A hypersonic inlet and control method based on front shock wave adjustment and fuel pre-injection regulation

Abstract

The application belongs to the field of aerospace engines, and discloses a hypersonic inlet and a control method based on leading edge shock adjustment and fuel pre-injection regulation and control. The inlet comprises a lip cover, an inner wall surface, a forebody compression surface and a high-pressure fuel cavity; the lip cover and the inner wall surface of the inlet jointly enclose an inlet passage; the forebody compression surface is connected at a position extending forward from the inner wall surface of the inlet; an adjustable wedge fuel injection structure is rotatably arranged at the leading edge of the forebody compression surface, and wall fuel injection holes are arranged side by side on the surface; the high-pressure fuel cavity comprises a first high-pressure fuel cavity and a second high-pressure fuel cavity; a fuel passage is arranged in the adjustable wedge fuel injection structure, one end of the fuel passage is in communication with the first high-pressure fuel cavity, and the opening at the other end faces the inlet passage. The application realizes inlet shock regulation and fuel pre-injection mixing through local mechanical adjustment of the adjustable wedge fuel injection structure, integrated design and collaborative control of the fuel pre-injection aerodynamic regulation and control on the compression surface of the inlet.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field related to aerospace engines, and more particularly, relates to a hypersonic inlet and control method based on leading edge shock adjustment and fuel pre-injection regulation. BACKGROUND

[0002] Future horizontal take-off and landing reusable space shuttle vehicles need to have the ability to work in a very wide speed range and airspace from zero speed to hypersonic speed, near space and even near-orbit space, have excellent specific impulse and thrust-to-weight ratio comprehensive performance, compact structure, and are suitable for reusable characteristics. Traditional single type power such as turbine, ramjet, rocket cannot meet the requirements, and air-breathing combined engine is the inevitable trend. The ramjet becomes an indispensable part of the combined engine due to its good performance at hypersonic speed.

[0003] Generally, the ramjet enters the working speed range of Mach 3 or above, realizes gas pressurization based on the principle of shock wave compression of supersonic airflow, organizes combustion on this basis, and finally forms high-temperature gas that is expanded by the tail nozzle to generate thrust. At present, the scramjet engine in the medium speed range of Mach 3-7 has made overall breakthrough progress and entered the stage of engineering application. However, as the flight Mach number increases, the ramjet will face the problems of efficient fuel injection mixing and combustion organization under the conditions of extreme high-enthalpy high-speed flow environment, extremely short residence time, greatly increased wall friction, and increased heat protection cost. At present, aerodynamic regulation (plasma injection, fuel pre-injection, etc.) or combustion enhancement technology has been applied to the development of hypersonic propulsion technology at Mach 10 or higher Mach number, which has alleviated the above problems to some extent, but the problems of integrated performance improvement and air-breathing working boundary expansion still need to be solved.

[0004] Theoretically, air-breathing hypersonic propulsion systems can work effectively in the range of Mach 3-15 and altitude 0-40 km. As higher Mach number propulsion systems above Mach 7 enter the theoretical research range, various new combustion modes (shock-induced combustion, detonation combustion) have been proposed, the fundamental purpose of which is to realize high Mach number working ability and optimized propulsion performance output through integrated matching and optimization of internal flow and combustion organization. Whether it is supersonic combustion, shock-induced combustion or oblique detonation combustion, the basic premise is that fuel injection and mixing meet the requirements of efficient combustion organization, and the fuel injection group mode and premixing requirements will depend on the internal flow conditions and specific combustion organization mode. Under the condition of high Mach number hypersonic flight, the internal flow speed is extremely high and the residence time is extremely short, and it is extremely difficult to realize short-distance, rapid and efficient fuel mixing and combustion organization within the limited space and time, which is one of the technical factors restricting the upper limit of the working speed range of air-breathing engines.

[0005] How to expand the working boundary of high Mach number propulsion system, and then use the above new type of combustion organization and more efficient combustion mode become high supersonic propulsion system problems to be solved. SUMMARY

[0006] In view of the above defects or improvement needs of the prior art, the present application provides a hypersonic inlet based on leading edge shock regulation and fuel pre-injection regulation and control method, which aims to realize precise inlet shock regulation and fuel pre-injection mixing effect through local mechanical regulation mode of adjustable wedge fuel injection structure at the leading edge of the inlet, integrated design and collaborative control of fuel pre-injection aerodynamic regulation on the compression surface of the inlet, thereby solving the practical difficulties faced by wide speed range efficient flow organization and multi-mode efficient combustion organization in hypersonic propulsion system.

[0007] To achieve the above object, according to one aspect of the present application, a hypersonic inlet based on leading edge shock regulation and fuel pre-injection regulation and control method is provided, comprising: a lip cover, an inlet inner wall surface, a forebody compression surface and a high pressure fuel cavity;

[0008] The lip cover is located on the inlet inner wall surface, and the lip cover and the inlet inner wall surface together form an inlet inner channel;

[0009] The forebody compression surface is connected at the front extension of the inlet inner wall surface; an adjustable wedge fuel injection structure is rotatably arranged at the leading edge of the forebody compression surface, and wall fuel injection holes are arranged side by side on the surface of the forebody compression surface;

[0010] The high pressure fuel cavity includes a first high pressure fuel cavity and a second high pressure fuel cavity; the first high pressure fuel cavity is in communication with the adjustable wedge fuel injection structure, and the second high pressure fuel cavity is in communication with the wall fuel injection hole; a fuel channel is arranged inside the adjustable wedge fuel injection structure;

[0011] Wherein, the adjustable wedge fuel injection structure is internally provided with a fuel channel, one end of the fuel channel is in communication with the first high pressure fuel cavity, and the other end of the fuel channel is open towards the inlet inner channel.

[0012] As a preferred embodiment of the present application, the end of the adjustable wedge fuel injection structure towards the inlet inner channel is provided with an outward cantilever beam, and the opening of one end of the fuel channel is arranged on the outward cantilever beam and towards the inlet inner channel.

[0013] As a preferred embodiment of the present application, the forebody compression surface further comprises a rotating shaft at the leading edge, and the rotating shaft is rotatably connected with the adjustable wedge fuel injection structure.

[0014] As a preferred embodiment of the present application, the adjustable wedge fuel injection structure is flush with the precursor compression surface when not lifted, and the contact surface with the inner wall of the inlet duct is a circular arc surface.

[0015] As a preferred embodiment of the present application, the adjustable wedge fuel injection structure is lifted at an angle ranging from 0 to 10 degrees relative to the precursor compression surface.

[0016] As a preferred embodiment of the present application, the diameter of the wall fuel injection hole is 1-2 mm when using hydrogen fuel, and the diameter of the wall fuel injection hole is 0.3-0.5 mm when using kerosene fuel.

[0017] As a preferred embodiment of the present application, the precursor compression surface sequentially includes a first-stage compression surface, a second-stage compression surface, and a third-stage compression surface arranged in the direction of the inlet duct passage; the front end of the second-stage compression surface forms a turning point with the first-stage compression surface, and the front end of the front end of the third-stage compression surface forms a turning point with the second-stage compression surface; the rear end of the third-stage compression surface is connected with the inner wall of the inlet duct; the first-stage compression surface is divided into a front segment and a rear segment by the rear end of the adjustable wedge fuel injection structure; the front segment is the upper surface of the adjustable wedge fuel injection structure; when the adjustable wedge fuel injection structure is in a closed state, the front segment is collinear with the rear segment; when the adjustable wedge fuel injection structure is in a lifted state, the front segment and the rear segment form an included angle equal to the rotation angle of the adjustable wedge fuel injection structure.

[0018] According to another aspect of the present application, a control method for an inlet duct based on leading edge shock wave regulation and fuel pre-injection regulation is provided, including the following steps:

[0019] S1: After obtaining the flight state, the engine comprehensive control system determines the required working mode of the inlet duct and instructs the inlet duct to preliminarily adjust the angle of the adjustable wedge fuel injection structure; when the inlet duct is in a sub-rated or rated working state, the working mode of the adjustable wedge fuel injection structure is controlled to be closed; when the inlet duct is in a super-rated working state, the preliminary lifting angle of the adjustable wedge fuel injection structure is determined according to the compression wave system regulation requirement.

[0020] S2: The final lifting angle of the adjustable wedge fuel injection structure and the overall injection strategy of the wall fuel injection hole are determined by the requirement of downstream combustion organization for fuel mixing efficiency.

[0021] As a preferred embodiment of the present application, after preliminarily adjusting the angle of the adjustable wedge fuel injection structure, the overall injection strategy is adjusted by combining the requirement of downstream combustion organization for fuel mixing efficiency with the local wall drag reduction and heat protection requirement.

[0022] As a preferred embodiment of the present application, the engine integrated control system acquires the inflow parameters in real time, and adjusts the preliminary lifting angle of the adjustable wedge fuel injection structure in real time according to the air intake performance requirements and the air intake performance parameters at the moment.

[0023] Overall, compared with the prior art, the above technical solutions conceived by the present application mainly have the following technical advantages:

[0024] (1) When the adjustable wedge fuel injection structure of the present application cooperates with fuel jets, due to the rotatable structure design, it can be finely adjusted towards the direction of the air intake passage, can play a role in compression wave system regulation during the over-rating stage of the air intake, can improve the wide-speed-range air intake flow capture efficiency based on the low Mach number design point for engine air intake design, can expand the upper limit of the air intake working Mach number, can effectively shorten the air intake length, and can reduce the wall friction resistance and thermal protection cost; at the same time, the fuel pre-injection action of the adjustable wedge and the wall hole can effectively improve the fuel premixing efficiency, provide convenience for downstream combustion organization, reduce the fuel mixing distance requirement of the combustion chamber, effectively shorten the combustion chamber structure length, and thus reduce the flow wall resistance and thermal protection cost in the combustion chamber.

[0025] (2) The preferred adjustable wedge fuel injection structure of the present application has an adjustable wedge with a cantilever beam injection structure, and the overhanging cantilever beam is used for fuel injection, which aims to realize fuel downstream injection, improve the penetration depth, and avoid fuel gathering in the backflow area downstream of the wedge to cause local intense combustion.

[0026] (3) When the air intake of the present application is applied, by fully combining the reliability of the mechanical structure and the technical advantages of the air intake fuel pre-injection, and by matching the control method with real-time feedback mechanism, the upper limit of the working Mach number of the traditional air intake can be expanded. Thus, a new idea based on the low Mach number design point / weak compression aerodynamic surface design is formed, the lower Mach number design point air intake can meet the higher Mach number speed range requirement, and the beneficial effects of enhancing fuel premixing efficiency, shortening the engine size, reducing the wall friction resistance and thermal protection cost, etc. are simultaneously realized, so as to achieve the purposes of improving the overall performance of the propulsion system and expanding the upper limit of the working boundary.

[0027] The fuel pre-injection strategy includes the following: according to the working state of the engine air intake, the present application adjusts the fuel pre-injection strategy in real time, when the air intake is in a sub-rating (rating) working state, the adjustable wedge close to the compression surface in the air intake is used for injection, which can realize fuel premixing while avoiding the decrease of the air intake flow capture capacity; when the air intake is in an over-rating working state, the adjustable wedge at the leading edge of the forebody compression surface is used for injection, which can realize fuel premixing while realizing compression wave system regulation and reducing the flow distortion at the air intake outlet. Thus, the air intake can work normally in a wider speed range.

[0028] (4) Near-wall fuel jets form a cooling film effect on the outer compression surface of the precursor, reducing the cost of thermal protection, and the oil-gas mixture can form a boundary layer combustion after being induced by a shock wave, having a wall friction drag reduction effect. Therefore, the regulation and cooperation of the wedge injection structure with the wall fuel injection can be used as an active cooling and drag reduction measure.

[0029] (5) The application proposes a new type of leading edge shock wave regulation and fuel pre-injection integrated high Mach number inlet and its control method suitable for a flight Mach number of 7-15+, which can be used in air-breathing hypersonic propulsion systems. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The inlet schematic diagram with an adjustable wedge fuel injection structure is shown in the application;

[0031] Figure 2 The fuel pre-injection control method based on the inlet with an adjustable wedge fuel injection structure is shown in the application;

[0032] Figure 3 The existing different Mach number design point inlets; wherein Figure 3 (a) is a design point inlet with Ma 8, and (b) is a design point inlet with Ma 15;

[0033] Figure 4 The inlet schematic diagram based on the Ma=8 design point is shown in the application; wherein Figure 4 (a) is a cross-sectional view of the inlet, and (b) is a top view of the inlet;

[0034] Figure 5 The adjustable wedge fuel injection structure local enlarged schematic diagram is shown in the application; wherein Figure 5 (a) is an adjustable wedge fuel injection structure lifting state diagram, and (b) is an adjustable fuel injection structure closing state diagram;

[0035] Figure 6 The adjustable wedge fuel injection structure adjustment angle calculation model schematic diagram is shown in the application;

[0036] Figure 7 The typical two-dimensional inlet over-rated working state of the inlet is shown in the application;

[0037] Figure 8 The compression wave system adjustment schematic diagram of the inlet in the over-rated working state is shown in the application.

[0038] In all the drawings, the same reference signs are used to represent the same structures, wherein:

[0039] 1-Lip cover, 2-Inner wall of intake duct, 3-Pressure body compression surface, 4-Adjustable wedge fuel injection structure, 5-High pressure fuel chamber, 6-Fuel injection hole on wall, 7-Inner passage of intake duct. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0041] This invention provides an air intake with integrated leading-edge shock wave regulation and fuel pre-injection.

[0042] like Figure 1 As shown, an intake duct integrating leading-edge shock wave adjustment and fuel pre-injection includes: an inner wall surface 2 of the intake duct, a lip cover 1 located on the inner wall surface 2 of the intake duct, and the inner wall surface 2 and the lip cover 1 together forming an inner channel 7 of the intake duct; a forebody compression surface 3 extending forward from the inner wall surface 2 of the intake duct, an adjustable wedge fuel injection structure 4 rotatably disposed at the leading edge of the forebody compression surface 3, and wall fuel injection holes 6 arranged side by side on the surface of the forebody compression surface 3; a high-pressure fuel chamber including a first high-pressure fuel chamber communicating with the adjustable wedge fuel injection structure 4, and a second high-pressure fuel chamber correspondingly communicating with the wall fuel injection holes 6; wherein, the adjustable wedge fuel injection structure 4 has a fuel channel inside the first high-pressure fuel chamber, and the opening at one end of the fuel channel faces the inner channel 7 of the intake duct.

[0043] In some embodiments, the adjustable wedge fuel injection structure 4 has an extended cantilever beam at one end facing the inner intake passage 7, and the opening at one end of the fuel passage is located on the extended cantilever beam, facing the inner intake passage 7. The extended cantilever beam is used for fuel injection to increase fuel penetration depth and prevent fuel accumulation in the downstream backflow area of ​​the wedge, thus avoiding localized intense combustion. The length L of the cantilever beam is determined by the size of the backflow area during the design phase.

[0044] In some embodiments, the adjustable wedge fuel injection structure 4 is located at the leading edge of the forebody compression surface 3, and the lifting angle δ0 can be adjusted by a rotating shaft located inside the leading edge of the forebody compression surface 3. The rotating shaft is driven by a motor and a corresponding mechanical structure.

[0045] Furthermore, the adjustable wedge fuel injection structure 4 is the same width as the inner wall surface 2 of the intake duct.

[0046] Furthermore, when the adjustable wedge fuel injection structure 4 is in the open state, the range of its lifting angle relative to the forebody compression surface 3 is generally less than 10°.

[0047] Further, the adjustable wedge fuel injection structure 4 is flush with the upper surface of the precursor compression surface 3 in the closed state, and the inner entity contact surface of the inlet duct is a circular arc surface, which ensures the sealing during the adjustment process.

[0048] In some embodiments, the wall fuel injection hole size is related to the type of fuel used. When hydrogen fuel is used, the diameter of the wall fuel injection hole 6 is 1-2 mm, and when kerosene fuel is used, the diameter of the wall fuel injection hole 6 is 0.3-0.5 mm.

[0049] In some embodiments, the precursor compression surface 3 includes a first compression surface, a second compression surface, and a third compression surface arranged in sequence and extending backward, the front end of the second compression surface forms a turning point with the first compression surface, and the front end of the third compression surface is similar, and the rear end is connected with the inner wall surface of the inlet duct; the first compression surface is divided into a front section and a rear section by the rear end of the adjustable wedge fuel injection structure, the front section is the upper surface of the adjustable wedge fuel injection structure, in the closed state of the adjustable wedge fuel injection structure, the front section is collinear with the rear section, in the open state of the adjustable wedge fuel injection structure, the front section and the rear section form an included angle, and the included angle is equal to the rotation angle of the adjustable wedge fuel injection structure.

[0050] It should be noted that the precursor compression surface is generally designed according to the equal shock intensity criterion, and the key point coordinate values of the outer compression surface are calculated based on the geometric relationship.

[0051] Therefore, when the above inlet duct is used in a air-breathing propulsion system, a first compression wave will be generated at the leading edge of the precursor compression surface under the condition of supersonic incoming flow, and the subsequent compression surfaces arranged in sequence will generate different compression wave systems according to the type of the inlet duct. Generally, when the inlet duct is in the rated working state, the compression wave system will converge at the lip of the inlet duct. The position of the adjustable wedge fuel injection structure 4 at the leading edge of the precursor compression surface 3 is relatively fixed, and when the inlet duct is in the overrated working state, the angle of the adjustable wedge fuel injection structure 4 is adjusted by the rotation shaft, and then the shock wave regulation is realized. The wall fuel injection hole 6 can be flexibly designed and configured according to the specific configuration and size of the inlet duct. Therefore, based on the structural design of the adjustable wedge fuel injection structure 4 and the specific configuration and size of the inlet duct, the requirements of shock wave regulation and fuel premixing can be met.

[0052] The present application provides a control method of the inlet duct based on the foregoing any leading edge shock wave regulation and fuel pre-injection regulation, which is connected with the engine comprehensive control system based on the motor control (specifically: the adjustable wedge fuel injection structure 4 is connected with the engine comprehensive control system through the rotation control motor, and the high-pressure fuel cavity is connected with the engine comprehensive control system through the electromagnetic valve), the working state of the adjustable wedge fuel injection structure 4 is determined according to the current working state and demand of the inlet duct, and the working state of the adjustable wedge fuel injection structure 4 is adjusted according to the working state of the inlet duct. Figure 2The fuel pre-injection control method based on the adjustable wedge fuel injection structure of the inlet is described in detail, and a specific example is as follows:

[0053] S1: After obtaining the flight state, the engine comprehensive control system determines the required working mode of the inlet and instructs the inlet to complete the structure adjustment; wherein the structure adjustment is the angle adjustment of the adjustable wedge fuel injection structure, which is as follows:

[0054] By determining that when the designed inlet is in a sub-rating or rating working state, the working mode of the adjustable wedge fuel injection structure is closed, and when the designed inlet is in a super-rating working state, the working mode of the adjustable wedge fuel injection structure is opened, and the lifting angle of the adjustable wedge fuel injection structure is calculated according to the compression wave system regulation and control demand; wherein the lifting angle δ0 is preliminarily determined by the shock wave relationship, which is as follows: given the wave front airflow parameters, assume the deflection angle initial value δ, obtain the x value according to the wave front parameters, thereby obtaining the wave front and wave back density ratio ρ2 / ρ1 and the y value, and the wave front and wave back static pressure ratio is calculated by the formula:

[0055]

[0056] Wherein Wherein γ1, γ2 are the wave front and wave back specific heat ratio, β is the shock wave compression angle, ρ1, ρ2 are the wave front and wave back gas density, Ma 1n , Ma 2n are the wave front and wave back Mach numbers;

[0057] The ratio of the wave front and wave back static temperature and static pressure is derived as follows:

[0058]

[0059] Based on the energy conservation formula, it is determined whether the given deflection angle initial value δ satisfies the energy conservation, and if not, the deflection angle δ is updated for the next iteration until the accuracy requirement is met.

[0060]

[0061] The preliminary lifting angle δ0 of the adjustable wedge fuel injection structure is calculated by δ0=δ-δ1, wherein δ1 is the current lifting angle of the wedge.

[0062] After preliminarily determining the lifting angle of the adjustable wedge fuel injection structure, the final lifting angle of the adjustable wedge fuel injection structure and the overall injection strategy of the wall fuel injection hole are determined by the demand of downstream combustion organization for fuel mixing efficiency.

[0063] Wherein, the combustion organization is generally represented by the along-the-way combustion efficiency η com , which is related to the fuel mixing efficiency η mixThe relationship is as follows:

[0064] η com = f(η mix , Ma, T, σ, x) (6);

[0065] Where Ma, T, σ respectively correspond to the Mach number, temperature, total pressure recovery coefficient of the inlet exit; x is the streamwise distance. The final lifting angle of the adjustable wedge fuel injection structure and the overall injection strategy of the wall fuel injection hole can be determined by engine full-flow numerical simulation analysis.

[0066] In some embodiments, after the lifting angle of the adjustable wedge fuel injection structure is preliminarily determined, the overall injection strategy is adjusted by combining the requirements of downstream combustion organization for fuel mixing efficiency with the local wall drag reduction and heat protection requirements.

[0067] In some embodiments, the changes of the incoming flow parameters (including flight Mach number, height, angle of attack, etc.) are fed back to the engine integrated control system in real time, and the output signal of the rotating motor is adjusted in real time according to the inlet performance requirements and the current inlet performance parameters to control the lifting angle of the adjustable wedge fuel injection structure; the engine combustion chamber performance parameter monitoring results are fed back to the engine integrated control system in real time, the high-pressure fuel cavity is controlled by the electromagnetic valve to control fuel delivery, and fuel injection mixing is performed by the fuel injection structure and the wall fuel injection hole.

[0068] In order to make the purpose, technical scheme and advantages of the patent more clear and explicit, the present application is further described in detail below in combination with the drawings and examples.

[0069] In order to facilitate the description of the advantages of the structure of the present application, the traditional inlet is designed as follows: two Mach numbers (Ma=8 and Ma=15) are selected as the reference design conditions, the equal shock intensity method is used for two-dimensional inlet design,

[0070] That is, given the initial value of the first deflection angle δ1, based on the variable specific heat single shock wave calculation, the first shock wave angle θ1 and the corresponding flow parameters after the shock wave are obtained. Based on the equal shock intensity method, the second shock wave angle θ2 and the corresponding flow parameters after the shock wave are calculated from the first shock wave angle θ1. Similarly, the third shock wave angle θ2 and the corresponding flow parameters after the shock wave can also be obtained.

[0071] M0sinθ1=M1sinθ2=M2sinθ3(7);

[0072] At this time, the second and third shock wave angles and the wave front wave back parameters are used to obtain the second and third deflection angles δ2 and δ3. Based on the given total deflection angle δ of the inlet, the first deflection angle δ1 of the next iteration is updated, the above calculation is repeated, and the three deflection angles δ1, δ2 and δ3 are repeatedly updated until the accuracy requirement is met. After determining the first three deflection angles δ1, δ2 and δ3, for the fourth and fifth deflection angles δ4 and δ5, based on the given total deflection angle δ and the outer cover inclination θ, the fourth and fifth deflection angles δ4 and δ5 are derived according to the geometric relationship:

[0073] δ = δ1 + δ2 + δ3

[0074] δ4 = δ - θ

[0075] δ5 = θ (8);

[0076] Both are three-way external compression wave structure, after the design is completed in the design point converges in the lip, as shown in Figure 3 . Among them, the Ma 15 design point inlet overall length is 10100mm, which is about 42.3% longer than the Ma 8 design point inlet. If the traditional inlet wall surface internal flow friction resistance is used under the condition of hypersonic incoming flow, it will obviously increase, and the structure thermal protection cost will also increase.

[0077] The present application provides a kind of front edge shock wave regulation and fuel pre-injection integrated high Mach number inlet (with Ma 8 design point structure as benchmark), including lip cover, inner wall surface, inlet inner passage, forebody compression surface, adjustable wedge fuel injection structure, wall fuel injection hole, high pressure fuel cavity;And according to the above detailed design. As shown in Figure 4 (a) is the inlet cross-sectional view, (b) is the top view of the inlet.

[0078] Wherein the wedge structure is installed at the front edge of the forebody compression surface, and the specific structure is shown in Figure 5 , its width is consistent with the width of the inlet inner compression section. The adjustable wedge side wall has fuel input interface, which is connected with the first high pressure fuel cavity placed at the front edge of the forebody compression surface, and the fuel is sprayed out by the cantilever beam on the wedge. The length L of the cantilever beam is determined according to the size of the wedge backflow area, that is, the size of the wedge backflow area needs to be calculated by high-precision numerical simulation. More specific size can be determined according to the performance requirements of inlet and engine in the design iteration stage.

[0079] Further, the rotating shaft on which the wedge is placed is connected with a rotating motor through a mechanical structure. The rotating motor drives the adjustable wedge to rotate with the rotating shaft, and the adjustable wedge can be adjusted to any position within a limited angle range. Figure 5and fully immersed in the compression surface, respectively. The control method is described below. The overall structure control will be incorporated into the engine's integrated control system, which will determine the use of the adjustable wedge for fuel injection based on the incoming flow conditions and the current operating state of the inlet, and will continue to determine the fuel supply requirements based on the current operating state requirements of the combustion chamber, thereby ultimately determining the control requirements for wedge adjustment and oil supply. The overall idea is as shown in Figure 2 The two control requirements will be described in sequence below.

[0080] (1) Structure adjustment requirements: The adjustable wedge fuel injection position is determined by the lift angle δ0 and the cantilever beam length L. As shown in the structure Figure 5 , based on the current flight incoming flow conditions, it is determined whether to open the adjustable wedge at the leading edge of the forebody compression surface. At this time, it can be specifically divided into two cases: 1) when the inlet state is in sub-rated (rated) operating state, the adjustable wedge at the leading edge is immersed in the forebody compression surface, and wall fuel injection holes are used for fuel pre-injection; 2) when the inlet is in super-rated state, the adjustable wedge at the leading edge will be lifted, fuel injection is carried out through the cantilever beam, and the required wedge lift angle can be obtained through iterative calculation based on the compression wave system adjustment requirements, and the specific calculation process is shown in Figure 6 . After the wedge lift angle δ0 is preliminarily determined, as shown in Figure 8 , the size of the recirculation zone can also be established by numerical simulation or experimental means after the specific structure of the inlet is determined. After the wedge is lifted, a recirculation zone will be generated downstream, and direct injection from the wedge wall may cause fuel to stagnate in the recirculation zone and form local combustion, which seriously affects the performance of the inlet. Therefore, by using the cantilever beam structure with an extended length L for injection, this phenomenon can be avoided, and the fuel premixing efficiency can be increased to some extent.

[0081] (2) Supply control requirements: After the wedge lift angle δ0 is preliminarily determined, the fuel premixing efficiency index is determined based on the operating requirements of the combustion chamber, and whether the wall fuel injection hole is opened, and the specific supply control requirements of the current fuel injection action are finally given.

[0082] Further, as shown in Figure 7 , the fuel jet can form a local cooling film effect, reducing the cost of wall thermal protection, and the compression shock induced can form a relatively controllable boundary layer combustion, producing a wall friction resistance reduction effect, which affects the overall performance of the engine. The injection strategy can be flexibly adjusted according to the specific situation, as shown in Figure 2 .

[0083] Further, real-time monitoring of the operating state of the inlet and the combustion chamber and comparison with the current target performance requirements can be used to form a feedback to adjust the pre-injection strategy in real time.

[0084] In summary, the high Mach number inlet with integrated leading edge shock adjustment and fuel pre-injection can accept instructions from a comprehensive control system, and through the adjustment and control of the adjustable wedge fuel injection structure and the wall fuel injection hole, the fuel (or other working medium) pre-injection action can be realized, and functions such as fuel pre-mixing, compression wave system structure regulation, local wall heat protection, and wall friction drag reduction can be achieved, so as to replace the traditional inlet under higher flight Mach number flow conditions and improve the overall performance of the engine in many aspects.

[0085] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application belong to the scope of the present application and its equivalent technology, the present application also intends to include these modifications and variations. The above-described embodiments are only preferred embodiments for fully illustrating the present application, and the protection scope is not limited thereto. The equivalent substitutions or transformations made by those skilled in the art on the basis of the present application are within the protection scope of the present application.

Claims

1. A hypersonic inlet based on the regulation of the front shock wave and the control of the fuel pre-injection, characterized in that, It comprises: a lip cover (1), an air inlet channel inner wall (2), a precursor compression surface (3) and a high-pressure fuel cavity (5); the lip cover (1) is located on the air inlet channel inner wall (2) and cooperates with the air inlet channel inner wall (2) to form an air inlet channel (7); the precursor compression surface (3) is connected at the extension from the air inlet channel inner wall (2); a adjustable wedge fuel injection structure (4) is rotatably arranged at the front edge of the precursor compression surface (3), and wall fuel injection holes (6) are arranged side by side on the surface of the precursor compression surface (3); the high-pressure fuel cavity (5) comprises a first high-pressure fuel cavity and a second high-pressure fuel cavity; the first high-pressure fuel cavity is in communication with the adjustable wedge fuel injection structure (4), and the second high-pressure fuel cavity is in communication with the wall fuel injection holes (6); a fuel channel is arranged inside the adjustable wedge fuel injection structure (4); wherein, the adjustable wedge fuel injection structure (4) is internally provided with a fuel channel, one end of the fuel channel is in communication with the first high-pressure fuel cavity, and the opening at the other end faces the air inlet channel (7).

2. The front-shock-wave-based hypersonic inlet with fuel pre-injection regulation and control according to claim 1, characterized in that, The end of the adjustable wedge fuel injection structure (4) facing the air inlet channel (7) is provided with an outwardly extending cantilever beam, and the opening at one end of the fuel channel is arranged on the outwardly extending cantilever beam and faces the air inlet channel (7).

3. The front-shock-wave-based hypersonic inlet with fuel pre-injection regulation and control according to claim 1, wherein, A rotating shaft is further arranged at the front edge of the precursor compression surface (3), and the rotating shaft is rotatably connected with the adjustable wedge fuel injection structure (4).

4. The front-shock-wave-based hypersonic inlet with fuel pre-injection regulation and control according to claim 1, wherein, When the adjustable wedge fuel injection structure (4) is not lifted, it is flush with the precursor compression surface (3), and the contact surface between the adjustable wedge fuel injection structure (4) and the air inlet channel is a circular arc surface.

5. The front-shock-wave-based hypersonic inlet with fuel pre-injection regulation and control according to claim 1, wherein, The range of the lifting angle of the adjustable wedge fuel injection structure (4) relative to the precursor compression surface (3) is 0-10°.

6. The front-shock-wave-based hypersonic inlet with fuel pre-injection regulation and control according to claim 1, wherein, When hydrogen fuel is used, the diameter of the wall fuel injection hole (6) is 1-2mm, and when kerosene fuel is used, the diameter of the wall fuel injection hole (6) is 0.3-0.5mm.

7. The front-shock-wave-based hypersonic inlet with fuel pre-injection regulation and control according to claim 1, wherein, The precursor compression surface (3) comprises, in sequence, a primary compression surface, a secondary compression surface and a tertiary compression surface arranged in the direction of the air inlet channel (7); the front end of the secondary compression surface forms a turning point with the primary compression surface, the front end of the tertiary compression surface forms a turning point with the secondary compression surface, and the rear end of the tertiary compression surface is connected with the air inlet channel inner wall (2); the primary compression surface is divided into a front segment and a rear segment by the rear end of the adjustable wedge fuel injection structure (4), the front segment is the upper surface of the adjustable wedge fuel injection structure (4), when the adjustable wedge fuel injection structure (4) is in a closed state, the front segment is collinear with the rear segment, when the adjustable wedge fuel injection structure (4) is in a lifted state, the front segment and the rear segment form an included angle, and the included angle is equal to the rotation angle of the adjustable wedge fuel injection structure.

8. A control method of a hypersonic inlet based on the regulation of the front shock wave and the control of the fuel pre-injection according to any one of the preceding claims 1-7, characterized in that, It comprises the following steps: S1: After obtaining the flight state, the engine comprehensive control system determines the required working mode of the inlet and instructs the inlet to preliminarily adjust the angle of the adjustable wedge fuel injection structure; wherein, when the inlet is in a sub-rating or rating working state, the working mode of the adjustable wedge fuel injection structure is controlled to be closed; when the inlet is in a super-rating working state, the preliminary lifting angle of the adjustable wedge fuel injection structure is determined according to the compression wave system regulation and control requirement; S2: The final lifting angle of the adjustable wedge fuel injection structure and the overall injection strategy of the wall surface fuel injection hole are determined by the requirement of fuel mixing efficiency of downstream combustion organization.

9. The method of controlling a cowl shock based hypersonic inlet with fuel pre-injection regulation according to claim 8, wherein, After completing the preliminary angle adjustment of the adjustable wedge fuel injection structure, the overall injection strategy is adjusted by combining the requirement of fuel mixing efficiency of downstream combustion organization with the local wall surface drag reduction and heat protection requirement.

10. The method of claim 8, wherein the method further comprises: The engine comprehensive control system obtains the incoming flow parameters in real time, and adjusts the preliminary lifting angle of the adjustable wedge fuel injection structure in real time according to the inlet performance requirement and the current inlet performance parameters.

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