Embedded auxiliary intake valve

Abstract

The utility model belongs to the field of airplane air inlet system design, and particularly relates to an embedded type auxiliary air inlet valve. Comprising an auxiliary air inlet pipeline, a small baffle, a one-way valve and a hinge shaft, one end of the auxiliary air inlet pipeline is connected with the air inlet, and the other end of the auxiliary air inlet pipeline is located in the undercarriage cabin; the one-way valve is installed at the end, located in the undercarriage cabin, of the auxiliary air inlet pipeline through the hinge shaft, and the one-way valve is opened and closed under the control of pressure difference. The small baffle is arranged at the end, located in the undercarriage cabin, of the auxiliary air inlet pipeline and used for limiting the closing position of the one-way valve. The total pressure recovery coefficient can be greatly improved in the take-off stage and the landing stage, and therefore the engine installation thrust is improved.

Description

Technical Field

[0001] This application belongs to the field of aircraft air intake system design, and specifically relates to an embedded auxiliary air intake valve. Background Technology

[0002] An auxiliary air intake is a device designed after the inlet throat of the engine air intake to assist the air intake in supplying air to the engine during takeoff. The auxiliary air intake opens during takeoff to improve the total pressure recovery coefficient of the air intake, increase engine thrust, and shorten takeoff distance. Unmanned aerial vehicles (UAVs) performing special missions have increasingly demanding performance requirements. Stealth design typically requires extremely thin and swept-back inlet lips of the air intake, and internal ducts that shield the engine inlet. This results in large-scale flow separation near the air intake during takeoff, clogging the throat. The sharply bends in the internal duct further exacerbate this flow separation, leading to a decrease in total pressure recovery and consequently a reduction in engine thrust.

[0003] Third-generation UAVs commonly feature auxiliary air intakes in their air intake designs, such as the American F-18E / F and the Russian T-50. However, in this conventional layout, the air intake is usually located externally on the fuselage, allowing the auxiliary air intake to open directly onto the intake wall and connect to the atmosphere, simplifying the design. For flying-wing aircraft, which often employ dorsal-mounted air intakes, the design complexity of the auxiliary air intake significantly increases because the intake is typically embedded within the fuselage. The American B-2 aircraft features a hydraulically operated auxiliary air intake at the top of the intake, but this hydraulic system requires a complex actuation mechanism and sufficient space above the intake, making it unsuitable for small to medium-sized UAVs with limited space.

[0004] Therefore, there is an urgent need for a technical solution to overcome or mitigate at least one of the aforementioned defects in the existing technology. Utility Model Content

[0005] The purpose of this application is to provide an embedded auxiliary intake valve to solve at least one problem existing in the prior art.

[0006] The technical solution of this application is:

[0007] An embedded auxiliary air intake valve includes: an auxiliary air intake valve disposed within the landing gear bay at the lower part of the air intake duct; the auxiliary air intake valve includes: an auxiliary air intake duct, a small baffle, a one-way valve, and a hinge shaft.

[0008] One end of the auxiliary air intake pipe is connected to the air intake duct, and the other end is located inside the landing gear bay;

[0009] The one-way valve is installed at one end of the auxiliary air intake pipe located in the landing gear bay via the hinge shaft, and the one-way valve opens and closes under differential pressure control.

[0010] The small baffle is located at one end of the auxiliary air intake duct inside the landing gear bay, and is used to restrict the closing position of the one-way valve.

[0011] In at least one embodiment of this application, the end of the auxiliary air intake pipe connected to the air intake duct is flared.

[0012] In at least one embodiment of this application, the inner wall surface at the connection between the auxiliary air intake pipe and the air intake duct is rounded.

[0013] In at least one embodiment of this application, the auxiliary air intake pipe and the air intake duct form an angle of 30° rearward and 50° forward with the local wall surface.

[0014] In at least one embodiment of this application, the end of the auxiliary intake pipe connected to the intake duct has a slit-shaped opening, and the opening area is 0.1-0.3 of the throat area.

[0015] In at least one embodiment of this application, the aspect ratio of the opening at the end of the auxiliary intake pipe connected to the intake duct is 2-4.

[0016] In at least one embodiment of this application, the opening of the auxiliary intake pipe connected to the intake duct is located after the throat of the intake duct and before the outlet.

[0017] In at least one embodiment of this application, the length of the auxiliary air intake duct is less than a preset threshold to avoid interference with the landing gear and cabin equipment.

[0018] In at least one embodiment of this application, the one-way valve opens toward the inside of the auxiliary air intake duct.

[0019] The utility model has at least the following beneficial technical effects:

[0020] The embedded auxiliary air intake valve of this application can be applied to the dorsal air intake of high stealth UAVs. The auxiliary air intake valve is located in the landing gear bay. During takeoff and landing, the landing gear bay opens, and the air intake can form a pressure difference with the outside airflow, which drives the auxiliary air intake valve. This significantly improves the total pressure recovery coefficient during takeoff and landing, thereby increasing the thrust of the engine. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the auxiliary intake valve position according to one embodiment of this application;

[0022] Figure 2 This is an overall schematic diagram of the auxiliary intake valve according to one embodiment of this application;

[0023] Figure 3 This is a schematic diagram of the auxiliary intake valve closing according to one embodiment of this application;

[0024] Figure 4 This is a schematic diagram of the auxiliary intake valve opening according to one embodiment of this application;

[0025] Figure 5 This is a top view of an auxiliary intake valve according to one embodiment of this application.

[0026] in:

[0027] 1-Air intake duct, 2-Auxiliary air intake valve, 3-Landing gear bay, 4-Auxiliary air intake pipe, 5-Small baffle, 6-One-way door, 7-Hinge shaft. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0029] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this application.

[0030] The following is in conjunction with the appendix Figures 1 to 5 This application will be described in further detail.

[0031] This application provides an embedded auxiliary intake valve, such as Figure 1 As shown, it includes: an auxiliary air intake valve 2, which is located in the landing gear bay 3 at the lower part of the air intake duct 1. Figure 2As shown, the auxiliary intake valve 2 includes: an auxiliary intake pipe 4, a small baffle 5, a one-way valve 6, and a hinge shaft 7.

[0032] Specifically, one end of the auxiliary air intake duct 4 is connected to the air intake duct 1, and the other end is located inside the landing gear bay 3. A one-way valve 6 is installed at the end of the auxiliary air intake duct 4 located inside the landing gear bay 3 via a hinge shaft 7. The one-way valve 6 opens and closes under pressure differential control. A small baffle 5 is set at the end of the auxiliary air intake duct 4 located inside the landing gear bay 3 to limit the closed position of the one-way valve 6. The auxiliary air intake duct 4 is completely hidden inside the landing gear bay 3. When the aircraft takes off and lands, the landing gear bay 3 opens, and under the influence of the suction of the air intake duct 1, the auxiliary air intake valve 2 opens to achieve auxiliary air intake, increasing the total pressure recovery coefficient of the air intake duct 1. When the aircraft is flying at high speed, the landing gear bay 3 closes, the pressure inside the bay is less than the pressure inside the air intake duct 1, the auxiliary air intake valve 2 closes, and the performance of the air intake duct 1 is not affected.

[0033] The internally mounted auxiliary air intake 2 of this application is installed in the landing gear bay 3 below the air intake duct 1, preferably in the aircraft's nose landing gear bay. This not only avoids damaging the fuselage surface, ensuring stealth characteristics, but also shortens the pipe length, reducing weight and flow losses. The one-way valve 6 of the auxiliary air intake 2 is driven by differential pressure, eliminating the need for a complex hydraulic system, thereby reducing aircraft weight and maintenance complexity.

[0034] In a preferred embodiment of this application, the auxiliary intake duct 4 adopts a differential deflection flow-direction design. The end of the auxiliary intake duct 4 connected to the intake duct 1 is flared, and the inner wall surface at the connection between the auxiliary intake duct 4 and the intake duct 1 is rounded. By selecting an appropriate included angle, flow separation is reduced. In this embodiment, the included angle between the auxiliary intake duct 4 and the intake duct 1 at the local wall surface is 30° backward and 50° forward.

[0035] In a preferred embodiment of this application, the end of the auxiliary intake pipe 4 connected to the intake pipe 1 adopts a slit-shaped opening. According to the performance requirements, the opening area is reasonably designed to be 0.1-0.3 of the throat area, and the opening length-to-diameter ratio (L / D) is increased. For example, the opening length-to-diameter ratio is designed to be 2-4 to maximize the intake efficiency and auxiliary intake effect.

[0036] In a preferred embodiment of this application, the opening of the auxiliary intake pipe 4 connected to the intake duct 1 is located after the throat of the intake duct 1 and before the outlet, thereby reducing the mixing loss of internal and external flows.

[0037] The embedded auxiliary air intake valve of this application has an auxiliary air intake duct 4 with a length less than a preset threshold, which avoids interference with the landing gear and cabin equipment, and reduces the weight and flow loss of the auxiliary air intake duct 4. By precisely designing the size of the auxiliary air intake valve 2, interference with the flow field inside the air intake duct 1 is avoided when the auxiliary air intake valve 2 is open.

[0038] In a preferred embodiment of this application, the one-way valve 6 is a single-door, inward-opening type. The one-way valve 6 opens to the inside of the auxiliary air intake pipe 4, avoiding interference with the landing gear and piping equipment in the landing gear bay.

[0039] The internally mounted auxiliary air intake valve of this application operates as follows: the auxiliary air intake valve 2 is located within the landing gear bay 3. It cleverly utilizes the fact that the auxiliary air intake valve 2 is only used during takeoff and landing, and the landing gear bay 3 is only opened during these two phases. This allows the air intake duct 1 to create a pressure difference with the external airflow, driving the auxiliary air intake valve 2. During flight, the landing gear bay 3 remains closed, resulting in a lower pressure inside the bay compared to the air intake duct 1. This pressure difference causes the auxiliary air intake valve 2 to close. This achieves the goal of significantly increasing the total pressure recovery coefficient during takeoff and landing, thereby increasing the engine's thrust, while having no impact on the performance of the air intake duct 1 during high-speed flight.

[0040] This application presents an internally mounted auxiliary air intake valve designed for high-stealth flying-wing UAVs with dorsal air intakes. The main advantages are: the auxiliary air intake valve 2 is located within the landing gear bay 3, thus not damaging the aircraft surface and ensuring stealth characteristics; the auxiliary air intake valve 2 is located at the lower part of the air intake duct 1, shortening the duct length and reducing the weight and flow loss of the auxiliary air intake duct 4; the auxiliary air intake valve 2 is located in the front half of the air intake duct 1, injecting energy into the low-energy separated flow near the inlet, improving total pressure recovery, and ensuring sufficient mixing to reduce distortion. The auxiliary air intake valve 2 uses differential pressure drive, eliminating the complex hydraulic system, which reduces aircraft weight, improves maintainability, and saves space in the overall layout. The auxiliary intake duct 4 adopts a differential deflection flow direction design, with the forward included angle being greater than the backward included angle. This can improve the uniformity of intake mixing while reducing flow separation. The opening shape adopts a slit-shaped opening to maximize the length-to-diameter ratio (L / D), ensuring the maximum intake efficiency and mixing uniformity under the same opening area, maximizing the total pressure recovery coefficient and reducing distortion.

[0041] The embedded auxiliary air intake valve of this application has been verified through CFD numerical simulation and wind tunnel tests. The designed auxiliary air intake valve 2 can effectively improve the total pressure recovery coefficient of the air intake when it is stationary and at low speed, that is, improve the engine mounting thrust, shorten the takeoff run distance, and at the same time reduce the air intake distortion and improve the stability of the engine-intake matching.

[0042] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An embedded auxiliary intake valve, characterized in that, include: An auxiliary air intake valve (2) is located in the landing gear bay (3) at the lower part of the air intake duct (1). The auxiliary air intake valve (2) includes: an auxiliary air intake duct (4), a small baffle (5), a one-way valve (6), and a hinge shaft (7). One end of the auxiliary air intake pipe (4) is connected to the air intake pipe (1), and the other end is located inside the landing gear bay (3); The one-way valve (6) is installed at one end of the auxiliary air intake pipe (4) located in the landing gear bay (3) via the hinge shaft (7), and the one-way valve (6) opens and closes under differential pressure control; The small baffle (5) is located at one end of the auxiliary air intake pipe (4) inside the landing gear bay (3) to restrict the closing position of the one-way valve (6).

2. The embedded auxiliary intake valve according to claim 1, characterized in that, The auxiliary air intake pipe (4) is connected to the air intake pipe (1) at one end in a trumpet shape.

3. The embedded auxiliary intake valve according to claim 1, characterized in that, The inner wall surface at the connection between the auxiliary air intake pipe (4) and the air intake pipe (1) is rounded.

4. The embedded auxiliary intake valve according to claim 1, characterized in that, The auxiliary air intake pipe (4) and the air intake pipe (1) form an angle of 30° backward and 50° forward with respect to the local wall surface.

5. The embedded auxiliary intake valve according to claim 1, characterized in that, The auxiliary air intake pipe (4) is connected to the air intake pipe (1) at one end with a slit-shaped opening, and the opening area is 0.1-0.3 of the throat area.

6. The embedded auxiliary intake valve according to claim 5, characterized in that, The length-to-slenderness ratio of the end of the auxiliary intake pipe (4) connected to the intake pipe (1) is 2-4.

7. The embedded auxiliary intake valve according to claim 6, characterized in that, The opening of the auxiliary air intake pipe (4) connected to the air intake pipe (1) is located after the throat of the air intake pipe (1) and before the outlet.

8. The embedded auxiliary intake valve according to claim 1, characterized in that, The length of the auxiliary air intake pipe (4) is less than a preset threshold to avoid interference with the landing gear and cabin equipment.

9. The embedded auxiliary intake valve according to claim 1, characterized in that, The one-way valve (6) opens to the inside of the auxiliary air intake pipe (4).

Images