Mutual impact air hydrogen torch igniter

Abstract

This invention belongs to the field of combustion and ignition technology, and discloses a mutual-impact air-hydrogen flare igniter. The combustion chamber of the mutual-impact air-hydrogen flare igniter is a cylindrical body; the front end of the combustion chamber is fixed to an injector via a flange, and a hydrogen nozzle is installed on the injector; the middle section has symmetrically arranged spark plug mounting seats, into which spark plugs are inserted, and the spark plugs are connected to an ignition cabinet; the rear section is connected to a pressure testing connector; the rear end is inserted with a flame transfer rod; a through-flow airflow channel is arranged on the horizontal central axis of the hydrogen nozzle, injector, combustion chamber, and flame transfer rod. The mutual-impact air-hydrogen flare igniter enhances the mixing of air and hydrogen, controls the gas temperature by adjusting the hydrogen-to-air equivalence ratio, and achieves reliable ignition; it adopts an air-hydrogen combustion organization mode to achieve long-term operation; it extends the working time through film cooling of the annular gap; and the flame transfer rod is made of a high-temperature alloy, enabling the flare igniter to operate for extended periods and repeatedly.

Description

Technical Field

[0001] This invention belongs to the field of combustion and ignition technology, specifically relating to a mutual-impact air-hydrogen torch igniter. Background Technology

[0002] Reliable ignition is a crucial consideration for combustion equipment such as liquid rocket engines and air heaters. Common ignition methods include gunpowder ignition, electric spark ignition, and torch ignition. Gunpowder ignition is simple in structure and reliable in operation, but it is for single use only, making it unsuitable for ground-based combustion heating equipment that requires repeated use and long-term operation. Electric spark ignition is also a convenient method, but its ignition energy is relatively low, making it difficult to guarantee reliability for high-flow-rate combustion equipment. Torch ignition systems, on the other hand, offer numerous advantages such as high ignition reliability, reusability, and ease of use, and are therefore widely used in liquid rocket engines and combustion air heaters. Torch ignition systems typically use either gaseous or liquid fuels; gaseous fuels are generally hydrogen or methane, while liquid fuels are mostly alcohol or kerosene.

[0003] To improve the ignition reliability and energy of the flare igniter, oxygen can be chosen as the oxidizer. Oxygen-hydrogen flare igniters typically employ a coaxial shear-type injection structure, which is simple in design and highly reliable. While choosing oxygen as the oxidizer eliminates the need for complex injector configurations to meet reliable ignition requirements, the flame temperature of oxygen-hydrogen flares exceeds 3000K. The flare igniter can only operate for a few hundred milliseconds, a duration insufficient to guarantee successful ignition of the combustion device. Furthermore, the installation space for the flare igniter within the combustion device is usually limited, making it difficult to add cooling structures. Additionally, oxygen is a highly dangerous combustion-supporting gas, significantly increasing the risk to the supply system.

[0004] If air is used as the oxidizer, the gas temperature produced by the flare igniter can be controlled below 2000K, and the flare igniter's operating time can be extended to 5 seconds without cooling measures, which is sufficient to ensure reliable ignition of the combustion device. However, coaxial shear nozzles cannot guarantee sufficient mixing of gaseous fuel and air, and ignition stability cannot be guaranteed. Taking air and hydrogen combinations as an example, the required ignition temperature for proper mixing of hydrogen and still air is 530°C to 590°C. Many air-hydrogen flare igniters using coaxial shear injection or wall injection have difficulty igniting and poor operational stability.

[0005] Flare igniters using gas-liquid combustion typically employ a coaxial centrifugal injection structure. While liquid fuel combustion can be achieved through proper nozzle design, the complex processes of atomization, evaporation, and mixing involved in liquid fuel combustion result in poor ignition reliability and combustion stability. Liquid fuel combustion is prone to oscillating combustion, posing a significant threat to equipment safety—a global problem that remains unsolved.

[0006] In summary, while oxygen-based flare igniters offer reliable ignition and high ignition energy, they suffer from short operating times and high risks. Furthermore, the reliability of ignition and the stability of combustion of liquid fuels remain unresolved. Therefore, there is an urgent need to develop a reliably ignited and stably operating mutual-impact air-hydrogen flare igniter. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a mutual-impact air-hydrogen torch igniter that can work stably for a long time, which effectively solves the problem of mixed combustion of gaseous fuel and air and can work stably for a long time.

[0008] The mutual-impact air-hydrogen torch igniter of the present invention is characterized in that the combustion chamber of the mutual-impact air-hydrogen torch igniter is a cylindrical body; a flange I is provided at the front end of the combustion chamber, through which an injector is fixed, and a hydrogen nozzle is connected to the injector, with a hydrogen inlet provided on the hydrogen nozzle; a symmetrically arranged spark plug mounting seats are provided in the middle section of the combustion chamber, with spark plugs inserted into the spark plug mounting seats respectively, and an ignition cabinet connected to the spark plugs; a pressure measuring connector is connected to the rear section of the combustion chamber; a flange II is provided at the rear end of the combustion chamber, and a flame transmission rod is also inserted at the rear end of the combustion chamber; the hydrogen nozzle, hydrogen inlet, injector, combustion chamber, and flame transmission rod are on the same horizontal central axis, and a through airflow channel is provided on the horizontal central axis, with the airflow channels in the middle and rear sections of the combustion chamber forming the combustion chamber; the distance between the vertical central axis of the spark plug mounting seat and the rear end face of the injector is 1.0 to 1.2 times the inner diameter of the combustion chamber;

[0009] The injector is a stepped cylinder, consisting of flange III, cylindrical section I, cylindrical section II, and cylindrical section III from front to back. Flange III of the injector has the same outer diameter and matching end faces as flange I of the combustion chamber. Cylindrical section I has a transition fit with the inner cavity of the combustion chamber. The diameter of cylindrical section II is smaller than the diameter of the airflow passage in the combustion chamber, and the cavity between cylindrical section II and the inner wall of the combustion chamber is an air cavity connected to the air inlet. The diameter of cylindrical section III is also smaller than the diameter of the airflow passage in the combustion chamber, and an circumferential gap is designed between cylindrical section III and the combustion chamber. The air film cooling annular gap is formed and connects to the air cavity. High-pressure air entering the air cavity from the air inlet enters the combustion cavity through the air film cooling annular gap, forming an air film on the inner wall of the combustion cavity. The airflow channel on the horizontal central axis of the rear section of the injector is a contraction and expansion channel. The contraction and expansion channel consists of a contraction section, a straight section and an expansion section from front to back. The expansion angle of the expansion section is 20°~30°. The expansion section is provided with air injection holes that are uniformly distributed circumferentially and communicate with the air cavity. The angle between the air injection holes and the horizontal central axis is 30°~60°.

[0010] High-pressure air enters the air chamber through the air inlet and then enters the expansion section through the air injection hole. High-pressure hydrogen enters through the hydrogen inlet and then enters the expansion section through the airflow channel. The high-pressure air and high-pressure hydrogen have relative radial velocities and collide with each other in the expansion section to achieve mixing and form a combustible mixture. The spark plug ignites the combustible mixture to form a high-temperature gas. The injection pressure drop of the high-pressure air through the gas film cooling annular gap and the air injection hole ranges from 0.1 MPa to 1 MPa.

[0011] The airflow channel of the fire rod is a contraction channel, which consists of a contraction section and a straight section from front to back; high-temperature gas is ejected through the contraction channel;

[0012] The equivalence ratio of high-pressure air to high-pressure hydrogen in the aforementioned mutual-impact air-hydrogen torch igniter is 0.8 to 2.0, and the flame temperature range is 2000K to 2400K. The flame rod of the mutual-impact air-hydrogen torch igniter is inserted into the combustion device to be ignited and is fixedly connected to the combustion device to be ignited by bolts fixed to the flange III at the end of the combustion chamber.

[0013] Furthermore, the ignition cabinet converts 220V AC power into 10kV high-voltage power and outputs it to the spark plug.

[0014] Furthermore, a sealing ring is provided on the contact end face of the flange III of the injector and the flange I of the combustion chamber.

[0015] Furthermore, the combustion chamber is made of stainless steel.

[0016] Furthermore, the pressure range of the high-pressure air is 7MPa~15MPa, and the flow rate range is 90~200g / s; the pressure range of the high-pressure hydrogen is 9MPa~15MPa, and the flow rate range is 2~10g / s.

[0017] Furthermore, the material of the fire-transmitting rod is a high-temperature alloy, specifically GH3128 or GH3230.

[0018] Furthermore, the fire-transmitting rod is fixed by welding.

[0019] The injector of the mutual-impact air-hydrogen torch igniter of this invention employs a contraction-expansion channel. The advantages of this channel are twofold: firstly, it increases the injection velocity of high-pressure hydrogen, enhancing the shearing effect between high-pressure hydrogen and high-pressure air; secondly, it gives the high-pressure hydrogen a radial velocity, improving the mixing efficiency between them. The number and inner diameter of the evenly distributed air injection holes in the expansion section are determined based on the air flow rate, ensuring that the injection pressure drop of high-pressure air is between 0.1 MPa and 1 MPa. The angle between the injection direction of high-pressure air and high-pressure hydrogen is between 30° and 60°, giving the high-pressure hydrogen and high-pressure air relative radial velocities, causing them to collide and greatly enhancing the mixing effect. The mutual-impact coaxial shear nozzle formed by the contraction-expansion channel ensures thorough mixing of high-pressure hydrogen and high-pressure air, forming a combustible mixture in the combustion chamber and reducing the required ignition energy.

[0020] The mutual-impact air-hydrogen torch igniter of the present invention features a gas film cooling annular gap between the injector and the combustion chamber. This gas film cooling annular gap prevents the combustion chamber from being eroded by high-temperature combustion gases. The width of the gas film cooling annular gap is determined based on the high-pressure air flow rate, ensuring that the injection pressure drop of the high-pressure air is within the range of 0.1 MPa to 1 MPa. A portion of the air enters the combustion chamber through the gas film cooling annular gap, forming an air film on the inner wall of the combustion chamber. This effectively reduces the heat transfer between the high-temperature combustion gases and the inner wall of the combustion chamber, allowing the combustion chamber to operate for a longer period of time without being eroded using ordinary stainless steel.

[0021] The mutual-impact air-hydrogen torch igniter of this invention has two symmetrically arranged high-energy spark plugs in the middle section of the combustion chamber. The distance between the horizontal central axis of the spark plug and the rear end face of the injector is 1.0 to 1.2 times the inner diameter of the combustion chamber. The spark plug and the spark plug mounting base are movably connected, making disassembly and assembly convenient. The spark plug is connected to the ignition cabinet, which converts 220V AC power into 10kV high-voltage power and outputs it to the spark plug, which ignites the combustible mixture.

[0022] The ignition rod of the mutual-impact air-hydrogen torch igniter of the present invention is inserted into the combustion device to be ignited, and is fixedly connected to the combustion device to be ignited by bolts fixed on the flange III at the end of the combustion chamber, making installation convenient.

[0023] The mutual-impact air-hydrogen flare igniter of this invention features a flame transfer rod welded to the end of the combustion chamber to ensure no leakage. The flame transfer rod is made of high-temperature alloy GH3128 (or GH3230), and maintains good structural strength without requiring additional cooling structures when the flare igniter's operating time is no more than 5 seconds. The airflow channel of the flame transfer rod is a contraction channel, consisting of a contraction section and a straight section from front to back. The contraction section increases the chamber pressure of the flare igniter's combustion chamber, ensuring complete combustion of high-pressure hydrogen and improving the flare igniter's combustion efficiency and the uniformity of the gas outlet temperature.

[0024] The mutual-impact air-hydrogen torch igniter of this invention can precisely control the flow rate of high-pressure hydrogen and high-pressure air through several air injection holes. Due to the excellent mixing effect of the mutual-impact coaxial shear nozzle, the torch igniter can ignite normally and operate stably within a wide range of equivalence ratios of high-pressure air and high-pressure hydrogen (0.8~2.0). At the same time, the flame temperature generated by the torch igniter is controlled at 2000K~2400K, which not only provides sufficient ignition energy to ensure that the combustion device is ignited, but also avoids excessively high flame temperature. Therefore, it can achieve long-term operation without considering a complex cooling structure.

[0025] The mutual-impact air-hydrogen torch igniter of the present invention has the following characteristics:

[0026] 1. It uses air and hydrogen ignition, which reduces the safety risks of the supply pipeline and can achieve long-term operation of about 5 seconds;

[0027] 2. The use of a mutual impact coaxial shear nozzle enhances the mixing effect of hydrogen and air, improving ignition reliability;

[0028] 3. The combustion chamber is designed with a film cooling annular gap to form a cooling film on the inner wall of the combustion chamber, thus preventing ablation;

[0029] 4. It can reliably ignite high-pressure air and high-pressure hydrogen in an equivalence ratio of 0.8 to 2.0, with a wide operating range; the flame temperature is controlled within a suitable temperature range of 2000K to 2400K.

[0030] 5. The torch igniter is made of high-temperature alloy material to ensure that the torch igniter can work for a longer period of time;

[0031] 6. Simple structure, both injector and spark plug are replaceable; the flare igniter and the device to be burned are connected by bolts to flange III, making disassembly and assembly convenient;

[0032] 7. The spark plug of the ignition torch is a common civilian product, which is versatile, simple and reliable.

[0033] In summary, the mutual-impact air-hydrogen flare igniter of this invention employs a mutual-impact coaxial shear nozzle, enhancing the mixing of air and hydrogen for reliable ignition; it controls the gas temperature by controlling the equivalence ratio of high-pressure air and high-pressure hydrogen; it adopts an air-hydrogen combustion organization mode, reducing the safety risks of the supply system and enabling the flare igniter to operate for extended periods; it features a gas film cooling annular slit, forming a cooling gas film on the inner wall of the combustion chamber, preventing the combustion chamber from being eroded by high-temperature gas and extending the flare igniter's operating time; and the flame transfer rod in contact with the high-temperature gas is made of a high-temperature alloy, enabling the flare igniter to operate for extended periods and repeatedly. Attached Figure Description

[0034] Figure 1 This is a cross-sectional view of the mutual-impact air-hydrogen torch igniter of the present invention.

[0035] Figure 2 This is a perspective view of the mutual-impact air-hydrogen torch igniter of the present invention.

[0036] Figure 3 This is a schematic diagram of the mutual-impact coaxial shear injection structure in the mutual-impact air-hydrogen torch igniter of the present invention.

[0037] In the diagram, 1. Hydrogen inlet; 2. Injector; 3. Combustion chamber; 4. Spark plug mount; 5. Spark plug; 6. Ignition rod; 7. Air inlet; 8. Pressure test connector; 9. Air injection port. Implementation

[0038] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0039] Example 1

[0040] like Figure 1 , Figure 2 As shown, in this embodiment, the combustion chamber 3 of the mutual-impact air-hydrogen torch igniter is a cylindrical body; a flange I is provided at the front end of the combustion chamber 3, through which the injector 2 is fixed, and a hydrogen nozzle is connected to the injector 2, with a hydrogen inlet 1 provided on the hydrogen nozzle; a symmetrical spark plug mounting seat 4 is provided in the middle section of the combustion chamber 3, and spark plugs 5 are inserted into the spark plug mounting seat 4 respectively, with an ignition cabinet connected to the spark plugs 5; a pressure measuring connector 8 is connected to the rear section of the combustion chamber 3; a flange II is provided at the rear end of the combustion chamber 3, and a flame transmission rod 6 is also inserted at the rear end of the combustion chamber 3; the hydrogen nozzle, hydrogen inlet 1, injector 2, combustion chamber 3 and flame transmission rod 6 are on the same horizontal central axis, and a front-to-back airflow channel is provided on the horizontal central axis, with the airflow channels in the middle and rear sections of the combustion chamber 3 forming the combustion chamber; the distance between the vertical central axis of the spark plug mounting seat 4 and the rear end face of the injector 2 is 1.0 to 1.2 times the inner diameter of the combustion chamber;

[0041] The injector 2 is a stepped cylinder, consisting of flange III, cylindrical section I, cylindrical section II, and cylindrical section III from front to back. Flange III of injector 2 has the same outer diameter and matching end faces as flange I of combustion chamber 3. Cylindrical section I has a transition fit with the inner cavity of combustion chamber 3. The diameter of cylindrical section II is smaller than the diameter of the airflow channel of combustion chamber 3. The cavity between cylindrical section II and the inner wall of combustion chamber 3 is an air cavity, which connects to air inlet 7. Figure 3 As shown, the diameter of cylindrical section III is smaller than the diameter of the airflow passage of combustion chamber 3. An annular gap is designed between cylindrical section III and combustion chamber 3. The annular gap between cylindrical section III and combustion chamber 3 constitutes a film cooling annular gap. The film cooling annular gap connects to the air cavity. High-pressure air entering the air cavity from air inlet 7 enters the combustion cavity through the film cooling annular gap and forms an air film on the inner wall of the combustion cavity. The airflow passage on the horizontal central axis of the rear section of injector 2 is a contraction and expansion passage. The contraction and expansion passage consists of a contraction section, a straight section and an expansion section from front to back. The expansion angle of the expansion section is 20°~30°. Air injection holes 9 are uniformly distributed circumferentially and connected to the air cavity on the expansion section. The angle between the air injection holes 9 and the horizontal central axis is 30°~60°.

[0042] High-pressure air enters the air chamber through air inlet 7 and enters the expansion section through air injection hole 9. High-pressure hydrogen enters through hydrogen inlet 1 and enters the expansion section through the airflow channel. The high-pressure air and high-pressure hydrogen have relative radial velocities and collide with each other in the expansion section to achieve mixing and form a combustible mixture. Spark plug 5 ignites the combustible mixture to form a high-temperature gas. The injection pressure drop of high-pressure air through the gas film cooling annular gap and air injection hole 9 ranges from 0.1 MPa to 1 MPa.

[0043] The airflow channel of the flame rod 6 is a contraction channel, which consists of a contraction section and a straight section from front to back; high-temperature gas is ejected through the contraction channel;

[0044] The equivalence ratio of high-pressure air to high-pressure hydrogen in the aforementioned mutual-impact air-hydrogen torch igniter is 0.8 to 2.0, and the flame temperature range is 2000K to 2400K. The flame rod 6 of the mutual-impact air-hydrogen torch igniter is inserted into the combustion device to be ignited and is fixedly connected to the combustion device to be ignited by bolts fixed to the flange III at the end of the combustion chamber 3.

[0045] Furthermore, the ignition cabinet converts 220V AC power into 10kV high-voltage power and outputs it to the spark plug 5.

[0046] Furthermore, a sealing ring is provided on the contact end face of the flange III of the injector 2 and the flange I of the combustion chamber 3.

[0047] Furthermore, the combustion chamber 3 is made of stainless steel.

[0048] Furthermore, the pressure range of the high-pressure air is 7MPa~15MPa, and the flow rate range is 90~200g / s; the pressure range of the high-pressure hydrogen is 9MPa~15MPa, and the flow rate range is 2~10g / s.

[0049] Furthermore, the material of the fire rod 6 is a high-temperature alloy, with grades GH3128 or GH3230.

[0050] Furthermore, the fire-transmitting rod 6 is fixed by welding.

[0051] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments, and can be applied to various fields suitable for the present invention. Those skilled in the art will readily implement other improvements and modifications without departing from the principles of the present invention. The present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A mutual-impact air-hydrogen torch igniter, characterized in that, The combustion chamber (3) of the aforementioned mutual-impact air-hydrogen torch igniter is a cylindrical body; a flange I is provided at the front end of the combustion chamber (3), through which an injector (2) is fixed, and a hydrogen nozzle is connected to the injector (2), with a hydrogen inlet (1) provided on the hydrogen nozzle; a symmetrical spark plug mounting seat (4) is provided in the middle section of the combustion chamber (3), and spark plugs (5) are inserted into the spark plug mounting seat (4) respectively, with the spark plugs (5) connected to the ignition cabinet; a pressure measuring connector (8) is connected to the rear section of the combustion chamber (3). Flange II is provided at the rear end of the combustion chamber (3), and a ignition rod (6) is inserted into the rear end of the combustion chamber (3); the hydrogen nozzle, hydrogen inlet (1), injector (2), combustion chamber (3) and ignition rod (6) are on the same horizontal central axis, and a front-to-back airflow channel is provided on the horizontal central axis. The airflow channels in the middle and rear sections of the combustion chamber (3) are the combustion chamber; the distance between the vertical central axis of the spark plug mounting seat (4) and the rear end face of the injector (2) is 1.0 to 1.2 times the inner diameter of the combustion chamber; The injector (2) is a stepped cylinder, consisting of flange III, cylindrical section I, cylindrical section II, and cylindrical section III from front to back. The outer diameter of flange III of the injector (2) is the same as that of flange I of the combustion chamber (3), and their end faces match. Cylindrical section I is fitted with the inner cavity of the combustion chamber (3). The diameter of cylindrical section II is smaller than the diameter of the airflow channel of the combustion chamber (3). The cavity between cylindrical section II and the inner wall of the combustion chamber (3) is an air cavity, which is connected to the air inlet (7). The diameter of cylindrical section III is smaller than the diameter of the airflow channel of the combustion chamber (3). An annular gap is designed between cylindrical section III and the combustion chamber (3). 3) The annular gap between them forms a film cooling annular gap, which connects to the air cavity. High-pressure air entering the air cavity from the air inlet (7) enters the combustion cavity through the film cooling annular gap and forms an air film on the inner wall of the combustion cavity. The airflow channel on the horizontal central axis of the injector (2) is a contraction and expansion channel. The contraction and expansion channel consists of a contraction section, a straight section and an expansion section from front to back. The expansion angle of the expansion section is 20°~30°. The expansion section is provided with air injection holes (9) that are uniformly distributed along the circumference and connected to the air cavity. The angle between the air injection holes (9) and the horizontal central axis is 30°~60°. High-pressure air enters the air chamber through the air inlet (7) and enters the expansion section through the air injection hole (9). High-pressure hydrogen enters through the hydrogen inlet (1) and enters the expansion section through the airflow channel. High-pressure air and high-pressure hydrogen have relative radial velocities and collide with each other in the expansion section to achieve mixing and form a combustible mixture. The spark plug (5) ignites the combustible mixture to form a high-temperature gas. The injection pressure drop of high-pressure air through the gas film cooling ring and the air injection hole (9) ranges from 0.1 MPa to 1 MPa. The airflow channel of the fire rod (6) is a contraction channel, which consists of a contraction section and a straight section from front to back; high-temperature gas is ejected through the contraction channel; The equivalence ratio of high-pressure air to high-pressure hydrogen in the aforementioned mutual-impact air-hydrogen torch igniter is 0.8~2.0, and the flame temperature range is 2000K~2400K; the flame rod (6) of the mutual-impact air-hydrogen torch igniter is inserted into the combustion device to be ignited and is fixedly connected to the combustion device to be ignited by bolts fixed on the flange III at the end of the combustion chamber (3).

2. The mutual-impact air-hydrogen torch igniter according to claim 1, characterized in that, The ignition cabinet converts 220V AC power into 10kV high voltage power and outputs it to the spark plug (5).

3. The mutual-impact air-hydrogen torch igniter according to claim 1, characterized in that, A sealing ring is provided on the contact end face of the flange III of the injector (2) and the flange I of the combustion chamber (3).

4. The mutual-impact air-hydrogen torch igniter according to claim 1, characterized in that, The combustion chamber (3) is made of stainless steel.

5. The mutual-impact air-hydrogen torch igniter according to claim 1, characterized in that, The pressure range of the high-pressure air is 7MPa~15MPa, and the flow rate range is 90~200g / s; the pressure range of the high-pressure hydrogen is 9MPa~15MPa, and the flow rate range is 2~10g / s.

6. The mutual-impact air-hydrogen torch igniter according to claim 1, characterized in that, The fire rod (6) is made of a high-temperature alloy, with the grade being either GH3128 or GH3230.

7. The mutual-impact air-hydrogen torch igniter according to claim 1, characterized in that, The fire rod (6) is fixed by welding.

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