Design method for self-adaptive bump air inlet channel structure

Abstract

The invention discloses a self-adaptive bump air inlet channel structure design method, and belongs to the field of aircraft air inlet channel structure design. Comprising four parts of high-bearing and large-deformation flexible skin design, main bearing structure design, distributed pressure-driven multi-airbag system design and control system design. According to the design scheme of the honeycomb filling flexible skin, the pneumatic pressure of the air inlet channel can be effectively borne, large out-of-plane deformation can be achieved, and the honeycomb filling flexible skin is an important composition structural part for achieving the self-adaptive bulging function; deformation of the bump molded surface is achieved through inflation and deflation of the air bag, the driving form is simple, the response speed is high, and the occupied size of the driving system is small; the multi-air-bag driving mode plays a good distributed driving role, the molded surface can be directly and effectively driven to deform under the effect of incoming flow loads, and therefore high-precision control over the molded surface of the bulge air inlet channel can be achieved.

Description

Technical Field

[0001] The invention belongs to the field of aircraft air inlet structure design, and proposes a bulge air inlet structure design method capable of realizing adaptive deformation. Background Art

[0002] As an important airflow regulating component of the engine, the main function of the aircraft air intake is to introduce air into the engine to provide oxygen for fuel combustion, thereby driving the normal operation of the engine. The air intake directly affects the thrust performance and efficiency of the engine, and its design is very important. Some aircraft use adjustable dual air intakes, which adjust the roar area by driving the two-stage compression ramp to adjust the engine intake volume under different flight conditions. However, this type of air intake has the disadvantages of heavy weight, complex adjustment system, and poor stealth performance.

[0003] Some aircraft use a three-dimensional bulge-type boundary layer-free inlet (hereinafter referred to as the bulge inlet), which uses a fixed bulge to simulate the adjustable ramp in a conventional inlet and can achieve the purpose of compressing the airflow. The bulge inlet has the advantages of simple structure, light weight, and good stealth performance. However, since its profile is not adjustable, it can only meet the launch matching performance under a certain Mach number. For example, at high Mach numbers, the conical shock wave and the end shock wave induced by the bulge compression surface interfere with the boundary layer, and the shock wave / boundary layer interference problem is serious, affecting the aerodynamic performance of the inlet. Aerodynamic research shows that changing the profile of the bulge inlet can improve the launch matching performance under high Mach numbers. Therefore, realizing an adaptively adjustable bulge inlet structure is of great significance to improving the aerodynamic performance of the aircraft. Summary of the invention

[0004] The present invention provides a method for designing a bulge inlet structure capable of realizing adaptive deformation. The principle of adaptive deformation of the bulge inlet is to monitor the Mach number of the aircraft flow and feed it back to the control system. When the speed reaches a high Mach, the airbag is inflated to drive the flexible skin to deform. On the contrary, when the Mach number is low, the airbag is deflated. The adaptive deformation of the bulge in the air intake can be realized by actively controlling the bulge profile.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A design method for an adaptive bulge inlet structure includes four parts: a flexible skin design with high load-bearing capacity and large deformation, a main load-bearing structure design, a distributed pressure-driven multi-airbag system design, and a control system design.

[0007] The design method of the flexible skin with high load and large deformation is: combining the flexible honeycomb structure 6 with the flexible rubber skin 3. The flexible honeycomb structure 6 is filled with flexible rubber material inside, and the flexible rubber skin 3 is bonded to the outside of the flexible honeycomb structure 6 filled with the flexible rubber material. The flexible honeycomb structure 6 includes annular reinforcement 6.3, radial reinforcement 6.2 and outermost annular reinforcement 6.1. The annular reinforcement 6.3 provides overall support stiffness, the radial reinforcement 6.2 provides local stiffness and can deform radially, and the outermost annular reinforcement 6.1 is designed to be higher in height and is used to connect with the rigid annular frame 5.

[0008] The main bearing structure design includes the design of the rigid annular frame 5 and the rigid support plate 12, wherein the rigid annular frame 5 is the main bearing structure of the air inlet area. The rigid skin 4 is fixed to the outer peripheral edge of the rigid annular frame 5 and the flexible rubber skin 3. The rigid support plate 12 is arranged on the inner side wall of the rigid annular frame 5, and the rigid skin 4 and the rigid support plate 12 transfer the incoming flow pressure to the rigid annular frame 5. Rigid support plate 12 is designed with reinforcement to isolate each airbag 7.

[0009] The distributed pressure-driven multi-airbag system design includes multiple sets of inflatable airbags 7 and corresponding inflation and deflation system designs. Due to the uneven distribution of incoming flow pressure, it is necessary to divide the areas where the skin bears different pressure loads into zones, and design multiple sets of airbags 7 to resist the pressure in each area and produce bulging deformation, and each set of airbags 7 independently controls the internal pressure.

[0010] The inflation and deflation system comprises an air circuit 8, an electromagnetic inflation valve 9, an air pump 10 and an electromagnetic deflation valve 11. The airbag 7, the air circuit 8, the electromagnetic inflation valve 9 and the air pump 10 are connected in sequence, and the electromagnetic deflation valve 11 is connected to the airbag 7.

[0011] When designing the airbag 7 and the flexible honeycomb structure 6, it is necessary to consider the distribution of aerodynamic pressure at the inlet duct bulge. First, the height and density of the flexible honeycomb structure 6 are determined. Then, the shape, inflation pressure and arrangement of each airbag 7 are defined as design variables using a simulation optimization method. The objective function is to minimize the difference between the ideal deformation and the simulated deformation of the bulge, and an optimized iterative design is performed. Finally, the shape, inflation pressure value and arrangement of each airbag 7 are determined, so as to achieve consistency between the designed inlet duct bulge surface deformation and the ideal surface.

[0012] The control system design includes a microcomputer, control software and a pressure sensor 13. The pressure sensor 13 is arranged at the airbag 7. When the aircraft pitot sensor detects that the speed has increased to the specified flight speed, the microcomputer controls the air pump 10 to work and opens the electromagnetic inflation valve 9 to inflate the airbag 7. When the pressure sensor 13 detects that the pressure of the airbag 7 has reached the design value, the electromagnetic inflation valve 9 is closed and inflation is stopped. When the flight speed drops to a low speed, the electromagnetic deflation valve 11 is used to deflate the air to restore the bulge surface of the air intake. In summary, the adaptive deformation of the bulge is achieved.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] (1) The design of the honeycomb-filled flexible skin in the present invention can effectively withstand the aerodynamic pressure of the air inlet and can achieve large out-of-plane deformation, and is an important structural component for realizing the adaptive bulge function;

[0015] (2) The present invention realizes the deformation of the bulge surface by inflating and deflating the airbag, has a simple driving form, a fast response speed, and a small occupied volume of the driving system;

[0016] (3) The driving mode of multiple airbags in the present invention plays a good distributed driving role, which can directly and effectively drive the deformation of the profile under the action of the incoming flow load, thereby achieving high-precision control of the bulged inlet duct profile. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the aerodynamic layout of the aircraft bulge inlet;

[0018] Figure 2 It is a deformation scheme of the bulge air intake duct;

[0019] Figure 3 is an axonometric view of the bulged air inlet of the present invention;

[0020] Figure 4 is a cross-sectional view of the present invention;

[0021] Figure 5 It is the rigid bearing structure of the present invention;

[0022] Figure 6 The flexible skin and flexible honeycomb structure of the present invention;

[0023] Figure 7 The honeycomb structure of the present invention;

[0024] Figure 8 The invention relates to an air bag and an inflation and deflation system.

[0025] In the figure: 1 is the aircraft air inlet profile; 2 is the air inlet outer cover; 3 is the flexible skin; 4 is the rigid skin; 5 is the rigid annular frame; 6 is the flexible honeycomb structure; 6.1 is the outermost annular reinforcement; 6.2 is the radial reinforcement; 6.3 is the annular reinforcement; 7 is the airbag; 8 is the air path; 9 is the electromagnetic inflation valve; 10 is the air pump; 11 is the electromagnetic deflation valve; 12 is the rigid support plate; 13 is the pressure sensor. DETAILED DESCRIPTION

[0026] In order to better illustrate an adaptive bulge inlet structure design method according to the present invention, the method according to the present invention is further described in combination with the drawings and embodiments to make the technical solution and beneficial effects clearer.

[0027] The working principle of the present invention is:

[0028] By monitoring the Mach number of the aircraft's incoming flow, feeding it back to the control system, and inflating / deflating the airbag, the flexible skin is driven to deform and the bulge profile is controlled in real time to achieve adaptive deformation of the inlet bulge.

[0029] Embodiment 1:

[0030] like Figure 1 As shown, the bulge profile in the bulge inlet refers to a three-dimensional aerodynamic aircraft inlet profile 1, and the outer side is an inlet cover 2. By realizing the regulated deformation of the local deformation zone, the inlet matching performance at high Mach number can be improved.

[0031] According to the requirements of the aircraft aerodynamic layout design, the local area of ​​the inlet skin has different aerodynamic shapes at low Mach numbers and high Mach numbers, which is defined as the bulge deformation area, and its shape is approximately an ellipsoid configuration. Figure 2 shown.

[0032] The adaptive bulge inlet structure design method comprises four parts: high-load-bearing and large-deformation flexible skin design, main load-bearing structure design, distributed pressure-driven multi-airbag system design and control system design.

[0033] The design method of the flexible skin with high load-bearing capacity and large deformation is as follows: the flexible honeycomb structure 6 is combined with the flexible rubber skin 3. The honeycomb reinforced skin can effectively improve the out-of-plane stiffness of the rubber skin and can achieve large deformation. The interior of the flexible honeycomb structure 6 is filled with a flexible rubber material, and the flexible rubber skin 3 is bonded to the outside of the flexible honeycomb structure 6 filled with the flexible rubber material. The flexible rubber skin 3 is made of superelastic silicone rubber. The flexible honeycomb structure 6 includes an annular reinforcement 6.3 with greater stiffness, a radial reinforcement 6.2 with less stiffness, and an outermost annular reinforcement 6.1. The annular reinforcement 6.3 provides overall support stiffness, the radial reinforcement 6.2 provides local stiffness and can deform radially, and the outermost annular reinforcement 6.1 is designed to be higher in height for connection with the rigid annular frame 5. By using this honeycomb reinforced flexible skin, the shape of the bulge area can be changed under the impetus of pressure, thereby adjusting the aerodynamic shape under different flight conditions to improve the aerodynamic matching characteristics of the air inlet and the engine.

[0034] The main bearing structure is designed to bear the aerodynamic load at the air inlet bulge, including the design of the rigid annular frame 5 and the rigid support plate 12, wherein the rigid annular frame 5 is the main bearing structure in the air inlet area. The rigid skin 4 is fixed to the outer peripheral edge of the rigid annular frame 5 and the flexible rubber skin 3. The rigid support plate 12 is arranged on the inner side wall of the rigid annular frame 5, and the rigid skin 4 and the rigid support plate 12 and other structures transfer the incoming flow pressure to the rigid annular frame 5. Rigid support plates 12 are designed with reinforcement to isolate the airbags 7.

[0035] The distributed pressure-driven multi-airbag system design includes multiple sets of inflatable airbags 7 and corresponding inflation and deflation system designs. Due to the uneven distribution of incoming flow pressure, it is necessary to divide the areas where the skin bears different pressure loads into zones, and design multiple sets of airbags 7 to resist the pressure in each area and produce bulging deformation, and each set of airbags 7 independently controls the internal pressure.

[0036] The inflation and deflation system comprises an air circuit 8, an electromagnetic inflation valve 9, an air pump 10 and an electromagnetic deflation valve 11. The airbag 7, the air circuit 8, the electromagnetic inflation valve 9 and the air pump 10 are connected in sequence, and the electromagnetic deflation valve 11 is connected to the airbag 7.

[0037] When designing the airbag 7 and the flexible honeycomb structure 6, it is necessary to consider the distribution of aerodynamic pressure at the inlet duct bulge. First, the height and density of the flexible honeycomb structure 6 are determined. Then, the shape, inflation pressure and arrangement of each airbag 7 are defined as design variables using a simulation optimization method. The objective function is to minimize the difference between the ideal deformation and the simulated deformation of the bulge, and an optimized iterative design is performed. Finally, the shape, inflation pressure value and arrangement of each airbag 7 are determined, so as to achieve consistency between the designed inlet duct bulge surface deformation and the ideal surface.

[0038] The control system design includes a microcomputer, control software and a pressure sensor 13. The pressure sensor 13 is arranged at the airbag 7. When the aircraft pitot sensor detects that the speed has increased to the specified flight speed, the microcomputer controls the air pump 10 to work and opens the electromagnetic inflation valve 9 to inflate the airbag 7. When the pressure sensor 13 detects that the pressure of the airbag 7 has reached the design value, the electromagnetic inflation valve 9 is closed and inflation is stopped. When the flight speed drops to a low speed, the electromagnetic deflation valve 11 is used to deflate the air to restore the bulge surface of the air intake. In summary, the adaptive deformation of the bulge is achieved.

Claims

1. A method for designing an adaptive bulge inlet structure, characterized in that: It includes four parts: flexible skin design with high load-bearing capacity and large deformation, main load-bearing structure design, distributed pressure-driven multi-airbag system design, and control system design.

2. The method for designing an adaptive bulge inlet structure according to claim 1, characterized in that: The method for designing a flexible skin with high load-bearing capacity and large deformation is as follows: a flexible honeycomb structure (6) is combined with a flexible rubber skin (3); wherein the interior of the flexible honeycomb structure (6) is filled with a flexible rubber material, and the flexible rubber skin (3) is bonded to the outside of the flexible honeycomb structure (6) filled with the flexible rubber material; the flexible honeycomb structure (6) includes annular reinforcements (6.3), radial reinforcements (6.2) and outermost annular reinforcements (6.1); the annular reinforcements (6.3) provide overall support stiffness, the radial reinforcements (6.2) provide local stiffness and can deform radially, and the outermost annular reinforcements (6.1) are designed to be higher in height and are used to connect to the rigid annular frame (5).

3. The method for designing an adaptive bulge inlet structure according to claim 1, characterized in that: The main bearing structure design includes the design of a rigid annular frame (5) and a rigid support plate (12), wherein the rigid annular frame (5) is the main bearing structure of the air inlet area; the rigid skin (4) is fixed to the outer peripheral edge of the rigid annular frame (5) and the flexible rubber skin (3); the rigid support plate (12) is arranged on the inner side wall of the rigid annular frame (5), and the rigid skin (4) and the rigid support plate (12) transfer the incoming flow pressure to the rigid annular frame (5); and reinforcement is designed on the rigid support plate (12) to isolate each airbag (7).

4. The method for designing an adaptive bulge inlet structure according to claim 1, characterized in that: The distributed pressure-driven multi-airbag system design includes multiple sets of inflatable airbags (7) and corresponding inflation and deflation system designs; due to the uneven distribution of incoming flow pressure, it is necessary to divide the areas where the skin bears different pressure loads into zones, and design multiple sets of airbags (7) to resist the pressure in each area and produce bulging deformation, and each set of airbags (7) independently controls the internal pressure.

5. The method for designing an adaptive bulge air intake structure according to claim 4, characterized in that: The inflation and deflation system comprises an air circuit (8), an electromagnetic inflation valve (9), an air pump (10) and an electromagnetic deflation valve (11); wherein the air bag (7), the air circuit (8), the electromagnetic inflation valve (9) and the air pump (10) are connected in sequence, and the electromagnetic deflation valve (11) is connected to the air bag (7).

6. The method for designing an adaptive bulge inlet structure according to claim 4, characterized in that: When designing the airbag (7) and the flexible honeycomb structure (6), it is necessary to consider the distribution of aerodynamic pressure at the inlet duct bulge. First, the height and density of the flexible honeycomb structure (6) are determined. Then, the shape, inflation pressure and arrangement of each airbag (7) are defined as design variables using a simulation optimization method. The difference between the ideal deformation and the simulated deformation of the bulge is minimized as the objective function, and an optimization iterative design is performed. Finally, the shape, inflation pressure value and arrangement of each airbag (7) are determined, so that the deformation of the designed inlet duct bulge surface is consistent with the ideal surface.

7. The method for designing an adaptive bulge inlet structure according to claim 1, characterized in that: The control system design comprises a microcomputer, control software and a pressure sensor (13). The pressure sensor (13) is arranged at the airbag (7). When the aircraft pitot sensor detects that the speed has increased to a specified flight speed, the microcomputer controls the air pump (10) to work and open the electromagnetic inflation valve (9) to inflate the airbag (7). When the pressure sensor (13) detects that the pressure of the airbag (7) has reached a designed value, the electromagnetic inflation valve (9) is closed and inflation is stopped. When the flight speed drops to a low speed, the electromagnetic deflation valve (11) is used to deflate the air so that the inlet duct bulge surface is restored. In summary, adaptive deformation of the bulge is achieved.

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