Separable support plate structure in combustion chamber of scramjet-oblique detonation combined engine

Abstract

The separable supporting plate structure comprises two unit supporting plate structures and two sets of hydraulic telescopic mechanisms, the two unit supporting plate structures are used for being arranged in the combustion chamber of the engine, the combustion chamber of the engine is provided with an inlet and an outlet, and the two sets of hydraulic telescopic mechanisms are arranged in the combustion chamber of the engine. The two unit supporting plate structures are arranged in a mirror image mode with the connecting line of the inlet and the outlet as the center line, each unit supporting plate structure is provided with a first face, a second face and a third face, the first face is parallel to the center line, and the second face is arranged on the side, close to the inlet, of the first face and forms an included angle alpha with the first face. The third face is arranged on the side, close to the outlet, of the first face and forms an included angle beta with the extension line of the first face. The two hydraulic telescopic mechanisms are connected with the side walls of the unit supporting plate structures in a one-to-one correspondence mode and used for controlling the two unit supporting plate structures to be separated and combined in the vertical direction. Flames in the combustion chamber can be controlled to be extinguished, and conversion to an oblique detonation mode is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of aviation engines, in particular to a detachable support plate structure in a combustion chamber of a scramjet-oblique detonation combination engine. Background Art

[0002] Scramjet engines have become a hot topic for domestic and foreign research institutions to study due to their many advantages such as large specific impulse and high speed. Their composition structure is generally composed of four parts: inlet duct, isolation section, combustion chamber and tail nozzle. As for the working process of the combustion chamber in the scramjet engine, it mainly includes the mixed injection of fuel and incoming flow, ignition and subsequent flame stabilization process. The incoming air enters the combustion chamber through the inlet duct, and the intake speed is Mach 4 or even higher, and is reduced to Mach 1-3 after compression. The fuel is injected into the supersonic incoming flow and reacts with the air. At this time, the combustion mode in the combustion chamber is mainly diffusion mode; after ignition in the combustion chamber, the flame gradually develops downstream of the combustion chamber, so that the entire main combustion zone maintains stable combustion; however, in the combustion chamber, since the incoming flow speed is much greater than the flame propagation speed, the convective heat transfer intensity of the mixed gas is significantly enhanced in the high-speed incoming flow, and the low-temperature mixture in the early stage of development greatly affects the combustion of the flame, causing the flame to be easily extinguished. Therefore, how to stabilize the flame in the hypersonic airflow and achieve uniform mixing of the fuel and the incoming air is an urgent problem to be solved. In addition, in the hypersonic propulsion system, there is currently no air-breathing power that can independently meet the needs of near-space aircraft in a wide speed range. For flights above Mach 9, the oblique detonation engine is almost the only feasible solution, so the combined engine has become a new research direction.

[0003] At present, the solution to the above-mentioned problem of stabilizing the flame in the hypersonic airflow and achieving uniform mixing of the fuel and the incoming air can usually be achieved by reducing the inlet incoming flow velocity or increasing the flame propagation speed to achieve flame stabilization, but increasing the flame propagation speed requires the introduction of external energy such as lasers, so it has no practical application value. For another method, some scholars prefer to add an intrusive device in the combustion chamber, the most common of which is a support plate structure, such as the related support plate structure disclosed in the patents with publication numbers CN116817314A and CN115789698A. The working principle of this type of support plate structure is to establish a reflow zone at the bottom of the support plate, that is, to create a subsonic area so that the airflow can stay in the reflow zone. However, this type of support plate structure only has a reflow zone at the bottom, which mainly plays the role of stabilizing the flame and is difficult to convert to a higher oblique detonation mode, so it cannot be used in a scramjet-oblique detonation combination engine. Summary of the invention

[0004] The object of the present invention is to provide a detachable support plate structure in the combustion chamber of a scramjet-oblique detonation combination engine, which can stabilize the flame under a hypersonic flow to achieve stable combustion in the combustion chamber when the support plates are combined, and can control the flame to be extinguished while keeping the fuel full in the combustion chamber when the support plates are separated, so as to facilitate the conversion of the oblique detonation mode.

[0005] The technical solution of the present invention is:

[0006] A detachable support plate structure in a scramjet-oblique detonation combination engine combustion chamber, comprising two unit support plate structures and two sets of hydraulic telescopic mechanisms, wherein the two unit support plate structures are used to be arranged in the engine combustion chamber, wherein the engine combustion chamber has an inlet and an outlet, wherein the connecting line of the inlet and the outlet is taken as the center line, and the two unit support plate structures are arranged in mirror images on both sides of the center line, wherein the unit support plate structure has a first surface, a second surface and a third surface, wherein the first surface is arranged parallel to the center line, the second surface is arranged on a side of the first surface close to the inlet, and an angle α is formed between the second surface and the first surface, wherein the angle α is arranged toward the inlet, and the third surface is arranged on the first surface. The third surface is close to one side of the outlet, and an angle β is formed between the third surface and the extension line of the first surface, the angle β is set back to the outlet, the angle α and the angle β are both acute angles, and the angle α≤angle β; two groups of hydraulic telescopic mechanisms are connected to the side walls of each unit support plate structure respectively and one by one, and are used to control the two unit support plate structures to separate and merge in the vertical direction. When the two unit support plate structures are merged, an oblique shock wave is generated at the angle α when the gas flows in; when the two unit support plate structures are separated, the first surfaces of the two unit support plate structures are parallel to the gas flow entering the combustion chamber, generating shock waves that do not interfere with each other, and an expansion wave is generated at the angle β of the two unit support plate structures.

[0007] Preferably, as a further improvement of the present invention, the angle α is in the range of 6° to 10°, and the angle β is in the range of 28° to 32°.

[0008] Preferably, as a further improvement of the present invention, the angle α is 6°, and the angle β is 30°.

[0009] Preferably, as a further improvement of the present invention, the fourth surface is vertically arranged and connected to the third surface, the fifth surface is parallel to the first surface, and two ends of the fifth surface are respectively connected to the fourth surface and the second surface.

[0010] Preferably, as a further improvement of the present invention, the ratio of the width of the unit support plate structure to the length of the first surface is 48:95, the ratio of the vertical distance between the first surface to the fifth surface to the length of the first surface is 2:19, and the ratio of the height of the fourth surface to the vertical distance between the first surface to the fifth surface is 2:5.

[0011] Preferably, as a further improvement of the present invention, the fourth surface is provided with a plurality of fuel spray holes along its width direction, a fuel delivery port and an oxygen delivery port are opened on a side wall of one side of the unit support plate structure, and each of the fuel spray holes is connected to the fuel delivery port and the oxygen delivery port respectively.

[0012] Preferably, as a further improvement of the present invention, the ratio of the diameter of the fuel injection hole to the height of the fourth surface is 1:2.

[0013] Preferably, as a further improvement of the present invention, the unit support plate structure is made of a material with high thermal conductivity.

[0014] Preferably, as a further improvement of the present invention, the horizontal distance between the first surface 21 of the unit support plate structure and the entrance of the combustion chamber is greater than or equal to 35 mm.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The present invention can vertically merge and separate two unit support plate structures by setting two sets of hydraulic telescopic mechanisms to achieve the effect of stable combustion in the combustion chamber or control flame extinction;

[0017] When the two unit support plate structures are combined, the unit support plate structure is located at the center of the combustion chamber. At this time, the bottom of the unit support plate structure provides fuel for the combustion chamber. The unit support plate structure induces an oblique shock wave at the angle α, which is reflected by the wall to form a complex shock wave train, which can reduce the airflow velocity in the combustion chamber and increase its temperature, prolong the residence time of the airflow and fuel in the combustion chamber, thereby obtaining a better mixing effect and an environment more conducive to ignition, which is conducive to ignition and flame stability. In addition, a vortex system is generated on the third surface of the tail of the unit support plate structure, which is conducive to the mixing of fuel and air, and can reduce the inlet flow velocity to facilitate ignition and subsequent stable combustion.

[0018] When the two unit support plate structures are separated and move apart in the vertical direction, an expansion wave is generated at the angle β formed between the first surface and the third surface of the unit support plate structure to reduce the shock wave reflected by the wall, thereby reducing the temperature to extinguish the flame. Therefore, compared with the traditional support plate structure that needs to cut off the fuel supply to extinguish the flame, the two unit support plate structures of the present invention can extinguish the flame without cutting off the fuel supply, and keep the fuel able to fill the combustion chamber cavity, so as to facilitate the conversion of the oblique detonation mode, thereby providing a supplement to the propulsion technology of the scramjet-oblique detonation combination engine.

[0019] 2. In the separated state, the first surfaces of the two unit support plate structures are parallel to the incoming flow, generating shock waves that do not interfere with each other. The angle β formed between the first surface and the third surface of the unit support plate structure can generate expansion waves to weaken the intensity of the shock wave reflected by the wall and reduce the total pressure loss caused by the oblique shock wave. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a three-dimensional structural schematic diagram of a detachable support plate structure in a scramjet-oblique detonation combination engine of the present invention;

[0021] Figure 2 It is a schematic diagram of the front view of the separable support plate structure in the scramjet-oblique detonation combination engine of the present invention;

[0022] Figure 3 It is a front structural schematic diagram with annotations of a detachable support plate structure in a scramjet-oblique detonation combination engine of the present invention;

[0023] Figure 4 It is a schematic diagram of the side view structure of the detachable support plate structure in the scramjet-oblique detonation combination engine of the present invention with annotations;

[0024] Figure 5 It is a schematic diagram of a top view of the structure of the detachable support plate in the scramjet-oblique detonation combination engine of the present invention with annotations;

[0025] Figure 6 It is a schematic diagram of a calculation model when the separable support plate structure in the scramjet-oblique detonation combination engine of the present invention is in a merged state;

[0026] Figure 7 It is a schematic diagram of a calculation model when the detachable support plate structure in the scramjet-oblique detonation combination engine of the present invention is in a detached state;

[0027] Figure 8 This is a dimensional diagram of a calculation model of a detachable support plate structure in a scramjet-oblique detonation combination engine of the present invention. DETAILED DESCRIPTION

[0028] The following is combined with Figure 1 To the attached Figure 8 , the specific implementation methods of the present invention are described in detail. In the description of the invention, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0029] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of the invention, unless otherwise specified, "plurality" means two or more.

[0030] The current support plate structure is an integrated type, such as the related support plate structures disclosed in the patents with publication numbers CN116817314A and CN115789698A. The working principle of this type of support plate structure is to establish a recirculation zone at the bottom of the support plate, that is, to create a subsonic area so that the airflow can stay in the recirculation zone. However, this type of support plate structure only has a recirculation zone at the bottom, which mainly plays a role in stabilizing the flame. When the oblique detonation mode needs to be converted, the flame needs to be extinguished and the fuel needs to be kept continuously filling the combustion chamber. The above-mentioned conventional support plate itself does not have the function of extinguishing the flame, and the flame can only be extinguished by disconnecting the fuel supply. Thus, it does not have the function of converting the oblique detonation mode, and is therefore difficult to be applied to a scramjet-oblique detonation combination engine.

[0031] Based on the above problems, an embodiment of the present invention provides a detachable support plate structure in a combustion chamber of a scramjet-oblique detonation combination engine, such as Figure 1 and Figure 2 As shown, it includes two unit support plate structures 2 and two groups of hydraulic telescopic mechanisms. The two unit support plate structures 2 are used to be arranged in the engine combustion chamber. The engine combustion chamber has an inlet and an outlet. The line connecting the inlet and the outlet is used as the center line. The two unit support plate structures 2 are mirror-arranged on both sides of the center line. The unit support plate structure 2 has a first surface 21, a second surface 22 and a third surface 23. The first surface 21 is arranged parallel to the center line. The second surface 22 is arranged on a side of the first surface 21 close to the inlet, and an angle α is formed between the second surface 22 and the first surface 21. The angle α is arranged toward the inlet. The third surface 23 is arranged on a side of the first surface 21 close to the outlet, and the third surface 2 3 forms an angle β with the extension line of the first surface 21, the angle β is arranged opposite to the outlet, the angle α and the angle β are both acute angles, and the angle α≤angle β; two groups of hydraulic telescopic mechanisms are respectively connected to the side walls of each unit support plate structure 2 in a one-to-one correspondence, and are used to control the two unit support plate structures 2 to separate and merge in the vertical direction. When the two unit support plate structures 2 merge, an oblique shock wave is generated at the angle α when the gas flows in; when the two unit support plate structures 2 separate, the first surfaces 21 of the two unit support plate structures 2 are parallel to the gas flow entering the combustion chamber, generating shock waves that do not interfere with each other, and an expansion wave is generated at the angle β of the two unit support plate structures 2.

[0032] In this embodiment, when the two unit support plate structures 2 are in a merged state through the hydraulic telescopic mechanism, an oblique shock wave is induced at the front end angle α of the unit support plate structure 2, which is reflected by the wall to form a complex shock wave train, thereby reducing the incoming flow velocity and increasing its temperature, which is beneficial to ignition and flame stabilization. At the same time, the third surface of the tail of the unit support plate structure 2 generates a vortex system to enhance fuel mixing so that the fuel and the incoming flow can be evenly mixed; when the unit support plate structure 2 is in a separated state, the first surface 21 of the two unit support plate structures 2 is parallel to the gas flow entering the combustion chamber, generating shock waves that do not interfere with each other. At the same time, the angle β formed between the third surface 23 of the unit support plate structure and the first surface 21 generates an expansion wave to weaken the intensity of the shock wave reflected by the wall, reduce the total pressure loss, and enhance the ignition capability of the combustion chamber. At the same time, the temperature will also be reduced to extinguish the flame, which is convenient for subsequent conversion to the oblique detonation mode.

[0033] Further, such as Figure 2 As shown, in the design, the range of angle α is 6°~10°, which can avoid the oblique shock wave being too strong, and the range of angle β is 28°~32°, which can avoid the expansion wave being too weak, resulting in the problem of not being able to achieve the cooling effect. In specific applications, such as Figure 3 As shown, α is 6° and β is 30°.

[0034] Further, such as Figure 1 and Figure 2 As shown, the unit support plate structure 2 also includes a fourth surface 24 and a fifth surface 25. The fourth surface 24 is vertically arranged opposite to the inlet and connected to the third surface 23. The fifth surface 25 is arranged parallel to the first surface 21. The two ends of the fifth surface 25 are respectively connected to the fourth surface 24 and the second surface 22.

[0035] Among them, Figures 3 to 5 As shown, the ratio of the width of the unit support plate structure 2 to the length of the first surface 21 is 48:95, the ratio of the vertical distance between the first surface 21 to the fifth surface 25 to the length of the first surface 21 is 2:19, and the ratio of the height of the fourth surface 24 to the vertical distance between the first surface 21 to the fifth surface 25 is 2:5. In specific applications, the length L of the first surface 21 is 47.5 mm, the vertical distance H between the first surface 21 to the fifth surface 25 is 5 mm, the width W of the unit support plate structure 2 is 24 mm, and the height H1 of the fourth surface 24 is 2 mm.

[0036] Among them, Figure 1 As shown, the fourth surface 24 is provided with a plurality of fuel spray holes 31 along its width direction, and a fuel delivery port 32 and an oxygen delivery port 33 are provided on a side wall of one side of the unit support plate structure 2. Each fuel spray hole 31 is connected with the fuel delivery port 32 and the oxygen delivery port 33 respectively. In actual application, the fuel spray holes 31 are connected with the fuel delivery port 32 through a fuel delivery pipe, and are connected with the oxygen delivery port 33 through an oxygen delivery pipe.

[0037] Furthermore, the ratio of the diameter of the fuel injection hole 31 to the height of the fourth surface 24 is 1:2. When the height of the fourth surface 24 is 2 mm, the diameter of the fuel injection hole 31 is 1 mm.

[0038] The unit support plate structure 2 is made of a material with high thermal conductivity, and the material with high thermal conductivity is stainless steel or high-temperature alloy steel.

[0039] Specifically, Figure 8 As shown, the combustion chamber 1 is 300 mm long and 50 mm high. The left side of the combustion chamber 1 is the inlet and the right side of the combustion chamber is the outlet. The combustion chamber 1 is used to receive the supersonic flow compressed by the intake duct and to create conditions for mixing and ignition. The horizontal distance between the front end of the first surface 21 of the unit support plate structure 2 and the inlet of the combustion chamber 1 is greater than or equal to 35 mm.

[0040] Specifically, two hydraulic telescopic mechanisms are arranged on the upper and lower sides of the combustion chamber 1. The hydraulic telescopic mechanism is a hydraulic cylinder (not shown in the figure). The piston rod end of the hydraulic cylinder penetrates into the combustion chamber 1 through a connecting rod and is connected to the side walls of the two unit support plate structures. The two hydraulic cylinders can be used to synchronously control the two unit support plate structures to move away from or approach each other, thereby realizing the separation and merging process of the two unit support plate structures.

[0041] The working principle of the present invention is as follows:

[0042] First, the free air flow is compressed by the intake duct, and the temperature and pressure of the air flow entering the combustion chamber are increased accordingly, creating conditions for subsequent ignition. In the combustion chamber, the unit support plate structure is first in a merged state, and the fuel injection holes at the tail of the unit support plate structure inject fuel into the combustion chamber. The fuel injection scheme is as follows Figure 6 As shown, the incoming flow and the fuel are mixed under the action of the shock wave train at the angle α of the unit support plate structure. The shock wave train can reduce the air flow velocity in the combustion chamber, increase the temperature, and prolong the residence time of the air flow and fuel in the combustion chamber, so as to obtain a better mixing effect and an environment more conducive to ignition. After the mixture is evenly mixed and meets the ignition requirements, ignition is carried out; near the fuel injection hole at the tail of the unit support plate structure, since this area is in an oil-rich state and the oxygen concentration is low, combustion and heat release cannot be carried out in a long stroke; in the process of gradually developing downstream, the flame gradually stabilizes, chemical reactions proceed simultaneously, and combustion products begin to be generated.

[0043] As the flight Mach number increases, the unit support plate structure is in a separated state, such as Figure 7 As shown, the two unit support plate structures are driven by a hydraulic telescopic mechanism to move and separate in the vertical direction. After separation, an expansion wave is generated at the tail angle β of the unit support plate structure to achieve the purpose of controlling the flame extinction, which is convenient for the subsequent syncline detonation mode conversion.

[0044] The above disclosures are only several preferred specific embodiments of the present invention. However, the embodiments of the present invention are not limited thereto. Any changes that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A detachable support plate structure in a scramjet-oblique detonation combined engine combustion chamber, characterized in that: include: Two unit support plate structures (2) are used to be arranged in an engine combustion chamber, the engine combustion chamber has an inlet and an outlet, with the connecting line of the inlet and the outlet as the center line, and the two unit support plate structures (2) are arranged in mirror image on both sides of the center line, the unit support plate structure (2) has a first surface (21), a second surface (22) and a third surface (23), the first surface (21) is arranged parallel to the center line, the second surface (22) is arranged on the side of the first surface (21) close to the inlet, and an angle α is formed between the second surface (22) and the first surface (21), and the angle α is arranged toward the inlet, the third surface (23) is arranged on the side of the first surface (21) close to the outlet, and an angle β is formed between the third surface (23) and the extension line of the first surface (21), and the angle β is arranged away from the outlet, the angle α and the angle β are both acute angles, and the angle α ≤ the angle β; Two sets of hydraulic telescopic mechanisms are connected to the side walls of each unit support plate structure (2) in a one-to-one correspondence, and are used to control the separation and merging of the two unit support plate structures (2) in a vertical direction. When the two unit support plate structures (2) are merged, an oblique shock wave is generated at an angle α when the gas flows in; when the two unit support plate structures (2) are separated, the first surfaces (21) of the two unit support plate structures (2) are parallel to the gas flow entering the combustion chamber, generating shock waves that do not interfere with each other, and an expansion wave is generated at an angle β between the two unit support plate structures (2).

2. The detachable support plate structure in the combustion chamber of the scramjet-oblique detonation combined engine according to claim 1, characterized in that: The angle α ranges from 6° to 10°, and the angle β ranges from 28° to 32°.

3. The detachable support plate structure in the combustion chamber of the scramjet-oblique detonation combined engine according to claim 2, characterized in that: The angle α is 6°, and the angle β is 30°.

4. The detachable support plate structure in the combustion chamber of the scramjet-oblique detonation combined engine according to claim 1, characterized in that: The unit support plate structure (2) further comprises a fourth surface (24) and a fifth surface (25); the fourth surface (24) is vertically arranged and connected to the third surface (23); the fifth surface (25) is parallel to the first surface (21); and two ends of the fifth surface (25) are respectively connected to the fourth surface (24) and the second surface (22).

5. The detachable support plate structure in the combustion chamber of the scramjet-oblique detonation combined engine according to claim 3, characterized in that: The ratio of the width of the unit support plate structure (2) to the length of the first surface (21) is 48:95, the ratio of the vertical distance between the first surface (21) to the fifth surface (25) to the length of the first surface (21) is 2:19, and the ratio of the height of the fourth surface (24) to the vertical distance between the first surface (21) to the fifth surface (25) is 2:

5.

6. The detachable support plate structure in the combustion chamber of the scramjet-oblique detonation combined engine according to claim 4, characterized in that: The fourth surface (24) is provided with a plurality of fuel injection holes (31) along its width direction, and a fuel delivery port (32) and an oxygen delivery port (33) are provided on a side wall of one side of the unit support plate structure (2), and each of the fuel injection holes (31) is respectively connected to the fuel delivery port (32) and the oxygen delivery port (33).

7. The detachable support plate structure in the combustion chamber of the scramjet-oblique detonation combined engine according to claim 5, characterized in that: The ratio of the diameter of the fuel injection hole (31) to the height of the fourth surface (24) is 1:

2.

8. The detachable support plate structure in the combustion chamber of a scramjet-oblique detonation combined engine according to claim 1, characterized in that: The unit support plate structure (2) is made of a material with a high thermal conductivity.

9. The detachable support plate structure in the combustion chamber of a scramjet-oblique detonation combined engine according to any one of claims 1 to 8, characterized in that: The horizontal distance between the first surface (21) of the unit support plate structure (2) and the entrance of the combustion chamber (1) is greater than or equal to 35 mm.

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