A strong mixing structure for a oblique detonation engine

Abstract

The application discloses a reinforced mixing structure of an oblique detonation engine, which comprises a mixing cavity arranged on the inner bottom surface of a combustion chamber of the oblique detonation engine, a reinforced mixing step structure arranged on one side of the mixing cavity close to the inlet end of the combustion chamber, and an open structure with a flat bottom surface arranged on the other side of the mixing cavity away from the inlet end of the combustion chamber, wherein the open structure extends horizontally to the detonation wedge surface, the reinforced mixing step structure comprises a plurality of first steps and second steps arranged alternately along the width direction of the combustion chamber of the oblique detonation engine, the second steps are arranged protruding from the first steps, the steps on the side of the first steps and the second steps away from the outlet end of the combustion chamber are all inclined surfaces arranged in a downward inclination, and fuel injection holes are arranged on the inclined surfaces of the first steps and the second steps, and the fuel injection holes are communicated with a fuel delivery pipe arranged below the combustion chamber through connecting branch pipes. The reinforced mixing step structure is arranged to form a flow vortex to reinforce the mixing.

Description

Technical Field

[0001] This invention relates to the field of aero-engine technology, specifically to a reinforced hybrid structure for a slant detonation engine. Background Technology

[0002] like Figure 1 As shown, the concave structure within the rectangular frame is a commonly used structure for enhanced mixing and flame stabilization in scramjet engines. The concave cavity is located on the inner bottom surface of the combustion chamber. The side of the concave cavity near the combustion chamber inlet has a right-angled wall E forming a stepped structure. Behind the right-angled wall E is a sloping surface S that lifts the airflow. (Refer to...) Figure 2 As shown, the stepped structure of the concave cavity will form a spanwise vortex, which will then incite and enhance the mixing and stabilizing of the flame.

[0003] Traditional oblique detonation engines typically employ only fuel injection structures within their combustion chambers, rarely utilizing the concave cavity structure found in scramjet engines. This is due to two main reasons: First, the right-angled wall E at the concave cavity easily forms spanwise vortices, causing the flame to remain stationary within the cavity. This is advantageous for scramjet engines, as the concave cavity is designed to stabilize the flame. However, for oblique detonation engines, premature combustion within the concave cavity is undesirable, as the fuel detonates at the rear detonation wedge to generate the detonation wave. Premature combustion within the concave cavity would negatively impact the engine's performance. Second, the presence of the oblique surface S creates an oblique shock wave, which could also lead to premature combustion.

[0004] To improve the initiation performance of the oblique detonation engine and enhance mixing, the concave structure in the scramjet engine can be combined with the oblique detonation engine. However, it is necessary to overcome the problem mentioned above that premature combustion can affect the performance of the oblique detonation engine. Summary of the Invention

[0005] The purpose of this invention is to provide a reinforced blending structure for oblique detonation engines, so as to solve the problem that existing reinforced blending structures are difficult to apply to oblique detonation engines.

[0006] The technical solution of this invention is:

[0007] The application discloses a reinforced mixing structure of an oblique detonation engine, which comprises a mixing cavity arranged on the inner bottom surface of a combustion chamber of the oblique detonation engine, wherein a reinforced mixing step structure is arranged on one side of the mixing cavity close to the inlet end of the combustion chamber, and the other side of the mixing cavity away from the inlet end of the combustion chamber is an open structure with a flat bottom surface, the open structure extends to an ignition wedge surface in a horizontal direction away from the inlet end of the combustion chamber, and the reinforced mixing step structure comprises a plurality of first steps and second steps arranged alternately along the width direction of the combustion chamber of the oblique detonation engine, wherein the second steps are arranged protruding the first steps in the horizontal direction away from the inlet end of the combustion chamber, and the step surfaces on the sides, away from the inlet end of the combustion chamber, of the first steps and the second steps are all inclined surfaces arranged in a downward direction, and fuel injection holes are arranged on the inclined surfaces of the first steps and the second steps, and the fuel injection holes are communicated with a fuel delivery pipe arranged below the combustion chamber through connecting branch pipes.

[0008] Preferably, as a further improvement of the application, the inclined surface of the first step is arranged in parallel with the inclined surface of the second step.

[0009] Preferably, as a further improvement of the application, the included angle between the inclined surface of the first step and the horizontal plane of the bottom of the combustion chamber of the oblique detonation engine is 120°-150°.

[0010] Preferably, as a further improvement of the application, the included angle is 135°.

[0011] Preferably, as a further improvement of the application, the first step and the second step are arranged symmetrically along the center line in the length direction of the combustion chamber of the oblique detonation engine.

[0012] Preferably, as a further improvement of the application, the fuel injection holes are arranged on the inclined surfaces in a distributed manner, and the fuel injection holes are arranged in the horizontal direction.

[0013] Preferably, as a further improvement of the application, the horizontal distance between the inclined surface of the second step and the inclined surface of the first step is 10mm-50mm.

[0014] Preferably, as a further improvement of the application, the horizontal distance between the inclined surface of the second step and the inclined surface of the first step is 40mm.

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

[0016] 1. Improve the concave cavity structure in the original scramjet engine and apply it to the combustion chamber of the oblique detonation engine. By alternately setting multiple first and second platforms, a reinforced mixing step structure can be formed to replace the right-angled wall in the original concave cavity structure. The reinforced mixing step structure can form a flow vortex, which can enhance mixing. The lifting slope behind the previous concave cavity structure is eliminated and replaced with a horizontal wall to avoid the formation of oblique shock waves that cause premature combustion.

[0017] 2. Fuel injection holes are arranged on the inclined surfaces of each first platform and each second platform. The fuel injected through the fuel injection holes can further suppress premature combustion and ensure uniform fuel distribution on the wall surface. Attached Figure Description

[0018] Figure 1 This refers to the concave cavity structure found in existing scramjet engines.

[0019] Figure 2 This is a combustion simulation view of the concave cavity structure in an existing scramjet engine.

[0020] Figure 3 This is a three-dimensional structural diagram of a reinforced blending structure for a slant detonation engine according to the present invention.

[0021] Figure 4 For the present invention Figure 3 A magnified view of a portion of the image.

[0022] Figure 5 This is a top view schematic diagram of the enhanced mixing structure of a slant detonation engine according to the present invention.

[0023] Figure 6 For the present invention Figure 5 A cross-sectional view of the structure at point CC.

[0024] Figure 7 For the present invention Figure 5 A schematic diagram of the cross-sectional structure at point DD.

[0025] Figure 8 This is a cloud map showing the fuel distribution with a reinforced blended step structure.

[0026] Figure 9 This is a cloud map showing the fuel distribution without a reinforced blending step structure. Detailed Implementation

[0027] The following is combined Figures 3-9The specific embodiments of the present application are described in detail. In the description of the application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0028] The terms "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more of the features; in the description of the application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0029] Embodiments

[0030] As Figures 3-9 shown, the embodiment of the present application provides a reinforced mixing structure of an oblique detonation engine, which comprises a mixing cavity 2 arranged on the inner bottom surface of the combustion chamber 1 of the oblique detonation engine, and a reinforced mixing step structure is arranged on one side of the mixing cavity 2 close to the inlet end 11 of the combustion chamber. The other side of the mixing cavity 2 away from the inlet end 11 of the combustion chamber is an open structure with a flat bottom surface, and the open structure extends to the detonation wedge surface in the horizontal direction away from the inlet end 11 of the combustion chamber. The reinforced mixing step structure comprises a plurality of first steps 21 and second steps 22 arranged alternately along the width direction of the combustion chamber 1 of the oblique detonation engine. The second steps 22 are arranged protruding the first steps 21 in the horizontal direction away from the inlet end 11 of the combustion chamber. The step surfaces on the side away from the inlet end 11 of the combustion chamber of the first steps 21 and the second steps 22 are all inclined surfaces, and the inclined surfaces are arranged inclined downward. Fuel injection holes 3 are arranged on the inclined surfaces of the first steps 21 and the second steps 22. Each fuel injection hole 3 is communicated with a fuel delivery pipe 5 arranged below the combustion chamber through a connecting branch pipe 4.

[0031] In the present embodiment, the cavity structure in the previous scramjet engine is improved to adapt to the oblique detonation engine combustion chamber 1. The first improvement is that the original right-angle wall E is replaced by a plurality of first blocks 21 and a plurality of second blocks 22. The first blocks 21 and the second blocks 22 are arranged alternately, the second blocks 22 protrude the first blocks 21 in the horizontal direction away from the combustion chamber inlet end 11, and the surfaces of the first blocks 21 and the second blocks 22 on the side opposite to the combustion chamber outlet end 12 are both inclined surfaces. The above structure makes the first blocks 21 have concave inclined surfaces and the second blocks 22 have convex inclined surfaces, thereby forming a staggered-tooth-shaped reinforced mixing step structure. When the supersonic incoming flow passing through the concave inclined surfaces in the oblique detonation engine combustion chamber 1, expansion waves are formed, which reduce the pressure of the airflow. The airflow above the convex inclined surfaces has not been expanded, and the pressure difference between the airflow pressure and the incoming flow pressure forms a streamwise vortex, which plays a role in strengthening the mixing. The second improvement is that the lifting slope S behind the previous cavity structure is cancelled and replaced by a horizontal wall formed by the flat bottom surface, which can avoid the formation of oblique shock waves to cause pre-combustion. The third improvement is that fuel injection holes 3 are arranged on the inclined surfaces of the first blocks 21 and the second blocks 22. The fuel injected through the fuel injection holes 3 can further suppress pre-combustion and ensure the fuel distribution on the wall surface.

[0032] In another embodiment of the present application, as a preferred solution, the inclined surfaces of the first blocks 21 and the inclined surfaces of the second blocks 22 are arranged in parallel. Through the above arrangement, the shape and strength of the generated streamwise vortex can be more stable.

[0033] Further, as a further improvement of the above preferred solution, the angle between the inclined surface of the first block 21 and the horizontal surface of the bottom of the oblique detonation engine combustion chamber 1 is 120°-150°. This angle can effectively weaken the backflow area behind the step and prevent pre-combustion from forming behind the step. Meanwhile, streamwise vortices are formed between the concave inclined surfaces and the convex inclined surfaces, which play a role in strengthening the mixing. In specific implementation, the angle is 135°.

[0034] In another embodiment of the present application, as a preferred solution, as shown in Figure 5 the first blocks 21 and the second blocks 22 are symmetrically arranged along the center line in the length direction of the oblique detonation engine combustion chamber 1. The symmetric arrangement is conducive to forming a uniform flow field and fuel concentration field in the entire width range of the combustion chamber.

[0035] In another embodiment of the present application, as a preferred solution, the fuel injection holes 3 are a plurality of holes and are evenly arranged on the inclined surfaces. Each fuel injection hole 3 is arranged in the horizontal direction. The number of fuel injection holes 3 is determined by the incoming flow parameters. It is necessary to ensure that the equivalence ratio on the wall surface is 1, i.e. the fuel is just completely combusted, which can maximize the stable and reliable detonation initiation.

[0036] The horizontal interval of the inclined surface of the second table body 22 protruding the inclined surface of the first table body 21 is 10mm-50mm, and in a specific implementation, the horizontal interval of the inclined surface of the second table body 22 protruding the inclined surface of the first table body 21 is 40mm.

[0037] The working principle of the present application is as follows:

[0038] As shown in Figure 3 and Figure 5 The left side is the combustion chamber inlet, the right side is connected to the initiation wedge surface and the engine tail nozzle, and the fuel injection support plate 6 is arranged in the left side area of the mixing cavity 2. When the supersonic flow flows from left to right, the fuel is injected from the fuel injection support plate 6. At the same time, the fuel injection holes 3 arranged on the inclined surface of the first table body 21 and the fuel injection holes 3 arranged on the inclined surface of the second table body 22 also inject fuel. When the airflow passes through the concave inclined surface, an expansion wave is formed, and the expansion ratio reduces the airflow pressure. The airflow above the convex inclined surface has not been expanded, and the airflow pressure is different from the incoming flow pressure, which forms a streamwise vortex that strengthens the mixing. At the same time, due to the angle of the inclined surface being 120°-150°, the formation of spanwise vortices can be effectively prevented, and pre-combustion can be prevented from being formed behind the step.

[0039] The effect of the present application is verified by combining specific experiments. The parameters are as follows: incoming flow temperature 857K, pressure 61004Pa, Mach number 4.2, the horizontal interval of the inclined surface of the second table body 22 protruding the inclined surface of the first table body 21 is 40mm, the included angle between the inclined surface of the first table body 21 and the bottom horizontal surface of the oblique detonation engine combustion chamber 1 is 135°, and hydrogen is injected into the fuel injection support plate 6 and the fuel injection holes 3 of the strengthened mixing step structure. Figure 8 In order to strengthen the fuel distribution at the outlet of the oblique detonation engine combustion chamber 1 with the strengthened mixing step structure, it can be seen that in addition to the continuous fuel distribution in the longitudinal direction, a relatively uniform fuel distribution is also formed near the lower wall surface, which is very suitable for the initiation of the oblique detonation engine. Figure 9 As shown in the figure, it is the fuel distribution cloud diagram at the outlet of the oblique detonation engine combustion chamber 1 without the strengthened mixing step structure. It can be seen that there is only continuous fuel in the longitudinal direction, and there is little fuel distribution near the lower wall surface, which is not conducive to the initiation of the oblique detonation engine.

[0040] The above disclosure is only a few preferred specific embodiments of the present application, but the embodiments of the present application are not limited thereto, and any changes that can be thought of by those skilled in the art should fall within the protection scope of the present application.

Claims

1. A squish intensifier structure for a motored oblique detonation engine, characterized by, The application relates to a mixed cavity (2) arranged on the inner bottom surface of a combustion chamber (1) of a sloped detonation engine, wherein a reinforced mixed step structure is arranged on the side of the mixed cavity (2) close to the combustion chamber inlet end (11), the side of the mixed cavity (2) away from the combustion chamber inlet end (11) is an open structure with a flat bottom surface, the open structure extends to the detonation wedge surface in the horizontal direction away from the combustion chamber inlet end (11), the reinforced mixed step structure comprises a plurality of first steps (21) and second steps (22) arranged alternately along the width direction of the combustion chamber (1) of the sloped detonation engine, the second steps (22) are arranged in the horizontal direction away from the combustion chamber inlet end (11) and protrude from the first steps (21), the surfaces of the first steps (21) and the second steps (22) away from the combustion chamber inlet end (11) are inclined surfaces, and the inclined surfaces are arranged in a downward inclination mode, the inclined surface of the first step (21) is parallel to the inclined surface of the second step (22), the included angle between the inclined surface of the first step (21) and the horizontal surface of the bottom of the combustion chamber (1) is 120-150 DEG, and fuel injection holes (3) are arranged on the inclined surfaces of the first steps (21) and the second steps (22), and the fuel injection holes (3) are communicated with a fuel delivery pipe (5) arranged below the combustion chamber through connecting branch pipes (4).

2. The augmented mixing structure of a sloped detonation engine according to claim 1, wherein, The included angle is 135 DEG.

3. The augmented mixing structure of a sloped detonation engine according to claim 1, wherein, The first steps (21) and the second steps (22) are arranged in a center line symmetry mode along the length direction of the combustion chamber (1) of the sloped detonation engine.

4. The augmented mixing structure of a sloped detonation engine according to claim 1, wherein The fuel injection holes (3) are arranged on the inclined surfaces in a distributed mode, and the fuel injection holes (3) are arranged in the horizontal direction.

5. The augmented mixing structure of a sloped detonation engine of claim 1, wherein, The horizontal interval between the inclined surface of the second step (22) and the inclined surface of the first step (21) is 10-50 mm.

6. The augmented mixing structure of a sloped detonation engine according to claim 5, wherein, The horizontal interval between the inclined surface of the second step (22) and the inclined surface of the first step (21) is 40 mm.

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