A wide-range air intake with a two-stage continuously adjustable lip cover and curved inner flow channel, and its design method.

Abstract

This invention provides a wide-speed-range air inlet with a two-stage continuously adjustable lip and curved internal flow channel, and its design method. The wide-speed-range air inlet includes a fixed-geometry lower wall, inlet sidewalls, an independently translatable upper throat wall, and a lip. These components form the internal channel of the inlet, achieving decoupling of inlet capture flow rate and compression adjustment. Specifically, when adjusting the inlet compression by adjusting the throat area, the capture flow rate remains constant. At lower Mach numbers, moving the lip or upper throat wall backward reduces the inlet's internal contraction ratio, ensuring inlet startup. At higher Mach numbers, moving the lip or upper throat wall forward increases inlet compression, improving inlet performance. Compared to traditional variable-geometry inlets, this invention achieves throat area adjustment through simple translational movement, and the adjustment mechanism is simple in structure and highly reliable, contributing to high-performance operation of aircraft across a wide speed range.

Description

Technical Field

[0001] This invention relates to the field of air-breathing hypersonic vehicle propulsion systems, specifically to a wide-speed-range air intake with a dual-stage continuously adjustable lip and curved inner flow channel, and its design method. Background Technology

[0002] When designing hypersonic aircraft, traditional turbojet engines cannot be used. Instead, ramjet engines are used. The air intake, as the air source and compression channel for the ramjet engine, needs to provide the ramjet engine with sufficient high-quality air throughout the entire flight path of the aircraft. At the same time, it also needs to fully compress the incoming airflow. The performance of the air intake is directly linked to the thrust of the ramjet engine, and its importance is self-evident.

[0003] A wide range of flight speeds and altitudes is a crucial trend in the development of future air-breathing hypersonic vehicles. For fixed-geometry inlets, if a high Mach number is used as the design Mach number, starting problems arise at low speeds; if a lower Mach number is used, insufficient compression and inadequate back pressure resistance occur at high speeds. Furthermore, if the forebody shock wave is incident on and reflected inside the lip, it can cause significant separation, preventing the inlet from starting. Therefore, to maintain good aerodynamic performance across a wide speed range, variable-geometry inlets are essential. Compared to fixed-geometry inlets, variable-geometry inlets offer the advantage of adjusting their geometry according to the current flight Mach number to change the intake flow rate and compression, thereby meeting the propulsion system's requirements for airflow and quality.

[0004] Currently, there are various variable geometry designs for the air intakes of air-breathing hypersonic vehicles. However, these designs often fail to achieve independent adjustment of the intake compression and capture flow rate. For example, using a linkage mechanism to adjust the throat area reduces the throat area but also increases the shock angle of the forebody shock wave, decreasing the flow rate captured by the intake. Furthermore, adjusting the throat height using a linkage mechanism involves complex motion of the movable parts, and the change in throat height and the translation of the drive mechanism do not satisfy a linear relationship, making the adjustment process less intuitive. Additionally, the multiple links in the linkage mechanism are mostly connected by hinges, which are unreliable. Finally, if the compression surface has venting slots, the design of the venting system becomes more complex because the compression surface is movable while the sidewalls are generally immovable. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a wide-range air intake with dual-stage continuously adjustable lip cover and throat passage.

[0006] Technical solution: A wide-range air intake with dual-stage continuously adjustable lip cover and curved inner flow channel, comprising a fixed geometry lower wall, air intake sidewalls symmetrically arranged on both sides of the fixed geometry lower wall, a throat upper wall located above the air intake sidewalls, and a lip cover slidably disposed in a groove opened in the throat upper wall; the fixed geometry lower wall, air intake sidewalls, throat upper wall, and lip cover together form an inner channel of the air intake; the rear end of the throat upper wall is connected to a throat drive module, and the sides of the lip cover are connected to lip cover drive modules; the throat drive module drives the throat upper wall to translate relative to the fixed geometry lower wall, and the lip cover drive module drives the lip cover to translate relative to the throat upper wall.

[0007] Specifically, the lower wall of the fixed geometry has a first bleed groove on one side of the channel inside the air intake.

[0008] Specifically, the intake duct sidewall is provided with a drain outlet hole corresponding to the first drain groove.

[0009] Specifically, the lip cover is provided with a second drainage groove.

[0010] Specifically, the upper wall of the throat is provided with a first threaded hole at its rear end. The throat drive module includes a throat drive motor and a first lead screw connected to the throat drive motor. The first lead screw cooperates with the first threaded hole to drive the upper wall of the throat to move axially along the first lead screw.

[0011] Specifically, sliding grooves are symmetrically provided on the side walls of the air intakes on both sides.

[0012] Specifically, the lip mask driving module includes symmetrically arranged and fixedly connected driving side plates to the lip mask, a driving block disposed inside the lower wall of a fixed geometry, a lip mask driving motor, and a second lead screw connected to the lip mask driving motor; the driving side plates are respectively connected to the driving block through sliding grooves, the driving block is provided with a second threaded hole, the second lead screw cooperates with the second threaded hole, driving the driving block to move along the axial direction of the second lead screw, thereby moving the lip mask.

[0013] Specifically, the wide-speed-range air intake operates at Mach numbers from 0 to 4.

[0014] Preferably, at Mach 0 to 2, the upper wall of the throat and the lip cover are fixed in a preset position relative to the lower wall of a certain geometry; at Mach 2 to 4, the upper wall of the throat and the lip cover are adjusted by translation relative to the preset position.

[0015] The present invention also provides a design method for the above-mentioned wide-speed-range air intake, comprising the following steps:

[0016] S1 determines the aerodynamic performance requirements of the air intake for the design flight state and other flight states within the flight envelope of the aircraft, and designs the reference configuration of the air intake and the translation of the upper wall of the throat and the lip.

[0017] S2 checks and modifies the baseline configuration obtained in S1 until it meets the aerodynamic performance requirements of the inlet under the design flight conditions.

[0018] Based on the baseline configuration obtained in S2, S3 adjusts the intake configuration by pre-setting the upper wall of the throat and the translation amount of the lip mask, and tests the performance indicators under another flight state. If the corresponding requirements are met, this step is repeated and the performance indicators under another flight state are tested; otherwise, proceed to step S4.

[0019] S4 Adjust the preset throat upper wall and lip mask translation amount, and then test the performance indicators in this flight state. If the corresponding requirements are met, proceed to step S3 to test the performance indicators in another flight state; otherwise, proceed to step S5.

[0020] S5 adjusts the baseline configuration obtained in S2, and then adjusts the translation of the upper wall of the throat and the lip mask until the performance index requirements of the flight state are met. Based on the adjusted translation of the upper wall of the throat and the lip mask, the air intake configuration in the flight state in S2 is derived back, and the configuration is re-examined to see if it meets the performance index requirements of the flight state in S2.

[0021] S6 Repeat steps S3-S5;

[0022] S7 obtains an inlet configuration that satisfies all flight conditions and the corresponding translation of the throat upper wall and lip cover for each flight condition.

[0023] Beneficial Effects: Compared with existing technologies, the significant advantages of this invention are: It designs a translationally adjustable upper wall of the inlet throat and a lip mask, achieving decoupling between inlet capture flow rate and compression adjustment. That is, when adjusting the inlet throat area to regulate inlet compression, the inlet capture flow rate remains constant. At lower Mach numbers, moving the lip mask or upper throat wall backward reduces the inlet's internal contraction ratio, ensuring inlet startup. At higher Mach numbers, moving the lip mask or upper throat wall forward increases inlet compression, improving inlet performance. Compared to traditional variable geometry inlets with adjustable throat areas, this invention achieves throat area adjustment through simple translational motion. Furthermore, the adjustment mechanism has a simple structure and high reliability, contributing to high-performance aircraft operation across a wide speed range. Attached Figure Description

[0024] Figure 1 This is a schematic cross-sectional view of the variable geometry air intake of the present invention.

[0025] Figure 2This is a schematic diagram of the external three-dimensional structure of the variable geometry air intake of the present invention.

[0026] Figure 3 This is a schematic diagram of the partial structure of the lip mask driving module of the present invention.

[0027] Figure 4 This is a schematic diagram of the internal three-dimensional structure of the variable geometry air intake of the present invention.

[0028] Figure 5 This is a Mach number cloud map when the incoming Mach number is 4 in Embodiment 3 of the present invention.

[0029] Figure 6 This is a Mach number cloud map when the incoming Mach number is 3 in Embodiment 3 of the present invention.

[0030] Figure 7 This is a Mach number cloud map when the incoming Mach number is 2 in Embodiment 3 of the present invention. Detailed Implementation

[0031] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments.

[0032] Example 1

[0033] Please see Figure 1-4As shown, this embodiment provides a wide-speed-range air intake duct, including a fixed-geometry lower wall 1, air intake sidewalls 2 symmetrically arranged on both sides of the fixed-geometry lower wall 1, a throat upper wall 3 located between the air intake sidewalls 2, and a lip cover 4 slidably disposed in a groove 31 opened in the throat upper wall 3; the fixed-geometry lower wall 1, air intake sidewalls 2, throat upper wall 3, and lip cover 4 together form an inner air intake channel 5; the fixed-geometry lower wall 1 has two first venting grooves 11 opened on one side of the inner air intake channel 5; the air intake sidewalls 2 have two venting outlet holes 21 corresponding to the first venting grooves 11; the throat upper wall 3 is connected to a throat drive module at its rear end. In this embodiment, the throat drive module includes a throat drive motor 32 and a first lead screw 33 connected to the throat drive motor 32. The throat upper wall 3 has a first threaded hole at its rear end, and the first lead screw 33 and the first threaded hole are connected to each other. The lip cover 4 is connected to a lip cover drive module on both sides. In this embodiment, the lip cover drive module includes a drive side plate 42 symmetrically arranged and fixedly connected to the lip cover 4 on the outer side of the air intake sidewall 2, a drive block 43 disposed inside the fixed geometry lower wall 1, a lip cover drive motor 44, and a second lead screw 45 connected to the lip cover drive motor 44. Sliding grooves 22 are symmetrically opened on the air intake sidewall 2 on both sides. The drive side plate 42 passes through the sliding grooves 22 and is connected to the drive block 43. The drive block 43 is provided with a second threaded hole 431. The second lead screw 45 cooperates with the second threaded hole 431. In this embodiment, the cooperation method between the first threaded hole and the first lead screw 33 is the same as the cooperation method between the second threaded hole 431 and the second lead screw 45. In addition, the lip cover 4 is provided with a plurality of second venting grooves 41. The fixed geometry lower wall 1 is a convex curved surface on one side of the air intake inner channel 5.

[0034] In the aforementioned wide-range intake duct, the upper wall 3 of the throat is used to adjust the intake duct compression, and the lip cover 4 is used to adjust the intake duct capture flow. When the upper wall 3 of the throat moves back and forth to adjust the intake duct compression, the intake duct capture flow will not be affected. The second venting groove 41 uses the pressure difference between the inside and outside of the intake duct to directly discharge the low-energy fluid from the intake duct. The first venting groove 11 is located at the shock wave incident position of the lip cover 4. The low-energy fluid is discharged from the intake duct through the first venting groove 11 under the action of the pressure difference between the inside and outside of the intake duct. The rear end of the drive side plate 42 has a notch corresponding to the venting outlet hole 21 to ensure that the venting outlet hole 21 is not blocked when the position of the lip cover 4 is adjusted.

[0035] In the aforementioned wide-range intake duct, the adjustment method for the upper wall 3 of the throat is as follows: the throat drive motor 32 is started, driving the first lead screw 33 to rotate. The first lead screw 33 drives the upper wall 3 of the throat to translate back and forth along the axis of the first lead screw 33 through the first threaded hole. The adjustment method for the lip cover 4 is as follows: the lip cover drive motor 44 is started, driving the second lead screw 45 to rotate. The second lead screw 45 drives the drive block 43 to translate back and forth along the axis of the second lead screw 45 through the second threaded hole 431, thereby driving the drive side plate 42 to translate back and forth, so that the lip cover 4 translates synchronously. Please refer to [reference needed]. Figure 1 As shown, in this embodiment, the upper wall of the throat 3 and the lip cover 4 are translated on the same straight line, thereby independently adjusting the height of the intake inlet and the height of the throat. At lower Mach numbers, by moving the lip cover 4 or the upper wall of the throat 3 backward, the internal compression ratio of the intake can be reduced, ensuring that the intake can start. At higher Mach numbers, by moving the lip cover 4 or the upper wall of the throat 3 forward, the compression of the intake can be increased, improving the performance of the intake.

[0036] Example 2

[0037] This embodiment provides a design method for a wide-speed-range air intake as described in Embodiment 1, specifically including the following steps:

[0038] Step 1: Determine the parameters and corresponding aerodynamic performance requirements of the air intake under each flight state (N1, N2, N3...) in the flight envelope of the aircraft. The parameters of the flight state include the incoming Mach number, flight altitude, and flight attitude angle under that state. The performance requirements include the air intake outlet flow rate, critical total pressure recovery, and outlet distortion parameters. Based on the parameters under flight state N1, design the reference configuration of the air intake and the translation of the throat upper wall and the lip. The reference configuration includes the configuration of the fixed geometry lower wall, the air intake sidewall, the throat upper wall, the lip, and the overall configuration of the air intake inner channel enclosed by the above components.

[0039] Step 2: Inspect and modify the baseline configuration obtained in Step 1 until it meets the requirements of flight state N1;

[0040] Step 3: Based on the design state N1 baseline configuration obtained in Step 2, adjust the air intake configuration by pre-setting the throat upper wall and lip mask translation amount, and test the performance indicators under another flight state N2. If the corresponding requirements are met, repeat this step and test the performance indicators under another flight state N3; otherwise, proceed to Step 4.

[0041] Step 4: Adjust the preset throat upper wall and lip mask translation amount, and then test the performance indicators under flight state N2. If the corresponding requirements are met, proceed to step 3 and test the performance indicators under another flight state N3; otherwise, proceed to step 5.

[0042] Step 5: Adjust the baseline configuration for flight state N1 obtained in Step 2, and then adjust the translation of the upper wall of the throat and the lip mask until the performance requirements for flight state N2 are met. Based on the adjusted translation of the upper wall of the throat and the lip mask, the air intake configuration for flight state N2 in Step 2 is derived back, and the configuration is re-examined to see if it meets the performance requirements for flight state N1.

[0043] Step Six: Repeat steps Three through Five;

[0044] Step 7: Obtain the intake configuration that satisfies all flight conditions and the translation of the upper wall of the throat and the lip cover for each flight condition.

[0045] In this embodiment, flight state N1 refers to the flight state under the maximum Mach number condition, that is, the flight state when the incoming flow Mach number is 4, flight state N2 refers to the flight state when the incoming flow Mach number is 3, and flight state N3 refers to the flight state when the incoming flow Mach number is 2.

[0046] Example 3

[0047] Using the wide-speed-range intake design method provided in Example 2, a wide-speed-range intake with the structure described in Example 1 is designed to verify the feasibility of the wide-speed-range intake working under wide-speed-range conditions.

[0048] This embodiment is designed with the following requirements: incoming Mach number of 4, flight altitude of 25km, and angle of attack of 6°. A variable geometry two-dimensional mixed-pressure inlet with an incoming Mach number of 0 to 4 is designed. At Mach numbers of 0 to 2, the upper wall of the throat and the lip are fixed in a preset position relative to the lower wall of the fixed geometry. At Mach numbers of 2 to 4, the upper wall of the throat and the lip are adjusted relative to the preset position according to the incoming flow to change the configuration of the inlet.

[0049] Please see Figure 5-7 As shown, this embodiment displays Mach number contour plots of the intake duct and flow details near the throat when the incoming Mach numbers are 4, 3, and 2. Figure 5 The marked 6 indicates that the vent is closed, while the remaining unmarked vents are open. Figure 6 and Figure 7 Using this notation, it can be seen from the above Mach number cloud diagram that the variable geometry air intake can work normally at all tested Mach numbers, meeting the requirements for wide speed range operation, and verifying the feasibility of the overall scheme of the present invention.

Claims

1. A wide-range air intake with a dual-stage continuously adjustable lip cover and curved inner flow channel, characterized in that, The system includes a fixed geometry lower wall (1), air intake sidewalls (2) symmetrically arranged on both sides of the fixed geometry lower wall (1), a throat upper wall (3) located between the air intake sidewalls (2), and a lip cover (4) slidably disposed in a groove (31) opened in the throat upper wall (3); the fixed geometry lower wall (1), air intake sidewalls (2), throat upper wall (3), and lip cover (4) together form an air intake inner channel (5); the throat upper wall (3) is connected to a throat drive module at its rear end, and the lip cover (4) is connected to a lip cover drive module on both sides; the throat drive module drives the throat upper wall (3) to translate relative to the fixed geometry lower wall (1), and the lip cover drive module drives the lip cover (4) to translate relative to the throat upper wall (3); the throat upper wall (3) is provided with a first threaded hole at its rear end, and the throat drive module includes a throat drive motor (32) and a connecting wire to the throat drive motor. The first lead screw (33) engages with the first threaded hole to drive the upper wall (3) of the throat passage to move axially along the first lead screw (33); the side walls (2) of the air intake passage on both sides are symmetrically provided with sliding grooves (22); the lip mask drive module includes a drive side plate (42) symmetrically arranged and fixedly connected to the lip mask (4), a drive block (43) set inside the lower wall of the fixed geometry, a lip mask drive motor (44), and a second lead screw (45) connected to the lip mask drive motor (44); the drive side plate (42) passes through the sliding groove (22) to connect to the drive block (43), the drive block (43) is provided with a second threaded hole (431), the second lead screw (45) engages with the second threaded hole (431) to drive the drive block (43) to move axially along the second lead screw (45), thereby moving the lip mask (4).

2. The wide-speed-range air intake duct according to claim 1, characterized in that: The fixed geometry lower wall (1) has several first drain grooves (11) on one side of the air intake channel (5).

3. The wide-speed-range air intake duct according to claim 2, characterized in that: The intake sidewall (2) is provided with an outlet hole (21) corresponding to the first venting groove (11).

4. The wide-speed-range air intake duct according to claim 1, characterized in that: The lip cover (4) is provided with several second drainage grooves (41).

5. The wide-speed-range air intake duct according to claim 1, characterized in that: The lower wall (1) and the upper wall (3) of the throat are both curved surfaces.

6. The wide-speed-range air intake duct according to claim 1, characterized in that: The wide-speed-range air intake operates at Mach 0 to 4.

7. The wide-speed-range air intake duct according to claim 1, characterized in that: At Mach 0 to 2, the upper wall of the throat (3) and the lip cover (4) are fixed in a preset position relative to the lower wall of the fixed geometry (1); at Mach 2 to 4, the upper wall of the throat (3) and the lip cover (4) are adjusted by translation relative to the preset position.

8. A design method for a wide-speed-range air intake according to any one of claims 1-7, characterized in that, Includes the following steps: S1 determines the parameters of the design flight state and other flight states in the flight envelope of the aircraft, as well as the corresponding aerodynamic performance requirements of the air intake, and designs the reference configuration of the air intake and the translation of the upper wall of the throat and the lip. S2 checks and modifies the baseline configuration obtained in S1 until the aerodynamic performance requirements of the inlet under the design conditions are met. Based on the baseline configuration obtained in S2, S3 adjusts the intake configuration by pre-setting the upper wall of the throat and the translation amount of the lip mask, and tests the performance indicators under another flight state. If the corresponding requirements are met, this step is repeated and the performance indicators under another flight state are tested; otherwise, proceed to step S4. S4 Adjust the preset throat upper wall and lip mask translation amount, and then test the performance indicators under this flight state. If the corresponding requirements are met, proceed to step S3 to test the performance indicators under another flight state; otherwise, proceed to step S5. S5 adjusts the baseline configuration obtained in S2, and then adjusts the translation of the upper wall of the throat and the lip mask until the performance index requirements of the flight state are met. Based on the adjusted translation of the upper wall of the throat and the lip mask, the air intake configuration in the flight state in S2 is derived back, and the configuration is re-examined to see if it meets the performance index requirements of the flight state in S2. S6 Repeat steps S3-S5; S7 obtains an inlet configuration that satisfies all flight conditions and the corresponding translation of the throat upper wall and lip cover for each flight condition.

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