A slanting detonation-powered aircraft with S-shaped curved wedge surface structure

Abstract

The present application relates to a kind of oblique detonation power aircraft containing S-shaped curved surface wedge structure, belong to hypersonic aircraft design field, especially oblique detonation engine design field.It includes: aircraft body, for carrying load;Fuel injection structure is equipped with injection hole, for spouting fuel;Engine inlet, for generating oblique shock to compress gas;Engine combustion chamber, for detonating reactants, using a S-shaped curved surface wedge structure instead of flat wedge structure, using the more powerful compression ability curved shock instead of oblique shock, so that oblique detonation wave short distance induction detonation;Engine nozzle, for expanding and discharging detonation product, generate thrust.The present application can realize the acceleration of oblique detonation wave, realize the accurate positioning of oblique detonation wave initiation position, greatly reduce the length of oblique detonation wave induction section, reduce the structure length of oblique detonation engine combustion chamber, reduce the structure weight of oblique detonation engine combustion chamber, improve the working performance of aircraft.

Description

Technical Field

[0001] This invention belongs to the field of hypersonic vehicle design, particularly the field of oblique detonation engine design. Background Technology

[0002] Air-breathing hypersonic propulsion systems are one of the most important research hotspots in the aerospace field in the 21st century. Detonation combustion can release fuel energy within microseconds, while the propagation speed of the detonation wave can reach kilometers per second, which can greatly reduce the residence time of fuel during combustion and significantly reduce the size and weight of the engine. Detonation combustion is close to isochoric combustion, which can greatly improve the thermal efficiency of the cycle and reduce flight fuel consumption, making it an ideal combustion organization mode for hypersonic propulsion systems of next-generation aircraft. The oblique detonation engine uses oblique detonation wave organized combustion, that is, the fuel and oxides undergo detonation combustion inside the engine combustion chamber, carrying out a violent chemical reaction and generating thrust. Compared with traditional scramjet engines, it has advantages such as shorter combustion chamber size, higher flight Mach number, lighter engine structure weight, and no need for ignition for self-starting, and plays an important role in the development of hypersonic aircraft propulsion systems.

[0003] The working principle of a tilt-detonation engine is as follows: a supersonic flow impacts and compresses on a wedge surface, forming a tilted shock wave. The temperature and pressure rise behind the shock wave, while the velocity decreases. After passing through an induction section of a certain length, the tilted detonation wave initiates the explosion. Traditional tilt-detonation engines have a flat, tilted wedge-shaped combustion chamber structure, such as... Figure 1 As shown. Based on the working characteristics of oblique detonation shock waves, the wedge length is finite. An excessively long wedge length increases the engine's size and weight, causing thermal congestion; an excessively short wedge length prevents the combustible gas from passing through a sufficiently long induction section, preventing the oblique detonation shock wave from initiating. Similarly, the wedge angle is also fixed. An excessively large angle causes the oblique detonation shock wave to detach, preventing the engine from operating normally; an excessively small angle results in insufficient static temperature after the oblique shock wave, increasing the induction section distance and further increasing the engine's size and weight. Furthermore, a straight wedge surface makes it difficult to control the initiation position of the oblique detonation shock wave. Summary of the Invention

[0004] To address the insufficient detonation capability of existing flat wedge-faced oblique detonation engines, this invention provides an oblique detonation power vehicle with an S-shaped curved wedge structure, which relies on the compression control of the S-shaped curved surface to induce short-distance detonation of the oblique detonation wave.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A slanted explosive shock-generating aircraft with an S-shaped curved wedge structure includes an aircraft fuselage, a fuel injection structure, an engine air intake, an engine combustion chamber, and an engine tail nozzle.

[0007] The airframe of an aircraft, used to carry the load and provide lift;

[0008] The fuel injection structure is equipped with injection holes for injecting liquid or gaseous fuel;

[0009] The engine intake duct is used to generate oblique shock waves to decelerate and pressurize the incoming gas flow;

[0010] The engine combustion chamber, used to detonate reactants, utilizes an S-shaped curved wedge structure instead of a flat wedge structure, and uses a curved shock wave with stronger compressibility instead of an oblique shock wave, so that the oblique detonation shock wave induces detonation over a short distance.

[0011] The engine exhaust nozzle is used to expand and expel knock products, generating thrust.

[0012] Furthermore, the S-shaped curved wedge structure includes a concave surface and a convex surface, with the concave and convex surfaces smoothly tangent at their connection. The concave surface is used to form a curved shock wave in the mixed gas, the tangency of the concave and convex surfaces is used to form an oblique detonation shock wave in the mixed gas and control the detonation position, and the convex surface is used to reduce gas resistance and total pressure loss after the oblique detonation shock wave.

[0013] Furthermore, the concave and convex surfaces are not limited to circular arc surfaces, elliptical arc surfaces, streamlined surfaces, and other surfaces.

[0014] Furthermore, the oblique detonation shock-generating aircraft containing an S-shaped curved wedge structure also includes an engine mixing section, wherein the fuel injection structure is located at the inlet of the engine mixing section, and the engine mixing section is used for premixing compressed gas and fuel.

[0015] Furthermore, the front part of the concave curved surface can be tangent to the straight oblique wedge, forming a wedge surface structure of oblique wedge + S-shaped curved surface.

[0016] Furthermore, by adjusting the curvature of the surface and controlling the tangent position of the concave and convex surfaces, the detonation position of the oblique detonation shock wave can be controlled.

[0017] Furthermore, the detonation location of the oblique detonation shock wave is near the center of the S-shaped curved surface, that is, above the tangent position of the concave and convex curved surfaces.

[0018] The significant advantages of this invention compared to existing technologies are:

[0019] (1) This invention proposes a slanted detonation shock vehicle with an S-shaped curved wedge structure. In the combustion chamber of the slanted detonation engine, the S-shaped curved surface is used instead of the flat wedge. The supersonic premixed flow forms a curved shock wave at the concave curved surface of the front half of the S-shaped curved surface. The curved shock wave has a stronger compression capacity than the traditional slanted shock wave, which greatly reduces the induction section distance, thereby controlling the early detonation of the slanted detonation wave.

[0020] (2) At the same time, the point of tangency between the concave and convex surfaces is the detonation position of the oblique detonation shock wave. By adjusting the point of tangency, the detonation position of the oblique detonation shock wave can be precisely controlled.

[0021] (3) In theory, using an S-shaped curved surface to replace a flat wedge surface can significantly shorten the length of the lower wall of the combustion chamber of a detonation engine, thereby reducing the size and weight of the detonation engine and increasing flight speed. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a traditional flat wedge surface.

[0023] Figure 2 This is a schematic diagram of a novel S-shaped curved wedge surface.

[0024] Figure 3 This is a schematic diagram of a wedge with an S-shaped curved surface.

[0025] Figure 4 A schematic diagram of an oblique-explosion shock-forced aircraft with external fuel injection, with a partial enlargement. Figure I-I A partial enlargement of the schematic diagram of the S-shaped curved wedge surface installation. Figure I-II This is a schematic diagram of the installation of a wedge with an S-shaped curved surface.

[0026] Figure 5 A schematic diagram of an oblique-explosion shock-force aircraft with internal fuel injection, with a partial enlargement. Figure II-I A partial enlargement of the schematic diagram of the S-shaped curved wedge surface installation. Figure II-II This is a schematic diagram of the installation of a wedge with an S-shaped curved surface.

[0027] Figures 6-10 The figure shows a numerical simulation of an S-shaped curved wedge structure under ethylene-air premixed uniform inflow conditions. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0029] Example 1

[0030] like Figure 4 As shown, an externally fuel-injected oblique detonation shock-force aircraft includes an aircraft body 1, a fuel injection structure 2, an engine air intake 3, an engine combustion chamber 4, and an engine tail nozzle 5. An S-shaped curved wedge structure 6 is provided on the lower wall of the engine combustion chamber 4.

[0031] like Figure 4 As shown, the supersonic airflow generates an oblique shock wave as it passes through the engine intake duct 3. The airflow behind the oblique shock wave mixes with the fuel injected by the fuel injection structure 2. The mixed gas is compressed through the intake duct and then enters the engine combustion chamber 4. The supersonic airflow has a Mach number Ma ≥ 8.

[0032] There are two types of wedge structures 6 installed in the engine combustion chamber 4: S-shaped curved wedge structure and inclined wedge + S-shaped curved wedge structure.

[0033] The first type of S-shaped curved wedge structure is as follows: Figure 2 As shown, it includes a concave surface and a convex surface, and the concave surface and the convex surface are smoothly tangent at the connection point.

[0034] S-shaped curved wedge structure installation method as follows: Figure 4 Local magnification Figure I-I As shown, the mixed gas entering the engine combustion chamber 4 impacts the S-shaped curved wedge structure 6 on the lower wall of the combustion chamber, forming a bending shock wave. After the bending shock wave, the gas undergoes induction and compression over a certain distance, resulting in a rapid increase in temperature and pressure. It then detonates above the tangent point of the concave and convex curved surfaces of the S-shaped surface, forming an oblique detonation shock wave. The gas following the oblique detonation shock wave flows out of the combustion chamber and finally enters the engine exhaust nozzle 5, where it expands to generate thrust.

[0035] The second type of wedge structure, consisting of a slanted wedge and an S-shaped curved surface, is as follows: Figure 3 As shown, the S-shaped surface segment consists of a wedge segment, a concave surface, and a convex surface, with the wedge and the S-shaped surface being smoothly tangent.

[0036] Installation method of wedge + S-shaped curved wedge structure as follows Figure 4 Local magnification Figure I-II As shown, the mixed gas entering the engine combustion chamber 4 impacts the concave surface of the inclined wedge and S-shaped curved surface on the lower wall of the combustion chamber, forming an oblique shock wave + bending shock wave structure. After the bending shock wave, the gas undergoes induction and compression over a certain distance, resulting in a rapid increase in temperature and pressure. It then detonates above the tangent point of the concave and convex curved surfaces of the S-shaped curved surface, forming an oblique detonation shock wave. The gas following the oblique detonation shock wave flows out of the combustion chamber and finally enters the engine exhaust nozzle 5, where it expands to generate thrust.

[0037] The wedge structure provides the initial compression angle, which, while meeting the requirements for oblique detonation wave initiation, can reduce the curvature of the S-shaped surface, reduce the gas resistance and total pressure loss caused by the S-shaped wedge structure, and help improve the propulsion performance of the engine combustion chamber.

[0038] Example 2

[0039] like Figure 5 As shown, an internally fuel-injected oblique detonation shock-force aircraft includes an aircraft body 1, an engine air intake 2, a fuel injection structure 3, an engine mixing section 4, an engine combustion chamber 5, and an engine tail nozzle 7. An S-shaped curved wedge structure 6 is provided on the lower wall of the engine combustion chamber 5.

[0040] like Figure 5As shown, the supersonic airflow passing through the engine intake duct 2 generates an oblique shock wave. Behind this shock wave, the gas is compressed, increasing its temperature and pressure. The gas exits the engine intake duct 2 and enters the engine mixing section 4, where it mixes with fuel injected from the fuel injection structure 3 at the inlet of the mixing section 4. The mixed gas then exits the mixing section 4 and enters the engine combustion chamber 5. The supersonic airflow has a Mach number Ma ≥ 8.

[0041] There are two types of wedge structures 6 installed in the engine combustion chamber 5: an S-shaped curved wedge structure and a combination of a wedge and an S-shaped curved wedge structure. The specific structures are as follows: Figure 2 and Figure 3 As shown.

[0042] The first type of S-shaped curved wedge structure installation method is as follows: Figure 5 Local magnification Figure II-I As shown, the mixed gas entering the engine combustion chamber 5 impacts the S-shaped curved wedge structure 6 on the lower wall of the combustion chamber, forming a bending shock wave. After the bending shock wave, the gas undergoes induction and compression over a certain distance, resulting in a rapid increase in temperature and pressure. It then detonates above the tangent point of the concave and convex surfaces of the S-shaped curved surface, forming an oblique detonation shock wave. The gas following the oblique detonation shock wave flows out of the combustion chamber and finally enters the engine exhaust nozzle 7, where it expands to generate thrust.

[0043] The second type of installation method for the inclined wedge + S-shaped curved wedge structure is as follows: Figure 5 Local magnification Figure II-II As shown, the mixed gas entering the engine combustion chamber 5 impacts the inclined wedge and S-shaped curved wedge structure 6 on the lower wall of the combustion chamber, forming an oblique shock wave + bending shock wave structure. After the bending shock wave, the gas undergoes induction and compression over a certain distance, resulting in a rapid increase in temperature and pressure. It then detonates above the tangent point of the concave and convex curved surfaces of the S-shaped surface, forming an oblique detonation shock wave. The gas following the oblique detonation shock wave flows out of the combustion chamber and finally enters the engine exhaust nozzle 7, where it expands to generate thrust.

[0044] Oblique detonation combustion falls under the category of chemical reaction flow. For the initiation problem of oblique detonation combustion, the Euler equation, which does not consider the influence of viscosity, can be used for simulation and solution. Therefore, the governing equation of the numerical model in this invention is the Euler equation. Simultaneously, a ten-step chemical reaction mechanism of ethylene-air with nine components is used for numerical simulation and solution.

[0045] like Figure 6 , Figure 7 , Figure 8 and Figure 9 As shown, the parameters of the uniformly premixed incoming flow entering the wedge are the same, with an ethylene-air chemical equivalence ratio of 1, a static temperature of T = 800 K, a static pressure of P = 50 kPa, and an incoming flow Mach number of Ma = 5.

[0046] like Figure 10As shown, the uniform premixed incoming flow entering the wedge surface is under the condition of ethylene to air chemical equivalence ratio 1, static temperature T = 850K, static pressure P = 60KPa, and incoming flow Mach number Ma = 4.5.

[0047] like Figure 6 The conventional flat wedge structure shown, under given incoming flow parameters, forms an oblique shock wave at the wedge's apex after being impacted by the flow. The gas following the oblique shock wave travels along the entire 88mm length of the wedge without detonation, and no oblique detonation shock wave is formed. This indicates that the wedge is short and has a small angle, failing to achieve detonation.

[0048] like Figure 7 The S-shaped curved wedge structure shown has a length and height that are similar to... Figure 6 This is consistent with the traditional flat wedge structure shown. The concave surface is a circular arc surface with a radius of 100mm, the convex surface is a circular arc surface with a radius of 100mm, and the curvature of the S-shaped surface is 0.01mm. -1 The concave and convex surfaces are tangent at x = 39.82 mm and y = 16.94 mm. The incoming flow first forms a flexural shock wave at the sharp corner of the concave surface of the S-shaped surface. Behind the flexural shock wave, the gas is continuously compressed, and the temperature and pressure rise sharply. Finally, it detonates above the tangent point of the concave and convex surfaces, forming an oblique detonation shock wave.

[0049] contrast Figure 6 and Figure 7 It can be observed that the S-shaped curved wedge structure can achieve short-distance detonation on a shorter wedge surface, accelerate detonation, reduce the wedge length, and reduce the length and weight of the engine combustion chamber.

[0050] like Figure 8 It is a wedge-shaped surface structure with an S-shaped curved surface. Figure 8 The wedge shown has a length of 20mm. The concave surface of the S-shaped wedge structure is a circular arc surface with a radius of 100mm, and the convex surface is also a circular arc surface with a radius of 100mm. The curvature of the S-shaped surface is 0.01mm. -1 The concave and convex surfaces are tangent at x = 60.05 mm and y = 21.01 mm. The incoming flow first forms an oblique shock wave at the sharp corner of the wedge. After passing through the wedge surface, the airflow enters the concave part of the S-shaped wedge, forming a curved shock wave. The gas behind the curved shock wave is continuously compressed, and the temperature and pressure rise sharply, eventually detonating above the tangency of the concave and convex surfaces, forming an oblique detonation shock wave.

[0051] like Figure 9 An S-shaped wedge structure is used to modify the curvature of a surface, wherein the concave surface is a circular arc surface with a radius of 75 mm, and the convex surface is a circular arc surface with a radius of 75 mm. The curvature of the S-shaped surface is 0.0133 mm. -1The concave and convex surfaces are tangent at x = 37.28 mm and y = 12.45 mm. The incoming flow first forms a flexural shock wave at the sharp corner of the concave surface of the S-shaped surface. Behind the flexural shock wave, the gas is continuously compressed, and the temperature and pressure rise sharply. Finally, it detonates above the tangent point of the concave and convex surfaces, forming an oblique detonation shock wave.

[0052] contrast Figure 7 and Figure 9 It can be found that changing the curvature and tangent position of the S-shaped surface can control the initiation position of the oblique detonation wave, which is always at the tangent point of the concave and convex surfaces. The S-shaped wedge structure can achieve precise positioning of the oblique detonation wave initiation position.

[0053] like Figure 10 The wedge structure shown is similar to Figure 9 Similarly, in the S-shaped curved wedge structure, both the concave and convex surfaces are tangent at x = 37.28 mm and y = 12.45 mm, with only the incoming flow conditions altered. The incoming flow first forms a bending shock wave at the sharp corner of the concave surface of the S-shaped curved surface. Behind the bending shock wave, the gas is continuously compressed, and the temperature and pressure rise sharply, eventually detonating above the tangent point of the concave and convex surfaces, forming an oblique detonation shock wave.

[0054] contrast Figure 9 and Figure 10 It can be observed that the flow field structures shown are basically consistent, the initiation positions of the oblique detonation waves are the same, and they are all at the tangent of the concave and convex curved surfaces. This indicates that by using the S-shaped curved wedge structure, small-scale changes in flight conditions do not affect the initiation of the oblique detonation wave. The S-shaped curved wedge structure can improve the wide-range flight capability of oblique detonation shock vehicles.

[0055] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A slanted explosive shock-generating aircraft containing an S-shaped curved wedge structure, comprising an aircraft fuselage, a fuel injection structure, an engine air intake, an engine combustion chamber, and an engine exhaust nozzle; characterized in that, An S-shaped curved wedge structure is provided on the lower wall of the engine combustion chamber; The engine intake duct is used to generate oblique shock waves to compress gas. The fuel injection structure is located at the intake duct inlet and is used to inject fuel. The mixture of compressed gas and fuel enters the engine combustion chamber and detonates to generate oblique detonation shock waves. The gas behind the oblique detonation shock waves expands and is ejected through the engine tail nozzle to generate thrust. The S-shaped curved wedge structure includes a concave surface and a convex surface. The concave and convex surfaces are smoothly tangent at the connection point. The concave surface is used to form a curved shock wave in the mixed gas. The tangent point between the concave and convex surfaces is used to form an oblique detonation wave in the mixed gas and control the detonation position. The convex surface is used to reduce the gas resistance and total pressure loss after the oblique detonation wave.

2. The oblique detonation shock-generating aircraft with an S-shaped curved wedge structure according to claim 1 further includes an engine mixing section, wherein the fuel injection structure is located at the inlet of the engine mixing section, and the engine mixing section is used for premixing compressed gas and fuel.

3. The oblique detonation shock vehicle with an S-shaped curved wedge structure according to claim 1 or 2, wherein the S-shaped curved wedge structure further includes an oblique wedge segment, which is disposed at the front of the concave curved surface and is smoothly tangent to the concave curved surface, and is used to provide an initial compression angle, reduce the curvature of the S-shaped curved surface, and reduce the total pressure loss caused by the bending shock wave.

4. The oblique detonation shock wave aircraft with an S-shaped curved wedge structure according to claim 1 or 2, by adjusting the curvature of the curved surface and controlling the tangent position of the concave and convex curved surfaces, thereby controlling the detonation position of the oblique detonation shock wave.

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