A hydrogen fuel injector applied to high temperature gas inflow conditions

Abstract

The application belongs to the field of hypersonic combustion wind tunnel, and discloses a hydrogen fuel injector applied to high-temperature gas inflow conditions. The hydrogen fuel injector is located between a high-temperature oxygen-rich air supply cavity and a heater combustion chamber, is a concentric outer ring and inner disc structure, the outer ring is a gas collecting ring, and the inner disc is a nozzle disc; the outer ring of the gas collecting ring is welded with a high-pressure hydrogen supply pipeline of an external high-pressure hydrogen source, and the inner ring of the gas collecting ring is welded with a connecting pipe; the nozzle disc is welded by front and rear cover plates which are parallel and have the same outer diameter; the rear cover plate is provided with a hydrogen gas flow channel corresponding to the connecting pipe, and the left and right side surfaces are both provided with a circular boss; a plurality of nozzles penetrating through the nozzle disc are installed on the nozzle disc, the nozzles are close to the outlet position, and hydrogen injection holes are uniformly distributed and opened. The hydrogen fuel injector does not need to be separately configured with an igniter, can realize full mixing and self-ignition of hydrogen and high-temperature oxygen-rich air, and then generates high-temperature combustion gas, which is used for carrying out hypersonic wind tunnel test.

Description

Technical Field

[0001] This invention belongs to the field of hypersonic combustion wind tunnels, specifically relating to a hydrogen fuel injector used under high-temperature gas flow conditions. Background Technology

[0002] With the development and deepening of research on air-breathing hypersonic technology, hypersonic high-temperature wind tunnels have received increasing attention in recent years. Air heaters, as the main equipment of hypersonic high-temperature wind tunnels, can be classified into four types according to their heating methods: electric arc heating, regenerative heating, combustion heating, and shock tube heating. Among these, electric arc heaters and regenerative heaters have very high construction and operating costs; shock tube heaters can be used to simulate hypersonic flows for testing, but the duration of a single test is very short. Considering factors such as operating costs and test time, combustion heating is currently the most common method for air heaters.

[0003] For high Mach number aircraft, the total temperature of the incoming flow can reach over 2500K. To conduct such hypersonic propulsion experiments, corresponding high-enthalpy ground test equipment is required. Although the oxygen-enriched combustion heating mode of "hydrogen fuel + oxygen + air" can generate a high-temperature airflow of over 2500K, the use of hydrogen fuel will result in the formation of a large amount of water (H2O) in the high-temperature gas. This high-temperature airflow with high water content will inevitably affect the accuracy of the test results.

[0004] To reduce water contamination from combustion heating and improve the accuracy of experimental data, a combined heating mode of "primary electric heating + secondary combustion heating" is typically used. This combined heating mode uses an electric heater and a combustion heater in series. The electric heater first heats the room-temperature oxygen-enriched air to create high-temperature oxygen-enriched air at 800K-1000K.

[0005] The heated, high-temperature oxygen-enriched air flows into the combustion heater through a high-temperature pipeline and serves as a combustion aid. At the same time, hydrogen fuel is injected into the combustion heater using an injector. The hydrogen fuel spontaneously combusts and releases heat in the high-temperature oxygen-enriched air environment, ultimately generating a high-temperature, high-pressure test gas with relatively low water content and minimal water pollution.

[0006] The combined heating mode of "primary electric heating + secondary combustion heating" enables the self-ignition of hydrogen in the secondary combustion heater, eliminating the need for a separate ignition device and simplifying the heater's structure. However, because the hydrogen injector operates under the high-temperature gas flow conditions generated by the primary heater, with ambient temperatures typically exceeding 1000K, conventional coaxial injectors cannot operate in this high-temperature environment and are highly susceptible to ablation. Therefore, there is an urgent need to develop a hydrogen fuel injector suitable for high-temperature gas flow conditions. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a hydrogen fuel injector applicable to high-temperature gas flow conditions.

[0008] The present invention relates to a hydrogen fuel injector for use under high-temperature gas flow conditions, characterized in that the hydrogen fuel injector is located between the oxygen-enriched air supply chamber and the heater combustion chamber, and the hydrogen fuel injector has a concentric outer ring and inner disk structure, wherein the outer ring is a gas collecting ring and the inner disk is a nozzle disk.

[0009] The outer ring of the gas collecting ring is welded with several high-pressure hydrogen supply pipes evenly distributed along the circumference of the outer ring, and the high-pressure hydrogen supply pipes are connected to a high-pressure hydrogen source; the inner ring of the gas collecting ring is welded with several connecting pipes evenly distributed along the circumference of the inner ring.

[0010] The nozzle disc is assembled and welded together from a front cover plate and a rear cover plate with the same outer diameter arranged side by side, and several nozzles that penetrate the front cover plate and the rear cover plate.

[0011] The left side surface of the front cover plate faces the outlet flange of the oxygen-enriched air supply chamber. The left side surface of the front cover plate has a circular boss, which is used to fit into a matching circular groove of the same diameter on the outlet flange of the oxygen-enriched air supply chamber, thereby ensuring the strength and sealing of the connection position. The right side surface of the front cover plate faces the left side surface of the rear cover plate. The right side surface of the front cover plate has a circular groove, which is used to fit into a matching circular boss of the same diameter on the left side surface of the rear cover plate, thereby ensuring the strength and sealing of the connection position.

[0012] The rear cover plate is equipped with a vent pipe corresponding to the connecting pipe; the vent pipe opening on the surface of the rear cover plate is welded to the connecting pipe, so that hydrogen can enter the hydrogen collection chamber through the connecting pipe and the vent pipe opening; the left side surface of the rear cover plate faces the right side surface of the front cover plate, and the left side surface of the rear cover plate is provided with a circular boss, which is used to embed into a matching circular groove of the same diameter on the right side surface of the front cover plate, thereby ensuring the strength and sealing of the connection position; the right side surface of the rear cover plate faces the combustion chamber inlet flange, and the right side surface of the rear cover plate is provided with a circular boss, which is used to embed into a matching circular groove of the same diameter on the combustion chamber inlet flange, thereby ensuring the strength and sealing of the connection position;

[0013] The nozzle disk has several conical through holes for installing hydrogen nozzles. The inner diameter of the left side of the conical through hole is larger than that of the right side. One conical through hole is located at the center of the nozzle disk, and the remaining conical through holes are centrally symmetrically distributed. Each conical through hole is fitted with a conical nozzle. Several injection holes are evenly distributed circumferentially at the position of the nozzle near the right side surface of the rear cover. When the nozzle is installed on the nozzle disk, the left side surface of the nozzle is flush with the left side surface of the front cover, and the right side surface of the nozzle is flush with the right side surface of the rear cover.

[0014] The inner surface of the nozzle disk formed by the combination of the front cover plate and the rear cover plate, and the outer surface of the nozzles after they are installed into the conical through hole, form the boundary, which constitutes the hydrogen gas collection chamber.

[0015] High-pressure hydrogen from the high-pressure hydrogen source enters the gas collecting ring from the high-pressure hydrogen supply pipe, and then enters the connecting pipe and hydrogen gas collecting chamber in sequence along the gas collecting ring. It then enters the airflow channel of the nozzle from the injection hole. In the latter part of the airflow channel, it mixes with the high-temperature oxygen-enriched air entering from the high-temperature oxygen-enriched air supply chamber. During the mixing process, the hydrogen spontaneously combusts in the high-temperature oxygen-enriched air, thereby generating high-temperature gas, which is then ejected from the nozzle.

[0016] The formula for calculating the hydrogen flow rate of a single nozzle is:

[0017]

[0018] in: — Hydrogen flow rate, kg / s; n — Number of injection holes in the nozzle;

[0019] A h —Flow area of ​​the nozzle orifice; T —Hydrogen temperature, taken as 300K;

[0020] P—Nozzle inlet pressure; R—Hydrogen gas constant, taken as 4124;

[0021] γ—Specific heat ratio of hydrogen, taken as 1.4; M—Mach number, taken as 1.

[0022] Furthermore, the components of the hydrogen fuel injector are made of high-temperature alloy GH3030.

[0023] Furthermore, the welding method is argon arc welding.

[0024] Furthermore, the airflow channel has a contraction-expansion profile, with the diameters of the inlet and outlet cross-sections being equal, and the minimum cross-sectional area of ​​the airflow channel being 70% of the inlet and outlet cross-sectional areas.

[0025] Furthermore, the distance between the inlet cross-section of the airflow channel and the minimum cross-section of the airflow channel is 40% of the nozzle length, and the distance between the outlet cross-section of the airflow channel and the minimum cross-section of the airflow channel is 60% of the nozzle length.

[0026] Furthermore, the injection hole is a circular hole of equal diameter, and the angle between the axis of the circular hole and the central axis of the airflow channel is 45°.

[0027] Furthermore, the length from the opening position of the injection hole to the inlet cross-section of the airflow channel is 70% of the total length of the nozzle.

[0028] The nozzle of the hydrogen fuel injector of the present invention, which is applied under high-temperature gas flow conditions, has uniformly distributed injection holes to form an impact nozzle, which can achieve full mixing and self-ignition of hydrogen and high-temperature oxygen-enriched air.

[0029] The components of the hydrogen fuel injector of the present invention, which is applied under high-temperature gas flow conditions, are made of high-temperature alloy GH3030. Each component has a thick-walled structure with a wall thickness sufficient to withstand the scouring of high-temperature oxygen-rich air flow of 5.0MPa and above 1000K. It has good heat sinking capacity and can effectively withstand the scouring of high-temperature and high-pressure airflow.

[0030] The high-pressure hydrogen continuously injected into the hydrogen fuel injector under high-temperature gas flow conditions according to the present invention can form a gas film boundary layer on the nozzle wall, thereby protecting the nozzle from ablation.

[0031] The hydrogen fuel injector of the present invention, applicable to high-temperature gas flow conditions, does not require a separate igniter, thus reducing structural complexity.

[0032] The hydrogen fuel injector of the present invention, applied under high-temperature gas flow conditions, can achieve full mixing and self-ignition of hydrogen and oxygen-enriched air, thereby generating high-temperature combustion gas, which can be used to carry out hypersonic wind tunnel tests in high total enthalpy pulse combustion wind tunnels. Attached Figure Description

[0033] Figure 1 This is a schematic diagram (three-dimensional view) of the hydrogen fuel injector of the present invention applied under high-temperature gas flow conditions;

[0034] Figure 2 This is a schematic diagram (main cross-sectional view) of the hydrogen fuel injector of the present invention applied under high-temperature gas flow conditions;

[0035] Figure 3 This is a schematic diagram (A-A1 cross-sectional view) of the hydrogen fuel injector of the present invention applied under high temperature gas flow conditions;

[0036] Figure 4 This is a schematic diagram (B-B1 cross-sectional view) of the hydrogen fuel injector of the present invention applied under high temperature gas flow conditions;

[0037] Figure 5 This is a schematic diagram of the nozzle structure in a hydrogen fuel injector applied under high-temperature gas flow conditions according to the present invention.

[0038] In the diagram, 1. Gas collecting ring; 2. Connecting pipe; 3. Front cover plate; 4. Rear cover plate; 5. Hydrogen gas collecting chamber; 6. Nozzle; 7. Injection hole; 8. Gas flow channel. Detailed Implementation

[0039] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0040] In this embodiment, the hydrogen fuel injector for use under high-temperature gas flow conditions is installed on the heater of a hypersonic wind tunnel. The gas collecting ring 1 has two high-pressure hydrogen supply pipes, eight connecting pipes 2, one front cover plate 3, one rear cover plate 4, and seven nozzles 6 penetrating the front cover plate 3 and the rear cover plate 4. Each nozzle 6 has six injection holes 7 and one airflow channel 8. The left side of the front cover plate 3 of the injector is connected to the high-temperature oxygen-enriched air supply chamber, and the right side of the rear cover plate 4 is connected to the heater combustion chamber. The high-temperature oxygen-enriched air flows towards the combustion chamber through the airflow channel 8 in the middle of the nozzles 6 on the injector. At the same time, the hydrogen supplied by the high-pressure gas source is collected by the gas collecting ring 1, enters the hydrogen collecting chamber 5 evenly through the connecting pipes 2, and then enters the airflow channel 8 through the injection holes 7. It mixes with the high-temperature oxygen-enriched air supplied upstream and spontaneously combusts, burning in the downstream combustion chamber to produce the high-temperature fuel gas required for the experiment.

[0041] like Figures 1-5 As shown, the hydrogen fuel injector of this embodiment, which is applied under high temperature gas flow conditions, is located between the oxygen-enriched air supply chamber and the heater combustion chamber. The hydrogen fuel injector is a concentric outer ring and inner disk structure. The outer ring is the gas collecting ring 1, and the inner disk is the nozzle disk.

[0042] The outer ring of the gas collecting ring 1 is welded with several high-pressure hydrogen supply pipes evenly distributed along the circumference of the outer ring, and the high-pressure hydrogen supply pipes are connected to a high-pressure hydrogen source; the inner ring of the gas collecting ring 1 is welded with several connecting pipes 2 evenly distributed along the circumference of the inner ring.

[0043] The nozzle disc is assembled and welded together from a front cover plate 3 and a rear cover plate 4 with the same outer diameter, which are arranged side by side, and several nozzles 6 that penetrate the front cover plate 3 and the rear cover plate 4.

[0044] The left side surface of the front cover plate 3 faces the outlet flange of the oxygen-enriched air supply chamber. A circular boss is formed on the left side surface of the front cover plate 3, which is used to fit into a matching circular groove of equal diameter on the outlet flange of the oxygen-enriched air supply chamber, thereby ensuring the strength and sealing of the connection position. The right side surface of the front cover plate 3 faces the left side surface of the rear cover plate 4. A circular groove extends from the right side surface of the front cover plate 3. This groove is used to fit into a matching circular boss of equal diameter on the left side surface of the rear cover plate 4, thereby ensuring the strength and sealing of the connection position.

[0045] The rear cover plate 4 is provided with a ventilation pipe corresponding to the connecting pipe 2; the left side surface of the rear cover plate 4 faces the right side surface of the front cover plate 3, and a circular boss is opened on the left side surface of the rear cover plate 4 to be embedded into a matching circular groove of equal diameter on the right side surface of the front cover plate 3, thereby ensuring the strength and sealing of the connection position; the right side surface of the rear cover plate 4 faces the combustion chamber inlet flange, and a circular boss is opened on the right side surface of the rear cover plate 4 to be embedded into a matching circular groove of equal diameter on the combustion chamber inlet flange, thereby ensuring the strength and sealing of the connection position;

[0046] The nozzle disk has several tapered through holes for mounting nozzles 6. The inner diameter of the left side of the tapered through hole is larger than that of the right side. One tapered through hole is located at the center of the nozzle disk, and the remaining tapered through holes are centrally symmetrically distributed. Each tapered through hole is fitted with one tapered nozzle 6. Several injection holes 7 are evenly distributed circumferentially at the position of the nozzle 6 near the right side surface of the rear cover plate 4.

[0047] The right side surface of the front cover plate 3, the circular groove, and the surfaces of several nozzles 6 constitute the hydrogen gas collection chamber 5;

[0048] High-pressure hydrogen from the high-pressure hydrogen source enters the gas collecting ring 1 from the high-pressure hydrogen supply pipe, and then enters the connecting pipe 2 and the hydrogen gas collecting chamber 5 in sequence along the gas collecting ring 1. It then enters the nozzle 6 from the injection hole 7. In the latter part of the nozzle 6, it mixes with the oxygen-enriched air that enters from the high-temperature oxygen-enriched air supply chamber. During the mixing process, the hydrogen spontaneously combusts in the high-temperature oxygen-enriched air, thereby generating high-temperature gas, which is then ejected from the nozzle 6.

[0049] The formula for calculating the hydrogen flow rate of a single nozzle 6 is:

[0050]

[0051] in: — Hydrogen flow rate, kg / s; n — Number of injection holes in the nozzle;

[0052] A h —Flow area of ​​the nozzle orifice; T —Hydrogen temperature, taken as 300K;

[0053] P—Nozzle inlet pressure; R—Hydrogen gas constant, taken as 4124;

[0054] γ—Specific heat ratio of hydrogen, taken as 1.4; M—Mach number, taken as 1.

[0055] Furthermore, the components of the hydrogen fuel injector are made of high-temperature alloy GH3030.

[0056] Furthermore, the welding method is argon arc welding.

[0057] Furthermore, the airflow channel 8 has a contraction-expansion profile, the diameters of the inlet cross-section and the outlet cross-section of the airflow channel 8 are equal, and the minimum cross-sectional area of ​​the airflow channel 8 is 70% of the inlet and outlet cross-sectional areas.

[0058] Furthermore, the distance between the inlet cross-section of the airflow channel 8 and the minimum cross-section of the airflow channel 8 is 40% of the length of the nozzle 6, and the distance between the outlet cross-section of the airflow channel 8 and the minimum cross-section of the airflow channel 8 is 60% of the length of the nozzle 6.

[0059] Furthermore, the injection hole 7 is a circular hole of equal diameter, and the angle between the axis of the circular hole and the central axis of the airflow channel 8 is 45°.

[0060] Furthermore, the length from the opening position of the injection hole 7 to the inlet cross-section of the airflow channel 8 is 70% of the total length of the nozzle 6.

[0061] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various hypersonic combustion wind tunnel fields suitable for the present invention. For those skilled in the art, other improvements and modifications can be easily made 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 hydrogen fuel injector for use under high-temperature gas flow conditions, characterized in that, The hydrogen fuel injector is located between the oxygen-enriched air supply chamber and the heater combustion chamber. The hydrogen fuel injector is a concentric outer ring and inner disk structure. The outer ring is a gas collecting ring (1), and the inner disk is a nozzle disk. The outer ring of the gas collecting ring (1) is welded with several high-pressure hydrogen supply pipes evenly distributed along the circumference of the outer ring, and the high-pressure hydrogen supply pipes are connected to a high-pressure hydrogen source; the inner ring of the gas collecting ring (1) is welded with several connecting pipes (2) evenly distributed along the circumference of the inner ring. The nozzle disc is assembled and welded together from a front cover plate (3) and a rear cover plate (4) with the same outer diameter arranged side by side, and several nozzles (6) penetrating the front cover plate (3) and the rear cover plate (4); The left side surface of the front cover plate (3) faces the outlet flange of the oxygen-enriched air supply chamber. The left side surface of the front cover plate (3) is provided with a circular boss, which is used to be embedded into the matching circular groove of the same diameter on the outlet flange of the oxygen-enriched air supply chamber, thereby ensuring the strength and sealing of the connection position. The right side surface of the front cover plate (3) faces the left side surface of the rear cover plate (4). The right side surface of the front cover plate (3) has a circular groove, which is used to be embedded into the matching circular boss of the same diameter on the left side surface of the rear cover plate (4), thereby ensuring the strength and sealing of the connection position. The rear cover plate (4) is provided with a ventilation pipe corresponding to the connecting pipe (2); the ventilation pipe opening on the surface of the rear cover plate (4) is welded to the connecting pipe (2), so that hydrogen can enter the hydrogen collection chamber (5) through the connecting pipe (2) and the ventilation pipe opening; the left side surface of the rear cover plate (4) faces the right side surface of the front cover plate (3), and the left side surface of the rear cover plate (4) is provided with a circular boss, which is used to be embedded into the matching circular groove of equal diameter on the right side surface of the front cover plate (3), so as to ensure the strength and sealing of the connection position; the right side surface of the rear cover plate (4) faces the combustion chamber inlet flange, and the right side surface of the rear cover plate (4) is provided with a circular boss, which is used to be embedded into the matching circular groove of equal diameter on the combustion chamber inlet flange, so as to ensure the strength and sealing of the connection position; The nozzle disk has several conical through holes for installing nozzles (6). The inner diameter of the left side of the conical through hole is larger than that of the right side. One conical through hole is located at the center of the nozzle disk, and the remaining conical through holes are symmetrically distributed. Each conical through hole is fitted with a conical nozzle (6). Several injection holes (7) are evenly distributed around the nozzle (6) near the right side surface of the rear cover plate (4). When the nozzle (6) is installed on the nozzle disk, the left side surface of the nozzle (6) is flush with the left side surface of the front cover plate (3), and the right side surface of the nozzle (6) is flush with the right side surface of the rear cover plate (4). The inner surface of the nozzle disk formed by the front cover plate (3) and the rear cover plate (4), and several nozzles (6) are installed on the outer surface of the tapered through hole as boundaries, forming the hydrogen gas collection chamber (5). The components of the hydrogen fuel injector are made of high-temperature alloy GH3030. Each component has a thick wall structure, and the wall thickness is sufficient to withstand the scouring of oxygen-rich air flow at a high temperature of 5.0MPa and above 1000K. High-pressure hydrogen from the high-pressure hydrogen source enters the gas collecting ring (1) from the high-pressure hydrogen supply pipe, and then enters the connecting pipe (2) and hydrogen gas collecting chamber (5) in sequence along the gas collecting ring (1). It enters the airflow channel (8) of the nozzle (6) from the injection hole (7), forming a gas film boundary layer on the wall of the nozzle (6) to protect the nozzle (6) from ablation. In the later section of the airflow channel (8), it mixes with the high-temperature oxygen-enriched air entering from the high-temperature oxygen-enriched air supply chamber. During the mixing process, the hydrogen spontaneously combusts in the high-temperature oxygen-enriched air, thereby generating high-temperature gas, which is ejected from the nozzle (6). The formula for calculating the hydrogen flow rate of a single nozzle (6) is as follows: ； in: — Hydrogen flow rate, kg / s; —Number of injection holes in the nozzle; —Flow area of ​​the nozzle orifice; — Hydrogen temperature, taken as 300K; — Nozzle inlet pressure; — Hydrogen gas constant, taken as 4124; —Specific heat ratio of hydrogen, taken as 1.4; — Mach number, set to 1.

2. The hydrogen fuel injector according to claim 1, applicable to high-temperature gas flow conditions, characterized in that, The welding method described is argon arc welding.

3. The hydrogen fuel injector according to claim 1, applicable to high-temperature gas flow conditions, characterized in that, The airflow channel (8) is a contraction-expansion type. The diameters of the inlet cross-section and the outlet cross-section of the airflow channel (8) are equal. The minimum cross-sectional area of ​​the airflow channel (8) is 70% of the inlet and outlet cross-sectional areas.

4. The hydrogen fuel injector according to claim 1, applicable to high-temperature gas flow conditions, characterized in that, The distance between the inlet cross section of the airflow channel (8) and the minimum cross section of the airflow channel (8) is 40% of the length of the nozzle (6), and the distance between the outlet cross section of the airflow channel (8) and the minimum cross section of the airflow channel (8) is 60% of the length of the nozzle (6).

5. The hydrogen fuel injector according to claim 1, applicable to high-temperature gas flow conditions, characterized in that, The injection hole (7) is a circular hole of equal diameter, and the angle between the axis of the circular hole and the central axis of the airflow channel (8) is 45°.

6. The hydrogen fuel injector according to claim 1, applicable to high-temperature gas flow conditions, characterized in that, The length from the opening position of the injection hole (7) to the inlet cross section of the airflow channel (8) is 70% of the total length of the nozzle (6).

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