Fuel oil diffusion-combustion self-excitation enhancing method for low-Mach ramjet engine

Abstract

The invention discloses a fuel oil diffusion-combustion self-excitation enhancing method for a low-Mach ramjet engine, and relates to the technical field of scramjet engines, a fuel oil diffusion-combustion self-excitation enhancing method for the low-Mach ramjet engine comprises a combustion stabilizer main body, a plurality of first injection holes, a plurality of second injection holes and an ignition device, and the combustion stabilizer main body is provided with an outer side wall, a first inner flow channel, an air inlet and an air outlet; the outer side wall is the surface in the circumferential direction of the outer side of the combustion stabilizer body, and the air inlet and the exhaust port communicate with the first inner flow channel. The first injection hole is formed in the first inner flow channel and used for injecting fuel oil into the first inner flow channel. The second injection hole is formed in the outer side wall and is used for injecting fuel oil to the outside of the combustion stabilizer main body; and the ignition device is provided with an ignition end, and the ignition end is used for igniting the fuel oil injected by the first injection hole, so that the evaporation and diffusion capacity of the fuel oil under the low Mach number of the engine is improved, the fuel oil is sufficiently combusted and releases heat within a short time, and the combustion efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of scramjet engines, and in particular to a method for enhancing the fuel diffusion-combustion self-excitation of a low Mach ramjet engine. Background Art

[0002] Hypersonic vehicles have super strong penetration, strike and destruction capabilities. In the future, they will expand their working capabilities in the direction of wide speed range and large airspace. The research on propulsion systems operating in a wide speed range (Mach 2 to Mach 7) has become a major national strategic need and an important academic frontier. However, in supersonic combustion chambers, the complex flow field environment of supersonic strong turbulence is still a huge problem for fuel mixing and combustion organization, especially under low Mach number (Mach 2 to Mach 4) conditions, the total enthalpy of supersonic incoming flow is low, the evaporation and diffusion capacity of fuel is reduced, and the difficulty of fuel ignition and flame establishment is significantly increased, which brings great difficulties to the high-performance operation of ramjet engine combustion chambers. Summary of the invention

[0003] The purpose of the present invention is to provide a method for enhancing the fuel diffusion-combustion self-excitation of a low Mach ramjet engine to solve the problems existing in the above-mentioned prior art, so as to improve the evaporation and diffusion capacity of the fuel at a low Mach number of the engine, so that the fuel can be fully burned and heat released in a short time, thereby improving the combustion efficiency.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] The present invention provides a flame stabilizer, comprising: a flame stabilizer body, a plurality of first injection holes, a plurality of second injection holes and an ignition device, the flame stabilizer body having an outer wall, a first inner flow channel, an air inlet and an exhaust port, the outer wall being the surface on the outer circumferential side of the flame stabilizer body, the air inlet and the exhaust port being connected to the first inner flow channel; the first injection hole being arranged on the first inner flow channel, the first injection hole being used for injecting fuel into the first inner flow channel; the second injection hole being arranged on the upper outer wall, the second injection hole being used for injecting fuel outside the flame stabilizer body; the ignition device having an ignition end, the ignition end being used for igniting the fuel injected from the first injection hole.

[0006] In some embodiments, the first inner flow channel has a first equal-flow channel and a first expansion channel connected in sequence, the first equal-flow channel is closer to the air inlet than the first expansion channel, the cross-sectional size of the first equal-flow channel in the direction perpendicular to the axis of the burn stabilizer body remains unchanged, and the cross-sectional size of the first expansion channel in the direction perpendicular to the axis of the burn stabilizer body gradually increases along the direction approaching the exhaust port.

[0007] In some embodiments, the outer wall includes a second expansion wall, a second straight wall and a third expansion wall connected in sequence, the second expansion wall is closer to the air inlet than the third expansion wall, the cross-sectional size of the second straight wall in the direction perpendicular to the axis of the stabilizer body remains unchanged, and the cross-sectional sizes of the second expansion wall and the third expansion wall in the direction perpendicular to the axis of the stabilizer body gradually increase along the direction approaching the exhaust port; the second expansion wall is connected to the side of the first straight flow channel close to the air inlet; the third expansion wall is connected to the side of the first expansion flow channel close to the exhaust port.

[0008] In some embodiments, the ignition end is fixed to the rear of the flame stabilizer body.

[0009] In some embodiments, the angle between the first expansion flow channel and the axis of the stabilizer body is less than or equal to 45°, the angle between the second expansion wall and the axis of the stabilizer body is less than or equal to 45°, and the angle between the third expansion wall and the axis of the stabilizer body is less than or equal to 30°.

[0010] The present invention also provides a combustion chamber, comprising: a combustion chamber body, an ignition device and a flame stabilizer as described above, wherein the combustion chamber body has a second inner flow channel, a combustion chamber inlet and a combustion chamber outlet, and the combustion chamber inlet and the combustion chamber outlet are both connected to the second inner flow channel; the flame stabilizer is used to be fixed inside the second inner flow channel, and the air inlet is close to the combustion chamber inlet, and the exhaust port is arranged close to the combustion chamber outlet.

[0011] In some embodiments, the inner wall of the combustion chamber body includes a third straight wall surface, a fourth expansion wall surface and a fifth expansion wall surface connected in sequence, the third straight wall surface is closer to the combustion chamber inlet than the fifth expansion wall surface, the cross-sectional size of the third straight wall surface in the direction perpendicular to the length of the combustion chamber body remains unchanged, and the cross-sectional sizes of the fourth expansion wall surface and the fifth expansion wall surface in the direction perpendicular to the length of the combustion chamber body gradually increase along the direction approaching the combustion chamber outlet.

[0012] In some embodiments, the maximum cross-sectional area of ​​the fourth expansion wall surface perpendicular to the length direction of the combustion chamber body is greater than or equal to 1.3 times the combustion chamber inlet area and less than or equal to 1.6 times the combustion chamber inlet area; the maximum cross-sectional area of ​​the fifth expansion wall surface perpendicular to the length direction of the combustion chamber body is greater than or equal to 1.0 times the maximum cross-sectional area of ​​the fourth expansion wall surface perpendicular to the length direction of the combustion chamber body and less than or equal to 1.1 times the maximum cross-sectional area of ​​the fourth expansion wall surface perpendicular to the length direction of the combustion chamber body.

[0013] The present invention also provides an ignition method for the combustion chamber as described above:

[0014] Fuel is injected through the first injection hole to form a first oil mist in the first inner flow channel; the ignition device is started to ignite the oil mist to establish an initial flame, and the ignition device is turned off after the initial flame is successfully established; fuel is injected through the second injection hole, and the fuel injected from the second injection hole forms a second oil mist that diffuses onto the initial flame.

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

[0016] The present invention provides a method for self-excitation enhancement of fuel diffusion-combustion of a low Mach ramjet engine. A stabilizer body has a first inner flow channel, and the first inner flow channel and an outer wall are provided with a first injection hole and a second injection hole. The fuel injected from the first injection hole is ignited to form an initial flame at the rear side of an exhaust port. After the initial flame is formed, the fuel is injected through the second injection hole, and the fuel injected from the second injection hole surrounds the initial flame. The initial flame can heat the fuel injected from the second injection hole, and the energy of the initial flame can be used to promote rapid evaporation and diffusion of the fuel injected from the second injection hole. Since the density gradient generated by the evaporation of the fuel can promote the diffusion of kerosene, the further diffusion of the fuel and contact with the surrounding air can realize efficient mixing of the fuel and the air, thereby making the fuel fully burn and release heat in a shorter time, thereby improving the combustion efficiency of the fuel. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a structural schematic diagram of the combustion stabilizer in the first embodiment;

[0019] Figure 2 for Figure 1 Schematic diagram of the dimensions of the main body of the medium stable burner;

[0020] Figure 3a This is a schematic diagram of the overall structure of the fuel combustion efficiency experiment of the stabilizer in Example 1;

[0021] Figure 3b This is a schematic diagram of the overall structure of the conventional support plate fuel stabilizer fuel combustion efficiency;

[0022] Figure 4 The fuel combustion efficiency comparison diagram of the combustion stabilizer in the experiment of Figure 3 and the conventional support plate combustion stabilizer;

[0023] Figure 5It is a structural schematic diagram of the combustion chamber in the second embodiment;

[0024] Figure 6 for Figure 2 Schematic diagram of various dimensions of the combustion chamber body;

[0025] Figure 7 This is a timing sequence diagram of engine ignition using the ignition method of Example 3.

[0026] In the figure: 1-burner stabilizer; 11-air inlet; 12-exhaust port; 13-first injection hole; 14-second injection hole; 15-first straight channel; 16-first expansion channel; 17-second expansion wall; 18-second straight wall; 19-third expansion wall; 2-combustion chamber body; 21-combustion chamber inlet; 22-combustion chamber outlet; 23-third straight wall; 24-fourth expansion wall; 25-fifth expansion wall; 3-ignition device; A-first oil mist; B-initial flame; C second oil mist; D-center flame. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The purpose of the present invention is to provide a low Mach ramjet engine fuel diffusion-combustion self-excitation enhancement method to solve the problems existing in the prior art, so as to improve the evaporation and diffusion capacity of the fuel at a low Mach number of the engine, so that the fuel can be fully burned and heat released in a short time, thereby improving the combustion efficiency.

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, the following is a brief description of the present invention in conjunction with the attached drawings. Figures 1 to 7 The present invention is further described in detail with reference to the accompanying drawings and specific embodiments.

[0030] Embodiment 1

[0031] This embodiment provides a combustion stabilizer 1, referring to Figures 1-2, including: a stabilizer body, a plurality of first injection holes 13, a plurality of second injection holes 14 and an ignition device 3, the stabilizer body having an outer wall, a first inner flow channel, an air inlet 11 and an exhaust port 12, the outer wall being the outer circumferential surface of the stabilizer body, the air inlet 11 and the exhaust port 12 being connected to the first inner flow channel; the first injection hole 13 is arranged on the first inner flow channel, the first injection hole 13 is used to inject fuel into the first inner flow channel, and the first injection holes 13 are evenly distributed in the circumferential direction of the first inner flow channel; the second injection hole 14 is arranged on the outer wall, the second injection hole 14 is used to inject fuel outside the stabilizer body, and the second injection holes 14 are evenly distributed in the circumferential direction of the outer wall; the ignition device 3 has an ignition end, and the ignition end is used to ignite the fuel injected by the first injection hole 13. The present invention provides a flame stabilizer 1, a combustion chamber and an ignition method. The flame stabilizer body has a first inner flow channel, which is arranged along the axis of the flame stabilizer body, and the first inner flow channel and the outer wall are provided with a first injection hole 13 and a second injection hole 14. The fuel injected from the first injection hole 13 is ignited to form an initial flame B at the rear side of the exhaust port 12. After the initial flame B is formed, the fuel is injected through the second injection hole 14. The fuel injected from the second injection hole 14 surrounds the initial flame B. The initial flame B can heat the fuel injected from the second injection hole 14. The energy of the initial flame B can be used to promote the rapid evaporation and diffusion of the fuel injected from the second injection hole 14. Since the density gradient generated by the evaporation of the fuel can promote the diffusion of the fuel, the further diffusion of the fuel and the contact with the surrounding air can achieve efficient mixing of the fuel and the air, thereby making the fuel fully burn and release heat in a shorter time, thereby improving the combustion efficiency of the fuel.

[0032] In some implementations of the present embodiment, the first inner flow channel has a first straight flow channel 15 and a first expansion flow channel 16 connected in sequence. The first straight flow channel 15 is closer to the air inlet 11 than the first expansion flow channel 16. The cross-sectional size of the first straight flow channel 15 in the direction perpendicular to the axis of the main body of the burner stabilizer remains unchanged, and the cross-sectional size of the first expansion flow channel 16 in the direction perpendicular to the axis of the main body of the burner stabilizer gradually increases in the direction close to the exhaust port 12. The first straight flow channel 15 and the first expansion flow channel 16 are arranged, and the angle between the first straight flow channel 15 and the first expansion flow channel 16 is utilized so that when the fuel is ejected from the first injection hole 13 and moves from the first straight flow channel 15 to the first expansion flow channel 16 driven by the incoming flow, the cross-sectional size of the first expansion flow channel 16 in the direction perpendicular to the axis of the main body of the burner stabilizer gradually increases in the direction close to the exhaust port 12, that is, the first expansion flow channel 16 is an inclined plane at an angle to the axis of the main body of the burner stabilizer, which can enhance the diffusion of the fuel and enable the fuel to burn more fully.

[0033] In some implementations of the present embodiment, the outer wall includes a second expansion wall 17, a second straight wall 18 and a third expansion wall 19 which are connected in sequence. The second expansion wall 17 is closer to the air inlet 11 than the third expansion wall 19. The cross-sectional size of the second straight wall 18 in a direction perpendicular to the axis of the stabilizer body remains unchanged. The cross-sectional sizes of the second expansion wall 17 and the third expansion wall 19 in a direction perpendicular to the axis of the stabilizer body gradually increase along the direction close to the exhaust port 12. The second expansion wall 17 is connected to the side of the first straight channel 15 close to the air inlet 11. The third expansion wall 19 is connected to the side of the first expansion channel 16 close to the exhaust port 12. A second expansion wall 17 is provided, and the second expansion wall 17 is connected to the side of the first equal-flow channel 15 close to the air inlet 11. An angle is formed at the connection between the second expansion wall 17 and the first equal-flow channel 15, and the opening direction of the angle is toward the exhaust port 12, so as to reduce the resistance to the incoming flow and the friction loss of the incoming flow, thereby reducing the total pressure loss of the incoming flow; a third expansion wall 19 is provided, and the third expansion wall 19 is connected to the side of the first expansion channel 16 close to the exhaust port 12. When the high-speed incoming flow passes through the third expansion wall 19, the direction of the incoming flow changes, and a low-pressure area is formed at the exhaust port 12. A part of the air flows back to the low-pressure area to form a recirculation area. Since the speed of the gas in the recirculation area is relatively low, the fuel and oxygen are more easily and fully mixed to meet the combustion conditions, the fuel can be fully burned in a shorter time, and the combustion performance of the fuel is improved. The second expansion wall 17, the second straight wall 18 and the third expansion wall 19 are all annular in cross-section in the direction perpendicular to the axis of the main body of the flame stabilizer. The ring shape here can be rectangular, circular, polygonal or the like. In this embodiment, the second expansion wall 17, the second straight wall 18 and the third expansion wall 19 are rectangular in cross-section in the direction perpendicular to the axis of the main body of the flame stabilizer.

[0034] In some implementations of this embodiment, the ignition end of the ignition device 3 is fixed at the tail of the flame stabilizer body. Since a low-pressure area is formed at the exhaust port 12, part of the air flows back to the low-pressure area to form a reflux area, and the fuel and oxygen are more easily fully mixed to meet the combustion conditions. The ignition device 3 is installed at the tail of the flame stabilizer body to facilitate successful ignition to form the initial flame B.

[0035] In some implementations of this embodiment, reference Figure 2, the angle between the first expansion channel 16 and the main axis of the stabilizer is less than or equal to 45°, the angle between the second expansion wall 17 and the main axis of the stabilizer is less than or equal to 45°, and the angle between the third expansion wall 19 and the main axis of the stabilizer is less than or equal to 30°. Setting the angle β between the second expansion wall 17 and the main axis of the stabilizer is less than or equal to 45°, which can avoid the influence of too large angle on the stability of the incoming flow in the case of high-speed incoming flow, and also reduce the total pressure loss of the incoming flow; setting the angle α between the first expansion channel 16 and the main axis of the stabilizer is less than or equal to 45°, and the angle γ between the third expansion wall 19 and the main axis of the stabilizer is less than or equal to 30°, the fuel sprayed from the first injection hole 13 and the second injection hole 14 is more likely to diffuse to both sides driven by the incoming flow, which can increase the speed of fuel diffusion and mixing, shorten the time for complete combustion of the fuel, and thus improve the combustion efficiency of the fuel.

[0036] Figure 3a Schematic diagram of the overall structure of the fuel combustion efficiency experiment of the combustion stabilizer 1 in this embodiment. Figure 3b Schematic diagram of the overall structure of the conventional support plate stabilizer fuel combustion efficiency experiment. The stabilizer 1 in this embodiment and the conventional support plate stabilizer are respectively provided with two. Under the same combustion chamber conditions and the large support plate stabilizer is also provided upstream, the inflow velocity of the combustion chamber is set to 2 Mach, and the following is obtained: Figure 4 The fuel combustion efficiency comparison diagram of the flame stabilizer 1 in this embodiment and the conventional support plate flame stabilizer is shown. The horizontal axis is the flow distance of the combustion chamber, that is, the length of the path that the airflow in the combustion chamber passes along the flow direction. The coordinate origin is the 100mm position of the flame stabilizer 1 and the tail end of the conventional support plate flame stabilizer along the flow direction of the airflow. The vertical axis is the combustion efficiency. It can be seen that under the same experimental conditions, the fuel combustion efficiency of the flame stabilizer 1 in this embodiment is higher.

[0037] Embodiment 2

[0038] This embodiment provides a combustion chamber, referring to Figures 5-6, including a combustion chamber body 2 and the flame stabilizer 1 in the first embodiment, the combustion chamber body 2 has a second inner flow channel, a combustion chamber inlet 21 and a combustion chamber outlet 22, the combustion chamber inlet 21 and the combustion chamber outlet 22 are both connected to the second inner flow channel; the flame stabilizer 1 is used to be fixed inside the second inner flow channel, and the air inlet 11 is close to the combustion chamber inlet 21, and the exhaust port 12 is close to the combustion chamber outlet 22. The second inner flow channel of the combustion chamber body 2 is provided with the flame stabilizer 1 as in the first embodiment, the axial direction of the flame stabilizer 1 is arranged along the length direction of the combustion chamber body 2, and the air enters the second inner flow channel. By arranging the flame stabilizer 1 in the combustion chamber body 2, the flame stabilizer 1 has a first inner flow channel, and the first inner flow channel and the outer wall of the flame stabilizer 1 are provided with a first injection hole 13 and a second injection hole 14. The fuel injected from the first injection hole 13 is ignited by the ignition device 3, and an initial flame B can be formed at the rear side of the exhaust port 12. After the initial flame B is formed, fuel is injected through the second injection hole 14, and the second injection hole 1 The injected fuel surrounds the initial flame B, and the initial flame B can heat the fuel injected from the second injection hole 14, so the energy of the initial flame B can be used to promote the rapid evaporation and diffusion of the fuel injected from the second injection hole 14. Since the density gradient generated by the evaporation of the fuel can promote the diffusion of the fuel, the further diffusion of the fuel and the contact with the surrounding air can achieve efficient mixing of the fuel and the fuel and the heat release in a shorter time, thereby improving the combustion efficiency of the fuel. Therefore, the distance traveled by the fuel in the combustion chamber for full combustion is shorter, and the total length of the combustion chamber can be further shortened.

[0039] In some implementations of the present embodiment, the inner wall of the combustion chamber body 2 includes a third straight wall surface 23, a fourth expansion wall surface 24 and a fifth expansion wall surface 25 connected in sequence, the third straight wall surface 23 is closer to the combustion chamber inlet 21 than the fifth expansion wall surface 25, the cross-sectional size of the third straight wall surface 23 in the direction perpendicular to the length of the combustion chamber body 2 remains unchanged, and the cross-sectional size of the fourth expansion wall surface 24 and the fifth expansion wall surface 25 in the direction perpendicular to the length of the combustion chamber body 2 gradually increases along the direction close to the combustion chamber outlet 22. Due to the poor anti-backpressure capability of the incoming flow under low Mach number conditions, after the downstream of the stabilizer 1 is successfully ignited, the heat generated by the combustion of the fuel heats the air, causing the air to expand and increase the pressure in the combustion chamber, which is prone to blockage of the incoming flow and difficulty in ignition. The fourth expansion wall surface 24 and the fifth expansion wall surface 25 can increase the volume in the second inner flow channel, thereby reducing the pressure generated by the combustion in the combustion chamber, and reducing the blockage of the incoming flow, so as to ensure the performance of the combustion chamber.

[0040] In some implementations of this embodiment, the flame stabilizer 1 is fixed inside the second inner flow channel surrounded by the fourth expansion wall 24. The flame stabilizer 1 is fixed inside the second inner flow channel surrounded by the fourth expansion wall 24. The internal space of the second inner flow channel surrounded by the fourth expansion wall 24 is larger than the space inside the second inner flow channel surrounded by the third straight wall 23. The space occupied by the flame stabilizer 1 is compensated by the space surrounded by the fourth expansion wall 24, which reduces the change in the flow area of ​​the incoming flow, and the total pressure loss of the incoming flow is small, which can avoid the combustion chamber from reducing the flow area due to the presence of the flame stabilizer 1, resulting in performance degradation. In some other embodiments, the exhaust port 12 of the flame stabilizer 1 is flush with the end of the fourth expansion wall 24 close to the combustion chamber outlet 22.

[0041] In some implementations of this embodiment, reference Figure 6, the maximum cross-sectional area of ​​the fourth expansion wall 24 perpendicular to the length direction of the combustion chamber body 2 is greater than or equal to 1.3 times the area of ​​the combustion chamber inlet 21 and less than or equal to 1.6 times the area of ​​the combustion chamber inlet 21; the maximum cross-sectional area of ​​the fifth expansion wall 25 perpendicular to the length direction of the combustion chamber body 2 is greater than or equal to 1.0 times the maximum cross-sectional area of ​​the fourth expansion wall 24 perpendicular to the length direction of the combustion chamber body 2 and less than or equal to 1.1 times the maximum cross-sectional area of ​​the fourth expansion wall 24 perpendicular to the length direction of the combustion chamber body 2. Specifically, the cross-section of the inner wall of the combustion chamber body 2 perpendicular to the length direction of the combustion chamber body 2 is rectangular everywhere. In this embodiment, the height of the rectangular cross section of the inner wall of the combustion chamber body 2 perpendicular to the length direction of the combustion chamber body 2 is equal everywhere, so the maximum width L2 of the fourth expansion wall 24 is greater than or equal to 1.3 times the width L1 of the combustion chamber inlet 21 and less than or equal to 1.6 times the width L1 of the combustion chamber inlet 21, that is, 1.3*L1≤L2≤1.6*L1. By setting the angle to increase the volume of the combustion chamber to reduce the pressure generated by the combustion in the combustion chamber, the obstruction of the combustion chamber to the incoming flow after the fuel is ignited can be reduced, while ensuring the anti-back pressure ability of the combustion chamber, avoid excessive total pressure loss of the incoming flow to ensure the performance of the combustion chamber. The combustion chamber inlet width is 100cm, and the maximum width of the fourth expansion wall 24 is 150cm. The maximum cross-sectional area of ​​the fifth expansion wall 25 perpendicular to the length direction of the combustion chamber body 2 is set to be greater than or equal to 1.0 times the maximum cross-sectional area of ​​the fourth expansion wall 24 perpendicular to the length direction of the combustion chamber body 2 and less than or equal to 1.1 times the maximum cross-sectional area of ​​the fourth expansion wall 24 perpendicular to the length direction of the combustion chamber body 2. In this embodiment, the maximum width L3 of the fifth expansion wall 25 is greater than or equal to 1.0 times the maximum width L2 of the fourth expansion wall 24 and less than or equal to 1.1 times the maximum width L2 of the fourth expansion wall 24, 1.0*L2≤L3≤1.1*L2, by setting the angle to increase the volume of the combustion chamber to reduce the pressure generated by combustion in the combustion chamber, so that the obstruction of the combustion chamber to the incoming flow after the fuel is ignited can be reduced, while ensuring the anti-back pressure ability of the combustion chamber, avoiding excessive total pressure loss of the incoming flow to ensure the performance of the combustion chamber. In this embodiment, the maximum width L3 of the fifth expansion wall 25 is set to 1.1 times the maximum width L2 of the fourth expansion wall 24, that is, L3=1.1*L2. The inner wall of the combustion chamber can also be provided with a plurality of third injection holes, and a fifth expansion wall 25 is provided to reduce the obstruction of the pressure generated by the combustion of the third injection fuel to the incoming flow. The total width L4 of the stabilizer 1 is less than or equal to the difference between the maximum width L2 of the fourth expansion wall 24 and the width L1 of the combustion chamber inlet 21, that is, L4≤L2-L1, and the width L5 of the first inner flow channel is less than or equal to half of the total width L4 of the stabilizer 1, that is, L5≤(L2-L1) / 2. In this embodiment, the maximum width of the fifth expansion wall 25 is 165cm, the total width of the stabilizer 1 is set to 40cm, and the width of the first equal straight flow channel 15 of the inner flow is set to 20cm.In some other embodiments, the maximum width of the fifth expansion wall 25 is the same as the maximum width of the fourth expansion wall 24, and the third injection hole may not be provided on the inner wall of the combustion chamber. In some other embodiments, the height of the rectangular cross section of the inner wall of the combustion chamber body 2 perpendicular to the length direction of the combustion chamber body 2 can be adjusted accordingly according to actual conditions.

[0042] Embodiment 3

[0043] This embodiment provides an ignition method for the combustion chamber in the second embodiment, referring to Figure 5 as well as Figure 7 , including: injecting fuel through the first injection hole 13 to form a first oil mist A in the first inner flow channel; starting the ignition device 3 to ignite the oil mist to establish an initial flame B, and closing the ignition device 3 after the initial flame B is successfully established; injecting fuel through the second injection hole 14, and the fuel injected from the second injection hole 14 forms a second oil mist C that diffuses onto the initial flame B. At time T1, fuel is injected through the first injection hole 13, and the fuel equivalence ratio (i.e., the amount of fuel injected by the injection system / the amount of fuel that can be completely reacted in the combustion chamber) is 0.1-0.2, and the fuel forms a fully mixed first oil mist A at the tail of the stabilizer 1; at time T2, starting the ignition device 3 to ignite the first oil mist A to establish an initial flame B, and closing the ignition device 3 after the initial flame B is successfully established; at time T3, injecting fuel through the second injection hole 14, and the fuel injected from the second injection hole 14 forms a second oil mist C that diffuses onto the initial flame B, and the fuel equivalence ratio gradually increases, and the fuel is heated to enhance diffusion and accompanied by combustion, forming a strong central flame D. In this embodiment, the first injection hole 13 is connected to the first fuel pump through the first flow channel, and the second injection hole 14 is connected to the second fuel pump through the second flow channel. By opening and closing the first fuel pump and the second fuel pump, the first injection hole 13 and the second injection hole 14 can be controlled to spray fuel respectively. The fuel injected from the first injection hole 13 is ignited by the ignition device 3 to form an initial flame B. After the initial flame B is formed, the fuel is injected through the second injection hole 14. The fuel injected from the second injection hole 14 surrounds the initial flame B. The initial flame B can heat the fuel injected from the second injection hole 14. The energy of the initial flame B can be used to promote the rapid evaporation and diffusion of the fuel injected from the second injection hole 14. Since the density gradient generated by the evaporation of the fuel can promote the diffusion of the fuel, the further diffusion of the fuel and the contact with the surrounding air can achieve efficient mixing of the fuel and the air, so that the fuel can be fully burned and release heat in a shorter time, thereby improving the combustion efficiency of the fuel. The heat released by the combustion of the fuel can promote the rapid evaporation and diffusion of the fuel. At the same time, the diffusion of the fuel can also promote the combustion of the fuel. Therefore, under the condition of fuel diffusion-combustion self-excitation, the performance of the engine combustion chamber is improved, and the length of the combustion chamber can be shortened.

[0044] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A flame stabilizer, characterized in that: include: A flame stabilizer body, the flame stabilizer body having an outer wall, a first inner flow channel, an air inlet and an exhaust port, the outer wall being a surface on the outer circumference of the flame stabilizer body, the air inlet and the exhaust port both being in communication with the first inner flow channel; a plurality of first injection holes, wherein the first injection holes are arranged on the first inner flow channel, and the first injection holes are used to inject fuel into the first inner flow channel; a plurality of second injection holes, wherein the second injection holes are arranged on the outer side wall and are used to inject fuel oil outside the main body of the combustion stabilizer; as well as An ignition device is provided with an ignition end, and the ignition end is used for igniting the fuel injected from the first injection hole.

2. The combustion stabilizer according to claim 1, characterized in that: The first inner flow channel has a first equal-flow channel and a first expansion channel connected in sequence. The first equal-flow channel is closer to the air inlet than the first expansion channel. The cross-sectional size of the first equal-flow channel in the direction perpendicular to the axis of the flame stabilizer body remains unchanged, and the cross-sectional size of the first expansion channel in the direction perpendicular to the axis of the flame stabilizer body gradually increases along the direction approaching the exhaust port.

3. The combustion stabilizer according to claim 2, characterized in that: The outer side wall comprises a second expansion wall surface, a second straight wall surface and a third expansion wall surface which are connected in sequence, the second expansion wall surface is closer to the air inlet than the third expansion wall surface, the cross-sectional size of the second straight wall surface in the direction perpendicular to the axis of the main body of the stabilizer is constant, and the cross-sectional size of the second expansion wall surface and the third expansion wall surface in the direction perpendicular to the axis of the main body of the stabilizer gradually increases along the direction close to the exhaust port; The second expansion wall surface is connected to a side of the first equal flow channel close to the air inlet; The third expansion wall surface is connected to a side of the first expansion channel close to the exhaust port.

4. The combustion stabilizer according to claim 1, characterized in that: The ignition end is fixed at the rear of the flame stabilizer body.

5. The combustion stabilizer according to claim 3, characterized in that: The angle between the first expansion flow channel and the axis of the stabilizer body is less than or equal to 45°, the angle between the second expansion wall and the axis of the stabilizer body is less than or equal to 45°, and the angle between the third expansion wall and the axis of the stabilizer body is less than or equal to 30°.

6. A combustion chamber, characterized in that: include: A combustion chamber body, wherein the combustion chamber body has a second inner flow channel, a combustion chamber inlet and a combustion chamber outlet, wherein the combustion chamber inlet and the combustion chamber outlet are both in communication with the second inner flow channel; as well as The flame stabilizer as described in any one of claims 1 to 5 is used to be fixed inside the second inner flow channel, and the air inlet is close to the inlet of the combustion chamber, and the exhaust port is arranged close to the outlet of the combustion chamber.

7. The combustion chamber according to claim 6, characterized in that: The inner wall of the combustion chamber body includes a third straight wall surface, a fourth expansion wall surface and a fifth expansion wall surface which are connected in sequence. The third straight wall surface is closer to the combustion chamber inlet than the fifth expansion wall surface. The cross-sectional size of the third straight wall surface in the direction perpendicular to the length of the combustion chamber body remains unchanged. The cross-sectional sizes of the fourth expansion wall surface and the fifth expansion wall surface in the direction perpendicular to the length of the combustion chamber body gradually increase along the direction approaching the combustion chamber outlet.

8. The combustion chamber according to claim 7, characterized in that: The flame stabilizer is fixed inside the second inner flow channel surrounded by the fourth expansion wall surface.

9. The combustion chamber according to claim 7, characterized in that: The maximum cross-sectional area of ​​the fourth expansion wall surface perpendicular to the length direction of the combustion chamber body is greater than or equal to 1.3 times the inlet area of ​​the combustion chamber and less than or equal to 1.6 times the inlet area of ​​the combustion chamber; The maximum cross-sectional area of ​​the fifth expansion wall perpendicular to the length direction of the combustion chamber body is greater than or equal to 1.0 times the maximum cross-sectional area of ​​the fourth expansion wall perpendicular to the length direction of the combustion chamber body and is less than or equal to 1.1 times the maximum cross-sectional area of ​​the fourth expansion wall perpendicular to the length direction of the combustion chamber body.

10. A combustion chamber ignition method according to any one of claims 6 to 9, characterized in that: include: Injecting fuel through the first injection hole to form a first oil mist in the first inner flow channel; Starting the ignition device to ignite the first oil mist to establish an initial flame, and closing the ignition device after the initial flame is successfully established; The fuel is injected through the second injection hole, and the fuel injected from the second injection hole forms a second oil mist which is diffused onto the initial flame.

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