Yaran ramjet combustion chamber fuel injection rod concentric annular plasma fuel activation device

Abstract

A concentric annular plasma fuel activation device for the injector rod of a ramjet combustion chamber is provided, comprising a combustion chamber housing (1), an injector rod (2), a flame stabilizer (3), an outer ring low-pressure electrode (4), and an inner ring high-pressure electrode (5). The outer ring low-pressure electrode (4) consists of a circular outer ring body (6), an outer ring fixing rod (7), and an outer ring discharge contact (8). The inner ring high-pressure electrode (5) consists of an inner ring high-pressure terminal (9), an inner ring body (10), and an inner ring discharge contact (11). To achieve insulation between the inner ring high-pressure terminal (9) and the combustion chamber housing (1), a hollow cylindrical inner ring fixing sleeve (12) is designed. A method for activating concentric annular plasma fuel for the injector rod of a ramjet combustion chamber is also provided. This invention addresses the problems of difficult ignition and low combustion efficiency of ramjet combustion chambers under low operating conditions. This invention employs an innovative sliding arc plasma excitation device after the fuel injector rod in the ramjet combustion chamber, which can optimize the working performance of the ramjet combustion chamber over a wide range of incoming flow parameters without the need for an external geometrically adjustable mechanism.

Description

Technical Field

[0001] This invention relates to the field of aero-engines, and more particularly to a concentric annular plasma fuel activation device for the fuel injector rod of a subsonic ramjet combustion chamber. Background Technology

[0002] Turbine-based combined cycle (TBCC) engines are one of the ideal power forms for high-speed near-space vehicles. Among various combination forms, the technical solution that combines turbojet engines and subsonic ramjet engines has advantages such as high technical maturity and controllable development risks.

[0003] At low speeds, the TBCC engine is powered by the turbine engine. As the flight speed increases, the engine enters a mode transition phase, the turbine engine gradually stops working, and the subsonic ramjet engine ignites and starts, providing thrust to the aircraft independently.

[0004] Turbojet engines typically operate at speeds between Mach 0 and 2.0, while subsonic ramjet engines operate at Mach 2.0 to 5.0. Because the speed ranges of the two power forms overlap little, TBCC engines suffer from insufficient thrust and poor acceleration during mode transitions, which seriously affects flight safety.

[0005] There are two main approaches to solving the above problems: one is to broaden the upper limit of the operating speed of the turbine engine, and the other is to broaden the lower limit of the ignition and start-up speed of the subsonic ramjet engine. When adopting the second approach, namely broadening the lower limit of the start-up speed of the subsonic ramjet engine, the relatively low flight speed results in a lower total inlet temperature of the combustion chamber and poor fuel atomization and evaporation characteristics, leading to difficulties in ignition of the subsonic ramjet combustion chamber, insufficient combustion efficiency, and difficulty in meeting the performance requirements of the aircraft's propulsion system.

[0006] A typical sub-gas ramjet combustion chamber mainly consists of two parts: the fuel injector and the flame stabilizer. The fuel injector serves as the main fuel supply line to the combustion chamber, accounting for approximately 80%-90% of the total fuel supply. The remaining fuel is supplied to the flame stabilizer and ignited, thus igniting the fuel in the main fuel line. Existing technologies primarily improve the ignition performance of the combustion chamber under low operating conditions by optimizing the stabilizer's geometry and dimensions. However, due to the relatively small fuel supply to the stabilizer, optimization studies targeting it are unlikely to significantly improve the overall combustion efficiency of the combustion chamber. Therefore, the improvement in engine thrust performance is limited, and the problem of insufficient thrust during the mode transition phase of a TBCC engine remains unresolved.

[0007] Existing research results indicate that plasma possesses significant thermal and chemical effects, showing promising application prospects in promoting the atomization and evaporation of liquid kerosene and enhancing its chemical activity.

[0008] In summary, applying plasma to the fuel injector of a submersible ramjet combustion chamber to treat the fuel in the main fuel circuit is expected to significantly improve the chemical activity of liquid kerosene, thereby widening the lower limit of the ignition and start-up speed of the submersible ramjet combustion chamber and improving the thrust performance of the engine under low operating conditions. Summary of the Invention

[0009] Based on the above requirements and the problems existing in the prior art, the present invention proposes a concentric annular plasma fuel activation device for a ramjet combustion chamber injector rod, comprising a combustion chamber shell 1, an injector rod 2, a flame stabilizer 3, an outer ring low-pressure electrode 4, and an inner ring high-pressure electrode 5.

[0010] The combustion chamber shell 1 is a cylindrical hollow cylinder made of high-temperature alloy;

[0011] The fuel injector 2 is a hollow metal rod. On the cross-section near the combustion chamber inlet, multiple identical fuel injectors 2 are evenly arranged along the circumference. Each fuel injector 2 is fixed to the combustion chamber shell 1 by welding along the circumference radius of the combustion chamber. One end of the fuel injector 2 is closed inside the combustion chamber, and the other end outside the combustion chamber shell is connected to the engine fuel supply line. Multiple fuel injector holes are opened on the wall of each fuel injector 2. The direction of the injection holes is downstream along the axis of the combustion chamber. Two injection holes are kept at a certain distance from the far end of the fuel injector 2.

[0012] The flame stabilizer 3 is a common evaporative flame stabilizer in sub-fuel ramjet combustion chambers. It is coaxial with the combustion chamber housing 1, located downstream of the fuel injector, and fixedly connected to the combustion chamber housing 1.

[0013] The outer ring low-pressure electrode 4 consists of a circular outer ring body 6, an outer ring fixing rod 7, and an outer ring discharge contact 8. The circular outer ring body 6 of the outer ring low-pressure electrode 4 is arranged coaxially with the combustion chamber shell 1. Viewed axially, the plane where the outer ring low-pressure electrode 4 is located is downstream of the axial section inside the combustion chamber where the fuel injection rod is located and maintains a certain distance from it. To fix the outer ring low-pressure electrode 4, multiple identical outer ring fixing rods 7 extend outward from the outer ring low-pressure electrode 4 radially. The multiple outer ring fixing rods 7 are evenly distributed along the outer ring body 6 of the outer ring low-pressure electrode 4. The outer ring fixing rods 7 are fixedly connected to the combustion chamber shell 1 to fix the outer ring low-pressure electrode 4 in the combustion chamber. The length of the outer ring fixing rods 7 is determined by the dimensions of the outer ring body 6 and the combustion chamber shell 1. The outer ring discharge contact 8 consists of multiple identical short rods extending radially from the outside to the inside of the outer ring low-pressure electrode 4. The multiple outer ring discharge contacts 8 are evenly distributed circumferentially along the outer ring body 6.

[0014] The inner ring high-voltage electrode 5 is composed of an inner ring high-voltage terminal 9, an inner ring body 10, and an inner ring discharge contact 11; the inner ring high-voltage terminal 9, the inner ring body 10, and the inner ring discharge contact 11 are a whole;

[0015] The inner ring body 10 is a circular electrode, which is on the same axis as the combustion chamber shell 1 and the outer ring body 6 of the outer ring low-pressure electrode 4. When viewed along the axial direction, the plane where the inner ring high-pressure electrode 5 is located is downstream of the plane where the outer ring low-pressure electrode 4 is located and maintains a certain distance from it; the diameter of the inner ring body 10 is smaller than the diameter of the outer ring body 6.

[0016] To fix the inner ring high voltage electrode 5 and connect it to the high voltage power supply, multiple identical inner ring high voltage terminals 9 extend radially from the inside to the outside along the inner ring body 10. The multiple inner ring high voltage terminals 9 are evenly distributed along the circumference of the inner ring body 10.

[0017] A hollow cylindrical inner ring fixing sleeve 12 is provided, which extends into the combustion chamber through a pre-drilled mounting hole on the combustion chamber shell 1 along the radial direction and remains fixed to the combustion chamber shell 1, wrapping around and fixing the inner ring high-voltage terminal 9; the inner ring high-voltage terminal 9 maintains good contact with the high-voltage electrode extension section 13 inserted from the outside to the inside in the inner ring fixing sleeve 12, and the high-voltage electrode extension section 13 is connected to the plasma power supply; the position and number of the pre-drilled mounting holes on the combustion chamber shell 1 need to be determined according to the inner ring high-voltage terminal 9;

[0018] The inner ring discharge contact 11 consists of multiple identical short rods extending radially from the inside to the outside of the inner ring body 10. The multiple inner ring discharge contacts 11 are evenly distributed around the circumference of the inner ring body 10. The outer ends of the multiple inner ring discharge contacts 11 are opposite to the inner ends of the outer ring discharge contacts 8 of the outer ring low-voltage electrode 4, but a certain distance is maintained between them as a discharge gap. Therefore, the number and position of the inner ring discharge contacts 11 and the outer ring discharge contacts 8 correspond one-to-one.

[0019] In one specific embodiment of the present invention, two injection holes are opened on the wall of each injection rod, and the distances of the two injection holes from the far end of the injection rod are 15mm and 40mm, respectively.

[0020] In another specific embodiment of the present invention, viewed axially, the plane where the outer ring low-pressure electrode 4 is located is 20 mm downstream of the axial section inside the combustion chamber where the fuel injector is located.

[0021] In another specific embodiment of the present invention, viewed along the axial direction, the plane where the inner ring high voltage electrode 5 is located is located 6 mm downstream of the plane where the outer ring low voltage electrode 4 is located.

[0022] In another specific embodiment of the present invention, there are 6 fuel injection rods, which are evenly arranged along the axial direction.

[0023] Six discharge contacts are arranged on both the outer ring low-pressure electrode 4 and the inner ring high-pressure electrode 5, forming six sliding arc channels during discharge; the six outer ring discharge contacts 8 and the six inner ring discharge contacts 11 are evenly distributed on the outer ring body 6 and the inner ring body 10, respectively; the six sets of discharge electrodes are all located directly behind the downstream of the fuel injector rod.

[0024] In another specific embodiment of the present invention

[0025] The combustion chamber shell 1 has a wall thickness of 10mm, an inner diameter of 240mm, and a length of 400mm;

[0026] The outer diameter of the fuel injector 2 is 8mm, the inner diameter is 4mm, the total length is 120mm, the length extending into the combustion chamber is 100mm, and there are 2 fuel injection holes arranged on the fuel injector 2, which are 15mm and 40mm away from the far end of the fuel injector 2, respectively, and the diameter of the fuel injection hole is 1mm.

[0027] The outer ring body 6 of the outer ring low-pressure electrode 4 has an inner diameter of 112 mm and an outer diameter of 116 mm; the outer ring fixing rod 7 is cylindrical with a diameter of 2 mm and a length of 61 mm, and is welded to the inner surface of the combustion chamber shell 1; the six outer ring discharge contacts 8 are all cylindrical with a diameter of 2 mm and a length of 12.5 mm.

[0028] The inner ring high-voltage electrode 5 has an inner ring body 10 with an inner diameter of 60 mm and an outer diameter of 64 mm. The inner ring high-voltage terminal 9 has a diameter of 4 mm and a length of 80 mm. The six inner ring discharge contacts 11 are all cylindrical with a diameter of 2 mm and a length of 12.5 mm. The inner ring fixing sleeve 12 is a hollow cylinder with an inner diameter of 4 mm, an outer diameter of 8 mm, and a length of 70 mm. The lower end is 20 mm away from the inner ring body 10, and the upper end extends out of the combustion chamber shell 1. The high-voltage electrode extension section 13 is cylindrical with a diameter of 4 mm and a length of 20 mm.

[0029] Along the axis of the combustion chamber housing 1, the fuel injector is 40 mm from the inlet of the combustion chamber housing 1, the stabilizer is 188 mm from the inlet of the combustion chamber housing 1, the outer ring low-pressure electrode 4 is 20 mm downstream of the fuel injector, and the inner ring high-pressure electrode 5 is 6 mm downstream of the outer ring low-pressure electrode 4.

[0030] In another specific embodiment of the present invention, the fuel injector 2, the outer ring discharge contact 8, and the inner ring discharge contact 11 are all distributed radially from the center; taking the radial direction of the fuel injector as a reference, the outer ring discharge contact 8 is rotated 2° clockwise and the inner ring discharge contact 11 is rotated 3° counterclockwise, so that the outer ring discharge contact 8 and the inner ring discharge contact 11 form an included angle of 5°.

[0031] In one embodiment of the present invention, the flame stabilizer 3 is made of a high-temperature alloy, and the outer ring low-pressure electrode 4 and the inner ring high-pressure electrode 5 are both made of tungsten metal.

[0032] A method for activating liquid kerosene plasma fuel gas in the injector rod of a ramjet combustion chamber is also provided. This method is based on the aforementioned concentric annular plasma fuel activation device for the injector rod of a ramjet combustion chamber. Specifically, when the ramjet combustion chamber of a TBCC engine is started, the output end of the plasma power supply is connected to the high-voltage electrode extension 13 of the inner ring high-voltage electrode 5. A high voltage is applied to the inner ring high-voltage electrode 5. When the voltage is high enough, an arc plasma discharge can be formed between each set of outer ring discharge contacts 8 and inner ring discharge contacts 11, achieving simultaneous discharge of 6 sets of electrodes in the entire circumferential direction. Under the action of airflow, the arc plasma discharge channel is continuously stretched and eventually breaks down. Subsequently, a new breakdown discharge is formed between the electrodes to form an arc, and the above process is repeated periodically.

[0033] The advantages of this invention are as follows:

[0034] By generating an electric arc plasma discharge to activate the fuel injected by the fuel injector, the ignition and shutdown performance and combustion efficiency of the subsonic ramjet combustion chamber under low operating conditions can be improved, significantly enhancing the propulsion efficiency during the mode transition phase of the TBCC engine.

[0035] Plasma discharge has the advantages of simple structure, adjustable discharge parameters, high frequency response, and good adaptability to incoming flow. It can achieve ignition and combustion control over a wide parameter range without changing the geometry of the combustion chamber.

[0036] The concentric ring electrode layout allows for the arrangement of multiple sets of discharge electrodes inside the combustion chamber, increasing the plasma's effective area and activating more of the oil-gas mixture. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the implementation of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0038] Figure 1 This is a simplified cross-sectional view of the present invention;

[0039] Figure 2 Here is a simplified structural diagram of the outer ring low-voltage electrode 4;

[0040] Figure 3 Here is a simplified structural diagram of the inner ring high-voltage electrode 5;

[0041] Figure 4 This is a simplified rear view of the structure of the fuel injector 2, the outer ring low-pressure electrode 4, and the inner ring high-pressure electrode 5 in this invention.

[0042] Figure 5 This is a schematic diagram of the working principle of a sliding arc plasma exciter.

[0043] Attached reference numerals: ① Combustion chamber housing, ② Injection rod, ③ Flame stabilizer, ④ Outer ring low-pressure electrode, ⑤ Inner ring high-pressure electrode, ⑥ Circular outer ring body, ⑦ Outer ring fixing rod, ⑧ Outer ring discharge contact, ⑨ Inner ring high-pressure terminal, ⑩ Inner ring body. Inner ring discharge contact, Inner ring fixing sleeve, High-voltage electrode extension section. Detailed Implementation

[0044] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and the following embodiments.

[0045] The present invention provides a concentric annular plasma fuel activation device for the fuel injector rod of a ramjet combustion chamber, comprising a combustion chamber housing 1, a fuel injector rod 2, a flame stabilizer 3, an outer ring low-pressure electrode 4, and an inner ring high-pressure electrode 5.

[0046] The combustion chamber shell 1 is a cylindrical hollow cylinder made of high-temperature alloy.

[0047] The fuel injector 2 is a hollow metal rod. Multiple identical fuel injectors 2 are evenly arranged circumferentially on a cross-section near the combustion chamber inlet. Each fuel injector 2 is welded to the combustion chamber shell 1 along the circumferential radius of the combustion chamber, with one end inside the combustion chamber closed and the other end outside the combustion chamber shell connected to the engine fuel supply line. Each fuel injector has, for example, two injection holes on its wall, pointing downstream along the combustion chamber axis. In one specific embodiment of the invention, the distances from the two injection holes to the distal end of the fuel injector are 15mm and 40mm, respectively (the distal end refers to the end furthest from the fuel supply inlet, i.e., the end inserted into the combustion chamber). High-pressure kerosene is ejected from the injection holes, atomized into fine droplets under pressure, and sprayed downstream in an approximately conical shape.

[0048] The flame stabilizer 3 is a common evaporative flame stabilizer in sub-gas ramjet combustion chambers (Zheng Dianfeng, Zhang Huiqiang, Lin Wenyi, et al. Experimental study on the combustion performance of evaporative stabilizers at normal and low pressure [J]. Journal of Harbin Institute of Technology, 2004(12): 1724-1728.). It is coaxial with the combustion chamber shell 1, made of high-temperature alloy, located downstream of the fuel injector rod, and fixed to the combustion chamber shell 1 by bolts through a mounting bracket.

[0049] The outer ring low-voltage electrode 4 consists of a circular outer ring body 6, an outer ring fixing rod 7, and an outer ring discharge contact 8. The outer ring low-voltage electrode 4 is made of tungsten metal. Figure 2As shown. The circular outer ring body 6 of the outer ring low-pressure electrode 4 is coaxially arranged with the combustion chamber housing 1. In a specific embodiment of the present invention, viewed axially, the plane where the outer ring low-pressure electrode 4 is located is 20 mm downstream of the axial section inside the combustion chamber where the fuel injection rod is located. To fix the outer ring low-pressure electrode 4, multiple identical outer ring fixing rods 7 extend radially outward from the outer ring low-pressure electrode 4. The multiple outer ring fixing rods 7 are evenly distributed along the outer ring body 6 of the outer ring low-pressure electrode 4. The outer ring fixing rods 7 are connected to the combustion chamber housing 1 by welding, fixing the outer ring low-pressure electrode 4 in the combustion chamber. The length of the outer ring fixing rods 7 is determined by the dimensions of the outer ring body 6 and the combustion chamber housing 1. The outer ring discharge contacts 8 are multiple identical short rods extending radially from the outside to the inside of the outer ring low-pressure electrode 4. The multiple outer ring discharge contacts 8 are evenly distributed circumferentially along the outer ring body 6. The outer ring discharge contacts 8 are used to conduct with the discharge contacts of the inner ring high-pressure electrode 5 to generate arc plasma.

[0050] The inner ring high-voltage electrode 5 consists of an inner ring high-voltage terminal 9, an inner ring body 10, and an inner ring discharge contact 11, as follows: Figure 3 As shown. The inner ring high-voltage terminal 9, the inner ring body 10, and the inner ring discharge contact 11 are a single unit made of tungsten metal.

[0051] like Figure 3 As shown, the inner ring body 10 is a circular electrode, which is coaxial with the combustion chamber shell 1 and the outer ring body 6 of the outer ring low-pressure electrode 4. In a specific embodiment of the present invention, viewed axially, the plane of the inner ring high-pressure electrode 5 is located 6 mm downstream of the plane of the outer ring low-pressure electrode 4. The diameter of the inner ring body 10 is smaller than the diameter of the outer ring body 6.

[0052] To fix the inner ring high voltage electrode 5 and connect it to the high voltage power supply, multiple identical inner ring high voltage terminals 9 extend radially from the inside to the outside along the inner ring body 10. The multiple inner ring high voltage terminals 9 are evenly distributed along the circumference of the inner ring body 10.

[0053] In order to achieve insulation between the inner ring high-voltage terminal 9 and the combustion chamber shell 1, a hollow cylindrical inner ring fixing sleeve 12 is designed.

[0054] To facilitate installation, the length of the inner ring high-voltage terminal 9 is first shortened, allowing the inner ring body 10, including the inner ring high-voltage terminal 9, to be placed entirely within the combustion chamber housing 1. Then, through pre-drilled mounting holes (e.g., threaded mounting holes) on the combustion chamber housing 1, the inner ring fixing sleeve 12 is inserted radially into the combustion chamber and fixed to the combustion chamber housing 1, for example, by threading, wrapping around and fixing the inner ring high-voltage terminal 9, for example, by using high-temperature adhesive. Since the inner ring high-voltage terminal 9 is too short to extend beyond the outside of the combustion chamber housing 1, a high-voltage electrode extension section 13 is inserted from the outside in into the inner ring fixing sleeve 12 and fixed, ensuring good contact with the inner ring high-voltage terminal 9. The high-voltage electrode extension section 13 is then connected to the plasma power supply to apply a high voltage to the electrode. For example, high-temperature adhesive is used to bond the high-voltage electrode extension section 13 to the inner ring fixing sleeve 12. Therefore, the position and number of pre-drilled mounting holes on the combustion chamber housing 1 need to be determined based on the inner ring high-voltage terminal 9.

[0055] The inner ring discharge contact 11 consists of multiple identical short rods extending radially from the inside to the outside of the inner ring body 10. These inner ring discharge contacts 11 are evenly distributed around the circumference of the inner ring body 10. The outer ends of the inner ring discharge contacts 11 are opposite to the inner ends of the outer ring discharge contacts 8 of the outer ring low-voltage electrode 4, but a certain distance is maintained between them as a discharge gap. Therefore, the number and position of the inner ring discharge contacts 11 and the outer ring discharge contacts 8 correspond one-to-one.

[0056] In one specific embodiment of the present invention, there are 6 fuel injection rods, which are evenly arranged along the axial direction.

[0057] In another embodiment of the invention, six discharge contacts are arranged on both the outer ring low-pressure electrode 4 and the inner ring high-pressure electrode 5, forming six sliding arc channels during discharge. The six outer ring discharge contacts 8 and the six inner ring discharge contacts 11 are evenly distributed on the outer ring body 6 and the inner ring body 10, respectively. All six sets of discharge electrodes are located directly downstream of the injection rod to process more kerosene.

[0058] In another specific embodiment of the present invention:

[0059] The combustion chamber shell 1 has a wall thickness of 10mm, an inner diameter of 240mm, and a length of 400mm;

[0060] The outer diameter of the fuel injector 2 is 8mm, the inner diameter is 4mm, the total length is 120mm, the length extending into the combustion chamber is 100mm, and there are 2 fuel injection holes arranged on the fuel injector 2, which are 20mm and 45mm away from the bottom of the fuel injector 2, respectively, and the diameter of the fuel injection hole is 1mm.

[0061] The outer ring low-voltage electrode 4 has an inner diameter of 112 mm and an outer diameter of 116 mm. The outer ring fixing rod 7 is cylindrical with a diameter of 2 mm and a length of 61 mm, and is welded to the inner surface of the combustion chamber shell 1. The six outer ring discharge contacts 8 are all cylindrical with a diameter of 2 mm and a length of 12.5 mm.

[0062] The inner ring high-voltage electrode 5 has an inner ring body 10 with an inner diameter of 60 mm and an outer diameter of 64 mm. The inner ring high-voltage terminal 9 has a diameter of 4 mm and a length of 80 mm. The six inner ring discharge contacts 11 are all cylindrical with a diameter of 2 mm and a length of 12.5 mm. The inner ring fixing sleeve 12 is a hollow cylinder with an inner diameter of 4 mm, an outer diameter of 8 mm, and a length of 70 mm. The lower end is 20 mm away from the inner ring body 10, and the upper end extends out of the combustion chamber shell 1. The high-voltage electrode extension section 13 is cylindrical with a diameter of 4 mm and a length of 20 mm to ensure that it can extend out of the inner ring fixing sleeve 12 for easy connection to the high-voltage output terminal of the power supply.

[0063] Along the axis of the combustion chamber housing 1, the fuel injector is 40 mm from the inlet of the combustion chamber housing 1, the stabilizer is 188 mm from the inlet of the combustion chamber housing 1, the outer ring low-pressure electrode 4 is 20 mm downstream of the fuel injector, and the inner ring high-pressure electrode 5 is 6 mm downstream of the outer ring low-pressure electrode 4.

[0064] As mentioned above, the combustion chamber housing 1, the outer ring body 6 of the outer ring low-pressure electrode 4, and the inner ring body 10 of the inner ring high-pressure electrode 5 are all circular, and the centers of the three rings are on the same axis. Therefore, viewed from the combustion chamber inlet, the combustion chamber housing 1, the outer ring body 6, and the inner ring body 10 are three concentric circles. In a specific embodiment of the present invention, the fuel injection rod 2, the outer ring discharge contact 8, and the inner ring discharge contact 11 are all radially distributed from the center. Taking the radius direction of the fuel injection rod as a reference, rotating the outer ring discharge contact 8 clockwise by 2° and the inner ring discharge contact 11 counterclockwise by 3° will make the outer ring discharge contact 8 and the inner ring discharge contact 11 form a 5° angle. Figure 4 As shown.

[0065] A method for activating liquid kerosene plasma fuel gas in the injector rod of a ramjet combustion chamber is also provided. This method is based on the aforementioned concentric ring plasma fuel activation device for the injector rod of a ramjet combustion chamber. Specifically, when the ramjet combustion chamber of the TBCC engine starts, the output terminal of the plasma power supply is connected to the high-voltage electrode extension 13 of the inner ring high-voltage electrode 5. A high voltage is applied to the inner ring high-voltage electrode 5. When the voltage is sufficiently high, an arc plasma discharge can be formed between each set of outer ring discharge contacts 8 and inner ring discharge contacts 11, achieving simultaneous discharge of all six sets of electrodes along the entire circumference. Figure 5As shown, under the action of airflow, the arc plasma discharge channel is continuously stretched and eventually breaks down. Subsequently, a new arc is formed by breakdown discharge between the electrodes, and the above process is repeated periodically.

[0066] By generating an electric arc plasma through discharge, the significant thermal effect of the arc heats the kerosene ejected from the injection hole, accelerating its atomization and evaporation into small droplets. Simultaneously, the chemical reactivity of the arc plasma causes some of the kerosene to undergo a cracking chemical reaction, producing highly reactive small-molecule products such as H2, CH4, and C2H2, thereby enhancing the chemical reactivity of the fuel-air mixture. Through these two effects, the difficulty of igniting the ramjet combustion chamber is reduced, and the combustion efficiency is improved, thus enhancing the performance of the ramjet combustion chamber.

Claims

1. A concentric annular plasma fuel activation device for a hyperbolic combustion chamber fuel injection rod characterized by, It includes a combustion chamber housing (1), an injection rod (2), a flame stabilizer (3), an outer ring low-pressure electrode (4), and an inner ring high-pressure electrode (5); The combustion chamber shell (1) is a cylindrical hollow cylinder made of high-temperature alloy; The fuel injector (2) is a hollow metal rod. On the cross section near the combustion chamber inlet, multiple identical fuel injectors (2) are evenly arranged along the circumference. Each fuel injector (2) is fixed to the combustion chamber shell (1) by welding along the circumference radius of the combustion chamber. One end of the fuel injector is closed inside the combustion chamber, and the other end outside the combustion chamber shell is connected to the engine fuel supply line. Multiple fuel injector holes are opened on the wall of each fuel injector. The direction of the injector holes is downstream along the axis of the combustion chamber. Two injector holes are kept at a certain distance from the far end of the fuel injector. The flame stabilizer (3) is a common evaporative flame stabilizer in ramjet combustion chambers. It is coaxial with the combustion chamber housing (1), located downstream of the fuel injector, and is fixedly connected to the combustion chamber housing (1). The outer ring low-pressure electrode (4) consists of a circular outer ring body (6), an outer ring fixing rod (7), and an outer ring discharge contact (8). The circular outer ring body (6) of the outer ring low-pressure electrode (4) is coaxially arranged with the combustion chamber shell (1). In the axial direction, the plane where the outer ring low-pressure electrode (4) is located is downstream of the axial section of the combustion chamber where the fuel injection rod is located and maintains a certain distance from it. In order to fix the outer ring low-pressure electrode (4), multiple identical outer ring fixing rods extend outward from the outer ring low-pressure electrode (4) radially. 7) Multiple outer ring fixing rods (7) are evenly distributed along the outer ring body (6) of the outer ring low-pressure electrode (4); the outer ring fixing rods (7) are fixedly connected to the combustion chamber shell (1) to fix the outer ring low-pressure electrode (4) in the combustion chamber. The length of the outer ring fixing rods (7) is determined by the size of the outer ring body (6) and the combustion chamber shell (1); the outer ring discharge contacts (8) are multiple identical short rods extending radially from the outside to the inside along the outer ring low-pressure electrode (4). The multiple outer ring discharge contacts (8) are evenly distributed along the circumference of the outer ring body (6). The inner ring high voltage electrode (5) is composed of an inner ring high voltage terminal (9), an inner ring body (10), and an inner ring discharge contact (11); the inner ring high voltage terminal (9), the inner ring body (10), and the inner ring discharge contact (11) are a whole; The inner ring body (10) is a circular electrode, which is on the same axis as the combustion chamber shell (1) and the outer ring body (6) of the outer ring low-pressure electrode (4). When viewed along the axial direction, the plane where the inner ring high-pressure electrode (5) is located is downstream of the plane where the outer ring low-pressure electrode (4) is located and maintains a certain distance from it; the diameter of the inner ring body (10) is smaller than the diameter of the outer ring body (6). To fix the inner ring high voltage electrode (5) and connect it to the high voltage power supply, multiple identical inner ring high voltage terminals (9) are extended radially from the inside to the outside along the inner ring body (10). The multiple inner ring high voltage terminals (9) are evenly distributed along the circumference of the inner ring body (10). A hollow cylindrical inner ring fixing sleeve (12) is provided, which extends into the combustion chamber through the pre-reserved mounting hole on the combustion chamber shell (1) along the radial direction and is fixed to the combustion chamber shell (1), wrapping around the inner ring high-voltage terminal (9) and keeping it fixed; the inner ring high-voltage terminal (9) and the high-voltage electrode extension section (13) inserted from the outside to the inside in the inner ring fixing sleeve (12) maintain good contact, and the high-voltage electrode extension section (13) is connected to the plasma power supply; the position and number of the pre-reserved mounting holes on the combustion chamber shell (1) need to be determined according to the inner ring high-voltage terminal (9); The inner ring discharge contact (11) consists of multiple identical short rods extending radially from the inside to the outside of the inner ring body (10). The multiple inner ring discharge contacts (11) are evenly distributed around the circumference of the inner ring body (10). The outer ends of the multiple inner ring discharge contacts (11) are opposite to the inner ends of the outer ring discharge contacts (8) of the outer ring low-voltage electrode (4), but a certain distance is maintained between them as a discharge gap. Therefore, the number and position of the inner ring discharge contacts (11) and the outer ring discharge contacts (8) correspond one-to-one.

2. The concentric annular plasma fuel activation device for the ramjet combustion chamber injector rod as described in claim 1, characterized in that, Each fuel injector has two fuel injection holes on its wall, and the distances from the far end of the fuel injector are 15mm and 40mm, respectively.

3. The concentric annular plasma fuel activation device for the ramjet combustion chamber injector rod as described in claim 1, characterized in that, Looking along the axial direction, the plane where the outer ring low-pressure electrode (4) is located is 20 mm downstream of the axial section inside the combustion chamber where the fuel injector is located.

4. The concentric annular plasma fuel activation device for the ramjet combustion chamber injector rod as described in claim 1, characterized in that, Looking along the axial direction, the plane where the inner ring high voltage electrode (5) is located is 6 mm downstream of the plane where the outer ring low voltage electrode (4) is located.

5. The concentric annular plasma fuel activation device for the fuel injector rod in a ramjet combustion chamber as described in claim 1, characterized in that, There are 6 fuel injection rods, evenly arranged along the axial direction; Six discharge contacts are arranged on both the outer ring low-pressure electrode (4) and the inner ring high-pressure electrode (5), forming six sliding arc channels during discharge; the six outer ring discharge contacts (8) and the six inner ring discharge contacts (11) are evenly distributed on the outer ring body (6) and the inner ring body (10), respectively; the six sets of discharge electrodes are all located directly behind the downstream of the fuel injector rod.

6. The concentric annular plasma fuel activation device for the ramjet combustion chamber injector rod as described in claim 1, characterized in that, The combustion chamber shell (1) has a wall thickness of 10 mm, an inner diameter of 240 mm, and a length of 400 mm; The outer diameter of the fuel injector (2) is 8mm, the inner diameter is 4mm, the total length is 120mm, the length extending into the combustion chamber is 100mm, and there are two fuel injection holes arranged on the fuel injector, which are 15mm and 40mm away from the far end of the fuel injector, respectively, and the diameter of the fuel injection hole is 1mm. The outer ring body (6) of the outer ring low-voltage electrode (4) has an inner diameter of 112 mm and an outer diameter of 116 mm; the outer ring fixing rod (7) is cylindrical with a diameter of 2 mm and a length of 61 mm, and is welded to the inner surface of the combustion chamber shell (1); the six outer ring discharge contacts (8) are all cylindrical with a diameter of 2 mm and a length of 12.5 mm. The inner ring high voltage electrode (5) has an inner ring body (10) with an inner diameter of 60 mm and an outer diameter of 64 mm. The inner ring high voltage terminal (9) has a diameter of 4 mm and a length of 80 mm. The six inner ring discharge contacts (11) are all cylindrical with a diameter of 2 mm and a length of 12.5 mm. The inner ring fixing sleeve (12) is a hollow cylinder with an inner diameter of 4 mm, an outer diameter of 8 mm, and a length of 70 mm. The distance between the lower end and the inner ring body (10) is 20 mm, and the upper end extends out of the combustion chamber shell (1). The high voltage electrode extension section (13) is cylindrical with a diameter of 4 mm and a length of 20 mm. Along the axis of the combustion chamber housing (1), the fuel injector is 40 mm from the inlet of the combustion chamber housing (1), the stabilizer is 188 mm from the inlet of the combustion chamber housing (1), the outer ring low-pressure electrode (4) is 20 mm downstream of the fuel injector, and the inner ring high-pressure electrode (5) is 6 mm downstream of the outer ring low-pressure electrode (4).

7. The concentric annular plasma fuel activation device for the fuel injector rod in a ramjet combustion chamber as described in claim 1, characterized in that, The fuel injector (2), outer ring discharge contact (8), and inner ring discharge contact (11) are all distributed radially from the center of the circle. Taking the radius of the fuel injector as a reference, the outer ring discharge contact (8) is rotated 2° clockwise and the inner ring discharge contact (11) is rotated 3° counterclockwise, so that the outer ring discharge contact (8) and the inner ring discharge contact (11) form an angle of 5°.

8. The concentric annular plasma fuel activation device for the fuel injector rod in a ramjet combustion chamber as described in claim 1, characterized in that, The flame stabilizer (3) is made of high-temperature alloy, and the outer ring low-pressure electrode (4) and the inner ring high-pressure electrode (5) are both made of tungsten metal.

9. A method for activating liquid kerosene plasma fuel gas in a ramjet combustion chamber injector rod, based on the concentric annular plasma fuel activation device for a ramjet combustion chamber injector rod as described in any one of claims 1 to 8, characterized in that... Specifically, when the ramjet combustion chamber of the TBCC engine is started, the output end of the plasma power supply is connected to the high-voltage electrode extension section (13) of the inner ring high-voltage electrode (5), and a high voltage is applied to the inner ring high-voltage electrode (5). When the voltage is high enough, an electric arc plasma discharge can be formed between each set of outer ring discharge contacts (8) and inner ring discharge contacts (11), realizing the simultaneous discharge of 6 sets of electrodes in the entire circumferential direction. Under the action of airflow, the electric arc plasma discharge channel is continuously stretched and eventually breaks down. Then, the discharge between the electrodes is re-broken down to form an electric arc, and the above process is repeated periodically.

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