An air intake

Abstract

The present invention discloses an air inlet, which relates to the field of aircraft technology, and includes: an air inlet body, the air inlet body having an air inlet and an air outlet, an overflow hole being provided on the inner wall of the air outlet, an elastic cover plate being provided on the overflow hole, the overflow hole and the elastic cover plate being slidably connected, and the elastic cover plate being used for automatic closing and opening of the overflow hole. Compared with the air inlet with an overflow groove in the prior art, the air inlet in the present application can effectively avoid the problem of external gas flowing back into the air inlet through the overflow hole and reducing the aerodynamic performance and stability of the air inlet while reducing outlet distortion.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft, and in particular to an air inlet. Background Art

[0002] The air inlet is an important part of the aircraft propulsion system. As a key component for coupling the aircraft forebody and the ramjet, it is in direct contact with the free flow air. The main function of the air inlet is to efficiently provide sufficient air to the engine under different working conditions and to decelerate the inlet air to the intake speed required by the compressor with minimal capacity loss.

[0003] In order to reduce the flow field distortion caused by shock wave disturbance, make the outlet airflow flow even, and cool the rear-end equipment, overflow slots are often opened in the air inlet to allow the boundary layer airflow to flow out from the slotted position. However, when this method encounters back pressure at the overflow port, external gas will flow into the air inlet, disrupting the internal flow field of the air inlet and reducing the working stability of the air inlet. Summary of the invention

[0004] 1. Technical problem to be solved by the invention

[0005] In view of the technical problem that external gas backflow is prone to occur at the overflow groove of the existing air inlet duct, disrupting the internal flow field of the air inlet duct and resulting in poor aerodynamic performance and stability of the air inlet duct, the present invention provides an air inlet duct that can effectively prevent the backflow of external gas and improve the aerodynamic performance and stability of the air inlet duct.

[0006] 2. Technical solution

[0007] To solve the above problems, the technical solution provided by the present invention is:

[0008] An air inlet comprises: an air inlet body, wherein the air inlet body has an air inlet and an air outlet, an overflow hole is arranged on the inner wall of the air outlet, an elastic cover plate is arranged on the overflow hole, the overflow hole and the elastic cover plate are slidably connected, and the elastic cover plate is used for automatic closing and opening of the overflow hole.

[0009] In the present application, the initial state of the elastic cover plate refers to the state in which the elastic cover plate closes the overflow hole. In normal working state, when gas enters the overflow hole, a certain air pressure will be generated, and the elastic cover plate will be deformed downward under the action of the air pressure, so that the elastic cover plate slides toward the bottom away from the overflow hole, forming an air flow outlet to discharge the gas; when there is no gas flowing out, the elastic cover plate, under the action of its own elastic force, slides in the direction close to the overflow hole with the elastic cover plate to restore to the initial state, closes the overflow hole, and prevents external gas from flowing in, thereby controlling the air flow direction to unidirectional flow, and achieving the purpose of preventing backflow. Compared with the air inlet duct with an overflow groove in the prior art, the air inlet duct in the present application can effectively avoid the problem of external gas flowing back into the air inlet duct through the overflow hole and reducing the aerodynamic performance and stability of the air inlet duct while reducing the outlet distortion.

[0010] Optionally, the elastic cover plate has a fixed end and a sliding end that are relatively arranged, the fixed end of the elastic cover plate is fixedly connected to one end of the overflow hole, the sliding end of the elastic cover plate is slidably connected to the other end of the overflow hole, and the elastic cover plate is in an arched state toward the overflow hole.

[0011] Optionally, a plurality of partitions are vertically arranged around the outer side of the overflow hole, a guide channel is formed between the plurality of partitions, the elastic cover plate has a fixed end and a sliding end relatively arranged, the fixed end of the elastic cover plate is fixedly connected to the partition located on the same side of the fixed end, and the sliding end of the elastic cover plate is slidably connected to the partition located on the same side of the sliding end.

[0012] Optionally, the length of the partition at the sliding end of the elastic cover plate is greater than the length of the partition at the fixed end of the elastic cover plate.

[0013] Optionally, the air inlet body includes an inlet section, an internal air duct diffusion section and an equal straight section connected in sequence, the air inlet is the inlet section port, the air outlet is the equal straight section port, the overflow hole is arranged on the end face of the inner wall of the equal straight section, and the air outlet is used to connect to the engine air inlet.

[0014] Optionally, the elastic cover plate is made of metal material.

[0015] Optionally, there are multiple overflow holes, and the multiple overflow holes are arranged at equal intervals on the inner wall end surface of the air outlet.

[0016] Optionally, the sum of the areas of the plurality of overflow holes is 10% to 30% of the area of ​​the air outlet.

[0017] Optionally, the overflow hole is a waist-shaped hole.

[0018] Optionally, the overflow hole is arranged just below the axial centerline of the air outlet.

[0019] 3. Beneficial effects

[0020] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0021] (1) An air intake duct proposed in an embodiment of the present application has a simple structure. In the present application, the initial state of the elastic cover plate refers to the state in which the elastic cover plate closes the overflow hole. In normal working state, when gas enters the overflow hole, a certain air pressure will be generated. The elastic cover plate will deform downward under the action of the air pressure, so that the elastic cover plate slides toward the bottom away from the overflow hole, forming an air flow outlet to discharge the gas; when no gas flows out, the elastic cover plate, under the action of its own elastic force, slides in the direction close to the overflow hole to restore to the initial state, closes the overflow hole, and prevents external gas from flowing in, thereby controlling the air flow direction to unidirectional flow, and achieving the purpose of preventing backflow. Compared with the air intake duct with an overflow groove in the prior art, the air intake duct in the present application can effectively avoid the problem of external gas flowing back into the air intake duct through the overflow hole and reducing the aerodynamic performance and stability of the air intake duct while reducing the outlet distortion.

[0022] (2) An air intake duct proposed in an embodiment of the present application, by setting the elastic cover plate to be in an arched state toward the overflow hole, so that the elastic cover plate has a certain deformation in the initial state, effectively ensuring that the elastic cover plate returns to the initial state under the action of elastic force and closes the overflow hole.

[0023] (3) An air intake duct proposed in an embodiment of the present application is provided with a plurality of partitions vertically around the outer side of the overflow hole, and a guide channel is formed between the plurality of partitions. At this time, the initial state of the elastic cover plate refers to the closing of the guide channel formed between the elastic cover plate and the plurality of partitions, so as to achieve the closed state of the overflow hole. When gas enters the overflow hole, a certain air pressure will be generated, and the elastic cover plate will deform downward under the action of the air pressure, so that the sliding end of the elastic cover plate slides in the direction away from the overflow hole, and an air flow outlet is formed to discharge the gas; when no gas flows out, the elastic cover plate, under the action of its own elastic force, connects the sliding end of the elastic cover plate with the partition on the same side of the sliding end, and the elastic cover plate returns to the initial state, closes the guide channel, and then achieves the closure of the overflow hole, so that the external gas cannot flow into the air intake duct, thereby achieving the purpose of preventing backflow in the air intake duct.

[0024] (4) An air inlet duct proposed in an embodiment of the present application, by setting the length of the partition at the sliding end of the elastic cover plate to be greater than the length of the partition at the fixed end of the elastic cover plate, makes the elastic cover plate have a certain deformation in the initial state, effectively ensures that the elastic cover plate returns to the initial state under the action of elastic force, and closes the overflow hole.

[0025] (5) An air intake duct proposed in an embodiment of the present application can better meet the requirements of improving the aerodynamic performance of the air intake duct and reducing the outlet distortion by setting a plurality of overflow holes with equal spacing.

[0026] (6) An air inlet proposed in an embodiment of the present application limits the sum of the areas of the plurality of overflow holes to 10% to 30% of the area of ​​the air outlet. This can improve the aerodynamic performance of the air inlet and reduce the outlet distortion while better meeting the overflow volume requirements for aircraft equipment cooling.

[0027] (7) An air inlet duct proposed in an embodiment of the present application is arranged such that the overflow hole is arranged just below the axis of the air outlet, thereby ensuring that the boundary layer airflow flows out from the overflow hole and reducing flow field distortion. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of an air intake duct structure proposed in an embodiment of the present invention.

[0029] Figure 2 A right side view of an air intake duct provided in an embodiment of the present invention.

[0030] Figure 3 A schematic diagram of the structure of a medium straight section of an air intake duct proposed in an embodiment of the present invention.

[0031] Figure 4 A schematic diagram of the structure of a medium straight section of an air intake duct proposed in an embodiment of the present invention.

[0032] Figure 5 This is the total pressure distribution diagram of the intake duct outlet without an overflow hole in the prior art.

[0033] Figure 6 A total pressure distribution diagram of an inlet duct outlet proposed in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to further understand the content of the present invention, the present invention is described in detail with reference to the accompanying drawings and embodiments.

[0035] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are only used to explain the relevant inventions, rather than to limit the invention. It should also be noted that, for the convenience of description, only the parts related to the invention are shown in the accompanying drawings. The words "first", "second", etc. described in the present invention are set for the convenience of describing the technical solution of the present invention, and have no specific limiting effect. They are all general references and do not constitute a limiting effect on the technical solution of the present invention. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. In the description of the present invention, it should be noted that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be a connection between the insides of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Multiple technical solutions in the same embodiment, and multiple technical solutions in different embodiments, can be arranged and combined to form new technical solutions without contradictions or conflicts, all of which are within the scope of protection required by the present invention.

[0036] Example 1

[0037] Combined with Figure 1-6 The present embodiment provides an air inlet, comprising: an air inlet body 1, the air inlet body 1 having an air inlet 2 and an air outlet 3, an overflow hole 4 being arranged on the inner wall of the air outlet 3, an elastic cover plate 5 being arranged on the overflow hole 4, the overflow hole 4 and the elastic cover plate 5 being slidably connected, and the elastic cover plate 5 being used for automatic closing and opening of the overflow hole 4.

[0038] In the present application, the initial state of the elastic cover plate 5 refers to the state in which the elastic cover plate 5 closes the overflow hole 4. In normal working state, when gas enters the overflow hole 4, a certain air pressure will be generated, and the elastic cover plate 5 will be deformed downward under the action of the air pressure, so that the elastic cover plate 5 slides toward the bottom away from the overflow hole 4, forming an air flow outlet to discharge the gas; when there is no gas flowing out, the elastic cover plate 5, under the action of its own elastic force, slides in the direction close to the overflow hole 4 with the elastic cover plate 5 to restore to the initial state, closes the overflow hole 4, and prevents external gas from flowing in, thereby controlling the air flow direction to be unidirectional flow, and achieving the purpose of preventing backflow. Compared with the air inlet duct with an overflow groove in the prior art, the air inlet duct in the present application can effectively avoid the problem of external gas flowing back into the air inlet duct through the overflow hole 4 and reducing the aerodynamic performance and stability of the air inlet duct while reducing the outlet distortion.

[0039] In order to better illustrate that the setting of the overflow hole 4 in the present application can meet the requirements of improving the aerodynamic performance of the air inlet and reducing the outlet distortion, the present application uses the CFD method to simulate the flow field of the air inlet without the overflow hole 4 in the prior art and the air inlet in the present application, and the simulation calculation is performed at an altitude of 0m, a flight speed of Ma=0.8, and an angle of attack of 0° to obtain the outlet flow field total pressure distribution cloud diagram, as shown in FIG. Figure 5 and Figure 6 As shown. Figure 5 and Figure 6 It can be seen that in the prior art, when the airflow passes through the air inlet without the overflow hole 4, the boundary layer appears at the lower part of the air inlet outlet section, and two vortices are formed on the left and right sides, resulting in uneven airflow at the outlet; while in the present application, the overflow hole 4 is opened at the outlet, so that the boundary layer airflow flows out from the opening position, reducing the flow field distortion. At the same time, it is calculated that the total pressure recovery coefficient of the air inlet in the prior art is 98.0%, and the outlet flow field distortion is 0.23; the total pressure recovery coefficient of the air inlet in the present application is 98.4%, and the outlet flow field distortion is 0.12. It can be seen that the air inlet in the present application can meet the requirements of improving the aerodynamic performance of the air inlet and reducing the outlet distortion.

[0040] Example 2

[0041] An air intake duct of the present embodiment, compared with the technical solution of embodiment 1, can be improved as follows: the elastic cover plate 5 has a fixed end and a sliding end that are relatively arranged, the fixed end of the elastic cover plate 5 is fixedly connected to one end of the overflow hole 4, the sliding end of the elastic cover plate 5 is slidably connected to the other end of the overflow hole 4, and the elastic cover plate 5 is in an arched state toward the overflow hole 4.

[0042] When gas enters the overflow hole 4, a certain air pressure will be generated, and the elastic cover plate 5 will be deformed downward under the action of the air pressure, so that the sliding end of the elastic cover plate 5 slides toward the bottom of the overflow hole 4, forming an air flow outlet to discharge the gas; when there is no gas flowing out, the elastic cover plate 5, under the action of its own elastic force, restores the sliding end of the elastic cover plate 5 separated from the overflow hole 4 to the initial state with the overflow hole 4, closes the overflow hole 4, and prevents external gas from flowing in, thereby achieving the purpose of preventing backflow in the air intake duct. At the same time, the elastic cover plate 5 is in an arched state toward the overflow hole 4, so that the elastic cover plate 5 has a certain deformation in the initial state, effectively ensuring that the elastic cover plate 5 returns to the initial state under the action of the elastic force and closes the overflow hole 4.

[0043] Example 3

[0044] Combined with Figure 1-2 Compared with the technical solution of Example 1, an air intake duct of this embodiment can be improved as follows: a plurality of partitions 6 are vertically arranged around the outer side of the overflow hole 4, and a guide channel is formed between the plurality of partitions 6; the elastic cover plate 5 has a fixed end and a sliding end that are relatively arranged; the fixed end of the elastic cover plate 5 is fixedly connected to the partition plate 6 on the same side of the fixed end, and the sliding end of the elastic cover plate 5 is slidably connected to the partition plate 6 on the same side of the sliding end.

[0045] The initial state of the elastic cover plate 5 refers to the closure of the flow guide channel formed between the elastic cover plate 5 and the plurality of partitions 6, thereby achieving the closed state of the overflow hole 4. When gas enters the overflow hole 4, a certain air pressure will be generated, and the elastic cover plate 5 will be deformed downward under the action of the air pressure, so that the sliding end of the elastic cover plate 5 slides in the direction away from the overflow hole 4, and forms an air flow outlet to discharge the gas; when no gas flows out, the elastic cover plate 5, under the action of its own elastic force, connects the sliding end of the elastic cover plate 5 with the partition 6 on the same side of the sliding end, and the elastic cover plate 5 returns to the initial state, closing the flow guide channel, thereby achieving the closure of the overflow hole 4, so that the external gas cannot flow into the air inlet, thereby achieving the purpose of preventing backflow in the air inlet.

[0046] In actual use, there are four partitions 6, namely the first partition, the second partition, the third partition and the fourth partition. The first partition is arranged opposite to the second partition, and the third partition is arranged opposite to the fourth partition. The fixed end of the elastic cover plate 5 is fixedly connected to the first partition, and the sliding end of the elastic cover plate is movably connected to the second partition.

[0047] Example 4

[0048] Compared with the technical solution of Example 3, the air inlet of this embodiment can be improved as follows: the length of the partition plate 6 at the sliding end of the elastic cover plate 5 is greater than the length of the partition plate 6 at the fixed end of the elastic cover plate 5. This arrangement enables the elastic cover plate 5 to have a certain deformation in the initial state, effectively ensuring that the elastic cover plate 5 returns to the initial state under the action of elastic force and closes the overflow hole 4.

[0049] Example 5

[0050] Combined with Figure 1-2 Compared with the technical solution of embodiment 1, the air inlet of this embodiment can be improved as follows: the air inlet body 1 includes an inlet section 7, an internal airway diffusion section 8 and an equal straight section 9 connected in sequence, the air inlet 2 is the port of the inlet section 7, the air outlet 3 is the port of the equal straight section 9, the overflow hole is arranged on the inner wall end face of the equal straight section 9, and the air outlet 3 is used to connect with the engine air inlet. The air inlet of this structure can make the air flow more stable and reduce the flow field distortion.

[0051] Example 6

[0052] Compared with the technical solution of embodiment 1, the air intake duct of this embodiment can be improved as follows: the elastic cover plate 5 is made of metal material. In actual use, carbon steel, alloy steel and other materials with high elastic limit and fatigue limit are used.

[0053] Example 7

[0054] Combined with Figure 3-4 , compared with the technical solution of Example 1, an air inlet of this embodiment can be improved as follows: there are multiple overflow holes 4, and the multiple overflow holes 4 are evenly spaced on the inner wall end face of the air outlet 3. Usually, a boundary layer will appear in the lower part of the air inlet outlet cross section, and two vortices will be formed on the left and right sides, resulting in uneven flow of the outlet airflow. By opening an overflow hole 4 at a position corresponding to the inner wall end face of the air outlet 3 and the boundary layer, the boundary layer airflow flows out from the opening position, reducing the flow field distortion. At the same time, according to the different requirements for the air inlet in actual applications, by setting a plurality of equally spaced overflow holes 4, the requirements of improving the aerodynamic performance of the air inlet and reducing the outlet distortion can be better met.

[0055] like Figure 4 As shown, in actual use, there are two overflow holes 4, and the circumferential spacing between the two overflow holes 4 is 60°.

[0056] In actual use, there are three overflow holes 4, and the three overflow holes 4 are arranged at equal intervals, and the circumferential spacing between adjacent overflow holes 4 is 45°.

[0057] Example 8

[0058] Compared with the technical solution of Example 7, an air inlet of this embodiment can be improved as follows: the sum of the areas of the plurality of overflow holes 4 is 10% to 30% of the area of ​​the air outlet 3. This setting can better meet the requirements of the overflow volume for cooling of aircraft equipment while meeting the requirements of improving the aerodynamic performance of the air inlet and reducing the outlet distortion.

[0059] Example 9

[0060] Compared with the technical solution of embodiment 1, the air inlet of this embodiment can be improved as follows: the overflow hole 4 is a waist-shaped hole. This arrangement is convenient for processing. In actual use, the shape of the overflow hole 4 can be circular, elliptical or other geometric shapes.

[0061] Example 10

[0062] Compared with the technical solution of Example 1, the air inlet of this embodiment can be improved as follows: the overflow hole 4 is arranged just below the axis of the air outlet 3. This arrangement facilitates ensuring that the boundary layer airflow flows out from the overflow hole 4 and reduces flow field distortion.

[0063] The present invention and its embodiments are described schematically above, and the description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and designs a structural method and an embodiment similar to the technical solution without creativity without departing from the purpose of the invention, they shall all fall within the protection scope of the present invention.

Claims

1. An air intake duct, characterized in that: include: An air inlet body, the air inlet body having an air inlet and an air outlet, an overflow hole being arranged on the inner wall of the air outlet, an elastic cover plate being arranged on the overflow hole, the overflow hole and the elastic cover plate being slidably connected, and the elastic cover plate being used for automatically closing and opening the overflow hole; The elastic cover plate has a fixed end and a sliding end that are arranged opposite to each other, the fixed end of the elastic cover plate is fixedly connected to one end of the overflow hole, the sliding end of the elastic cover plate is slidably connected to the other end of the overflow hole, and the elastic cover plate is in an arched state toward the overflow hole; A plurality of partitions are vertically arranged around the outer side of the overflow hole, a guide channel is formed between the plurality of partitions, the elastic cover plate has a fixed end and a sliding end arranged opposite to each other, the fixed end of the elastic cover plate is fixedly connected to the partition located on the same side of the fixed end, and the sliding end of the elastic cover plate is slidably connected to the partition located on the same side of the sliding end; The length of the partition at the sliding end of the elastic cover plate is greater than the length of the partition at the fixed end of the elastic cover plate.

2. The air intake duct according to claim 1, characterized in that: The air inlet body includes an inlet section, an internal air duct diffusion section and an equal straight section which are connected in sequence. The air inlet is the inlet section port, the air outlet is the equal straight section port, the overflow hole is arranged on the inner wall end face of the equal straight section, and the air outlet is used to connect with the engine air inlet.

3. The air intake duct according to claim 1, characterized in that: The elastic cover plate is made of metal material.

4. The air intake duct according to claim 1, characterized in that: There are a plurality of overflow holes, and the plurality of overflow holes are arranged at equal intervals on the inner wall end surface of the air outlet.

5. The air intake duct according to claim 4, characterized in that: The sum of the areas of the plurality of overflow holes is 10% to 30% of the area of ​​the air outlet.

6. The air intake duct according to claim 1, characterized in that: The overflow hole is a waist-shaped hole.

7. The air intake duct according to claim 1, characterized in that: The overflow hole is arranged just below the axial center line of the air outlet.

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