Oblique detonation engine suitable for wide range of supersonic operation

Abstract

The application discloses a slanting detonation engine suitable for a wide-range operation condition of supersonic speed, a lower surface of a combustion chamber of which is provided with a wedge surface, and the wedge surface of the combustion chamber is designed in a curved surface structure in a direction perpendicular to a flow direction, so that the angle of the wedge surface continuously changes in a direction perpendicular to an inlet flow direction of the combustion chamber. The slanting detonation engine provided by the application forms the wedge surface with continuously changed angles at different positions in the direction perpendicular to the flow direction through the structural design of the three-dimensional curved wedge surface combustion chamber, the different positions have different ignition angles, so that the local detonation point is quickly triggered, and the formation and development of the slanting detonation wave in the whole combustion chamber are accelerated. Through the combustion chamber design of the three-dimensional curved wedge surface structure, the stable operation condition range of the supersonic speed propulsion system based on the slanting detonation combustion under the wide-range flight condition is improved, the through-flow area of the combustion chamber is improved while the fast and stable ignition is ensured, and the flow pressure loss in the combustion chamber is reduced.

Description

Technical Field

[0001] This invention relates to the field of supersonic vehicle design technology, and in particular to a slant detonation engine suitable for supersonic wide-range operating conditions. Background Technology

[0002] Oblique detonation propulsion (ODE) systems based on oblique detonation combustion have attracted increasing attention in the aerospace field due to their characteristics such as fast heat release rate, high thermal cycle efficiency, and wide operating range. Their feasibility and superiority have been confirmed in early studies, and they are suitable for air-breathing supersonic aircraft with flight Mach numbers higher than scramjet engines.

[0003] Unlike traditional combustion, oblique detonation combustion achieves self-ignition based on strong shock wave compression, enabling rapid conversion of chemical energy into thermal energy on a millimeter-scale scale. Therefore, oblique detonation propulsion systems possess engineering advantages such as simple and compact structure and superior high-speed flight performance, making them a research hotspot and development trend in the field of aerospace propulsion. However, the initiation and stabilization conditions of oblique detonation are extremely demanding, and stable operation is significantly affected by flight conditions. Therefore, achieving flexible and smooth startup and stable power output of oblique detonation propulsion systems is a highly challenging task.

[0004] Many factors influence the stationary position of oblique detonation waves, such as the equivalence ratio of the premixed combustible fuel in the incoming flow, the temperature and pressure of the incoming flow, the Mach number of the incoming flow, and the wedge angle. For a given wedge angle, when the Mach number of the combustion chamber incoming flow varies within a certain range, oblique detonation can achieve stationary combustion, and the initiation time and initiation distance also change accordingly. Currently, most existing oblique detonation combustion chambers adopt a flat wedge structure, or accelerate initiation by setting protrusions or other structures along the incoming flow direction. This increases flow losses to some extent. In addition, the wedge surface of this structure does not change along the width of the combustion chamber, which limits the range of angles from which oblique detonation can successfully initiate. Therefore, this type of structure has a limited range of oblique detonation stationary Mach numbers.

[0005] The size of the oblique detonation stationary range reflects the ease or difficulty of stable combustion of the oblique detonation wave. It is directly related to factors such as incoming flow conditions and combustion chamber structure. For oblique detonation engines under wide-range flight conditions, the design of the wedge structure inside the combustion chamber directly determines the initiation efficiency and stationary range of the oblique detonation. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a slant detonation engine and its design method suitable for supersonic wide-range operation conditions. The slant detonation engine achieves stable flight over a wide range at supersonic speeds through a three-dimensional curved wedge structure of the combustion chamber.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] The present invention provides a slant detonation engine suitable for supersonic wide-range operation conditions. The lower surface of the combustion chamber of the slant detonation engine is set as a wedge surface. The wedge surface of the combustion chamber adopts a curved surface structure design perpendicular to the flow direction, so that the angle of the wedge surface changes continuously in the direction perpendicular to the inlet flow of the combustion chamber.

[0009] Furthermore, the front edge of the wedge of the combustion chamber is straight, and the rear edge of the wedge is curved.

[0010] Furthermore, the surface is a variable wedge angle surface.

[0011] Furthermore, the curved surface has a cross-section perpendicular to the air intake direction, and the profile of the cross-section is a combination of several smooth curves.

[0012] Furthermore, the variable wedge angle surface adopts an n-shaped or / and U-shaped surface.

[0013] Furthermore, the wedge angles at different positions perpendicular to the incoming flow direction within the combustion chamber continuously vary between (θ1, θ2), where θ1 ranges from 15 to 30 degrees and θ2 ranges from 20 to 40 degrees. θ1 is the minimum wedge angle corresponding to the position with the maximum distance between the wedge surface and the upper surface of the combustion chamber, and θ2 is the maximum wedge angle corresponding to the position with the minimum distance between the wedge surface and the upper surface of the combustion chamber.

[0014] Furthermore, the angle change (θ1, θ2) of the wedge surface is within the stationary range (θ det,CJ ,θ det,max Within ) where θ det,CJ θ represents the wedge angle corresponding to the occurrence of the Chapman-Jouguet oblique detonation. det,max This represents the maximum wedge angle corresponding to the condition that the oblique detonation wave does not detach from the body.

[0015] Furthermore, the wedge angle formed by the curved surface varies from 0 to 15 degrees.

[0016] Furthermore, the angle of the oblique detonation wave generated in the combustion chamber varies from 0 to 20 degrees in the direction perpendicular to the wedge surface.

[0017] Furthermore, the Mach number of the inlet flow to the combustion chamber is between 3 and 15.

[0018] The beneficial effects of this invention are as follows:

[0019] This invention provides a slant detonation engine suitable for supersonic wide-range operation. The lower surface of the combustion chamber is designed as a wedge, and this wedge is designed with a curved structure perpendicular to the flow direction, allowing the angle of the wedge to continuously vary perpendicular to the inlet flow direction. Through the structural design of the three-dimensional curved wedge combustion chamber, this invention creates a wedge with continuously varying angles at different positions perpendicular to the inlet flow direction. These different positions have different detonation angles, thereby achieving rapid triggering of local detonation points and accelerating the formation and development of the slant detonation wave throughout the combustion chamber.

[0020] By employing an n-shaped or / and U-shaped three-dimensional curved wedge structure for the combustion chamber design, the system adapts to varying incoming flow conditions under different engine operating conditions. This improves the stable operating range and propulsion performance of the supersonic propulsion system based on oblique detonation combustion under wide-range flight conditions. While ensuring rapid and stable ignition, the system also increases the flow area of ​​the combustion chamber and reduces flow pressure loss within the combustion chamber, ultimately achieving rapid ignition and efficient wide-range flight of the oblique detonation engine under supersonic conditions.

[0021] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0022] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following drawings are provided for illustration.

[0023] Figure 1 This is a schematic diagram of an air-breathing supersonic propulsion system based on oblique detonation combustion and a partially enlarged schematic diagram of the combustion chamber.

[0024] Figure 2 It is the oblique detonation angle (β) det ) and oblique shock wave angle (β) sho A schematic diagram showing how the angle (θ) of the wedge changes.

[0025] Figure 3 This is a three-dimensional cross-sectional schematic diagram of the engine combustion chamber structure with an added n-shaped wedge surface design.

[0026] Figure 4 This is a schematic diagram of the combustion chamber of an engine with an added n-shaped wedge surface design.

[0027] Figure 5 This is a schematic diagram of the engine combustion chamber with an added U-shaped wedge surface design.

[0028] Figure 6 This is a schematic diagram of the engine combustion chamber with an added n- and U-shaped wedge surface design.

[0029] Explanation of the reference numerals: 1 represents the engine air intake; 2 represents the engine block; 3 represents the engine combustion chamber; 4 represents the curved wedge surface; 5 represents the engine exhaust nozzle; θ1 represents the minimum wedge angle of the combustion chamber wedge surface; θ2 represents the maximum wedge angle of the combustion chamber wedge surface. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0031] like Figure 1 As shown in the figure, the oblique detonation engine provided in this embodiment is suitable for supersonic wide-range operation. The oblique detonation engine includes a fuselage, which includes a forebody, a combustion chamber, and a nozzle. The lower surface of the combustion chamber of the oblique detonation engine is set as a wedge surface. The wedge surface of the combustion chamber adopts a curved surface structure design perpendicular to the flow direction, so that the angle of the wedge surface continuously changes in the direction perpendicular to the inlet flow of the combustion chamber, thereby increasing the initiation efficiency of oblique detonation, expanding the stable combustion range of oblique detonation, improving the combustion efficiency of the supersonic propulsion system, and realizing wide-range stable flight under supersonic conditions.

[0032] In this embodiment, the angle of the wedge surface is the angle between the direction of the incoming gas flow in front of the combustion chamber and the wedge surface; in this embodiment, the front edge of the wedge surface of the combustion chamber is a straight line, and the rear edge of the wedge surface is a curve; in this embodiment, the curved surface is a variable wedge angle surface, and the variable wedge angle surface adopts an n-shaped or / and U-shaped surface.

[0033] The curved surface is a cross-section of the wedge surface along the air intake direction, and its cross-sectional profile is a smooth curve of different shapes or a combination thereof; the smooth curve includes circular arc, ellipse or parabola, etc.; in this embodiment, the wedge surface angle formed by the curved surface cross-section varies from 0 to 15 degrees, with the optimal range being 5 to 15 degrees; in this embodiment, the angle of the oblique detonation wave varies from 0 to 20 degrees in the direction perpendicular to the wedge surface, with the optimal range being 5 to 10 degrees.

[0034] In this embodiment, the stable combustion range of oblique detonation in the combustion chamber can be controlled by adjusting the cross-sectional shape of the wedge and the range of wedge angle variation.

[0035] In this embodiment, the Mach number of the inlet flow to the combustion chamber is between 3 and 15.

[0036] The oblique detonation combustor provided in this embodiment is suitable for supersonic wide-range operating conditions, and can achieve stable and rapid ignition of the oblique detonation combustor, improve the stability and reliability of combustion in the engine combustor in a wider Mach number range, so as to ensure the stable and efficient output of the aircraft's power.

[0037] This embodiment uses a combustion chamber with a variable wedge angle to control the initiation and stationary range of the oblique detonation wave. This structure can be applied to air-breathing supersonic propulsion systems based on oblique detonation combustion. The combustion chamber uses a wedge surface with continuously varying angles at different positions perpendicular to the incoming flow direction, so that different positions of the combustion chamber wedge surface have different initiation angles. Through the rapid triggering of local detonation points, the formation and development of detonation in the entire combustion chamber are accelerated, so as to adapt to the variable incoming flow state under different engine operating conditions, and finally realize the rapid initiation and stable stationary of oblique detonation in the combustion chamber of the supersonic propulsion system under a wide range of operating conditions.

[0038] This embodiment, in conjunction with the accompanying drawings, details the working principle of a slant-detonation engine applicable to supersonic wide-range operating conditions:

[0039] like Figure 1 As shown, the supersonic airflow is compressed by two appendage shock waves induced by the forebody and mixed with the fuel injected into the front of the fuselage. The mixed gas flows into the combustion chamber through the fairing and forms a slanted detonation under the induction of the wedge surface in the combustion chamber. The detonation combustion products are ejected through the nozzle to generate thrust, providing power for the air-breathing supersonic aircraft.

[0040] like Figure 2 As shown, Figure 2 It is the oblique detonation angle (β) det ) and oblique shock wave angle (β) sho This diagram illustrates the variation of the wedge angle (θ). The solid lines in the diagram represent the angular range within which oblique detonation and oblique shock waves can stably reside. As the wedge angle (θ) increases, the angles at which oblique detonation waves and oblique shock waves can be formed also increase. For a given incoming flow condition, the residing ranges of oblique detonation waves and oblique shock waves are shown by the solid lines in the diagram, reflected in the change of the wedge angle (θ). det,CJ ,θ det,max ) and (0,θ sho,max ), also known as the stationary range.

[0041] In this embodiment, the oblique detonation angle β det It refers to the angle between the oblique detonation wave and the direction of the incoming gas flow in the combustion chamber during oblique detonation combustion.

[0042] In this embodiment, the wedge angle θ refers to the angle between the direction of the incoming gas flow in front of the combustion chamber in the detonation engine and the wedge surface;

[0043] In this embodiment, θ det,CJThis refers to the wedge angle corresponding to the occurrence of the Chapman-Jouguet oblique detonation;

[0044] In this embodiment, θ det,max This represents the maximum wedge angle corresponding to the condition where the oblique detonation wave does not detach from the body;

[0045] In this embodiment, θ sho,max This represents the maximum wedge angle corresponding to the condition where the oblique shock wave does not detach from the body;

[0046] In this embodiment, β det,CJ The angle of detonation corresponding to the occurrence of Chapman-Jouguet angled detonation;

[0047] In this embodiment, β det,max The maximum oblique detonation angle that can be maintained under the condition that the oblique detonation wave does not detach from the body;

[0048] In this embodiment, β sho,max The maximum angle of the oblique shock wave that can be maintained under the condition that the oblique shock wave does not detach from the body;

[0049] In this embodiment, Ma n This represents the Mach number in the normal direction after the oblique detonation wave.

[0050] Combination Figure 3-4 The illustrated embodiment, by setting an n-shaped (e.g., Figure 4 As shown in section BB, the wedge-shaped surface has a smaller distance between the middle part of the n-shaped wedge surface and the upper surface of the combustion chamber than the distance between the two sides of the edge and the upper surface of the combustion chamber. This allows the wedge angle at different positions in the combustion chamber perpendicular to the incoming flow direction to continuously change between (θ1, θ2), and enables rapid triggering of local detonation points on the wedge surface near the wedge angle of θ2, accelerating the formation and development of oblique detonation waves in the entire combustion chamber. The wedge surface at a smaller angle increases the flow area of ​​the combustion chamber, which is beneficial to reducing flow losses in the combustion chamber.

[0051] Wherein, θ1 is the minimum wedge angle corresponding to the maximum distance between the two sides of the edge of the n-shaped wedge surface in the combustion chamber and the upper surface of the combustion chamber; θ2 is the maximum wedge angle corresponding to the minimum distance between the middle of the n-shaped wedge surface in the combustion chamber and the upper surface of the combustion chamber; the value range of θ1 is 15-30 degrees; the value range of θ2 is 20-40 degrees.

[0052] Combination Figure 5 In the embodiment shown, the combustion chamber is U-shaped (e.g., Figure 5 (As shown in section BB) wedge-shaped surface, the rest of the structure is the same as... Figure 4 The same, its working principle is the same as Figure 4 The same as in the above. The distance between the middle of the U-shaped wedge surface and the upper surface of the combustion chamber is greater than the distance between the two sides of the edge and the upper surface of the combustion chamber.

[0053] Combination Figure 6 The embodiment shown has a combustion chamber configured with a combination of U-shaped and n-shaped shapes (such as...). Figure 6 (As shown in section BB) wedge-shaped surface, the rest of the structure is the same as... Figure 4 Similarly, for wider combustion chambers, this configuration allows for the formation of more detonation points on the wedge-shaped surface of the combustion chamber, increasing the speed at which the detonation wave develops within the combustion chamber. Its working principle is the same as... Figure 4 The same as in.

[0054] The above-described embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A slant detonation engine suitable for supersonic wide-range operating conditions, characterized in that: The lower surface of the combustion chamber of the oblique detonation engine is set as a wedge surface. The wedge surface of the combustion chamber adopts a curved surface structure design perpendicular to the flow direction, so that the angle of the wedge surface changes continuously in the direction perpendicular to the inlet flow of the combustion chamber.

2. The oblique detonation engine suitable for supersonic wide-range operation as described in claim 1, characterized in that: The front edge of the wedge of the combustion chamber is straight, and the rear edge of the wedge is curved.

3. The oblique detonation engine suitable for supersonic wide-range operation as described in claim 1, characterized in that: The surface in question is a variable wedge angle surface.

4. The oblique detonation engine suitable for supersonic wide-range operation as described in claim 1, characterized in that: The curved surface is cross-sectioned perpendicular to the air intake direction, and the outline shape of the cross-section is a combination of several smooth curves.

5. The oblique detonation engine suitable for supersonic wide-range operation as described in claim 3, characterized in that: The variable wedge angle surface adopts an n-type or / and U-type surface.

6. The oblique detonation engine suitable for supersonic wide-range operation as described in claim 4 or 5, characterized in that: The wedge angles at different positions perpendicular to the incoming flow direction within the combustion chamber continuously vary between (θ1, θ2), where θ1 ranges from 15 to 30 degrees and θ2 ranges from 20 to 40 degrees. θ1 is the minimum wedge angle corresponding to the position with the maximum distance between the wedge surface and the upper surface of the combustion chamber, and θ2 is the maximum wedge angle corresponding to the position with the minimum distance between the wedge surface and the upper surface of the combustion chamber.

7. The oblique detonation engine suitable for supersonic wide-range operation as described in claim 6, characterized in that: The angle change (θ1, θ2) of the wedge surface is within the stationary range (θ1, θ2). det,CJ ,θ det,max Within ) where θ det,CJ θ represents the wedge angle corresponding to the occurrence of the Chapman-Jouguet oblique detonation. det,max This represents the maximum wedge angle corresponding to the condition that the oblique detonation wave does not detach from the body.

8. The oblique detonation engine suitable for supersonic wide-range operation as described in claim 1, characterized in that: The wedge angle formed by the curved surface varies from 0 to 15 degrees.

9. The oblique detonation engine suitable for supersonic wide-range operation as described in claim 1, characterized in that: The angle of the oblique detonation wave generated by the combustion chamber varies from 0 to 20 degrees in the direction perpendicular to the wedge surface.

10. The oblique detonation engine suitable for supersonic wide-range operation as described in claim 1, characterized in that: The Mach number of the inlet flow to the combustion chamber is between 3 and 15.

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