A fuel injection and intensifying mixing device for an oblique detonation engine

Abstract

The application discloses a fuel injection and reinforced mixing device for an oblique detonation engine, which comprises a fuel injection support plate arranged in a combustion chamber, a plurality of fuel injection holes are arranged on the tail end of the fuel injection support plate along the width direction of the fuel injection support plate, and a cylindrical reinforced mixing plate is horizontally arranged and fixed in the combustion chamber, and the circumferential side wall of the cylindrical reinforced mixing plate is arranged opposite to the tail end of the fuel injection support plate; the cylindrical reinforced mixing plate and the fuel injection support plate simultaneously satisfy the following conditions: H>D; L<2H; wherein, D is the diameter of the cylindrical reinforced mixing plate, H is the height of the tail end of the fuel injection support plate, and L is the horizontal straight line distance between the center of the cylindrical reinforced mixing plate and the tail end of the fuel injection support plate. The cylindrical reinforced mixing plate can induce new vortex structures to be formed for reinforced mixing when fuel is injected, the cylindrical reinforced mixing plate can divide the fuel into two layers, so that the fuel can be mixed respectively, and the fuel mixing efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engine, in particular to a fuel injection and reinforced mixing device for oblique detonation engine. BACKGROUND

[0002] The running speed of oblique detonation engine exceeds 7 Mach, and the residence time of fuel after being injected from fuel injection hole in the combustion chamber is only a few milliseconds, so it is very difficult to achieve uniform mixing of fuel in such a short time, and uneven fuel mixing has a huge impact on the detonation performance and stability performance of oblique detonation engine.

[0003] At present, fuel injection support plate is widely used as the main fuel supply and flame stabilization scheme in oblique detonation engine, fuel injection support plate is injected by single support plate or multiple support plate combination, and the conventional fuel injection support plate has only one main recirculation zone, although this recirculation zone helps to anchor the flame, but its scale is limited, the vortex intensity rapidly decays with the downstream distance, resulting in that the entrainment and mixing of fuel and air mainly concentrate in the near-field region, and the fuel injected from the fuel injection hole of the fuel injection support plate often concentrates in the center position of the fuel injection support plate, which is not conducive to the diffusion and mixing of fuel. SUMMARY

[0004] The purpose of the present application is to provide a fuel injection and reinforced mixing device for oblique detonation engine, so as to solve the problem of low fuel mixing efficiency existing in the prior oblique detonation engine.

[0005] The technical scheme of the present application is as follows:

[0006] A fuel injection and reinforced mixing device for oblique detonation engine, comprising a fuel injection support plate arranged in a combustion chamber, a plurality of fuel injection holes are arranged on the tail end of the fuel injection support plate along the width direction of the fuel injection support plate, and a cylindrical reinforced mixing plate is horizontally arranged and fixed in the combustion chamber, and the circumferential side wall of the cylindrical reinforced mixing plate is arranged opposite to the tail end of the fuel injection support plate, and the cylindrical reinforced mixing plate and the fuel injection support plate satisfy the following conditions at the same time:

[0007] H>D;

[0008] L<2H;

[0009] Wherein, D is the diameter of the cylindrical reinforced mixing plate, H is the height of the tail end of the fuel injection support plate, and L is the horizontal straight line distance between the center of the cylindrical reinforced mixing plate and the tail end of the fuel injection support plate.

[0010] Preferably, as a further improvement of the present application, the ratio of H to D is in the range of 1: (0.41-0.99), and the ratio of H to L is in the range of 1: (0.5-1.99).

[0011] Preferably, as a further improvement of the present application, the ratio of H to D is 1:0.9, and the ratio of H to L is 1:1.4.

[0012] Preferably, as a further improvement of the present application, the cylindrical reinforced mixing plate is provided with a plurality of annular grooves in the circumferential direction, and the plurality of annular grooves are uniformly distributed along the axial direction of the cylindrical reinforced mixing plate. The plurality of annular grooves make the cylindrical reinforced mixing plate have a plurality of alternating convex segments and concave segments, and the diameter of the convex segment is D.

[0013] Preferably, as a further improvement of the present application, the circumferential side wall of the convex segment and the circumferential side wall of the concave segment are both straight surfaces.

[0014] Preferably, as a further improvement of the present application, the circumferential side wall of the convex segment is an outwardly convex arc surface, and the circumferential side wall of the concave segment is an inwardly concave arc surface.

[0015] Preferably, as a further improvement of the present application, the axial length of the convex segment is equal to the axial length of the concave segment.

[0016] Preferably, as a further improvement of the present application, the material of the cylindrical reinforced mixing plate is a high-temperature-resistant alloy or a high-temperature-resistant ceramic matrix composite material.

[0017] Compared with the prior art, the present application has the following beneficial effects:

[0018] 1. By arranging the cylindrical reinforced mixing plate behind the fuel injection support plate, a new vortex structure can be induced during fuel injection, and the vortex structure can be used for reinforced mixing. In addition, the cylindrical reinforced mixing plate can divide the fuel into two layers, so that the mixing can be carried out separately, and the fuel will not be concentrated in the middle of the support plate as in the traditional method, thereby improving the fuel mixing efficiency and further improving the performance of the oblique detonation engine.

[0019] 2. The cylindrical reinforced mixing plate can lift the fuel, thereby increasing the penetration depth. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 FIG. 1 is a perspective view of a fuel injection and reinforced mixing device for an oblique detonation engine according to the present application.

[0021] Figure 2 FIG. 4 is a schematic view of the horizontal distance between the fuel injection support plate and the cylindrical reinforced mixing plate in the fuel injection and reinforced mixing device for an oblique detonation engine according to the present application.

[0022] Figure 3 FIG. 5 is a perspective view of an optimized structure of the cylindrical reinforced mixing plate in the fuel injection and reinforced mixing device for an oblique detonation engine according to the present application.

[0023] Figure 4 For the present invention Figure 3 Front view diagram.

[0024] Figure 5 This is a three-dimensional schematic diagram of another optimized structure of the cylindrical reinforcing blending plate in the fuel injection and reinforcing blending device for a detonation engine according to the present invention.

[0025] Figure 6 For the present invention Figure 5 Front view diagram.

[0026] Figure 7 This is a comparative experimental data graph showing the fuel mass fraction distribution in two cases: one without the cylindrical reinforcing blending plate and the other with the cylindrical reinforcing blending plate.

[0027] Figure 8 This is a comparative experimental data graph showing the distribution of the reflux zone in two cases: one without the cylindrical reinforcing blending plate and the other with the cylindrical reinforcing blending plate. Detailed Implementation

[0028] The following is combined Figures 1-8 The specific embodiments of the present invention will be described in detail below. In the description of the invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

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

[0030] Example 1

[0031] like Figures 1-7 As shown, this embodiment of the invention provides a fuel injection and enhanced mixing device for a detonation engine, including a fuel injection support plate 2 disposed in a combustion chamber 1. In specific implementation, the shape of the fuel injection support plate 2 can be selected as an isosceles triangle, and the tip of the fuel injection support plate 2 is positioned directly opposite the inlet 11 of the combustion chamber 1. The bottom edge of the fuel injection support plate 2 serves as the tail end of the fuel injection support plate 2, and a plurality of fuel injection holes 3 are provided along the width direction of the fuel injection support plate 2.

[0032] In order to facilitate the diffusion and mixing of fuel, a cylindrical reinforced mixing plate 4 is additionally arranged behind the tail end of the fuel injection support plate 2, the cylindrical reinforced mixing plate 4 is horizontally arranged and fixed in the combustion chamber 1, the two ends of the cylindrical reinforced mixing plate 4 are fixed with the two side inner walls of the combustion chamber 1, and the circumferential side wall of the cylindrical reinforced mixing plate 4 is arranged opposite to the tail end of the fuel injection support plate 2.

[0033] In the embodiment, supersonic incoming flow enters the combustion chamber from the combustion chamber inlet 11, the incoming flow is air compressed through the inlet channel, the air is mixed with fuel and then flows out from the combustion chamber outlet 12 to complete the oblique detonation wave initiation in the initiation section. When mixing, fuel is sprayed from the fuel injection holes 3 behind the tail end of the fuel injection support plate 2 and mixed with the incoming air flow, and when the air flow passes through the cylindrical reinforced mixing plate 4, a boundary layer separation will be formed behind the cylindrical reinforced mixing plate 4, thereby forming a vortex structure, which can be used for reinforced mixing, and the cylindrical reinforced mixing plate 4 can divide the fuel into two layers, thereby allowing separate mixing, unlike the traditional single fuel injection support plate 2, which causes the fuel to concentrate in the middle behind the fuel injection support plate 2, thereby improving the fuel mixing efficiency and the performance of the oblique detonation engine, in addition, the cylindrical reinforced mixing plate 4 can lift the fuel to increase the penetration depth.

[0034] It should be noted that the cylindrical reinforced mixing plate 4 and the fuel injection support plate 2 of the present application simultaneously satisfy the following conditions:

[0035] H>D;

[0036] L<2H;

[0037] Wherein, D is the diameter of the cylindrical reinforced mixing plate 4, H is the height of the tail end of the fuel injection support plate 2, and L is the horizontal straight line distance between the center of the cylindrical reinforced mixing plate 4 and the tail end of the fuel injection support plate 2.

[0038] If H<D, the cylindrical reinforced mixing plate 4 cannot be hidden by the fuel injection support plate 2, and the high-speed air flow directly acts on the cylindrical reinforced mixing plate 4, which will induce the formation of an arc-shaped shock wave to increase the flow resistance and total pressure loss.

[0039] Since the low-speed backflow area behind the fuel injection support plate 2 gradually recovers to be consistent with the main flow area as the distance L increases, it is necessary to limit the distance of the cylindrical reinforced mixing plate 4 to L<2H, so as to ensure that the cylindrical reinforced mixing plate 4 is always hidden in the low-speed backflow area behind the fuel injection support plate 2.

[0040] Further, the ratio of H to D ranges from 1: (0.41-0.99). If the ratio is lower than this range, the diameter of the cylindrical reinforced mixing plate 4 will be too small, close to the diameter of the fuel injection hole 3, and the diameter of the cylindrical reinforced mixing plate 4 will be relatively small, which will result in insufficient vortex strength and limited disturbance range, making it difficult to effectively divide and lift the fuel cloud, and the reinforced mixing effect will be greatly reduced.

[0041] The ratio of H to L ranges from 1: (0.5-1.99). If the ratio is lower than this range, the cylindrical reinforced mixing plate 4 will be too close to the fuel injection hole 3, which will interfere with the initial development and penetration of the fuel jet, disrupt the mixing process, and cause local overheating and ablation of the cylindrical reinforced mixing plate 4.

[0042] In specific implementation, the ratio of H to D is preferably 1:0.9, and the ratio of H to L is preferably 1:1.4.

[0043] Example 2

[0044] This embodiment is based on Example 1, and the structure of the cylindrical reinforced mixing plate 4 is improved so that its axial profile is no longer smooth. Specifically, as shown in Figure 3 and Figure 4 a plurality of annular grooves are formed in the circumferential direction of the cylindrical reinforced mixing plate 4, and the plurality of annular grooves are evenly distributed along the axial direction of the cylindrical reinforced mixing plate 4. The formation of the plurality of annular grooves causes the circumferential side wall of the cylindrical reinforced mixing plate 4 to have alternating convex segments 41 and concave segments 42 along the axial direction, thereby forming a cylindrical structure with a variable cross-section. The diameter of the convex segment 41 is D, and the axial length of the convex segment 41 is equal to the axial length of the concave segment 42.

[0045] By alternating the convex segments 41 and the concave segments 42, as shown in Figure 4 a flow direction vortex structure 5 can be induced at the end face angle of the convex segment 41, which can further enhance the mixing.

[0046] Further, as shown in Figure 3 and Figure 4 as an optimization of the cylindrical reinforced mixing plate 4, the circumferential side wall of the convex segment 41 and the circumferential side wall of the concave segment 42 are straight surfaces, which changes the cylindrical reinforced mixing plate 4 into a stepped cylindrical structure with a few-shaped outer contour, and the flow direction vortex structure 5 induced by the straight surface has higher strength.

[0047] Further, as shown in Figure 5 and Figure 6As another optimization scheme of the cylindrical reinforced mixing plate 4, the circumferential side wall of the convex section 41 is an outwardly convex arc surface, and the circumferential side wall of the concave section 42 is an inwardly concave arc surface, so that the cylindrical reinforced mixing plate 4 is converted into a wave-shaped cylinder, which is better in structural stability, especially in resisting supersonic airflow erosion. The arc surface design of the wave-shaped cylinder is more suitable for a high total temperature incoming flow environment than the stepped cylindrical structure, and the end face of the alternating stepped cylinder is relatively sharp and easy to ablate.

[0048] In another embodiment of the present application, the material of the cylindrical reinforced mixing plate 4 is a high-temperature-resistant alloy or a high-temperature-resistant ceramic matrix composite, which can adapt to a high-temperature environment and avoid ablation.

[0049] The effect of the embodiment of the present application is verified by combining with the test data graph. The fuel injection support plate 2 is set to be an isosceles triangle, the height H of the tail end of the fuel injection support plate 2 is 7 mm, the diameter D of the cylindrical reinforced mixing plate 4 is 6.3 mm, and the horizontal straight line distance L between the center of the cylindrical reinforced mixing plate 4 and the tail end of the fuel injection support plate 2 is 9.8 mm. The data graph obtained by performing a simulation experiment in this parameter range is shown in FIGS. 1 and 2. Figure 7 and Figure 8

[0050] Referring to FIGS. 1 and 2, Figure 7 (a) in FIG. 1 is a fuel mass fraction distribution diagram when the fuel is injected by the fuel injection support plate 2 without the cylindrical reinforced mixing plate 4 below, and the fuel is concentrated at the center of the fuel injection support plate 2, Figure 7 (b) in FIG. 2 is a fuel mass fraction distribution diagram when the fuel is injected by the fuel injection support plate 2 with the cylindrical reinforced mixing plate 4 below. It can be seen from the comparison between the two that the penetration depth of the fuel is greater after the cylindrical reinforced mixing plate 4 is added, and the cylindrical reinforced mixing plate 4 divides the fuel into two parts, which can be mixed with the air on both sides of the support plate, further strengthening the mixing. Figure 7 Referring to FIGS. 3 and 4,

[0051] (a) in FIG. 3 is a backflow region distribution diagram when the fuel is injected by the fuel injection support plate 2 without the cylindrical reinforced mixing plate 4, and there are only four vortex structures of the main vortex region behind the fuel injection support plate 2, Figure 8 (b) in FIG. 4 is a backflow region distribution diagram when the fuel is injected by the fuel injection support plate 2 with the cylindrical reinforced mixing plate 4. It can be seen from the comparison between the two that a secondary backflow region is formed behind the cylindrical reinforced mixing plate 4 after the cylindrical reinforced mixing plate 4 is added, and the vortex structure of the main backflow region behind the fuel injection support plate 2 is larger, which is more conducive to mixing, and the secondary backflow region further strengthens the mixing. Figure 8 Figure 8 ​​​

[0052] The foregoing merely illustrates the principles of the application. It will be apparent to those skilled in the art that modifications can be made to the application without departing from the spirit and scope of the application.

Claims

1. A fuel injection and intensifying mixing device for an oblique detonation engine, comprising a fuel injection plate (2) disposed in a combustion chamber (1), a plurality of fuel injection holes (3) being provided in the width direction of the tail end of the fuel injection plate (2), characterized in that, Also included are: A cylindrical reinforced mixing plate (4) is horizontally fixed in the combustion chamber (1), and the circumferential side wall of the cylindrical reinforced mixing plate (4) is arranged opposite to the tail end of the fuel injection support plate (2), and the cylindrical reinforced mixing plate (4) and the fuel injection support plate (2) satisfy the following conditions at the same time: H>D; L<2H; Wherein, D is the diameter of the cylindrical reinforced mixing plate (4), H is the height of the tail end of the fuel injection support plate (2), and L is the horizontal straight line distance from the center of the cylindrical reinforced mixing plate (4) to the tail end of the fuel injection support plate (2).

2. The fuel injection and augmentation mixing apparatus for an oblique detonation engine according to claim 1, characterized by, The ratio of H to D is 1:(0.41~0.99), and the ratio of H to L is 1:(0.5~1.99).

3. The fuel injection and augmentation mixing apparatus for an oblique detonation engine of claim 1, wherein The ratio of H to D is 1:0.9, and the ratio of H to L is 1:1.

4.

4. The fuel injection and augmentation mixing apparatus for an oblique detonation engine of claim 1, wherein The circumferential side wall of the cylindrical reinforced mixing plate (4) is provided with a plurality of annular grooves, and the plurality of annular grooves are uniformly arranged along the axial direction of the cylindrical reinforced mixing plate (4), and the plurality of annular grooves make the cylindrical reinforced mixing plate (4) have a plurality of alternating convex segments (41) and concave segments (42), and the diameter of the convex segment (41) is D.

5. The fuel injection and augmentation mixing apparatus for an oblique detonation engine according to claim 4, characterized by, The circumferential side wall of the convex segment (41) and the circumferential side wall of the concave segment (42) are straight surfaces.

6. The fuel injection and augmentation mixing apparatus for an oblique detonation engine of claim 4, wherein The circumferential side wall of the convex segment (41) is an outwardly convex arc surface, and the circumferential side wall of the concave segment (42) is an inwardly concave arc surface.

7. The fuel injection and augmentation mixing apparatus for an oblique detonation engine of claim 4, wherein The axial length of the convex segment (41) is equal to the axial length of the concave segment (42).

8. The fuel injection and reinforced mixing device of the oblique detonation engine according to any one of claims 1~7, wherein the material of the cylindrical reinforced mixing plate (4) is a high-temperature-resistant alloy or a high-temperature-resistant ceramic matrix composite material.

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