A supersonic air inlet with a belly layout

Abstract

The invention discloses a supersonic air inlet with a belly layout. The invention comprises a supersonic air inlet front body compression surface (2) located at the belly of a supersonic missile body (1), and the rear of the supersonic air inlet front body compression surface (2) is connected to the air inlet body; a coordinate system is established on the symmetry plane of the supersonic missile body (1), wherein: the XY coordinate plane is the symmetry plane, and the X, Y, and Z axes are the heading, vertical, and horizontal directions, respectively; the supersonic air inlet front body compression surface (2) is a variable curved surface design, and three-level local isentropic compression is adopted along the X-axis direction, and the corresponding compression angles δ1, δ2, and δ3 are designed according to equal intensity compression. The invention adopts the missile belly air inlet layout form, which can make room for the missile head, which is conducive to the installation of components such as the seeker, and at the same time, the variable curved surface compression surface design can effectively change the flow direction of the low-energy flow in the boundary layer, effectively eliminate the low-energy flow in the boundary layer, and improve the air inlet performance.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft air inlet design, and in particular relates to a subventral supersonic air inlet. Background Art

[0002] With the advancement of science and technology and the gradual upgrading of weapons and equipment, supersonic cruise missiles with strong penetration and strike capabilities are important weapons in modern warfare. Supersonic cruise missiles usually use air-breathing propulsion systems, and supersonic inlets, as one of the main components of air-breathing propulsion systems, mainly function to decelerate and pressurize high-speed airflow, provide high-energy air flow for the power unit, and are an important part of the air-breathing power unit of supersonic cruise missiles. The performance of the supersonic inlet directly affects the combustion efficiency of the combustion chamber and the overall performance of the engine. Therefore, the research on supersonic inlet design technology is crucial for tactical missiles powered by high-performance ramjet engines.

[0003] Common supersonic inlet layouts include head intake, rear intake with partitions, and belly intake. The rear intake with partitions has low inlet flow capture rate and compression efficiency, and the inlet resistance is large due to the partitions; the head intake layout has better inlet performance and smaller inlet resistance, but the head layout has a large inlet space occupancy rate, which has a greater impact on the installation of components such as the seeker and the window for missiles. The belly layout of the inlet can free up space for the missile head, which is conducive to the installation of components such as the seeker, and has no impact on the seeker window. At the same time, the belly layout of the inlet has better angle of attack characteristics. However, the performance of the belly layout inlet is greatly affected by the belly boundary layer of the missile body. Summary of the invention

[0004] The purpose of the present invention is to provide a supersonic air inlet under the belly. The present invention adopts the air inlet layout under the belly of the missile, which can free up space for the missile head, which is conducive to the installation of components such as the seeker. At the same time, the variable curved surface compression surface design can effectively change the flow direction of the low-energy flow in the boundary layer, effectively eliminate the low-energy flow in the boundary layer, improve the performance of the air inlet, and has good engineering application value.

[0005] The technical scheme of the present invention is: a supersonic air inlet with a belly layout, comprising a supersonic air inlet front body compression surface located at the belly of a supersonic missile body, the front body compression surface of the supersonic air inlet is connected to the air inlet body; a coordinate system is established on the symmetry surface of the supersonic missile body, wherein: an XY coordinate plane is a symmetry plane, and the X, Y, and Z axes are respectively heading, vertical, and horizontal; the supersonic air inlet front body compression surface is a variable curved surface design, and three-level local isentropic compression is adopted along the X-axis direction, which are respectively: front-stage oblique shock wave compression, middle-stage isentropic compression wave, and rear-stage oblique shock wave compression, and the corresponding compression angles δ1, δ2, and δ3 are designed according to equal-intensity compression.

[0006] In the above-mentioned underbelly supersonic inlet, the compression surface of the supersonic inlet front body is symmetrical about the symmetry plane, and a variable compression angle design is adopted along the Z axis: the compression angle starts from the symmetry plane and decreases successively toward both sides along the Z axis direction.

[0007] In the aforementioned underbelly layout supersonic air inlet, the air inlet body includes a supersonic air inlet isolation section, the front end of the supersonic air inlet isolation section is the air inlet; the bottom of the air inlet is a supersonic air inlet lip cover, and the two sides are supersonic air inlet side panels; the supersonic air inlet lip cover adopts a shock wave sealing design.

[0008] Optionally, in the aforementioned underbelly layout supersonic inlet, the supersonic inlet lip cover also adopts a forward-swept design, and the forward-swept angle is determined in combination with the variable-curved surface compression wave formed on the inlet compression surface along the Z-axis.

[0009] Optionally, in the aforementioned underbelly layout supersonic inlet, the supersonic inlet lip cover also adopts a swept design, and the swept angle is determined in combination with the variable curved surface compression wave formed by the inlet compression surface along the Z-axis.

[0010] Optionally, in the aforementioned underbelly layout supersonic air inlet, the front end of the supersonic air inlet side panel adopts a swept design.

[0011] Optionally, in the aforementioned underbelly layout supersonic air inlet, the front end of the supersonic air inlet side panel adopts a forward-swept design.

[0012] In the aforementioned underbelly supersonic air inlet, an air inlet vent is also provided on the top of the supersonic air inlet isolation section, and the air inlet vent is connected to the supersonic air inlet vent cavity; the supersonic air inlet vent cavity is arranged between the supersonic air inlet isolation section and the belly of the supersonic missile body.

[0013] In the above-mentioned subventral supersonic air inlet, the rear end of the supersonic air inlet isolation section is connected to the air inlet expansion section, and the air inlet expansion section is connected to the supersonic air inlet outlet.

[0014] The advantages of the present invention are as follows: in order to solve the problem that the performance of the belly-layout supersonic air inlet is affected by the boundary layer on the belly of the missile body, the present invention adopts a variable curved surface design for the supersonic air inlet front body compression surface located at the lower abdomen of the supersonic missile body, and utilizes the different airflow pressure distributions under different compression degrees of the air inlet. The supersonic air inlet front body compression surface adopts a variable compression angle design along the first-level outer compression of the air inlet along the Z axis, and changes the flow direction of the boundary layer by changing the pressure gradient of the outer compression surface of the air inlet along the Z axis, thereby eliminating the low-energy flow in the boundary layer.

[0015] The difference between the present invention and the conventional non-divided ventral supersonic inlet aerodynamic surface design is the variable curved surface design of the supersonic inlet front body compression surface. The advantages of this design are: the inlet compression surface is designed with three-stage local isentropic compression along the X-axis to improve the compression efficiency of the inlet, while the inlet compression surface is designed with symmetric features about the XY plane, and a variable compression angle is designed along the Z-axis, and the variable compression angle design is used to change the shock wave intensity along the Z-axis of the inlet, so that the inlet forms a forward pressure gradient along the Z-axis, so that the flow direction of the low-energy flow in the boundary layer of the belly of the projectile in front of the inlet is changed from the X-axis to the Z-axis, thereby eliminating the formation of low-energy flow in the boundary layer on the belly of the projectile in front of the inlet, improving the aerodynamic performance of the inlet while improving the influence of the boundary layer on the actual flow area of ​​the inner flow channel.

[0016] Furthermore, compared with the traditional underbelly layout supersonic inlet design without stealth features, the present invention designs the supersonic inlet lip cover as a forward-swept or swept-back structure, so that it is a sawtooth-shaped lip cover; this structure can effectively reduce the radar scattering area of ​​the inlet and improve the stealth characteristics of the inlet. Specifically, its design features are: the sawtooth-shaped lip cover is located at the rear lower part of the supersonic inlet front body compression surface, and the inlet lip cover adopts the inlet compression wave sealing design. In order to improve the stealth characteristics of the inlet, the inlet lip cover is designed as a sawtooth-shaped lip cover based on the variable curved surface compression wave formed along the Z axis of the inlet compression surface; optionally, in order to further improve the inlet performance (such as: total pressure recovery coefficient and low speed range), the inlet lip cover can be designed as a swept-back sawtooth-shaped lip cover. Optionally, in order to further improve the inlet flow capture efficiency, the inlet lip cover can also be designed as a forward-swept sawtooth-shaped lip cover.

[0017] The belly-underlay supersonic inlet of the present invention can effectively eliminate the low-energy flow of the boundary layer formed on the belly of the missile body and improve the performance of the inlet. According to simulation calculations, compared with conventional dual-dimensional inlets designed with the same size and airflow deflection angle, the total pressure recovery coefficient of the inlet throat of the present invention is increased by about 5%, and the thickness of the boundary layer of the inlet throat is reduced by about 20% when the incoming flow Mach number is 3.5, the angle of attack is 2°, and the sideslip angle is 0°.

[0018] The belly-underlay supersonic air inlet of the present invention has good air intake performance, good angle of attack characteristics, low aerodynamic drag and good stealth characteristics, and the air inlet does not occupy the missile head space, which can free up the missile head space, which is conducive to the installation of components such as the seeker. At the same time, the belly-underlay supersonic air inlet of the present invention also has the advantages of fixed geometric structure, simple aerodynamic profile structure molding, flexible structural design, easy implementation, etc., and has good engineering application value.

[0019] In summary, the belly-underlay supersonic air inlet proposed in the present invention adopts the belly-underlay air inlet layout of the missile, which can free up space for the missile head, which is beneficial to the installation of components such as the seeker. At the same time, the variable curved compression surface design can effectively change the flow direction of the low-energy flow in the boundary layer, effectively eliminate the low-energy flow in the boundary layer, and improve the air inlet performance, which has good engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall layout of a subventral supersonic air inlet of the present invention.

[0021] Figure 2 It is a local symmetrical surface view of a subventral supersonic air inlet of the present invention.

[0022] Figure 3 This is a schematic diagram of a supersonic air inlet with a swept-back structure and a belly-underlaying supersonic air inlet lip.

[0023] Figure 4 It is a schematic diagram of the structure of the compression surface of the supersonic inlet forebody.

[0024] Figure 5 This is the characteristic diagram of the boundary layer flow on the compression surface of the supersonic inlet forebody.

[0025] Figure 6 This is a schematic diagram of a supersonic air inlet with a forward-swept supersonic inlet lip and an underbelly layout.

[0026] Figure 7 This is an enlarged schematic diagram of the supersonic inlet lip cover as a forward-swept structure.

[0027] Figure numerals: 1-supersonic missile body, 2-supersonic air inlet front body compression surface, 21-front stage oblique shock wave compression, 22-intermediate isentropic compression wave, 23-rear stage oblique shock wave compression, 3-supersonic air inlet lip cover, 4-supersonic air inlet side panel, 5-inlet vent, 6-supersonic air inlet vent cavity, 7-supersonic air inlet isolation section, 8-inlet expansion section, 9-supersonic air inlet outlet. DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0029] Embodiment 1. A supersonic air inlet arranged under the abdomen, comprising: Figure 1-7As shown, it comprises a supersonic missile body 1, a supersonic air inlet front body compression surface 2, a supersonic air inlet lip cover 3, a supersonic air inlet side plate 4, a supersonic air inlet isolation section 7, a supersonic air inlet vent 5, a supersonic air inlet vent cavity 6, a supersonic air inlet expansion section 8 and a supersonic air inlet outlet 9. The supersonic air inlet is composed of the air inlet front body compression surface 2, the supersonic air inlet lip cover 3, the supersonic air inlet side plate 4, the supersonic air inlet isolation section 7, the supersonic air inlet vent 5, the supersonic air inlet vent cavity 6, the supersonic air inlet expansion section 8 and the supersonic air inlet outlet 9. When the missile is flying, the high-speed airflow passes through the air inlet compression surface 2 to form a series of compression wave systems that converge on the air inlet lip cover 3. The airflow is compressed by the shock wave system and then decelerated and pressurized. It passes through the air inlet isolation section 7 and the air inlet expansion section 8 and enters the engine through the air inlet outlet 9. The low-energy flow of the boundary layer develops to a certain thickness through the belly of the missile, which has a great influence on the performance of the air inlet. Through the variable curved surface design of the air inlet compression surface 2, there is an obvious pressure gradient in the YZ plane of the compression surface outside the air inlet, so that the flow direction of the low-energy flow of the boundary layer changes and is discharged from the air inlet through both sides of the air inlet compression surface, which can improve the performance of the air inlet. Further, the air inlet vent 5 and the air inlet vent cavity 6 are designed in the air inlet isolation section 7 to further remove the boundary layer, thereby improving the performance of the air inlet. Among them, the air inlet lip cover 3 can be designed as a straight type or a sawtooth type according to the requirements of the stealth design. Further, the air inlet lip cover 3 can be designed as a forward swept type according to the flow capture requirements to form a concave inlet surface, thereby improving the efficiency of air inlet flow capture.

[0030] Embodiment 2. A supersonic air inlet arranged under the abdomen, comprising: Figure 1-7 As shown, it includes a supersonic air inlet front body compression surface 2 located at the lower abdomen of a supersonic missile body 1, and the rear of the supersonic air inlet front body compression surface 2 is connected to the air inlet body; a coordinate system is established on the symmetry plane of the supersonic missile body 1, wherein: the XY coordinate plane is the symmetry plane, and the X, Y, and Z axes are respectively the heading, vertical, and horizontal directions; the supersonic air inlet front body compression surface 2 is a variable curved surface design, and it adopts three-level local isentropic compression along the X-axis direction, which are respectively: the front stage oblique shock wave compression 21, the middle stage isentropic compression wave 22, and the rear stage oblique shock wave compression 23, and the corresponding compression angles δ1, δ2, and δ3 are designed according to equal intensity compression. This design can effectively improve the air inlet performance.

[0031] The aforementioned supersonic inlet front body compression surface 2 is symmetrical about the symmetry plane, and a variable compression angle design is adopted along the Z axis: the compression angle starts from the symmetry plane and decreases successively along the Z axis to both sides. Through this design, the airflow can change in pressure gradient along the Z axis, change the flow direction of the boundary layer, and eliminate the low-energy flow in the boundary layer.

[0032] Furthermore, the aforementioned air inlet body includes a supersonic air inlet isolation section 7, the front end of which is an air inlet; the bottom of the air inlet is a supersonic air inlet lip cover 3, and both sides are supersonic air inlet side panels 4; the supersonic air inlet lip cover 3 adopts a shock wave seal design. This design can improve the air inlet flow capture efficiency.

[0033] Optionally, the aforementioned supersonic inlet lip cover 3 may adopt a forward-swept design, and the forward-swept angle is determined in combination with the variable-curved surface compression wave formed along the Z-axis on the inlet compression surface.

[0034] Optionally, the aforementioned supersonic inlet lip cover 3 may also adopt a swept design, and the swept angle is determined in combination with the variable curved surface compression wave formed along the Z-axis on the inlet compression surface.

[0035] The forward and backward swept designs can make the supersonic inlet lip 3 form a sawtooth shape, effectively reducing the inlet radar scattering area and improving the inlet stealth characteristics. In addition, the swept design can improve the inlet performance (such as the total pressure recovery coefficient and low-speed range); the forward swept design can further improve the inlet flow capture efficiency.

[0036] Optionally, the front end of the aforementioned supersonic inlet side panel 4 adopts a swept design.

[0037] Optionally, the front end of the aforementioned supersonic inlet side panel 4 adopts a forward-swept design.

[0038] The swept-back design can eliminate low-energy flow in the boundary layer and improve the inlet performance and speed range; the forward-swept design can improve the inlet flow capture efficiency.

[0039] Furthermore, an air inlet vent 5 is also provided on the top of the aforementioned supersonic air inlet isolation section 7, and the air inlet vent 5 is connected to a supersonic air inlet vent cavity 6; the supersonic air inlet vent cavity 6 is arranged between the supersonic air inlet isolation section 7 and the belly of the supersonic missile body 1.

[0040] Furthermore, the rear end of the aforementioned supersonic inlet isolation section 7 is connected to the inlet expansion section 8, and the inlet expansion section 8 is connected to the supersonic inlet outlet 9.

Claims

1. A subventral supersonic air inlet, characterized in that: The invention comprises a supersonic air inlet forebody compression surface (2) located at the lower abdomen of a supersonic missile body (1), the rear of the supersonic air inlet forebody compression surface (2) being connected to the air inlet body; a coordinate system is established on the symmetry plane of the supersonic missile body (1), wherein: the XY coordinate plane is the symmetry plane, and the X, Y and Z axes are respectively the heading, the vertical and the horizontal directions; the supersonic air inlet forebody compression surface (2) is a variable curved surface design, and three levels of local isentropic compression are adopted along the X-axis direction, which are respectively: a front-stage oblique shock wave compression (21), a middle-stage isentropic compression wave (22) and a rear-stage oblique shock wave compression (23), and the corresponding compression angles δ1, δ2 and δ3 are designed according to equal intensity compression; the supersonic air inlet forebody compression surface (2) is symmetrical about the symmetry plane, and a variable compression angle design is adopted along the Z axis: the compression angle starts from the symmetry plane and decreases in sequence along the Z axis to both sides.

2. The subventral supersonic air inlet according to claim 1, characterized in that: The air inlet body comprises a supersonic air inlet isolation section (7), the front end of which is an air inlet; the bottom of the air inlet is a supersonic air inlet lip cover (3), and the two sides are supersonic air inlet side panels (4); the supersonic air inlet lip cover (3) adopts a shock wave seal design.

3. The subventral supersonic air inlet according to claim 2 is characterized in that: The supersonic inlet lip cover (3) also adopts a forward-swept design, and the forward-swept angle is determined in combination with the variable-curved surface compression wave formed along the Z axis by the inlet compression surface.

4. The subventral supersonic air inlet according to claim 2, characterized in that: The supersonic inlet lip cover (3) also adopts a swept back design, and the swept back angle is determined in combination with the variable curved surface compression wave formed along the Z axis by the inlet compression surface.

5. The subventral supersonic air inlet according to claim 2, characterized in that: The front end of the supersonic air inlet side panel (4) adopts a swept back design.

6. The subventral supersonic air inlet according to claim 2, characterized in that: The front end of the supersonic air inlet side panel (4) adopts a forward-swept design.

7. The subventral supersonic air inlet according to claim 2, characterized in that: The top of the supersonic air inlet isolation section (7) is also provided with an air inlet vent (5), and the air inlet vent (5) is connected to the supersonic air inlet vent cavity (6); the supersonic air inlet vent cavity (6) is arranged between the supersonic air inlet isolation section (7) and the belly of the supersonic missile body (1).

8. The subventral supersonic air inlet according to claim 2, characterized in that: The rear end of the supersonic air inlet isolation section (7) is connected to the air inlet expansion section (8), and the air inlet expansion section (8) is connected to the supersonic air inlet outlet (9).

9. The subventral supersonic air inlet according to claim 1, characterized in that: The joining line between the front end of the supersonic air inlet front body compression surface (2) and the lower abdomen of the supersonic missile body (1) is a straight line or a curve.

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