A reusable gaseous oxygen-methane torch igniter

Abstract

This application provides a reusable gaseous-oxygen-methane torch igniter, comprising an igniter housing having a combustion chamber and a methane injection chamber. One end of the igniter housing is provided with a nozzle structure, including a first methane nozzle, a gaseous-oxygen nozzle, and a second methane nozzle coaxially arranged from the inside out. The three nozzles are respectively connected to the combustion chamber, and the first and second methane nozzles are respectively connected to the methane injection chamber. The gaseous-oxygen nozzle is connected to a gaseous-oxygen injection orifice. A first injection channel is connected between the methane injection chamber and the inner cavity of the first methane nozzle, the extension direction of the first injection channel being tangent to the outer periphery of the first methane nozzle. A second injection channel is connected between the methane injection chamber and the inner cavity of the second methane nozzle, the extension direction of the second injection channel being tangent to the outer periphery of the second methane nozzle. By providing three nozzles and injection channels, methane forms a rotating jet during injection, thereby significantly increasing the contact area and mixing intensity between gaseous-oxygen and methane.

Description

Technical Field

[0001] This application relates to the field of igniter technology, and more particularly to a reusable gaseous methane torch igniter. Background Technology

[0002] Oxygen / methane propellants have become the preferred propellant combination for next-generation reusable rocket engines due to their advantages such as being non-toxic, environmentally friendly, low-cost, and refillable. The igniter, as the core component for engine starting, needs to achieve efficient atomization and mixing of the propellant and stable ignition, withstand high-temperature gas environments of 1700~2500K, and meet the reliability requirements for multiple reuses.

[0003] In existing technologies, coaxial nozzles or direct-flow centrifugal nozzles are typically used to achieve propellant mixing and ignition. For example, in a coaxial direct-injection structure, oxygen and methane are usually ejected in laminar or direct-flow form. The shear mixing between them mainly relies on the diffusion and collision of the jet itself. The mixing path is limited, and the mixing uniformity is insufficient, resulting in a longer combustion length, increased ignition delay, and reduced combustion efficiency. In addition, some designs employ a single-layer swirl design, which can improve local mixing, but often fails to achieve uniform and sufficient mixing across the entire injection surface. This is especially true for propellant combinations like gaseous oxygen / methane, which require rapid and complete mixing, where the mixing intensity remains insufficient. Therefore, the common igniter nozzle structures in existing technologies have significant limitations in propellant mixing efficiency and cannot meet the stringent requirements of rapid, uniform, and reliable ignition for next-generation high-performance, reusable rocket engines. Summary of the Invention

[0004] The purpose of this application is to address the above problems by providing a reusable gaseous oxygen-methane torch igniter, comprising: An igniter housing, wherein the igniter housing has a combustion chamber and the shell wall of the igniter housing has a methane injection chamber; The nozzle structure is located at one end of the igniter housing. The nozzle structure includes a first methane nozzle, an oxygen gas nozzle, and a second methane nozzle arranged coaxially from the inside to the outside. The first methane nozzle, the oxygen gas nozzle, and the second methane nozzle are respectively connected to the combustion chamber. The first methane nozzle and the second methane nozzle are respectively connected to the methane injection chamber. The oxygen gas nozzle is connected to an oxygen gas injection hole. A first injection channel is connected between the methane injection chamber and the inner cavity of the first methane nozzle. Multiple first injection channels penetrate the oxygen nozzle and are distributed around the first methane nozzle. The extension direction of the first injection channel is tangent to the outer periphery of the first methane nozzle. A second injection channel is connected between the methane injection chamber and the inner cavity of the second methane nozzle. A plurality of the second injection channels are distributed around the second methane nozzle, and the extension direction of the second injection channels is tangent to the outer periphery of the second methane nozzle.

[0005] According to the technical solutions provided in certain embodiments of this application, a first gas collecting chamber is further connected between the methane injection chamber and the nozzle structure. The first gas collecting chamber is arranged around the nozzle structure. The first end of the first gas collecting chamber is connected to the inner cavity of the first methane nozzle through the first injection channel, and the second end of the first gas collecting chamber is connected to the inner cavity of the second methane nozzle through the second injection channel.

[0006] According to the technical solutions provided in certain embodiments of this application, the combustion chamber includes an integrally connected mixing section, a cylindrical section, a conical section and a throat section, wherein the mixing section is respectively connected to the first methane nozzle, the oxygen-gas nozzle and the second methane nozzle; The igniter housing is provided with spark plugs, and a plurality of spark plugs are distributed around the nozzle structure, with the ignition end of the spark plugs extending into the mixing section; Methane enters the first methane nozzle and the second methane nozzle through the methane injection chamber, while oxygen enters the oxygen injection nozzle through the oxygen injection hole. The methane and oxygen in the nozzle structure enter the mixing section, mix, and are ignited by the spark plug. The high-temperature combustion gas formed is expanded through the throat section and then ejected.

[0007] According to the technical solutions provided in certain embodiments of this application, the methane injection chamber includes an integrally connected first flow section, a variable cross-section flow channel, and a second flow section. The first flow section is arranged around the conical section, the variable cross-section flow channel is arranged around the throat section, and the second flow section is arranged around the cylindrical section and the conical section.

[0008] According to the technical solutions provided in certain embodiments of this application, the two ends of the variable cross-section flow channel extend in the same direction.

[0009] According to the technical solutions provided in certain embodiments of this application, a plurality of cylindrical protrusions are uniformly distributed in the first flow section and the second flow section.

[0010] According to the technical solutions provided in certain embodiments of this application, the variable cross-section flow channel is provided with baffles, and a plurality of baffles are distributed at equal intervals around the throat.

[0011] According to the technical solutions provided in certain embodiments of this application, a second gas collection chamber is provided at the inlet of the first flow section, and the second gas collection chamber is used to make methane evenly distributed along the circumference of the first flow section at the inlet of the first flow section.

[0012] According to the technical solutions provided in certain embodiments of this application, a protective coating is also provided. The protective coating includes a bottom adhesion layer, an intermediate transition layer, and a surface stabilizing layer sequentially covering the inner wall of the combustion chamber. The bottom adhesion layer is made of a cobalt-based high-temperature alloy material, the intermediate transition layer is made of zirconium oxide material, and the surface stabilizing layer is made of 6%-8% yttrium oxide-stabilized zirconium oxide material. The total thickness of the protective coating is 0.6mm-1.2mm, and the porosity is 8%-12%.

[0013] Compared with the prior art, the beneficial effects of this application are as follows: This application provides a reusable gaseous-oxygen-methane torch igniter, including an igniter housing, a combustion chamber inside the igniter housing, and a methane injection chamber inside the shell wall of the igniter housing; one end of the igniter housing is provided with a nozzle structure, the nozzle structure including a first methane nozzle, a gaseous-oxygen nozzle and a second methane nozzle coaxially arranged from the inside to the outside, the first methane nozzle, the gaseous-oxygen nozzle and the second methane nozzle respectively communicate with the combustion chamber, the first methane nozzle and the second methane nozzle respectively communicate with the methane injection chamber, the gaseous-oxygen nozzle communicates with a gaseous-oxygen injection hole; a first injection channel communicates between the methane injection chamber and the inner cavity of the first methane nozzle, a plurality of first injection channels penetrate the gaseous-oxygen nozzle and are distributed around the first methane nozzle, the extension direction of the first injection channel is tangent to the outer periphery of the first methane nozzle; a second injection channel communicates between the methane injection chamber and the inner cavity of the second methane nozzle, a plurality of second injection channels are distributed around the second methane nozzle, the extension direction of the second injection channel is tangent to the outer periphery of the second methane nozzle; By setting up a first methane nozzle, an oxygen-gas nozzle, and a second methane nozzle distributed from the inside out, and making the extension direction of the two injection channels tangential to the outer periphery of the corresponding methane nozzles, a rotating jet can be formed during methane injection. The central direct-flow oxygen simultaneously undergoes strong shearing with the methane swirling flow on both its inner and outer sides, forming a double shear mixing interface. This significantly increases the contact area and mixing intensity between the oxygen-gas and methane. The two methane swirling flows, both inner and outer, and the central oxygen are fully mixed in the nozzle structure outlet area, shortening the distance required for methane and oxygen to achieve uniform mixing. This facilitates the rapid formation of a uniform combustible mixture at the head of the combustion chamber.

[0014] It should be understood that the descriptions of technical features, technical solutions, beneficial effects, or similar language in this application do not imply that all features and advantages can be achieved in any single embodiment. Rather, it is understood that the description of a feature or beneficial effect means that a specific technical feature, technical solution, or beneficial effect is included in at least one embodiment. Therefore, the descriptions of technical features, technical solutions, or beneficial effects in this specification do not necessarily refer to the same embodiment. Furthermore, the technical features, technical solutions, and beneficial effects described in this embodiment can be combined in any suitable manner. Those skilled in the art will understand that embodiments can be implemented without one or more specific technical features, technical solutions, or beneficial effects of a particular embodiment. In other embodiments, additional technical features and beneficial effects may be identified in specific embodiments that do not embody all embodiments. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 An axial cross-sectional view of a reusable gaseous oxygen-methane torch igniter provided in an embodiment of this application; Figure 2 An axial cross-sectional view of the nozzle structure of a reusable gaseous methane torch igniter provided in this application embodiment; Figure 3 A radial cross-sectional view of the nozzle structure of a reusable gaseous methane torch igniter provided in an embodiment of this application; Figure 4 A partial cross-sectional view of the main body of a reusable gaseous methane torch igniter provided for an embodiment of this application; Figure 5 This is a schematic diagram of the protective coating structure of a reusable gaseous methane torch igniter provided in an embodiment of this application.

[0017] The text labels in the image represent: 1. Igniter housing; 2. Nozzle structure; 3. Spark plug; 4. Methane inlet pipe; 11. Combustion chamber; 12. First gas collection chamber; 13. First flow section; 14. Variable cross-section flow channel; 15. Second flow section; 16. Second gas collection chamber; 21. First methane nozzle; 22. Oxygen-gas nozzle; 23. Second methane nozzle; 24. First injection channel; 25. Second injection channel; 26. Connecting structure; 101. Bottom adhesion layer; 102. Intermediate transition layer; 103. Surface stabilizing layer; 111. Mixing section; 112. Cylindrical section; 113. Conical section; 114. Throat section; 131. Cylindrical protrusion; 141. Baffle. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. The descriptions in this section are merely illustrative and explanatory, and should not be construed as limiting the scope of protection of this application. Specifically, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort should fall within the scope of protection of this invention.

[0019] It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or apparatus.

[0020] As mentioned in the background section, in order to solve the problems existing in the prior art, this embodiment provides a reusable gaseous oxygen-methane torch igniter, comprising: Igniter housing 1, igniter housing 1 has a combustion chamber 11 inside, and a methane injection chamber inside the shell wall of igniter housing 1; Nozzle structure 2 is located at one end of igniter housing 1. Nozzle structure 2 includes a first methane nozzle 21, an oxygen gas nozzle 22 and a second methane nozzle 23 arranged coaxially from the inside to the outside. The first methane nozzle 21, the oxygen gas nozzle 22 and the second methane nozzle 23 are respectively connected to the combustion chamber 11. The first methane nozzle 21 and the second methane nozzle 23 are respectively connected to the methane injection chamber. The oxygen gas nozzle 22 is connected to an oxygen gas injection hole. A first injection channel 24 is connected between the methane injection chamber and the inner cavity of the first methane nozzle 21. Multiple first injection channels 24 penetrate the oxygen nozzle 22 and are distributed around the first methane nozzle 21. The extension direction of the first injection channel 24 is tangent to the outer periphery of the first methane nozzle 21. A second injection channel 25 is connected between the methane injection chamber and the inner cavity of the second methane nozzle 23. Multiple second injection channels 25 are distributed around the second methane nozzle 23, and the extension direction of the second injection channels 25 is tangent to the outer periphery of the second methane nozzle 23.

[0021] like Figure 1-4 As shown, the torch igniter adopts a split structure, including a head body and a body body. Both the head body and the body body are made of nickel-based high-temperature alloy material and are connected by welding after being processed separately. The body body is the aforementioned igniter housing 1. The igniter housing 1 is approximately cylindrical in shape and has a combustion chamber 11 inside. A methane inlet pipe 4 is provided on the igniter housing 1, which connects to a methane injection chamber inside the shell wall of the igniter housing 1. The nozzle structure 2 is set on the head body. The head body has a cylindrical space coaxial with and connected to the combustion chamber 11. An oxygen injection hole is provided at the end of the cylindrical space away from the combustion chamber 11. A first methane nozzle 21 is provided in the cylindrical space. The first methane nozzle 21 is fixed to the inner wall of the cylindrical space by a connecting structure 26. The space between the inner wall of the cylindrical space and the outer wall of the first methane nozzle 21 is the inner cavity of the oxygen nozzle 22. An annular space is provided around the cylindrical space on the head body, which is the second methane nozzle 23. The inner cavity of the first methane nozzle 21 is connected to the methane injection chamber through the first injection channel 24. The first injection channel 24 passes through the inner cavity of the oxygen nozzle 22 via the connecting structure 26. The number of first injection channels 24 can be set to 2-3. In this embodiment, two first injection channels 24 are provided. The two first injection channels 24 are distributed around the first methane nozzle 21 and their extension directions are tangent to the outer periphery of the first methane nozzle 21. The inner cavity of the second methane nozzle 23 is connected to the methane injection chamber through the second injection channel 25. The number of second injection channels 25 can be set to 3-6. In this embodiment, five second injection channels 25 are provided. The five second injection channels 25 are distributed around the second methane nozzle 23 and their extension directions are tangent to the outer periphery of the second methane nozzle 23. In specific use, the number of first injection channels 24 and second injection channels 25 can be determined according to the flow ratio of methane in the first methane nozzle 21 and the second methane nozzle 23 and the flow resistance loss.

[0022] By setting up a first methane nozzle 21, an oxygen-gas nozzle 22, and a second methane nozzle 23 distributed from the inside out, and making the extension direction of the two injection channels tangential to the outer periphery of the corresponding methane nozzles, a rotating jet can be formed during methane injection. The central direct-flow oxygen simultaneously undergoes strong shearing with the methane swirling flow on both its inner and outer sides, forming a double shear mixing interface, thereby significantly increasing the contact area and mixing intensity between the oxygen-gas and methane. The inner and outer methane swirling flows and the central oxygen are fully mixed in the outlet area of ​​the nozzle structure 2, shortening the distance required for methane and oxygen to achieve uniform mixing, which is conducive to the rapid formation of a uniform combustible mixture at the head of the combustion chamber 11. The strong swirling design of the nozzle structure 2 can accelerate the mixing of methane and oxygen, increasing the uniformity of the formed combustible mixture to over 89% and shortening the ignition response time to within 0.25s.

[0023] In a preferred embodiment, a first gas collecting chamber 12 is also connected between the methane injection chamber and the nozzle structure 2. The first gas collecting chamber 12 is arranged around the nozzle structure 2. The first end of the first gas collecting chamber 12 is connected to the inner cavity of the first methane nozzle 21 through the first injection channel 24, and the second end of the first gas collecting chamber 12 is connected to the inner cavity of the second methane nozzle 23 through the second injection channel 25.

[0024] like Figure 2 and Figure 3 As shown, the first gas collecting chamber 12 is approximately a stepped annular space, including a first annular cavity and a second annular cavity distributed along the axial direction of the igniter housing 1 and connected to it. The second annular cavity has a longer radial length than the first annular cavity. The first annular cavity is connected to the inner cavity of the first methane nozzle 21 through the first injection channel 24, and the second annular cavity is connected to the inner cavity of the second methane nozzle 23 through the second injection channel 25. By setting the first gas collecting chamber 12, the pressure and flow rate of methane tend to be balanced in the circumferential direction of the first gas collecting chamber 12 after entering it, thereby providing a stable methane supply to the first methane nozzle 21 and the second methane nozzle 23. At the same time, in conjunction with the first injection channel 24 and the second injection channel 25, the methane flow rate in the first methane nozzle 21 accounts for 20%-40% of the total methane flow rate.

[0025] In a preferred embodiment, the combustion chamber 11 includes an integrally connected mixing section 111, a cylindrical section 112, a conical section 113, and a throat section 114. The mixing section 111 is connected to a first methane nozzle 21, an oxygen-gas nozzle 22, and a second methane nozzle 23, respectively. Spark plugs 3 are provided on the igniter housing 1. Multiple spark plugs 3 are distributed around the nozzle structure 2, and the ignition end of the spark plugs 3 extends into the mixing section 111. Methane enters the first methane nozzle 21 and the second methane nozzle 23 through the methane injection chamber, and oxygen enters the oxygen injection nozzle 22 through the oxygen injection hole. The methane and oxygen in the nozzle structure 2 enter the mixing section 111 and are mixed and then ignited by the spark plug 3. The high-temperature gas formed by combustion expands through the throat section 114 and is then ejected.

[0026] like Figure 1 As shown, in this embodiment, the number of spark plugs 3 is set to two, and the two spark plugs 3 are symmetrically distributed about the central axis of the igniter housing 1. The mixing section 111 is the mixing space for methane and oxygen. The ignition end of the spark plug 3 is set in the mixing section 111, which can achieve reliable ignition in the early stage of the mixing of methane and oxygen. After the high-temperature gas generated by combustion is fully developed in the columnar section 112, it is accelerated in the conical section 113, and finally expanded in the throat section 114 and ejected at high speed. By setting the oxygen nozzle 22 between the two methane nozzles, the methane and oxygen in the nozzle structure 2 enter the mixing section 111 and mix. The outer ring of the mixed gas has a higher methane content. During combustion, the outer ring is in a fuel-rich state, which can effectively protect the spark plug 3 and prevent erosion caused by local high mixing ratio.

[0027] In a preferred embodiment, the methane injection chamber includes an integrally connected first flow section 13, a variable cross-section flow channel 14, and a second flow section 15. The first flow section 13 is arranged around the conical section 113, the variable cross-section flow channel 14 is arranged around the throat section 114, and the second flow section 15 is arranged around the cylindrical section 112 and the conical section 113.

[0028] Furthermore, the two ends of the variable cross-section flow channel 14 extend in the same direction.

[0029] For details, please refer to Figure 1 and Figure 4 The methane inlet pipe 4 is connected at the junction of the cylindrical section 112 and the conical section 113. After the methane is injected into the methane inlet pipe 4, it first flows from the larger diameter end of the conical section 113 to the smaller diameter end within the first flow section 13. The variable cross-section flow channel 14 is approximately a U-shaped channel. After passing through the variable cross-section flow channel 14, the flow direction of the methane changes, and it flows from the smaller diameter end of the conical section 113 to the larger diameter end within the second flow section 15. Then, it passes through the cylindrical section 112 and enters the first gas collecting chamber 1. 2; The methane injection chamber is located inside the shell wall of the igniter housing 1, so that the methane can exchange heat with the high-temperature gas in the combustion chamber 11 when it is injected, thereby cooling the igniter housing 1 and increasing its own temperature, ensuring that the methane can be stably ignited after mixing with oxygen; The variable cross-section flow channel 14 is arranged around the throat section 114. Since the temperature of the throat section 114 in the combustion chamber 11 is the highest when the high-temperature gas is ejected, the methane forms a backflow when flowing through the variable cross-section flow channel 14, which can further enhance the heat exchange effect of methane at the throat section 114.

[0030] Furthermore, multiple cylindrical protrusions 131 are evenly distributed in the first flow section 13 and the second flow section 15; baffles 141 are provided in the variable cross-section flow channel 14, and multiple baffles 141 are evenly distributed around the throat section 114.

[0031] For details, please refer to Figure 4 The cylindrical protrusions 131 are evenly distributed within the first flow section 13 and the second flow section 15. The diameter of each cylindrical protrusion 131 is 2-5 mm, and the spacing between two adjacent cylindrical protrusions 131 is 2-5 times the diameter of the cylindrical protrusion 131. The baffle 141 is arranged radially along the variable cross-section flow channel 14, which can uniformly divide the variable cross-section flow channel 14. By setting the cylindrical protrusions 131, the methane is disturbed as it flows through the first flow section 13 and the second flow section 15, disrupting its flow boundary layer and exhibiting... The turbulence of methane is enhanced, thereby significantly improving the convective heat transfer intensity between methane and the igniter housing 1, thus achieving higher heat transfer efficiency within a limited space. Equally spaced baffles 141 are set in the variable cross-section flow channel 14 surrounding the throat 114, dividing the variable cross-section flow channel 14 into multiple independent sub-flow channels, forcing methane to be evenly distributed in all areas around the throat 114, avoiding the segregation phenomenon caused by flow inertia, and ensuring that the throat 114 can receive circumferential uniform cooling protection.

[0032] Optionally, additive manufacturing technology can be used to process the structure within the methane injection cavity, such as selective laser melting (SLM). This process can precisely control the complex shape and dimensional accuracy of irregular cross-sections, ensuring the manufacturing quality of the structure. First, based on the designed 3D model, alloy powder is layered onto a worktable. A high-energy laser beam is then scanned along a predetermined trajectory, causing the powder to melt and solidify layer by layer. During the manufacturing process, process parameters such as laser power, scanning speed, and powder particle size are strictly controlled to ensure the dimensional requirements of the formed structure are met.

[0033] In a preferred embodiment, a second gas collecting chamber 16 is provided at the inlet of the first flow section 13. The second gas collecting chamber 16 is used to make methane evenly distributed along the circumference of the first flow section 13 at the inlet of the first flow section 13.

[0034] like Figure 1 and Figure 4As shown, the igniter housing 1 has an annular protrusion at the junction of the cylindrical section 112 and the conical section 113. The methane inlet pipe 4 is connected to the annular protrusion. A second gas collection chamber 16 is provided inside the annular protrusion. The second gas collection chamber 16 is located at the inlet of the first flow section 13. After the methane is injected through the methane inlet pipe 4, it first enters the second gas collection chamber 16. The second gas collection chamber 16 serves as a diffusion and flow equalization space, which can decelerate, diffuse, and redistribute the incoming flow from the methane inlet pipe 4. This effectively avoids the problem of uneven methane distribution that may be caused by the direct connection of the methane inlet pipe 4, so that the methane can enter the first flow section 13 with a uniform flow rate and pressure, ensuring that the methane in the entire methane injection chamber can achieve stable and uniform heat exchange with the high-temperature gas in the combustion chamber 11.

[0035] In a preferred embodiment, a protective coating is further provided, comprising a bottom adhesion layer 101, an intermediate transition layer 102, and a surface stabilizing layer 103 sequentially covering the inner wall of the combustion chamber 11. The bottom adhesion layer 101 is made of a cobalt-based high-temperature alloy material, the intermediate transition layer 102 is made of zirconium oxide material, and the surface stabilizing layer 103 is made of 6%-8% yttrium oxide-stabilized zirconium oxide material. The total thickness of the protective coating is 0.6mm-1.2mm, and the porosity is 8%-12%.

[0036] like Figure 5 As shown, after the head and body are processed, a zirconia-based protective coating is sprayed onto the inner wall. The protective coating is applied using a plasma spraying process to ensure a bonding strength of ≥20MPa. The coating consists of a bottom adhesion layer 101, an intermediate transition layer 102, and a surface stabilizing layer 103, with a total thickness of 0.6-1.2mm and a porosity controlled at 8-12%. The surface stabilizing layer 103 is a 6-8% yttrium-stabilized zirconia material. The zirconia-based protective coating has extremely low thermal conductivity and excellent resistance to high-temperature combustion gas erosion. This is achieved through the first flow section 13 and the second flow section... The igniter housing 1 is equipped with a cylindrical protrusion 131 and a variable cross-section flow channel 14, which improves the heat exchange efficiency of the igniter housing 1 by 30-50% compared with the traditional jacket cooling structure. At the same time, with the heat insulation protection of the zirconia-based protective coating, the temperature of the inner wall of the combustion chamber is controlled below 700K at a combustion temperature of 1700-2500K, which is more than 150K lower than the uncoated solution. The combination of the two can effectively extend the repeated service life of the igniter, increasing the number of times the igniter can be reused to more than 30 times. After 30 cycles, the inner wall erosion is only 0.1mm.

[0037] Working principle: During operation, methane is introduced into the methane injection chamber through the methane inlet pipe 4. The methane first enters the second gas collection chamber 16, and then flows sequentially through the first flow section 13, the variable cross-section flow channel 14, and the second flow section 15, absorbing the residual heat from the combustion chamber 11 wall to complete preheating. The preheated methane is collected in the first gas collection chamber 12 and injected into the mixing section 111 of the combustion chamber 11 in a rotating jet form through the first injection channel 24 and the second injection channel 25 according to a preset ratio. At the same time, oxygen enters the oxygen injection nozzle 22 through the oxygen injection hole and is injected into the mixing section 111 in a direct flow form. The two rotating methane jets and Central direct current oxygen is tangentially mixed in mixing section 111 to form a uniform combustible mixture. At this time, spark plug 3 on igniter housing 1 releases a high-energy electric spark to ignite the combustible mixture. The high-temperature gas generated by combustion expands and accelerates in combustion chamber 11 and is ejected through throat section 114. During this period, the high-temperature gas is partially insulated by the protective coating, while the methane flowing through the methane injection chamber continuously cools the side wall of combustion chamber 11, keeping the side wall temperature within a safe operating range. After a single ignition, methane continues to flow through the methane injection chamber to cool combustion chamber 11, restoring its temperature to a state where it can be ignited again. By setting a first methane nozzle 21, an oxygen nozzle 22, and a second methane nozzle 23 distributed from the inside out, and making the extension direction of the two injection channels tangent to the outer periphery of the corresponding methane nozzles, the contact area and mixing intensity of oxygen and methane are increased, which is beneficial to the rapid formation of a uniform combustible mixture at the head of the combustion chamber 11. By setting columnar protrusions 131 in the first flow section 13 and the second flow section 15, and combining them with the variable cross-section flow channel 14, the heat exchange efficiency of the igniter housing 1 in this embodiment is increased by 30-50% compared with the traditional jacket cooling structure. At the same time, with the heat insulation protection of the zirconia-based protective coating, the temperature of the inner wall of the combustion chamber is controlled below 700K at a combustion temperature of 1700-2500K, which is more than 150K lower than the uncoated solution. By setting a composite cooling structure of DC dual centrifugal nozzles, variable cross-section flow channel 14 and columnar protrusions 131, and zirconia-based protective coating, the problems of insufficient reliability and short service life of traditional igniters at high temperatures are solved, and the triple goals of efficient mixing, enhanced cooling and anti-ablation protection are achieved.

[0038] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. The above descriptions are only preferred embodiments of this application. It should be noted that due to the limitations of written expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of this invention, and can also combine the above technical features in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the inventive concept and technical solution to other situations without modification, should all be considered within the scope of protection of this application.

Claims

1. A reusable gaseous oxygen-methane torch igniter, characterized in that, include: Igniter housing (1), wherein the igniter housing (1) has a combustion chamber (11) and the shell wall of the igniter housing (1) has a methane injection chamber; Nozzle structure (2), the nozzle structure (2) is located at one end of the igniter housing (1), the nozzle structure (2) includes a first methane nozzle (21), an oxygen nozzle (22) and a second methane nozzle (23) arranged coaxially from the inside to the outside, the first methane nozzle (21), the oxygen nozzle (22) and the second methane nozzle (23) are respectively connected to the combustion chamber (11), the first methane nozzle (21) and the second methane nozzle (23) are respectively connected to the methane injection chamber, and the oxygen nozzle (22) is connected to an oxygen injection hole; A first injection channel (24) is connected between the methane injection chamber and the inner cavity of the first methane nozzle (21). Multiple first injection channels (24) penetrate the oxygen nozzle (22) and are distributed around the first methane nozzle (21). The extension direction of the first injection channel (24) is tangent to the outer periphery of the first methane nozzle (21). A second injection channel (25) is connected between the methane injection chamber and the inner cavity of the second methane nozzle (23). A plurality of second injection channels (25) are distributed around the second methane nozzle (23), and the extension direction of the second injection channel (25) is tangent to the outer periphery of the second methane nozzle (23).

2. The reusable gaseous oxygen-methane torch igniter according to claim 1, characterized in that, A first gas collecting chamber (12) is also connected between the methane injection chamber and the nozzle structure (2). The first gas collecting chamber (12) is arranged around the nozzle structure (2). The first end of the first gas collecting chamber (12) is connected to the inner cavity of the first methane nozzle (21) through the first injection channel (24). The second end of the first gas collecting chamber (12) is connected to the inner cavity of the second methane nozzle (23) through the second injection channel (25).

3. The reusable gaseous oxygen-methane torch igniter according to claim 1, characterized in that, The combustion chamber (11) includes an integrally connected mixing section (111), a cylindrical section (112), a conical section (113), and a throat section (114). The mixing section (111) is connected to the first methane nozzle (21), the oxygen nozzle (22), and the second methane nozzle (23), respectively. Spark plugs (3) are provided on the igniter housing (1), and a plurality of spark plugs (3) are distributed around the nozzle structure (2), with the ignition end of the spark plugs (3) extending into the mixing section (111). Methane enters the first methane nozzle (21) and the second methane nozzle (23) through the methane injection chamber, and oxygen enters the oxygen nozzle (22) through the oxygen injection hole. The methane and oxygen in the nozzle structure (2) enter the mixing section (111) and are mixed and then ignited by the spark plug (3). The high-temperature gas formed by combustion expands through the throat section (114) and is then ejected.

4. A reusable gaseous oxygen-methane torch igniter according to claim 3, characterized in that, The methane injection chamber includes an integrally connected first flow section (13), a variable cross-section flow channel (14), and a second flow section (15). The first flow section (13) is arranged around the conical section (113), the variable cross-section flow channel (14) is arranged around the throat section (114), and the second flow section (15) is arranged around the cylindrical section (112) and the conical section (113).

5. A reusable gaseous oxygen-methane torch igniter according to claim 4, characterized in that, The two ends of the variable cross-section flow channel (14) extend in the same direction.

6. A reusable gaseous oxygen-methane torch igniter according to claim 4, characterized in that, Multiple cylindrical protrusions (131) are evenly distributed in the first flow section (13) and the second flow section (15).

7. A reusable gaseous oxygen-methane torch igniter according to claim 4, characterized in that, The variable cross-section flow channel (14) is provided with baffles (141), and multiple baffles (141) are distributed at equal intervals around the throat section (114).

8. A reusable gaseous oxygen-methane torch igniter according to claim 4, characterized in that, A second gas collecting chamber (16) is provided at the inlet of the first flow section (13). The second gas collecting chamber (16) is used to make methane evenly distributed along the circumference of the first flow section (13) at the inlet of the first flow section (13).

9. A reusable gaseous oxygen-methane torch igniter according to claim 1, characterized in that, A protective coating is also provided, which includes a bottom adhesion layer (101), an intermediate transition layer (102), and a surface stabilizing layer (103) sequentially covering the inner wall of the combustion chamber (11). The bottom adhesion layer (101) is made of cobalt-based high-temperature alloy material, the intermediate transition layer (102) is made of zirconium oxide material, and the surface stabilizing layer (103) is made of 6%-8% yttrium oxide-stabilized zirconium oxide material. The total thickness of the protective coating is 0.6mm-1.2mm, and the porosity is 8%-12%.

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