A hydrogen-oxygen injector for use under high-temperature airflow conditions

Abstract

This invention belongs to the field of pulse combustion wind tunnel testing technology and discloses a hydrogen-oxygen injector for use under high-temperature airflow conditions. The hydrogen-oxygen injector includes an injector cover plate, an oxygen chamber cover plate, and a hydrogen chamber cover plate connected sequentially from front to back according to the airflow direction. An oxygen ring pipe is circumferentially arranged on the oxygen chamber cover plate, connected by uniformly distributed oxygen pipelines. A hydrogen ring pipe is circumferentially arranged on the hydrogen chamber cover plate, connected by uniformly distributed hydrogen pipelines. Several centrally symmetrically distributed injection units pass through the injector cover plate, oxygen chamber cover plate, and hydrogen chamber cover plate sequentially from front to back. The inner cavity of each injection unit is provided with a contraction-expansion type high-temperature airflow channel. In the expansion section of the high-temperature airflow channel, oxygen nozzles and hydrogen nozzles are arranged from front to back. Oxygen is injected through the oxygen nozzles, and hydrogen is injected through the hydrogen nozzles. Hydrogen, oxygen, and high-temperature air mix at the hydrogen nozzles. During the mixing process, the hydrogen spontaneously combusts, thereby generating high-temperature combustion gas.

Description

Technical Field

[0001] This invention belongs to the field of pulse combustion wind tunnel testing technology, specifically relating to a hydrogen-oxygen injector applied under high-temperature airflow conditions. Background Technology

[0002] Scramjet engines are ideal power sources for hypersonic flight and have broad application prospects. Scramjet engine technology is complex, and ground testing, flight testing, and numerical simulation are the main methods for conducting research on related technologies. Among these, ground testing can obtain direct performance data and is the most important means of tackling key technical challenges in scramjet engines.

[0003] To conduct ground tests of scramjet engines, it is necessary to construct ground simulation test equipment capable of simulating the actual flight conditions (total enthalpy, total pressure, Mach number, etc.) of a scramjet engine. Heaters are one of the key technologies in this ground simulation test equipment, used to generate high-enthalpy, high-pressure airflow. Based on the heating method, heaters can be classified into: combustion heating, shock wave heating, electric arc heating, adiabatic compression and multi-stage compression heating, regenerative heating, and direct online resistance heating. Among these, combustion heating is widely used in scramjet engine testing due to its advantages such as low investment, low technical risk, low operating costs, and wide operational range.

[0004] The fuel for combustion heaters is typically hydrocarbon fuel or hydrogen, and the oxidant is usually oxygen or oxygen-enriched air. Hydrogen-oxygen combustion has a high combustion temperature, enabling the simulation of higher total temperatures, and is therefore widely used. Injector technology is a key technology for hydrogen-oxygen combustion heaters; its performance determines whether hydrogen and oxygen can mix sufficiently and ignite reliably, affecting the heater's combustion stability over a wide range.

[0005] Currently, conventional combustion heating equipment (single-stage heating) can generate test gas flows at temperatures up to 3000K. However, the water molar content in this flow is as high as 40%, which has a serious negative impact on the accuracy of the test results. Therefore, a two-stage heating method of "regenerative heat storage + combustion," i.e., "high-temperature air + combustion heating," is adopted. This ensures that the air entering the combustion heater is high-temperature air, significantly reducing the water molar content in the test gas produced by combustion in the combustion chamber, thereby improving the accuracy of ground test simulations. Furthermore, the two-stage heating method allows for the self-ignition of hydrogen using high-temperature air, eliminating the need for an ignition device on the combustion heater and simplifying its complexity. However, the combustion heater in this two-stage heating method is a three-component heater, where high-temperature air, room-temperature hydrogen, and room-temperature oxygen are injected separately. The injector needs to withstand the high-temperature incoming flow without being ablated and must achieve reliable and effective mixing of hydrogen and oxygen. Research on such injector structures has not yet been publicly reported.

[0006] Currently, there is an urgent need to develop a hydrogen-oxygen injector for use under high-temperature airflow conditions. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a hydrogen-oxygen injector for use under high-temperature airflow conditions, thereby solving the problem of high water molar content in the test gas flow generated by conventional combustion heating equipment.

[0008] This invention relates to a hydrogen-oxygen injector under high-temperature airflow conditions. The injector comprises an injector cover plate, an oxygen chamber cover plate, and a hydrogen chamber cover plate connected sequentially from front to back according to the airflow direction. The injector cover plate, oxygen chamber cover plate, and hydrogen chamber cover plate are cylindrical with the same outer diameter. A circular groove I is provided inside the oxygen chamber cover plate, and circular groove I is closed by the rear end face of the injector cover plate. A circular groove II is provided inside the hydrogen chamber cover plate, and circular groove II is closed by the rear end face of the oxygen chamber cover plate. An oxygen ring pipe is circumferentially arranged on the oxygen chamber cover plate, and the oxygen chamber cover plate and the oxygen ring pipe are connected by uniformly distributed oxygen pipelines. The oxygen ring pipe is connected to an external high-pressure oxygen supply pipeline through uniformly distributed oxygen interfaces along the circumferential direction. Similarly, a hydrogen ring pipe is circumferentially arranged on the hydrogen chamber cover plate, and the hydrogen chamber cover plate and the hydrogen ring pipe are connected by uniformly distributed hydrogen pipelines. The hydrogen ring pipe is connected to an external high-pressure hydrogen supply pipeline through uniformly distributed hydrogen interfaces along the circumferential direction.

[0009] Several centrally symmetrically distributed injection units sequentially penetrate the injector cover plate, oxygen chamber cover plate, and hydrogen chamber cover plate from front to back; the front end face of each injection unit is flush with the front end face of the injector cover plate, and the rear end face of each injection unit is flush with the rear end face of the hydrogen chamber cover plate; the cavity formed by the injector cover plate, oxygen chamber cover plate, and injection units is the oxygen collection chamber, and the cavity formed by the oxygen chamber cover plate, hydrogen chamber cover plate, and injection units is the hydrogen collection chamber; the inner cavity of each injection unit is equipped with a contraction- An expanding high-temperature airflow channel has oxygen and hydrogen nozzles evenly distributed circumferentially along the expansion section from front to back. The central axes of the oxygen and hydrogen nozzles are perpendicular to the inner wall of the expansion section of the high-temperature airflow channel. Oxygen is injected through the oxygen nozzles, and hydrogen is injected through the hydrogen nozzles. At the hydrogen nozzles, hydrogen, oxygen, and high-temperature air flowing out of the high-temperature airflow channel mix. During the mixing process, hydrogen spontaneously combusts, thereby generating high-temperature combustion gas.

[0010] Furthermore, the oxygen pipeline is connected to the oxygen chamber cover plate and the oxygen loop pipe by welding, and the hydrogen pipeline is connected to the hydrogen chamber cover plate and the hydrogen loop pipe by welding.

[0011] Furthermore, the injection unit is connected to the injector cover plate, the oxygen chamber cover plate, and the hydrogen chamber cover plate by welding.

[0012] Furthermore, the injection unit is made of a high-temperature alloy.

[0013] Furthermore, the injector cover plate and the oxygen chamber cover plate, as well as the oxygen chamber cover plate and the hydrogen chamber cover plate, are fixedly connected by an interference fit of an annular groove and an annular boss on the end face.

[0014] Furthermore, sealing rings are provided on the end faces between the injector cover plate and the oxygen chamber cover plate, and on the end faces between the oxygen chamber cover plate and the hydrogen chamber cover plate. The sealing rings are made of copper.

[0015] Furthermore, the temperature range of the high-temperature air is 1100K~1700K, the temperature range of the high-temperature gas is 2300K~3000K, and the pressure range of the high-temperature gas is 20MPa~35MPa.

[0016] Furthermore, the pressure range of the high-pressure oxygen is 20MPa~35MPa, and the pressure range of the high-pressure hydrogen is 20MPa~35MPa.

[0017] Furthermore, the distance between the hydrogen nozzle and the outlet of the high-temperature air flow channel is 0.1R~0.2R, where R is the inner diameter of the outlet of the high-temperature air flow channel.

[0018] Furthermore, the calculation method for the hydrogen flow rate and oxygen flow rate of a single injection unit is as follows:

[0019]

[0020] in: —Gas flow rate, kg / s; —Gas flow coefficient;

[0021] —Flow area of ​​the gas nozzle orifice; —Gas temperature;

[0022] —Gas nozzle inlet pressure; — Nozzle outlet pressure;

[0023] —Gas constant; Specific heat ratio of gases.

[0024] The hydrogen-oxygen injector of the present invention, applied to high-temperature airflow, has the following characteristics:

[0025] a. Combustion organization method: Oxygen and hydrogen are injected sequentially in the expansion section of the injection unit and mixed with high-temperature air for combustion;

[0026] b. The design of the injection unit takes into account the form of the high-temperature airflow channel, the number, angle and relative position of the hydrogen and oxygen nozzles;

[0027] c. The combination method of the injection unit, taking into account the structural form and combination method of the injector cover plate, oxygen chamber cover plate, hydrogen chamber cover plate, and the arrangement of the injection unit.

[0028] The hydrogen-oxygen injector of this invention, applicable to high-temperature airflow, is suitable for high-temperature and high-pressure conditions, with hydrogen-oxygen combustion temperatures reaching over 3000K. Oxygen is injected through oxygen nozzles and hydrogen through hydrogen nozzles into the high-temperature airflow. By controlling the position and direction of the oxygen and hydrogen injections, the injector achieves self-ignition, eliminating the need for an igniter and reducing the structural complexity of the hydrogen-oxygen combustion heater. Furthermore, by arranging the hydrogen nozzles as close as possible to the outlet of the high-temperature airflow channel, excessive contact between the high-temperature ignition zone and the injector is avoided, thus preventing injector erosion and extending its service life.

[0029] The hydrogen-oxygen injector of the present invention, applied to high-temperature airflow, can effectively mix hydrogen, oxygen and high-temperature air, and can also achieve hydrogen self-ignition. The generated high-temperature gas can be used in high-enthalpy combustion wind tunnels to carry out hypersonic wind tunnel tests. Attached Figure Description

[0030] Figure 1 This is a schematic diagram (three-dimensional view) of the hydrogen-oxygen injector of the present invention applied to high-temperature airflow conditions.

[0031] Figure 2 This is a schematic diagram (top view) of the hydrogen-oxygen injector of the present invention applied to high-temperature airflow conditions.

[0032] Figure 3 This is a schematic diagram (AA cross-sectional view) of the hydrogen-oxygen injector of the present invention applied under high-temperature airflow conditions.

[0033] In the diagram, 1. Hydrogen loop pipe; 2. Oxygen loop pipe; 3. Hydrogen pipeline; 4. Oxygen pipeline; 5. Hydrogen collecting chamber; 6. Oxygen collecting chamber; 7. Hydrogen nozzle; 8. Oxygen nozzle; 9. Injection unit; 10. Hydrogen chamber cover plate; 11. Oxygen chamber cover plate; 12. Injector cover plate. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] Example 1

[0036] like Figures 1-3As shown, the hydrogen-oxygen injector of this embodiment, applied under high-temperature airflow conditions, includes a hydrogen ring pipe 1, an oxygen ring pipe 2, a hydrogen pipeline 3, an oxygen pipeline 4, a hydrogen collection chamber 5, an oxygen collection chamber 6, a hydrogen nozzle 7, an oxygen nozzle 8, an injection unit 9, a hydrogen chamber cover plate 10, an oxygen chamber cover plate 11, and an injector cover plate 12.

[0037] Hydrogen ring pipe 1 is connected to three high-pressure hydrogen supply pipelines by welding through a hydrogen interface. High-pressure hydrogen enters hydrogen ring pipe 1 evenly from three directions (120° apart) through the high-pressure hydrogen supply pipelines, ensuring that the hydrogen pressure and flow rate distribution in hydrogen ring pipe 1 is uniform.

[0038] Oxygen loop 2 is connected to three high-pressure oxygen supply lines by welding through an oxygen interface. High-pressure oxygen enters the oxygen loop 2 evenly from three directions (120° apart) through the high-pressure oxygen supply lines, ensuring uniform distribution of oxygen pressure and flow rate within the oxygen loop 2.

[0039] There are 8 hydrogen pipelines 3 in total, which are evenly distributed around the hydrogen ring pipe 1. The hydrogen pipelines 3 connect the hydrogen ring pipe 1 and the hydrogen chamber cover plate 10. The hydrogen pipelines 3 and the hydrogen ring pipe 1, as well as the hydrogen pipelines 3 and the hydrogen chamber cover plate 10, are connected by welding to ensure that the hydrogen pressure and flow rate entering the hydrogen collection chamber 5 are evenly distributed.

[0040] There are 8 oxygen pipelines 4 in total, which are evenly distributed around the oxygen ring pipe 2. The oxygen pipelines 4 connect the oxygen ring pipe 2 and the oxygen chamber cover plate 11. The oxygen pipelines 4 and the oxygen ring pipe 2, as well as the oxygen pipelines 4 and the oxygen chamber cover plate 11, are connected by welding to ensure that the oxygen pressure and flow rate distribution in the oxygen collection chamber 6 are uniform. Due to structural space interference, the oxygen ring pipe 2 is not a straight pipe, but is bent according to the space.

[0041] The high-pressure hydrogen from the high-pressure hydrogen supply pipeline is collected in the hydrogen collection chamber 5 after passing through the hydrogen pipeline 3, and then injected through the hydrogen nozzle 7.

[0042] The high-pressure oxygen supplied from the high-pressure oxygen supply pipeline is collected in the oxygen collection chamber 6 after passing through the oxygen pipeline 4, and then injected through the oxygen nozzle 8.

[0043] Hydrogen nozzles 7, there are 6 hydrogen nozzles 7 on each injection unit 9, which are evenly distributed around the circumference of the injection unit 9, and the hydrogen nozzles 7 are connected to the hydrogen collection chamber 5.

[0044] Oxygen nozzles 8, there are 6 oxygen nozzles 8 on each injection unit 9, evenly distributed around the circumference of the injection unit 9, and the oxygen nozzles 8 are connected to the oxygen collection chamber 6.

[0045] The injection unit 9 comprises seven centrally symmetrically distributed injection units 9. Each injection unit 9 is frustum-shaped and sequentially penetrates the injector cover plate 12, oxygen chamber cover plate 11, and hydrogen chamber cover plate 10 from front to back, following the airflow direction. The injection units 9 are connected to the injector cover plate 12, oxygen chamber cover plate 11, and hydrogen chamber cover plate 10 by welding. The front end face of each injection unit 9 is flush with the injector cover plate 12, and the rear end face of each injection unit 9 is flush with the hydrogen chamber cover plate 10. The cavity formed by the injector cover plate 12, oxygen chamber cover plate 11, and injection units 9 is the oxygen collection chamber 6. The cavity formed by the cover plate 11, the hydrogen chamber cover plate 10, and the injection unit 9 is the hydrogen gas collection chamber 5. The inner cavity of the injection unit 9 is provided with a contraction-expansion type high-temperature air flow channel. In the expansion section of the high-temperature air flow channel, oxygen nozzles 8 and hydrogen nozzles 7 are uniformly distributed along the circumference of the expansion section from front to back. The central axes of oxygen nozzles 8 and hydrogen nozzles 7 are perpendicular to the inner wall of the expansion section of the high-temperature air flow channel. Oxygen is injected through oxygen nozzles 8, and hydrogen is injected through hydrogen nozzles 7. At the hydrogen nozzles 7, hydrogen is mixed with the high-temperature air flowing out of the high-temperature air flow channel. During the mixing process, hydrogen spontaneously combusts, thereby generating high-temperature combustion gas.

[0046] The hydrogen chamber cover plate 10 is provided with 7 frustum-shaped holes corresponding to the injection units 9, with 1 hole in the center and 6 holes arranged in hexagonal shapes around the periphery. Each frustum-shaped hole is welded to one injection unit 9. The hydrogen chamber cover plate 10 is also provided with 8 hydrogen interfaces that are welded to the hydrogen pipeline 3.

[0047] The oxygen chamber cover plate 11 is provided with 7 frustum-shaped holes corresponding to the injection units 9, with 1 hole in the center and 6 holes arranged in hexagonal shapes around the periphery. Each frustum-shaped hole is welded to one injection unit 9. The oxygen chamber cover plate 11 is also provided with 8 oxygen interfaces that are welded to the oxygen pipeline 4.

[0048] The injector cover plate 12 has 7 frustum-shaped holes corresponding to the injector units 9, with 1 hole in the center and 6 holes arranged in hexagonal shapes around the perimeter. Each frustum-shaped hole is welded to one injector unit 9.

[0049] For a single injection unit 9, the calculation methods for hydrogen flow rate and oxygen flow rate are as follows:

[0050]

[0051] in: —Gas flow rate, kg / s; —Gas flow coefficient;

[0052] —Flow area of ​​the gas nozzle orifice; —Gas temperature;

[0053] —Gas nozzle inlet pressure; — Nozzle outlet pressure;

[0054] —Gas constant; Specific heat ratio of gases.

[0055] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. For those skilled in the art, all features disclosed in the present invention, or all steps in all methods or processes disclosed, except for mutually exclusive features and / or steps, can be combined in any way 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-oxygen injector for use under high-temperature airflow conditions, characterized in that, The hydrogen-oxygen injector includes an injector cover plate (12), an oxygen chamber cover plate (11), and a hydrogen chamber cover plate (10) connected sequentially from front to back according to the airflow direction. The injector cover plate (12) and the oxygen chamber cover plate (11), as well as the oxygen chamber cover plate (11) and the hydrogen chamber cover plate (10), are fixedly connected by an interference fit of an annular groove and an annular boss on the end face. The injector cover plate (12), the oxygen chamber cover plate (11), and the hydrogen chamber cover plate (10) are cylindrical with the same outer diameter. A circular groove I is provided in the oxygen chamber cover plate (11), and the circular groove I is closed by the rear end face of the injector cover plate (12). A circular groove I is provided in the hydrogen chamber cover plate (10). There is a circular groove II, which is closed by the rear end face of the oxygen chamber cover plate (11); an oxygen ring pipe (2) is provided around the oxygen chamber cover plate (11), and the oxygen chamber cover plate (11) and the oxygen ring pipe (2) are connected by a uniformly distributed oxygen pipeline (4), and the oxygen ring pipe (2) is connected to an external high-pressure oxygen supply pipeline through a uniformly distributed oxygen interface along the circumference; a hydrogen ring pipe (1) is provided around the hydrogen chamber cover plate (10), and the hydrogen chamber cover plate (10) and the hydrogen ring pipe (1) are connected by a uniformly distributed hydrogen pipeline (3), and the hydrogen ring pipe (1) is connected to an external high-pressure hydrogen supply pipeline through a uniformly distributed hydrogen interface along the circumference; Several centrally symmetrically distributed injection units (9) pass through the injector cover plate (12), oxygen chamber cover plate (11), and hydrogen chamber cover plate (10) sequentially from front to back; the front end face of each injection unit (9) is flush with the front end face of the injector cover plate (12), and the rear end face of each injection unit (9) is flush with the rear end face of the hydrogen chamber cover plate (10); the cavity formed by the injector cover plate (12), oxygen chamber cover plate (11), and injection units (9) is the oxygen collection chamber (6), and the cavity formed by the oxygen chamber cover plate (11), hydrogen chamber cover plate (10), and injection units (9) is the hydrogen collection chamber. Cavity (5); The inner cavity of the injection unit (9) is provided with a contraction-expansion type high-temperature air flow channel. In the expansion section of the high-temperature air flow channel, oxygen nozzles (8) and hydrogen nozzles (7) are uniformly distributed along the circumference of the expansion section from front to back. The central axes of the oxygen nozzles (8) and hydrogen nozzles (7) are perpendicular to the inner wall of the expansion section of the high-temperature air flow channel. Oxygen is injected through the oxygen nozzles (8), and hydrogen is injected through the hydrogen nozzles (7). At the hydrogen nozzles (7), hydrogen, oxygen and high-temperature air flowing out of the high-temperature air flow channel are mixed. During the mixing process, hydrogen spontaneously combusts, thereby generating high-temperature combustion gas.

2. The hydrogen-oxygen injector according to claim 1, applicable to high-temperature airflow conditions, characterized in that, The oxygen pipeline (4) is connected to the oxygen chamber cover plate (11) and the oxygen loop pipe (2) by welding, and the hydrogen pipeline (3) is connected to the hydrogen chamber cover plate (10) and the hydrogen loop pipe (1) by welding.

3. The hydrogen-oxygen injector according to claim 1, characterized in that, The injection unit (9) is connected to the injector cover plate (12), the oxygen chamber cover plate (11) and the hydrogen chamber cover plate (10) by welding.

4. The hydrogen-oxygen injector according to claim 1, characterized in that, The injection unit (9) is made of high-temperature alloy.

5. The hydrogen-oxygen injector according to claim 1, characterized in that, A sealing ring is provided on the end face between the injector cover plate (12) and the oxygen chamber cover plate (11), and on the end face between the oxygen chamber cover plate (11) and the hydrogen chamber cover plate (10). The sealing ring is made of copper.

6. The hydrogen-oxygen injector according to claim 1, characterized in that, The temperature range of the high-temperature air is 1100K~1700K, the temperature range of the high-temperature gas is 2300K~3000K, and the pressure range of the high-temperature gas is 20MPa~35MPa.

7. The hydrogen-oxygen injector according to claim 1, applicable to high-temperature airflow conditions, characterized in that, The pressure range of the high-pressure oxygen is 20MPa~35MPa, and the pressure range of the high-pressure hydrogen is 20MPa~35MPa.

8. The hydrogen-oxygen injector according to claim 1, characterized in that, The distance between the hydrogen nozzle (7) and the outlet of the high-temperature air channel is 0.1R~0.2R, where R is the inner diameter of the outlet of the high-temperature air channel.

9. The hydrogen-oxygen injector according to claim 1, characterized in that, The calculation method for the hydrogen flow rate and oxygen flow rate of a single injection unit (9) is as follows: ； in: —Gas flow rate, kg / s; —Gas flow coefficient; —Flow area of ​​the gas nozzle orifice; —Gas temperature; —Gas nozzle inlet pressure; — Nozzle outlet pressure; —Gas constant; Specific heat ratio of gases.

Images