Blended wing body back engine thrust reverser capable of suppressing inlet distortion

Abstract

The application provides a wing-body fusion back support engine reverse thrust device capable of inhibiting air intake distortion, which comprises a ring-shaped reverse thrust vane located on the inner side of a back support engine nacelle cover and reverse thrust flow guiding plates located on the two side surfaces of a back support engine nacelle support. When reverse thrust is needed, with the increase of the unfolding angle of the flow guiding plates, the hindering effect of the flow guiding plates on the forward movement of the reverse thrust air flow is more and more significant, so that the air intake quality of the turbofan engine during the reverse thrust work is ensured; in addition, the flow guiding plates also have the interference effect on the air flow similar to that of a spoiler, so that the form resistance is increased, which is beneficial to the faster deceleration of the airplane. The application effectively solves the adaptability problem of the reverse thrust device and the wing-body fusion back support engine, inhibits the occurrence of air intake distortion, strengthens the braking effect of the reverse thrust device, and guarantees the flight safety of the wing-body fusion back support engine layout.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine technology, specifically relating to a thrust reverser device suitable for blended wing-body engines and capable of effectively suppressing inlet distortion. Background Technology

[0002] The blended wing-body (BWB) aircraft is a novel type of aircraft that has entered the proof-of-concept stage. It integrates the traditional fuselage and wing structures, resulting in improved lift-to-drag ratio and fuel efficiency. Integrating high-bypass turbofan engines with a BWB aircraft presents significant challenges, and dorsal-straddle engines are the preferred solution for enabling the rapid deployment of BWB aircraft. Figure 1 The image shows a concept design for a blended wing-body dorsal strut engine.

[0003] During landing, aircraft typically need to activate engine thrust reversers to reduce the landing distance and improve safety. Thrust reversers are commonly classified as grab-type, cascade-type, and deflector-type. Cascade-type thrust reversers are usually used with high-bypass turbofan engines, featuring a compact structure, stable airflow, and high thrust reverser efficiency. Therefore, when considering designing thrust reversers for a blended wing-body turbofan engine, the following questions need to be considered: 1) Is it feasible to directly adapt existing thrust reversers to a blended wing-body turbofan engine? 2) If not, what improvements are needed?

[0004] Existing technologies, such as the thrust reversers mentioned in the relevant patents, do not provide detailed specifications regarding the relative position of the launch vehicle and do not consider the adaptability to new aircraft.

[0005] For example, Chinese patent CN113864079A discloses an aero-engine thrust reverser. By hinged a choke gate to the core nacelle cowl and movably connecting the movable outer cowl and the choke gate with a moving linkage, the choke gate can be rotated to the open and retracted positions, and the movable outer cowl moves synchronously with it, thereby realizing the opening and retraction of the thrust reverser. This avoids the need for an actuator, thus effectively increasing the blade area, reducing the structural weight, and improving the thrust reverser efficiency.

[0006] Chinese patent CN105329449A discloses a thrust reverser cascade for an aero-engine, characterized by through holes on some blades. The inlet of the through hole is located at the blade base, while the outlet of the through hole is located on the end face or the back of the blade. This can eliminate or reduce vortices on the blade base and increase the flow area of ​​the cascade. It can also increase the kinetic energy of the gas in the outlet section and eliminate boundary layer separation on the back of the blade.

[0007] European Patent EP2925991A and US Patent US8869507A each disclose a blade-type thrust reverser, differing in the mechanism's movement from the retracted to the extended state. In the former, the blades move as a whole through a combination of translation and rotation, while in the latter, the connecting rod and blades move in stages, with the connecting rod first moving axially and then driving the blades. A comparison of the accompanying drawings shows that both are designed for wing-mounted engines in conventionally laid-out aircraft.

[0008] Further research revealed that the paper "Blended Wing Body Thrust Reverser Cascade Feasibility Evaluation Through CFD," published in *IEEE Access*,... Figure 2 (This is quoted from the article, showing the vorticity distribution near the nacelle inlet at different Mach numbers) and the numerical study of the reverse thrust flow field of a blended wing-body dorsal-brace engine published in the *Journal of Aerospace Power*. Figure 3 (As shown in the article, which includes a total pressure cloud diagram of the engine's meridional section,) it is evident that directly applying existing blade-type thrust reversers to blended wing-body engines results in intake distortion, which can severely impact flight safety. Therefore, directly adapting existing thrust reversers to blended wing-body engines is not feasible; adaptive modifications to the existing thrust reversers are necessary. Summary of the Invention

[0009] To address the problems existing in the prior art, this invention proposes a thrust reverser suitable for blended wing-body engines. By designing the circumferential deflection angle distribution of the thrust reverser blade cascade and installing guide vanes on the side of the nacelle support, the goal of suppressing air intake distortion is achieved.

[0010] The technical solution of this invention is as follows:

[0011] A blended wing-body dorsal-braced engine thrust reverser that can suppress air intake distortion includes an annular thrust reverser blade located inside the dorsal-braced engine nacelle cover, and thrust reverser deflectors located on both sides of the dorsal-braced engine nacelle support.

[0012] The nacelle support is used to connect the blended wing-body aircraft to the dorsal-brace engine.

[0013] When thrust reverser action is required, the rear part of the nacelle can slide backward along the nacelle support to expose the thrust reverser blades; the front part of the thrust reverser deflector can deploy outward.

[0014] Furthermore, when thrust reversers are not required, the thrust reversers are embedded in the two sides of the nacelle support and are designed to maintain a smooth profile on both sides of the nacelle support.

[0015] Furthermore, the thrust reverser is a right-angled trapezoid with the side closer to the blended wing-body aircraft as the lower base, the side closer to the dorsal support engine as the upper base, and the rear part along the incoming flow direction as the waist, and is hinged to the side of the nacelle support.

[0016] Furthermore, when a reverse thrust effect is required, the front part of the reverse thrust deflector extends outward at an angle of not less than 60°.

[0017] Furthermore, the annular thrust reverser blades have different circumferential deflection angles in different regions along the circumference. The circumferential deflection angle of the section of the annular thrust reverser blades with the central angle facing the fuselage is not 0° and has a certain deflection angle, so that the thrust reverser airflow in this region obtains a certain spanwise velocity and avoids being re-inhaled by the engine inlet. The circumferential deflection angle refers to the angle between the connecting edge of adjacent blades in the circumferential direction and the radial direction at that position when viewed from the axial perspective.

[0018] Furthermore, the circumferential deflection angle of the annular reverse thrust blade segment with its central angle pointing towards the fuselage is 20°.

[0019] Beneficial effects

[0020] This invention proposes a blended wing-body domed thrust reverser for engines that can suppress inlet distortion. By installing thrust reverser deflectors on both sides of the nacelle support of the domed engine, the obstruction effect on the forward movement of the thrust reverser airflow becomes increasingly significant as the deflector's deployment angle increases, ensuring the intake quality of the turbofan engine during thrust reverser operation. Furthermore, the deflectors act as spoilers, increasing drag and facilitating faster aircraft deceleration. Additionally, the thrust reverser deflectors employ a trapezoidal structure, wider at the bottom and narrower at the top, allowing the more intensely accelerated airflow near the fuselage due to the Coanda effect to be guided by the longer deflectors, directing it as far as possible spanwise towards the rear of the fuselage. Moreover, the thrust reverser also includes annular thrust reverser blades. By designing the circumferential deflection angle of a section of the annular thrust reverser blades with its central angle facing the fuselage to be non-0°, the thrust reverser airflow in this region gains a certain spanwise velocity, preventing it from being re-intaken into the engine inlet.

[0021] This invention effectively solves the compatibility problem between the thrust reverser and the blended wing-body dome-shaped engine, suppresses the occurrence of intake distortion, strengthens the braking effect of the thrust reverser, and ensures the flight safety of the blended wing-body dome-shaped engine layout.

[0022] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0024] Figure 1 : Blended wing-body dorsal strut engine concept design;

[0025] Figure 2 : Vortex distribution near the nacelle inlet at different Mach numbers;

[0026] Figure 3 Total pressure cloud diagram of the engine's meridional section;

[0027] Figure 4 Comparison of the wing-body blended dorsal strut engine thrust reverser before and after activation; (a) before thrust reverser activation, (b) after thrust reverser activation;

[0028] Figure 5 : Blended wing-body dorsal strut engine thrust reverser; The fuselage portion has been removed from the image to highlight the various details of the thrust reverser.

[0029] Figure 6 : wing-body blended dorsal strut engine thrust reverser cascade; in actual use, the entire circumferential cascade is riveted together from fan-shaped cascades as shown in the figure;

[0030] Figure 7 : Inversely deduce the axial blade geometry parameters of the cascade;

[0031] Figure 8 : Inversely calculate the circumferential deflection angle distribution of the cascade; α is the circumferential deflection angle;

[0032] Figure 9 : Thrust reverser deflectors installed on the side of the nacelle; the deflector deployment angle θ is defined as the angle between the deflector's plane of symmetry and the engine's meridional plane, with 0° being the state where the deflector is not deployed;

[0033] Figure 10 : Total pressure cloud map of the AIP interface; In CFD calculation, the fan blades are simplified to the AIP interface, and the total pressure distribution of the AIP interface can characterize the degree of airflow distortion at the fan. It can be seen that as the deployment angle increases, the airflow quality becomes better and better. Detailed Implementation

[0034] The embodiments of the present invention are described in detail below. These embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0035] like Figure 5 As shown, the wing-body blended dome-support engine thrust reverser device that can suppress air intake distortion in this embodiment includes an annular thrust reverser blade located inside the dome-support engine nacelle outer cover, and thrust reverser deflectors located on both sides of the dome-support engine nacelle support.

[0036] like Figure 4 As shown, the nacelle includes a fixed nacelle section, a moving nacelle section, and a nacelle support frame; the nacelle support frame is used to connect the blended wing-body aircraft to the dorsal-brace engine. The nacelle has a maximum diameter of 3252 mm, and the AIP interface is used to represent the ducted fan inlet interface.

[0037] like Figure 4 and Figure 5 As shown, when thrust reversing is not required, the thrust reverser deflector is embedded in the two sides of the nacelle support and employs a conformal design to ensure a smooth profile on both sides of the nacelle support, without affecting the overall aerodynamic performance of the aircraft. When thrust reversing is required, the front part of the thrust reverser deflector is extended outward via a hydraulic device, and the rear part of the thrust reverser deflector is hinged to the side of the nacelle support. The outward extension of the front part of the thrust reverser deflector has two functions. The first function is to act as a spoiler, interfering with the airflow and increasing drag, which helps the aircraft decelerate faster. The second function, which is more important, is to impede the forward movement of the thrust reverser airflow. As the deflector's extension angle increases, the impediment effect on the forward movement of the thrust reverser airflow becomes more significant, ensuring the intake air quality of the turbofan engine during thrust reverser operation.

[0038] Here, CFD numerical simulation was used to investigate the effect of the deflector deployment angle θ on the total pressure distribution at the AIP interface. The deployment angle θ was taken as 0° / 30° / 60° / 90°, as follows: Figure 9 As shown. The geometric model was established using CATIA software, the unstructured mesh was generated using STARCCM software, and the flow field was calculated using CFX software. The CFD calculation state was selected as a typical landing run: Mach number 0.1, angle of attack 0°, actual aircraft dimensions, and a characteristic length of 26.5m. Figure 10 The calculation results prove that the reverse thrust guide vane in this invention can effectively suppress intake distortion when the deployment angle is greater than 60°.

[0039] Furthermore, since the airflow near the bottom is accelerated more intensely by the Coanda effect on the wall, the thrust reverser is designed as a right-angled trapezoid to direct the airflow near the fuselage longitudinally towards the rear of the fuselage as much as possible. The side closest to the blended wing-body aircraft is the lower base, the side closest to the dorsal-brace engine is the upper base, and the rear portion along the incoming flow direction is a straight waist, hinged to the side of the nacelle support. This allows the airflow near the bottom to be guided through a longer length, directing it longitudinally towards the rear of the fuselage as much as possible. In this embodiment, the upper edge of the thrust reverser is 667mm, the lower edge is 1485mm, the hypotenuse is 1261mm, and the side edge is 938mm.

[0040] Another component of the thrust reverser is the annular thrust reverser blade located inside the dome of the engine nacelle. When thrust reverser action is required, the rear of the nacelle can slide out along the nacelle support to expose the thrust reverser blade. Figure 6 The image shows a fan-shaped blade section with a 60° arc. Six such fan-shaped blades form a complete circumferential blade section. The blade section has a width of 525 mm, an outer diameter of 1590 mm, and an inner diameter of 1530 mm. Figure 7 The specific parameters for the blade cascade are as follows: vertical height of the cascade channel in the radial direction H = 60 mm, blade spacing X = 50 mm, blade thickness S = 2 mm, blade chord length L = 75 mm, blade width U = 30 mm, transition section radius R = 5 mm, inlet airflow angle β1 = 45° and outlet airflow angle β2 = 30°, and density ε = H / X = 1.2. The key geometric parameters here are the inlet airflow angle, outlet airflow angle, and density.

[0041] In addition, such as Figure 8 As shown, furthermore, the annular thrust reverser blades have different circumferential deflection angles in different regions along the circumference. The circumferential deflection angle of the section of the annular thrust reverser blades with the central angle facing the fuselage is not 0°, but has a 20° deflection angle, so that the thrust reverser airflow in this region obtains a certain spanwise velocity and avoids being re-inhaled by the engine inlet. The circumferential deflection angle refers to the angle between the connecting edge of adjacent blades in the circumferential direction and the radial direction at that position when viewed from the axial perspective.

[0042] In practical use, when the aircraft lands and begins to taxi, the rear of the nacelle canopy slides out along the nacelle support, exposing the thrust reverser blades. At the same time, the hydraulic mechanism drives the deflector installed on the side of the nacelle support to unfold until the aircraft's taxiing speed drops below 15m / s. Then, the nacelle canopy moves forward to cover the thrust reverser blades while the deflector retracts.

[0043] This invention effectively solves the compatibility problem between the thrust reverser and the blended wing-body dome-shaped engine, suppresses the occurrence of intake distortion, strengthens the braking effect of the thrust reverser, and ensures the flight safety of the blended wing-body dome-shaped engine layout.

[0044] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A blended wing-body dorsal strut engine thrust reverser capable of suppressing inlet distortion, characterized in that: This includes an annular thrust reverser blade array located inside the dome-supported engine nacelle cover, and thrust reverser deflectors located on both sides of the dome-supported engine nacelle support. The nacelle support is used to connect the upper fuselage surface of the blended wing-body aircraft to the dorsal-braced engine; When thrust reverser action is required, the rear part of the nacelle can slide out along the nacelle support to expose the thrust reverser blades; the front part of the thrust reverser deflector can unfold outward to obstruct the forward movement of the thrust reverser airflow, thereby suppressing the intake distortion of the engine inlet.

2. The wing-body blended dorsal strut engine thrust reverser capable of suppressing inlet distortion according to claim 1, characterized in that: When thrust reversers are not required, the thrust reversers are embedded in the two sides of the nacelle support and are designed to maintain a smooth profile on both sides of the nacelle support.

3. A blended wing-body engine thrust reverser capable of suppressing inlet distortion according to claim 1 or 2, characterized in that: The thrust reverser is a right-angled trapezoid with the side closer to the blended wing-body aircraft as the lower base, the side closer to the dorsal support engine as the upper base, and the rear part along the incoming flow direction as the waist, and is hinged to the side of the nacelle support.

4. The wing-body blended dorsal strut engine thrust reverser capable of suppressing inlet distortion according to claim 1, characterized in that: When a reverse thrust is required, the front of the reverse thrust deflector extends outward at an angle of not less than 60°.

5. The wing-body blended dorsal strut engine thrust reverser capable of suppressing inlet distortion according to claim 1, characterized in that: The annular thrust reverser blades have different circumferential deflection angles in different regions along the circumference. The circumferential deflection angle of the section of the annular thrust reverser blades with the central angle facing the fuselage is not 0° and has a certain deflection angle, so that the reverse airflow in this region obtains a certain spanwise velocity and avoids being re-inhaled by the engine inlet. The circumferential deflection angle refers to the angle between the connecting edge of adjacent blades in the circumferential direction and the radial direction at that position when viewed from the axial perspective.

6. The wing-body blended dorsal strut engine thrust reverser capable of suppressing inlet distortion according to claim 5, characterized in that: The circumferential deflection angle of the annular thrust reverser blade section with its central angle facing the fuselage is 20°.

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