one side of the first horizontal tail wing (303) is fixed to the inner side of the top of the first vertical tail wing (301); the other side of the first horizontal tail wing (303) is fixed to one side of the second horizontal tail wing (304); and the other side of the second horizontal tail wing (304) is fixed to the inner side of the top of the second vertical tail wing (302).

[0023] Preferably, a first rudder (305) is disposed at the trailing edge of the first vertical tail wing (301); and a second rudder (306) is disposed at the trailing edge of the second vertical tail wing (302);

[0024] A first elevator (307) is arranged at the trailing edge of the first horizontal tail (303); and a second elevator (308) is arranged at the trailing edge of the second horizontal tail (304).

[0025] Preferably, inside the first fuselage (101), a cockpit (1011), a first first-class cabin (1012) and a first economy cabin (1013) are arranged in sequence from front to back;

[0026] Inside the second fuselage (102), a super first-class cabin (1021), a second first-class cabin (1022) and a second economy cabin (1023) are arranged in sequence from front to back.

[0027] The present invention also provides a design method for a high fuel efficiency twin-fuselage passenger aircraft, comprising the following steps:

[0028] Step S1, according to the design requirements, determine the aircraft design parameter set, and determine the design space of each design parameter in the design parameter set; predetermine the maximum take-off weight target value m of the aircraft To_target ;

[0029] Step S2, sampling in the design space of each design parameter to obtain initial sampling values ​​of all design parameters;

[0030] Step S3, using formula (1), estimate the fuselage weight m of the fuselage (100) f :

[0031] m f =1.35·(L f ·D f ) 1.28 ·(1+0.05·N e )·(1+0.38·F c )·N f (1)

[0032] in:

[0033] L f is the length of the fuselage (100), specifically the sum of the lengths of the first fuselage (101) and the second fuselage (102); D f is the average diameter of the fuselage (100); N e The number of engines installed for the fuselage (100); F c is the aircraft floor coefficient; N f 2, indicating that it has two fuselages;

[0034] Step S4, using formula (2), the wing weight m of the wing (200) is estimated wingbox :

[0035]

[0036] Where: C is a constant; W / S is the wing loading; AR is the aspect ratio; Λ is the sweep angle of the quarter chord line of the wing; t / c is the relative thickness of the average wing airfoil; V m is the maximum operating speed; λ is the taper ratio of the wing; n z is the maximum positive load factor; Z f is the relative position of the fuselage relative to the wingspan; Z e is the relative position of the engine relative to the wingspan; E m 、E ws、E AR 、E Λ 、E t 、E V 、E λ 、E nz 、E zf and E ze , are the exponential terms of the corresponding terms respectively;

[0037] Step S5: Use formula (3) to estimate the horizontal tail weight m ht , specifically the sum of the weights of the first horizontal tail wing (303) and the second horizontal tail wing (304):

[0038] m ht =0.53·A ht ·DG 0.2 ·(λ ht +0.5) (3)

[0039] Where: S ht is the area of ​​a single horizontal tail; DG is the total design weight of the entire aircraft; λ ht is the aspect ratio of the horizontal tail;

[0040] Step S6: Use formula (4) to estimate the vertical tail weight m vt , specifically the sum of the weights of the second vertical tail wing (302) and the first vertical tail wing (301):

[0041]

[0042] Where: S vt is the area of ​​a single vertical tail; λ vt is the aspect ratio of the vertical tail; N vt is the number of vertical tail fins;

[0043] Step S7: Use formula (5) to estimate the weight m of the landing gear. LG :

[0044] m LG =N MLG ×0.0117×W LDG 0.95 ×X MLG 0.43 +N NLG ×0.048×W LDG 0.6 7×X NLG 0.43 (5)

[0045] Where: N MLG The number of main landing gears; W LDG Design landing weight for the aircraft; XMLG The length of the main landing gear strut; N NLG is the number of front landing gear; X NLG is the length of the front landing gear strut;

[0046] Step S8: Use formula (6) to estimate the weight of the propulsion system mps I :

[0047]

[0048] Where: N ENG is the number of engines; W ENGB is the reference engine weight; TR UST is the rated thrust of the engine; T RSO is the rated thrust of the reference engine; E EXP is the engine weight scaling parameter; the benchmark engine is the engine selected as the reference standard among various engines;

[0049] Step S9: Use formula (7) to estimate the empty mass m e :

[0050] m e =m f +m wingbox +m ht +m vt +m LG +m pSI (7)

[0051] Step S10, using formula (8), the maximum take-off weight of the aircraft is estimated to be m TO :

[0052] m TO =m crew +m pay +m fuel +m e (8)

[0053] Where: m crew is the crew mass; m pay为 Payload mass; m fuel is the fuel quality;

[0054] Step S11, the maximum take-off weight of the aircraft estimated in step S10 (mm) TO and the maximum take-off weight target value of the aircraft mm TO_target The sampling direction is determined by the deviation, and the sampling direction is determined, thereby returning to step S2, resampling in the design space of each design parameter, obtaining the sampling values ​​of all design parameters, and then repeating steps S3 to S11; if the iteration cycle is continuously performed until the maximum take-off weight m of the aircraft estimated in step S10 isTO and the maximum takeoff weight target value of the aircraft m TO_target The deviation meets the design accuracy requirement, and step S12 is executed;

[0055] Step S12: Output the sampled values ​​of all design parameters and the maximum take-off weight of the aircraft m TO ; Based on the sampling values ​​of all design parameters, a high fuel efficiency twin-fuselage layout passenger aircraft is designed.

[0056] The invention provides a high fuel efficiency twin-fuselage layout passenger aircraft and a design method thereof, which has the following advantages:

[0057] The present invention proposes a high fuel efficiency twin-fuselage layout passenger aircraft and a design method, which has the characteristics of energy saving and emission reduction, and proposes a corresponding twin-fuselage layout passenger aircraft design method and internal layout design method, which achieves energy saving and environmental protection by minimizing the fuselage structure weight and making full use of the fuselage internal space, and has the potential to bring more operating profits to airlines. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 A three-dimensional diagram of a fuel-efficient twin-fuselage passenger aircraft provided by the present invention;

[0059] Figure 2 A schematic diagram of the interior cabin of a fuel-efficient twin-fuselage passenger aircraft provided by the present invention.

[0060] in:

[0061] 100-fuselage; 101-first fuselage; 102-second fuselage; A1-middle fuselage section; A2-head fuselage; A3-tail fuselage; 1011-cockpit; 1012-first first class cabin; 1013-first economy cabin; 1021-super first class cabin; 1022-second first class cabin; 1023-second economy cabin;

[0062] 200-wing; 201-middle wing; 202-left wing; 2021-left flap; 2022-left aileron; 203-right wing; 2031-right flap; 2032-right aileron;

[0063] 300-tail; 301-first vertical tail; 302-second vertical tail; 303-first horizontal tail; 304-second horizontal tail; 305-first rudder; 306-second rudder; 307-first elevator; 308-second elevator;

[0064] 400-power unit; 401-first engine nacelle; 402-first engine mount; 403-second engine nacelle; 404-second engine mount. DETAILED DESCRIPTION

[0065] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0066] The present invention proposes a high fuel efficiency twin-fuselage layout passenger aircraft and a design method. Twin-fuselage layout passenger aircraft has significant advantages in energy efficiency compared to traditional passenger aircraft. Twin-fuselage layout can reduce the shear force of wing structure and the bending moment of wing root, allowing further increase of wing aspect ratio, improving aerodynamic efficiency and fuel efficiency of aircraft, and reducing emissions; adopting high horizontal tail layout can increase the control arm of tail, thereby reducing the required tail area, reducing the structural weight of horizontal tail, and also effectively reducing the adverse effect of wing downwash on horizontal tail. In addition, due to the end plate effect of high horizontal tail, the aerodynamic efficiency of vertical tail is increased, and the vertical tail area of ​​this layout can also be reduced; the most significant feature of the twin-fuselage concept is the unique fuselage layout. At present, no fuselage design method for twin-fuselage aircraft has been publicly published, and the present invention fills the gap; wherein, the nose of one fuselage is designed as a cockpit, and the nose of the other fuselage is arranged with two super first-class seats to provide the best view. This layout can make full use of the fuselage space and bring more operating profits to airlines.

[0067] See also Figure 1 , the present invention provides a high fuel efficiency twin-fuselage layout passenger aircraft, comprising a fuselage 100, a wing 200, a tail 300 and a power unit 400;

[0068] The fuselage 100 includes a first fuselage 101 and a second fuselage 102 which are arranged parallel to each other and symmetrically. A wing 200 is fixedly arranged above the middle of the first fuselage 101 and the second fuselage 102. The wing 200 adopts an upper monoplane layout with a symmetrical structure. The middle of the first fuselage 101 and the second fuselage 102 are connected as a whole through the wing 200. A tail 300 is fixedly arranged above the tail of the first fuselage 101 and the second fuselage 102. The tail 300 adopts an N-shaped layout with a symmetrical structure. The tail of the first fuselage 101 and the second fuselage 102 is connected as a whole through the tail 300. The power unit 400 adopts a wing-mounted double-engine layout and is symmetrically arranged at the leading edge positions on the left and right sides of the wing 200.

[0069] The fuselage 100, the wing 200, the tail 300 and the power unit 400 are described in detail below:

[0070] (I) Body 100

[0071] In the present invention, the first fuselage 101 and the second fuselage 102 have the same shape, the first fuselage 101 is the left fuselage, and the second fuselage 102 is the right fuselage, both of which include a fuselage middle section A1, a fuselage head section A2, and a fuselage tail section A3;

[0072] The middle section A1 of the fuselage is cylindrical, and the front end of the middle section A1 gradually shrinks forward along the axial direction of the fuselage to form a conical fuselage head A2; the lower surface of the tail end of the middle section A1 gradually shrinks upward along the axial direction of the fuselage to form a duckbill flat fuselage tail A3 with a horizontal top surface and an inclined and upward bottom surface;

[0073] Among them: the axial length of the middle section A1 of the fuselage is longer than the axial length of the tail section A3 of the fuselage; the axial length of the tail section A3 of the fuselage is longer than the axial length of the head section A2 of the fuselage.

[0074] The distance between the first fuselage 101 and the second fuselage 102 can be designed according to the requirements of the International Civil Aviation Organization (ICAO). For example, the ICAO code C airport requires that the wheel spacing of the main landing gear of the aircraft does not exceed 9 meters. In the present invention, a main landing gear is installed directly under each fuselage, so the wheel spacing constraint of the main landing gear is equal to the distance constraint between the two fuselages of the twin-fuselage aircraft, that is, the distance between the two fuselages does not exceed 9 meters.

[0075] Furthermore, inside the first fuselage 101, a cockpit 1011, a first first-class cabin 1012 and a first economy cabin 1013 are arranged in sequence from front to back; inside the second fuselage 102, a super first-class cabin 1021, a second first-class cabin 1022 and a second economy cabin 1023 are arranged in sequence from front to back.

[0076] Therefore, a double-cabin interior layout is adopted for twin-fuselage aircraft, with the nose of the left fuselage designed as the cockpit 1011, and the nose of the other fuselage arranged with two super first-class seats 1021 to obtain the best view and make full use of the fuselage space. This design can provide more choices for passengers and bring more operating profits to airlines.

[0077] Furthermore, for the twin-fuselage passenger aircraft provided by the present invention, the fuselage geometric dimension design method for the twin-fuselage passenger aircraft is adopted. In order to ensure that the passenger capacity is the same as that of the single-fuselage passenger aircraft used as a reference, it is necessary to ensure that the total floor area in the cabin is the same. When the twin-fuselage passenger aircraft is designed by the present invention, the fuselage cabin length l and the fuselage cabin equivalent diameter d of each fuselage are the same as those of the single-fuselage passenger aircraft. This ensures that the total floor area remains l*d, while ensuring that the total external surface area of ​​the twin-fuselage aircraft is the same as that of the single-fuselage aircraft, meeting the passenger luggage carrying space and weight requirements of passenger aircraft design standards and requirements.

[0078] (ii) Wing 200

[0079] In the present invention, the wing 200 adopts an upper wing layout with a symmetrical structure, and the wing 200 includes a middle wing 201, a left wing 202 and a right wing 203; the left and right sides of the middle wing 201 are respectively fixedly connected to the top center line of the first fuselage 101 and the top center line of the second fuselage 102; the left side of the middle wing 201 extends to the outside of the first fuselage 101 to form the left wing 202; the right side of the middle wing 201 extends to the outside of the second fuselage 102 to form the right wing 203.

[0080] The middle wing 201 is in a horizontally arranged rectangular shape; the left wing 202 and the right wing 203 are symmetrical, and the left wing 202 and the right wing 203 are arranged to be inclined upward relative to the middle wing 201; the width of the left wing 202 and the right wing 203 gradually decreases from the wing root to the wing tip, and they are trapezoidal wings.

[0081] Furthermore, a left flap 2021 and a left aileron 2022 are provided at the trailing edge of the left wing 202; the left aileron 2022 is located outside the left flap 2021; a right flap 2031 and a right aileron 2032 are provided at the trailing edge of the right wing 203; the right aileron 2032 is located outside the right flap 2031.

[0082] (III) Tail 300

[0083] In the present invention, the tail 300 is arranged above the rear of the double fuselage, including double vertical tails and a high-mounted forward-swept horizontal tail. The high-mounted forward-swept horizontal tail is embedded between the double vertical tails. The combined front view of the tail 300 presents an N shape.

[0084] Specifically, the tail 300 includes a first vertical tail 301, a second vertical tail 302, a first horizontal tail 303 and a second horizontal tail 304;

[0085] A first vertical tail 301 is fixedly installed above the tail centerline of the first fuselage 101; a second vertical tail 302 is fixedly installed above the tail centerline of the second fuselage 102; the second vertical tail 302 is symmetrical to the first vertical tail 301;

[0086] The first horizontal tail 303 and the second horizontal tail 304 are symmetrical and are arranged in sequence from the first vertical tail 301 to the second vertical tail 302; one side of the first horizontal tail 303 is fixed to the top inner side of the first vertical tail 301; the other side of the first horizontal tail 303 is fixed to one side of the second horizontal tail 304; the other side of the second horizontal tail 304 is fixed to the top inner side of the second vertical tail 302.

[0087] Furthermore, a first rudder 305 is disposed at the trailing edge of the first vertical tail 301 ; a second rudder 306 is disposed at the trailing edge of the second vertical tail 302 ; a first elevator 307 is disposed at the trailing edge of the first horizontal tail 303 ; and a second elevator 308 is disposed at the trailing edge of the second horizontal tail 304 .

[0088] (IV) Power plant 400

[0089] In the present invention, the power unit 400 is a wing-mounted twin-engine type, including a first engine nacelle 401, a first engine pylon 402, a second engine nacelle 403 and a second engine pylon 404; the first engine nacelle 401 is suspended below the left wing 202 through the first engine pylon 402; the second engine nacelle 403 is suspended below the right wing 203 through the second engine pylon 404.

[0090] The present invention proposes a high fuel efficiency twin-fuselage passenger aircraft, which has the following characteristics:

[0091] (1) Compared with conventional passenger aircraft, the wing 200 of the present invention significantly increases the aspect ratio, effectively reduces the induced drag, and can improve the aerodynamic efficiency and fuel efficiency of the passenger aircraft, reduce emissions, and increase the revenue of the airline.

[0092] (2) Increasing the aspect ratio of the wing will increase the bending moment and shear force of the wing structure, which increases the design requirements for the strength and stiffness of the wing structure. The present invention adopts a twin-fuselage layout, and reduces the maximum bending moment of the wing by replacing the traditional large fuselage located in the center with two first fuselages 101 and second fuselages 102 located outside the wing, making the wing structure lighter.

[0093] (3) At the same time, the present invention adopts a fuselage geometric dimension design method for a twin-fuselage passenger aircraft. In order to ensure that the passenger capacity is the same as that of a single-fuselage passenger aircraft used as a reference, it is necessary to ensure that the total floor area in the cabin is the same. The present invention designs a twin-fuselage passenger aircraft, and the fuselage cabin length l and the fuselage cabin equivalent diameter d of each fuselage are both the same as those of a single-fuselage passenger aircraft. This ensures that the total floor area remains l*d, while ensuring that the total external surface area of ​​the twin-fuselage aircraft is the same as that of the single-fuselage aircraft, meeting the passenger luggage carrying space and weight requirements of passenger aircraft design standards and requirements.

[0094] (4) The thickness of the aircraft fuselage structure is related to the fuselage diameter. The design of the present invention reduces the diameter of the two fuselages in the twin-fuselage layout compared to the conventional layout, resulting in a reduction in the thickness of each fuselage structure. The present invention ensures that the total external surface area of ​​the fuselage of the twin-fuselage aircraft is the same as that of the single-fuselage aircraft, thereby reducing the total weight of the aircraft and increasing the payload weight.

[0095] (5) The twin-fuselage layout eliminates the need for an external fairing for the main landing gear. The length and structure of the main landing gear struts can be shortened and simplified, which helps reduce the weight of the landing gear and its fairing and reduces drag.

[0096] (6) The distance between the two fuselages of the present invention is designed according to the requirements of the International Civil Aviation Organization (ICAO). For example, the ICAO code C airport requires that the wheelbase of the aircraft main landing gear does not exceed 9 meters. The present invention installs a main landing gear directly under each fuselage, so the wheelbase constraint of the main landing gear is equal to the distance constraint between the two fuselages of the twin-fuselage aircraft, that is, the distance between the two fuselages does not exceed 9 meters, which meets the design standards of passenger aircraft.

[0097] (7) The landing gear design of a twin-fuselage aircraft is different from that of a conventional aircraft. A twin-fuselage aircraft has a front landing gear and a main landing gear at the centerline of each fuselage. However, the twin-fuselage layout design makes the landing gear design simpler and lighter than that of a conventional aircraft even though the aircraft has an additional front landing gear. For very large cargo aircraft, this weight reduction can even reach 30%.

[0098] (8) The present invention adopts a high-mounted forward-swept horizontal tail, thereby reducing the area and structural weight of the horizontal tail by increasing the tail force arm, and preventing the stability and control effect of the horizontal tail from being affected by the downwash of the wing. The horizontal tail of the present invention is embedded between the double vertical tails, and uses the end plate effect to reduce the induced drag, thereby reducing the tail area and reducing the weight of the aircraft. The horizontal tail has a higher aspect ratio and a higher lift coefficient, thereby reducing the volume ratio of the aircraft's horizontal tail and making the horizontal tail lighter.

[0099] (9) The present invention adopts a double-cabin interior layout for a twin-fuselage aircraft, where the nose of one fuselage is designed as a cockpit, while the nose of the other fuselage is arranged with two super first-class seats to provide the best view and make full use of the fuselage space, thereby bringing more profits to the airline company.

[0100] The present invention also provides a design method for a high fuel efficiency twin-fuselage layout passenger aircraft, comprising the following steps:

[0101] Step S1, according to the design requirements, determine the aircraft design parameter set, and determine the design space of each design parameter in the design parameter set; predetermine the maximum take-off weight target value m of the aircraft TO_target ;

[0102] Step S2, sampling in the design space of each design parameter to obtain initial sampling values ​​of all design parameters;

[0103] Step S3, using formula (1), the weight m of the fuselage 100 is estimated f :

[0104] m f =1.35·(L f ·D f ) 1.28 ·(1+0.05·N e )·(1+0.38·F c )·N f (1)

[0105] in:

[0106] L f D is the length of the fuselage 100, specifically the sum of the lengths of the first fuselage 101 and the second fuselage 102; f is the average diameter of the fuselage 100; N e Number of engines installed for fuselage 100;

[0107] F c is the aircraft floor coefficient; N f 2, indicating that it has two fuselages;

[0108] Step S4, using formula (2), the wing weight m of the wing 200 is estimated wingbox :

[0109]

[0110] Where: C is a constant; W / S is the wing loading; AR is the aspect ratio; Λ is the sweep angle of the quarter chord line of the wing; t / c is the relative thickness of the average wing airfoil; V m is the maximum operating speed; λ is the taper ratio of the wing; n z is the maximum positive load factor; Z f is the relative position of the fuselage relative to the wingspan; Z e is the relative position of the engine relative to the wingspan; E m 、E ws 、E AR 、E Λ 、E t 、E V 、E λ 、E nz 、E zf and Ez e, respectively, are the exponential terms of the corresponding terms;

[0111] Specifically, the empty mass m of a twin-fuselage aircraft and a conventional aircraft is eThe most significant difference in the calculations is in the wing weight estimation, which is caused by the different load distribution of the wing. This means that the wing mass estimation method for traditional aircraft cannot be directly applied to twin-fuselage aircraft, so it is necessary to estimate the structural mass of the wing by combining the wing span-wise mass distribution (including wing structural mass, fuel mass and concentrated mass (such as engine)) with the aerodynamic load. However, the linear approximation method of lift distribution in the wing structure is not accurate enough for the physics-based wing mass estimation method. In addition, since this traditional method was published decades ago, it is not applicable to advanced composite structures.

[0112] Therefore, the present invention adopts the Vortex Lattice Method (VLM) tool AVL to estimate the aerodynamic load distribution in the wing span direction according to the input wing geometric parameters, and the reduced shear force caused by the aerodynamic load can be obtained by integrating the aerodynamic load distribution in the wing span direction along the wing span. Then, the reduced bending moment is obtained by integrating along the wing span. In addition, considering that composite materials will become the main material of the next generation of aircraft, the wing mass estimation method is further improved, and the cutoff strain method is used to determine the size of the composite wing structure in the preliminary design stage.

[0113] The performance of the aircraft with preliminary size design is analyzed and evaluated, and the proposed wing mass estimation method is used. After iterative calculation until convergence, the weight decomposition and mission segmentation are obtained. On this basis, the present invention innovatively proposes a semi-empirical formula of formula (2): medium-range (MR) aircraft made of metal materials, long-range (LR) aircraft made of metal materials, medium-range (MR) aircraft made of composite materials, and long-range (LR) aircraft made of composite materials. For each configuration, typical design parameters are selected, and experimental design (DoE) is performed using an improved physics-based wing mass estimation method. Finally, the estimated wing mass results are used for multivariate linear regression to obtain the semi-empirical formula of formula (2).

[0114] In formula (2), as a preferred method, constants C and E m 、E ws 、E AR 、E Λ 、E t 、E V 、E λ 、E nz 、E zf and E ze The values ​​of are as follows:

[0115]

[0116] Among them: AL refers to aluminum alloy material, CFRP refers to composite material, MR refers to medium range, and LR refers to long range.

[0117] The wing mass estimation method proposed in the present invention is mainly aimed at advanced twin-fuselage aircraft. The present invention improves the semi-analytical wing mass estimation method for twin-fuselage configuration, including improving the accuracy of aerodynamic analysis and extending the application to advanced composite structures. Since the semi-analytical method requires a large number of input parameters, which are difficult to obtain in the preliminary sizing stage, the experimental design (DoE) and regression methods are used to establish semi-empirical wing mass estimation methods for twin-fuselage configurations under different mission and material conditions. Finally, the established semi-empirical mass estimation method is integrated into the conceptual design and analysis process of twin-fuselage aircraft, and the preliminary design and sizing of medium-range twin-fuselage aircraft (MR TF) and long-range twin-fuselage aircraft (LR TF) are carried out respectively. Case studies show that the established twin-fuselage aircraft initial weight estimation method can efficiently analyze the weight distribution of twin-fuselage aircraft within the provided twin-fuselage aircraft sizing and analysis framework.

[0118] Step S5: Use formula (3) to estimate the horizontal tail weight m ht , specifically, the sum of the weights of the first horizontal tail 303 and the second horizontal tail 304:

[0119] m ht =0.53·S ht ·DG 0.2 ·(λ ht +0.5) (3)

[0120] Where: S ht is the area of ​​a single horizontal tail; DG is the total design weight of the entire aircraft; λ ht is the aspect ratio of the horizontal tail;

[0121] Step S6: Use formula (4) to estimate the vertical tail weight m vt , specifically, the sum of the weights of the second vertical tail 302 and the first vertical tail 301:

[0122]

[0123] Where: S vt is the area of ​​a single vertical tail; λ vt is the aspect ratio of the vertical tail; N vt is the number of vertical tail fins;

[0124] Step S7: Use formula (5) to estimate the weight m of the landing gear. LG :

[0125] m LG =N MLG ×0.0117×W LDG 0.95 ×XMLG 0.43 +N NLG ×0.048×W LDG 0.67 ×X NLG 0.43 (5)

[0126] Where: N MLG The number of main landing gears; W LDG Design landing weight for the aircraft; X MLG The length of the main landing gear strut; N NLG is the number of front landing gear; X NLG is the length of the front landing gear strut;

[0127] Step S8: Use formula (6) to estimate the weight m of the propulsion system. PSI :

[0128]

[0129] Where: N ENG is the number of engines; W ENGB is the reference engine weight; TR UST is the rated thrust of the engine; T RSo is the rated thrust of the reference engine; E EXP is the engine weight scaling parameter; the benchmark engine is the engine selected as the reference standard among various engines;

[0130] Step S9: Use formula (7) to estimate the empty mass m e :

[0131] m e =m f +m wingbox +m ht +m vt +m LG +m PSI (7)

[0132] Step S10, using formula (8), the maximum take-off weight of the aircraft is estimated to be m TO :

[0133] m TO =m crew+ m pay +m fuel +m e (8)

[0134] Where: m crew is the crew mass; m pay is the effective load mass; m fuel is the fuel quality;

[0135] Step S11, the maximum take-off weight of the aircraft estimated in step S10 (mm) TO and the maximum takeoff weight target value of the aircraft m TO_target The sampling direction is determined by the deviation, and the sampling direction is determined, thereby returning to step S2, resampling in the design space of each design parameter, obtaining the sampling values ​​of all design parameters, and then repeating steps S3 to S11; if the iteration cycle is continuously performed until the maximum take-off weight m of the aircraft estimated in step S10 is TO and the maximum takeoff weight target value of the aircraft m TO_target The deviation meets the design accuracy requirement, and step S12 is executed;

[0136] Step S12: Output the sampled values ​​of all design parameters and the maximum take-off weight of the aircraft m TO ; Based on the sampling values ​​of all design parameters, a high fuel efficiency twin-fuselage layout passenger aircraft is designed.

[0137] The design method of a high fuel efficiency twin-fuselage passenger aircraft provided by the present invention is applicable to the design of medium-range aircraft and long-range aircraft. An embodiment is described below:

[0138] The medium-range and long-range twin-fuselage transport aircraft are designed based on the A320 and B777, and some new technology assumptions are introduced, including the laminar area of ​​the wing and tail is assumed to be 55% due to the use of hybrid laminar flow control technology, the structural mass is assumed to be reduced by 20% due to the use of advanced composite materials and structures, and the maximum positive load factor is assumed to be +1.5g due to the application of load relief technology. Since the twin-fuselage configuration significantly reduces the bending moment and shear force in the wing structure, this twin-fuselage aircraft adopts an ultra-high aspect ratio wing to improve aerodynamic efficiency and reduce fuel consumption. Therefore, a high wing configuration is adopted to meet the clearance requirements between the engine and the wing tip. Taking into account the aeroelastic characteristics and avoiding downwash of the wing and engine exhaust flow, a high tail configuration is adopted.

[0139] By adopting the method of the present invention, as part of the parameters, the results are as follows:

[0140] When a passenger aircraft is designed as a medium-range aircraft, the maximum take-off weight is 59,000-60,000 kg, the fuel weight is 13,000-14,000 kg, the wing weight is 5,500-6,000 kg, the fuselage weight is 5,000-5,500 kg, the engine weight is 3,500-4,000 kg, and the landing gear weight is 2,000-2,500 kg; when a passenger aircraft is designed as a long-range aircraft, the maximum take-off weight is 242,000-246,000 kg, the fuel weight is 155,000-158,000 kg, the wing weight is 38,000-40,000 kg, the fuselage weight is 20,000-21,000 kg, the engine weight is 16,000-18,000 kg, and the landing gear weight is 5,000-7,000 kg.

[0141] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be considered as the scope of protection of the present invention.

Claims

1. A highly fuel-efficient twin-fuselage passenger aircraft, characterized in that: It comprises a fuselage (100), wings (200), a tail wing (300) and a power device (400); The fuselage (100) comprises a first fuselage (101) and a second fuselage (102) which are arranged parallel to each other and symmetrically. The wing (200) is fixedly arranged above the middle of the first fuselage (101) and the second fuselage (102). The wing (200) adopts an upper single-wing layout with a symmetrical structure. The middle of the first fuselage (101) and the second fuselage (102) are connected as a whole through the wing (200). The tail wing (300) is fixedly arranged above the tail of the first fuselage (101) and the second fuselage (102). The tail wing (300) adopts an N-shaped layout with a symmetrical structure. The tail of the first fuselage (101) and the second fuselage (102) are connected as a whole through the tail wing (300). The power unit (400) adopts a wing-mounted double-engine layout and is symmetrically arranged at the leading edge positions on the left and right sides of the wing (200).

2. A highly fuel-efficient twin-fuselage passenger aircraft according to claim 1, characterized in that: The first fuselage (101) and the second fuselage (102) have the same shape, and both include a fuselage middle section (A1), a fuselage head section (A2) and a fuselage tail section (A3); The fuselage middle section (A1) is cylindrical, and the front end of the fuselage middle section (A1) gradually shrinks forward along the fuselage axis to form the conical fuselage head (A2); the lower surface of the tail end of the fuselage middle section (A1) gradually shrinks upward along the fuselage axis to form the fuselage tail (A3) with a duckbill flat shape, the top surface of which is horizontal and the bottom surface of which is inclined and upturned; Wherein: the axial length of the middle section (A1) of the fuselage is longer than the axial length of the tail section (A3) of the fuselage; and the axial length of the tail section (A3) of the fuselage is longer than the axial length of the head section (A2) of the fuselage.

3. The high fuel efficiency twin-fuselage passenger aircraft according to claim 1, characterized in that: The wing (200) comprises a middle wing (201), a left wing (202) and a right wing (203); The left and right sides of the middle wing (201) are respectively fixedly connected to the top center line of the first fuselage (101) and the top center line of the second fuselage (102); The left side of the middle wing (201) extends toward the outer side of the first fuselage (101) to form the left wing (202); and the right side of the middle wing (201) extends toward the outer side of the second fuselage (102) to form the right wing (203).

4. A highly fuel efficient twin-fuselage passenger aircraft according to claim 3, characterized in that: The middle wing (201) is in a horizontally arranged rectangular shape; The left wing (202) and the right wing (203) are symmetrical, and the left wing (202) and the right wing (203) are arranged to be inclined upward relative to the middle wing (201); the width of the left wing (202) and the right wing (203) gradually decreases from the wing root to the wing tip, and they are trapezoidal wings.

5. The high fuel efficiency twin-fuselage passenger aircraft according to claim 3, characterized in that: The trailing edge of the left wing (202) is provided with a left flap (2021) and a left aileron (2022); the left aileron (2022) is located outside the left flap (2021); The trailing edge of the right wing (203) is provided with a right flap (2031) and a right aileron (2032); the right aileron (2032) is located outside the right flap (2031).

6. The high fuel efficiency twin-fuselage passenger aircraft according to claim 3, characterized in that: The power plant (400) comprises a first engine nacelle (401), a first engine pylon (402), a second engine nacelle (403) and a second engine pylon (404); The first engine nacelle (401) is suspended below the left wing (202) via the first engine pylon (402); The second engine nacelle (403) is suspended below the right wing (203) via the second engine pylon (404).

7. The high fuel efficiency twin-fuselage passenger aircraft according to claim 1, characterized in that: The tail wing (300) comprises a first vertical tail wing (301), a second vertical tail wing (302), a first horizontal tail wing (303) and a second horizontal tail wing (304); The first vertical tail wing (301) is fixedly mounted above the tail centerline of the first fuselage (101); the second vertical tail wing (302) is fixedly mounted above the tail centerline of the second fuselage (102); the second vertical tail wing (302) and the first vertical tail wing (301) are bilaterally symmetrical; The first horizontal tail wing (303) and the second horizontal tail wing (304) are bilaterally symmetrical and are arranged in sequence along the direction from the first vertical tail wing (301) to the second vertical tail wing (302); one side of the first horizontal tail wing (303) is fixed to the inner side of the top of the first vertical tail wing (301); the other side of the first horizontal tail wing (303) is fixed to one side of the second horizontal tail wing (304); and the other side of the second horizontal tail wing (304) is fixed to the inner side of the top of the second vertical tail wing (302).

8. The high fuel efficiency twin-fuselage passenger aircraft according to claim 7, characterized in that: A first rudder (305) is disposed at the trailing edge of the first vertical tail wing (301); and a second rudder (306) is disposed at the trailing edge of the second vertical tail wing (302); A first elevator (307) is arranged at the trailing edge of the first horizontal tail (303); and a second elevator (308) is arranged at the trailing edge of the second horizontal tail (304).

9. The high fuel efficiency twin-fuselage passenger aircraft according to claim 1, characterized in that: Inside the first fuselage (101), a cockpit (1011), a first first-class cabin (1012) and a first economy cabin (1013) are arranged in sequence from front to back; Inside the second fuselage (102), a super first-class cabin (1021), a second first-class cabin (1022) and a second economy cabin (1023) are arranged in sequence from front to back.

10. A method for designing a fuel-efficient twin-fuselage passenger aircraft according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step S1, determining an aircraft design parameter set according to design requirements, and determining a design space of each design parameter in the design parameter set; Determine the maximum take-off weight target value of the aircraft in advance m TO_target ; Step S2, sampling in the design space of each design parameter to obtain initial sampling values ​​of all design parameters; Step S3, using formula (1), estimate the fuselage weight m of the fuselage (100) f : m f =1.35·(L f ·D f ) 1.28 ·(1+0.05·N e )·(1+0.38·F c )·N f (1) in: L f is the length of the fuselage (100), specifically the sum of the lengths of the first fuselage (101) and the second fuselage (102); D f is the average diameter of the fuselage (100); N e The number of engines installed for the fuselage (100); F c is the aircraft floor coefficient; N f 2, indicating that it has two fuselages; Step S4, using formula (2), the wing weight m of the wing (200) is estimated wingbox : Where: C is a constant; W / S is the wing loading; AR is the aspect ratio; Λ is the sweep angle of the quarter chord line of the wing; t / c is the relative thickness of the average wing airfoil; V m is the maximum operating speed; λ is the taper ratio of the wing; n z is the maximum positive load factor; Z f is the relative position of the fuselage relative to the wingspan; Z e is the relative position of the engine relative to the wingspan; E m 、E ws 、E AR 、E Λ 、E t 、E V 、E λ 、E nz 、E zf and E ze , are the exponential terms of the corresponding terms respectively; Step S5: Use formula (3) to estimate the horizontal tail weight m ht , specifically the sum of the weights of the first horizontal tail wing (303) and the second horizontal tail wing (304): m ht =0.53·S ht ·DG 0.2 ·(l ht +0.5) (3) Where: S ht is the area of ​​a single horizontal tail; DG is the total design weight of the entire aircraft; λ ht is the aspect ratio of the horizontal tail; Step S6: Use formula (4) to estimate the vertical tail weight m vt , specifically the sum of the weights of the second vertical tail wing (302) and the first vertical tail wing (301): Where: S vt is the area of ​​a single vertical tail; λ vt is the aspect ratio of the vertical tail; N vt is the number of vertical tail fins; Step S7: Use formula (5) to estimate the weight m of the landing gear. LG : m LG =N MLG ×0.0117×W LDG 0.95 ×X MLG 0.43 +N NLG ×0.048×W LDG 0.67 ×X NLG 0.43 (5) Where: N MLG The number of main landing gears; W LDG Design landing weight for the aircraft; X MLG The length of the main landing gear strut; N NLG is the number of front landing gear; X NLG is the length of the front landing gear strut; Step S8: Use formula (6) to estimate the weight m of the propulsion system. PSI : Where: N ENG is the number of engines; W ENGB is the base engine weight; T RUST is the rated thrust of the engine; T RSO is the rated thrust of the reference engine; E EXP is the engine weight scaling parameter; the benchmark engine is the engine selected as the reference standard among various engines; Step S9: Use formula (7) to estimate the empty mass m e : m e =m f +m wingbox +m ht +m vt +m LG +m PSI (7) Step S10, using formula (8), the maximum take-off weight of the aircraft is estimated to be m TO : m TO =m crew +m pay +m fuel +m e (8) Where: m crew is the crew mass; m pay is the effective load mass; m fuel is the fuel quality; Step S11, the maximum take-off weight m of the aircraft estimated in step S10 TO and the maximum takeoff weight target value of the aircraft m TO_target The sampling direction is determined by the deviation, and the sampling direction is determined, thereby returning to step S2, resampling in the design space of each design parameter, obtaining the sampling values ​​of all design parameters, and then repeating steps S3 to S11; if the iteration cycle is continuously performed until the maximum take-off weight m of the aircraft estimated in step S10 is TO and the maximum takeoff weight target value of the aircraft m TO_target The deviation meets the design accuracy requirement, and step S12 is executed; Step S12: Output the sampled values ​​of all design parameters and the maximum take-off weight of the aircraft m TO ; According to the sampling values ​​of all design parameters, a twin-fuselage passenger aircraft with high fuel efficiency is designed.

Images