Oxygen-enriched fuel gas generator capable of adjusting mixing ratio in wide range and generation method

Abstract

The invention provides an oxygen-enriched gas generator capable of adjusting the mixing ratio in a wide range and a generation method, and aims to solve the problems that an existing oxygen-enriched gas generator is poor in mixing effect, large-particle fuel liquid drops are involved in a flame area and easily become a disturbance source, large-amplitude oscillation combustion is generated in the oxygen-enriched gas generator, and the combustion efficiency is low. And when the mixing ratio of the double centrifugal nozzles retracting into the chamber is far higher than the equivalent mixing ratio, the oxygen-enriched gas generator cannot provide oxygen-enriched gas with stable flow and pressure. According to the oxygen-enriched fuel gas generator, the liquid-liquid injector is adopted to organize the first oxidizing agent and the fuel to be subjected to atomization combustion in the primary mixing combustion part, the secondary injection annular cavity is formed in the side wall of the secondary mixing combustion part, the second oxidizing agent is injected into the secondary mixing combustion part to be subjected to mixing combustion, and oxygen-enriched fuel gas is formed; a large number of oxidizing agents are mixed in a secondary injection ring cavity mode, and it can be guaranteed that the mixing ratio of oxygen-enriched fuel gas can be adjusted within a wide range.

Description

Technical Field

[0001] The present invention relates to an oxygen-enriched gas generator, and more particularly to an oxygen-enriched gas generator with a wide-range adjustable mixing ratio and a generation method thereof. Background Art

[0002] Currently, high-pressure staged combustion engines often adopt the gas generator cycle mode. The liquid propellant is converted into oxygen-enriched gas by the gas generator, and the oxygen-enriched gas and the liquid fuel propellant are secondarily combusted in the thrust chamber to complete the energy conversion and generate driving force. In order to study the combustion process of the gas-liquid nozzle in the high-pressure staged combustion engine, an oxygen-enriched gas generator is required to provide high-temperature and high-pressure oxygen-enriched gas for the gas-liquid nozzle. The ground test device often requires that the propellant mixing ratio of the oxygen-enriched gas generator can be adjusted within a wide range, so that oxygen-enriched gas with given component, temperature and pressure ranges can be more conveniently provided in the ground test to meet the requirements of gas-liquid nozzle combustion research.

[0003] When designing an oxygen-enriched gas generator, the requirements of three aspects, namely combustion performance, combustion stability and gas temperature uniformity, should be mainly met. Taking the cryogenic propellants liquid oxygen / kerosene as an example, its corresponding stoichiometric mixing ratio is around 3, while in fact the mixing ratio of the oxygen-enriched gas generator exceeds dozens, showing an extreme surplus of oxidizer. Most of the existing nozzles of oxygen-enriched gas generators are liquid-liquid double centrifugal nozzles with a three-way injection channel structure. When the oxidizer and the fuel each occupy one path, a second oxidizer injection channel is arranged on the outer periphery of the nozzle for mixing, so as to achieve the preset high mixing ratio of the propellant in the oxygen-enriched gas generator. However, this mixing effect is poor, and large fuel droplets are easily involved in the flame area and become disturbance sources. When the disturbance reaches a certain threshold, large-amplitude oscillating combustion will occur in the oxygen-enriched gas generator. In addition, when the mixing ratio of the double centrifugal nozzle retracted into the chamber is much higher than the stoichiometric mixing ratio, the probability of unstable combustion will also increase, making the oxygen-enriched gas generator unable to provide oxygen-enriched gas with stable flow and pressure for the downstream gas-liquid nozzle test. Therefore, it is necessary to reduce the propellant mixing ratio near the nozzle retracted chamber to obtain a relatively stable combustion state. Summary of the Invention

[0004] The purpose of the present invention is to solve the technical problems that the existing oxygen-enriched gas generator has poor mixing effect, and large fuel droplets are easily involved in the flame area and become disturbance sources, resulting in large-amplitude oscillating combustion in the oxygen-enriched gas generator, and when the mixing ratio of the double centrifugal nozzle retracted into the chamber is much higher than the stoichiometric mixing ratio, the oxygen-enriched gas generator cannot provide oxygen-enriched gas with stable flow and pressure, and to provide an oxygen-enriched gas generator with a wide-range adjustable mixing ratio and a generation method thereof.

[0005] In order to achieve the above purpose, the technical solutions provided by the present invention are as follows:

[0006] An oxygen-rich gas generator with a wide-range adjustable mixing ratio, characterized in that it includes a generator body part and a secondary mixing part of the generator; the generator body part includes a liquid-liquid injector and a primary mixing combustion part, and the secondary mixing part of the generator includes a secondary mixing combustion part and a throat;

[0007] Both the primary mixing combustion part and the secondary mixing combustion part are cavity structures;

[0008] The outer side wall of the liquid-liquid injector is hermetically connected to the upper end of the primary mixing combustion part and the lower end extends into the primary mixing combustion part; the lower end of the primary mixing combustion part is fixedly connected to the upper end of the secondary mixing combustion part; the throat is coaxially installed at the lower end of the secondary mixing combustion part;

[0009] A first oxidant inlet and a fuel inlet are arranged on the side wall of the liquid-liquid injector;

[0010] A liquid injection ring is circumferentially arranged at a position near the upper end inside the secondary mixing combustion part; a circumferential groove is arranged circumferentially in the middle section of the outer side wall of the liquid injection ring, and the circumferential groove and the inner side wall of the corresponding position of the secondary mixing combustion part form a secondary injection ring cavity; a second oxidant inlet is arranged on the side wall of the secondary mixing combustion part corresponding to the secondary injection ring cavity; a plurality of downwardly inclined secondary injection holes are arranged circumferentially on the side wall of the liquid injection ring corresponding to the secondary injection ring cavity.

[0011] Furthermore, a torch igniter is arranged on the side wall of the primary mixing combustion part at a position corresponding to the downstream of the liquid-liquid injector.

[0012] Furthermore, the included angle between the secondary injection holes and the inner side wall of the liquid injection ring is 30° to 75°.

[0013] Furthermore, the included angle between the secondary injection holes and the inner side wall of the liquid injection ring is 45°.

[0014] The number of the secondary injection holes is 12.

[0015] Furthermore, the position near the outlet inside the secondary mixing combustion part is set as a transition contraction section;

[0016] The liquid-liquid injector is a liquid-liquid double centrifugal injector;

[0017] The throat is a subsonic throat or a sonic throat.

[0018] Furthermore, a first oxidant pre-injection pressure monitoring device is installed on the annular channel of the liquid-liquid injector corresponding to the first oxidant inlet;

[0019] A fuel pre-injection pressure monitoring device is installed on the annular channel of the liquid-liquid injector corresponding to the fuel inlet;

[0020] A second oxidant pre-injection pressure monitoring device is installed on the channel of the second oxidant inlet;

[0021] A chamber pressure monitoring device is installed on the side wall of the secondary mixing combustion section at a position corresponding to the lower part of the secondary injection annular cavity.

[0022] Furthermore, a stepped groove is circumferentially formed near the upper end inside the secondary mixing combustion section;

[0023] The liquid injection ring is installed in the stepped groove of the secondary mixing combustion section by means of clearance fitting or welding fitting.

[0024] Furthermore, a first sealing flange is circumferentially arranged on the outer side wall near the lower end of the liquid-liquid injector, a second sealing flange is arranged at the upper end of the primary mixing combustion section, a third sealing flange is arranged at the lower end thereof, and a fourth sealing flange is arranged at the top of the secondary mixing combustion section;

[0025] The first sealing flange and the second sealing flange are axially fixed by a plurality of fixing screws;

[0026] The third sealing flange and the fourth sealing flange are axially fixed by a plurality of fixing screws;

[0027] The throat is coaxially installed at the lower end of the secondary mixing combustion section through a throat flange.

[0028] In addition, a method for generating oxygen-rich gas with a wide-range adjustable mixing ratio, based on the above oxygen-rich gas generator with a wide-range adjustable mixing ratio, is characterized in that it includes the following steps:

[0029] Step 1, preset the flow rate and thermodynamic parameters of the oxygen-rich gas, and obtain the flow rates of the fuel and oxidant required for the combustion organization of the oxygen-rich gas generator through thermodynamic calculation;

[0030] Step 2, preset the propellant mixing ratio of the liquid-liquid injector, and determine the flow rate of the first oxidant according to the propellant mixing ratio of the liquid-liquid injector; then, in combination with the flow rate of the oxidant obtained in Step 1 and the flow rate of the first oxidant, determine the flow rate of the second oxidant;

[0031] Step 3, calculate the internal aperture of the throat according to the flow rate of the first oxidant, the flow rate of the second oxidant, the flow rate of the fuel obtained in Step 1, the target outlet pressure of the throat, and the target chamber pressure of the oxygen-rich gas generator;

[0032] Step 4, select a corresponding throat according to the internal aperture of the throat calculated in Step 3, and then build the above oxygen-rich gas generator with a wide-range adjustable mixing ratio;

[0033] Step 5: Input the first oxidant and fuel with a given flow rate. After the first oxidant and fuel are mixed in the liquid-liquid injector, they burn in the primary mixing combustion section. Input the second oxidant with a given flow rate, which is mixed and burned with the first oxidant and fuel in the secondary mixing combustion section to form oxygen-rich gas. The oxygen-rich gas flows out through the throat and enters other downstream test components.

[0034] Further, in Step 2, it also includes: respectively determining the target pre-injection pressures of the first oxidant, the second oxidant, and the fuel according to the flow rate of the first oxidant, the flow rate of the second oxidant, the flow rate of the fuel, and the target chamber pressure of the oxygen-rich gas generator.

[0035] In Step 5, the actual pre-injection pressure values of the corresponding ones are respectively monitored by the first oxidant pre-injection pressure monitoring device, the fuel pre-injection pressure monitoring device, and the second oxidant pre-injection pressure monitoring device, and are respectively compared with the target pre-injection pressures of the first oxidant, the second oxidant, and the fuel to determine whether the flow rate inputs of the first oxidant, the second oxidant, and the fuel are normal.

[0036] The actual chamber pressure value of the oxygen-rich gas generator is monitored by the chamber pressure monitoring device and compared with the target chamber pressure of the oxygen-rich gas generator to determine whether there is pulsation in the oxygen-rich gas generator.

[0037] The beneficial effects of the present invention compared with the prior art are as follows:

[0038] 1. An oxygen-rich gas generator with a wide-range adjustable mixing ratio provided by the present invention is provided with a liquid-liquid injector, a primary mixing combustion section, a secondary mixing combustion section, and a throat. The liquid-liquid injector is used to organize the atomization combustion of the first oxidant and fuel in the primary mixing combustion section, and a secondary injection annular cavity is arranged on the side wall of the secondary mixing combustion section. The second oxidant is injected into the secondary mixing combustion section through a plurality of uniformly distributed secondary injection holes for mixing combustion to form oxygen-rich gas. By arranging the secondary injection annular cavity on the side wall of the secondary mixing combustion section, a large amount of oxidant can be mixed in, which can ensure that the mixing ratio of the oxygen-rich gas can be adjusted within a wide range.

[0039] 2. An oxygen-rich gas generator with a wide-range adjustable mixing ratio provided by the present invention adopts the method of adjusting the flow rate of the second oxidant corresponding to the liquid-liquid injector and the secondary injection annular cavity, and the angle between the secondary injection hole and the inner side wall of the injection ring is 30° - 75°. Uniform and stable high-temperature oxygen-rich gas can be obtained within a wide mixing ratio range, providing oxygen-rich gas with uniform temperature and stable flow for the gas-liquid nozzle test.

[0040] 3. In the oxygen-enriched gas generator with a wide-range adjustable mixing ratio provided by the present invention, the position near the outlet inside the secondary mixing combustion part is set as a transition contraction section, which can accelerate and rectify the generated oxygen-enriched gas, further ensuring the uniform and stable oxygen-enriched gas at the outlet.

[0041] 4. In the present invention, a first oxidant pre-injection pressure monitoring device, a second oxidant pre-injection pressure monitoring device, and a fuel pre-injection pressure monitoring device are respectively arranged at the inlet positions of the first oxidant, the second oxidant, and the fuel. At the same time, a chamber pressure monitoring device is installed on the side wall of the secondary mixing combustion part to judge whether the propellant flow rates at the inlets of all propellants are in a normal state and whether there is pulsation in the secondary mixing combustion part, effectively ensuring the stability of combustion.

[0042] 5. The oxygen-enriched gas generation method with a wide-range adjustable mixing ratio provided by the present invention uses the oxygen-enriched gas generator to provide oxygen-enriched gas with a set temperature, composition, and pressure as the propellant according to the principle of simulation test, so as to provide oxygen-enriched gas closer to real conditions for subsequent gas-liquid nozzle tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic structural diagram of an embodiment of the oxygen-enriched gas generator with a wide-range adjustable mixing ratio of the present invention;

[0044] Figure 2 It is a longitudinal sectional view of the secondary mixing part of the generator in the embodiment of the present invention.

[0045] The reference numerals are as follows: 1 - generator body part, 2 - secondary mixing part of the generator, 3 - liquid-liquid injector, 4 - first oxidant pre-injection pressure monitoring device, 5 - fuel inlet, 6 - fuel pre-injection pressure monitoring device, 7 - first oxidant inlet, 8 - primary mixing combustion part, 9 - second oxidant inlet, 10 - chamber pressure monitoring device, 11 - throat, 12 - secondary injection annular cavity, 13 - secondary mixing combustion part, 14 - secondary injection holes, 15 - transition contraction section, 16 - throat flange, 17 - torch igniter. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] To make the advantages and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] In the ground test of the gas-liquid nozzle, oxygen-rich gas propellants with different components, temperatures, and pressures are required, which requires the oxygen-rich gas generator to operate normally under wide range of mixture ratio conditions. The commonly used method is to inject the excess oxidant through a liquid-liquid double centrifugal nozzle for the second time, but this injection may cause uneven mixing of the gas and may result in oscillating combustion in the oxygen-rich gas generator. To ensure that the oxygen-rich gas generator can operate smoothly within a wide mixture ratio range, the present invention incorporates a liquid collection chamber to secondarily incorporate a portion of the oxidant at a position downstream of the injector. The advantages of this secondary incorporation method are as follows: First, it meets the requirements of the high mixture ratio range under extreme operating conditions; in addition, the gas generating device can operate smoothly within a wide range of mixture ratios by reasonably distributing the flow rates of the two oxidants.

[0048] As Figure 1 shown, an oxygen-rich gas generator with a wide range adjustable mixture ratio includes a generator body part 1 and a generator secondary mixing part 2. Among them, the generator body part 1 includes a liquid-liquid injector 3 and a primary mixing combustion part 8, and the generator secondary mixing part 2 includes a secondary mixing combustion part 13 and a throat 11. Both the primary mixing combustion part 8 and the secondary mixing combustion part 13 are cavity structures. The outer wall of the liquid-liquid injector 3 is hermetically connected to the upper end of the primary mixing combustion part 8 and extends into the primary mixing combustion part 8 at the lower end. The lower end of the primary mixing combustion part 8 is fixedly connected to the upper end of the secondary mixing combustion part 13. The throat 11 is coaxially installed at the lower end of the secondary mixing combustion part 13 through a throat flange 16. The throat 11 can be designed as a subsonic throat or a sonic throat. In this embodiment, it is a subsonic throat.

[0049] Specifically, a first sealing flange is circumferentially arranged at the outer wall position near the lower end of the liquid-liquid injector 3, and a second sealing flange is arranged at the upper end of the primary mixing combustion part 8. The first sealing flange and the second sealing flange are axially connected by a plurality of fixing screws to achieve the sealing connection between the liquid-liquid injector 3 and the primary mixing combustion part 8. A third sealing flange is arranged at the lower end of the primary mixing combustion part 8, and a fourth sealing flange is arranged at the upper end of the secondary mixing combustion part 13. The third sealing flange and the fourth sealing flange are axially connected by a plurality of fixing screws to achieve the fixed connection between the primary mixing combustion part 8 and the secondary mixing combustion part 13.

[0050] In this embodiment, the liquid-liquid injector 3 is a liquid-liquid double centrifugal injector. A first oxidant inlet 7 and a fuel inlet 5 are provided on the side wall of the liquid-liquid injector 3 for inputting a given flow rate of the first oxidant and fuel.

[0051] A stepped groove is circumferentially provided at a position near the upper end inside the secondary mixing combustion part 13. A liquid injection ring is circumferentially arranged in the stepped groove. Preferably, the liquid injection ring is installed in the stepped groove by means of clearance assembly, which can facilitate the rapid replacement of liquid injection rings with different geometric parameters. In other embodiments of the present invention, the liquid injection ring can also be installed in the stepped groove of the secondary mixing combustion part 13 by means of welding assembly. An annular groove is circumferentially provided in the middle section of the outer side wall of the liquid injection ring, and the annular groove and the inner side wall at the corresponding position of the secondary mixing combustion part 13 form a secondary injection ring cavity 12. A second oxidant inlet 9 is provided on the side wall of the secondary mixing combustion part 13 at a position corresponding to the secondary injection ring cavity 12, and a plurality of downwardly inclined secondary injection holes 14 are circumferentially arranged on the side wall of the liquid injection ring at a position corresponding to the secondary injection ring cavity 12. A first oxidant and fuel with a given flow rate are respectively injected into the liquid-liquid injector 3 through the first oxidant inlet 7 and the fuel inlet 5, and after mixing, they burn in the primary mixing combustion part 8; a second oxidant with a given flow rate enters the secondary mixing combustion part 13 through the second oxidant inlet 9, the secondary injection ring cavity 12 and the secondary injection holes 14, and is mixed and burned with the first oxidant and fuel inside to form high-temperature and high-pressure oxygen-rich gas, which is used to provide oxygen-rich gas with a given flow rate and thermal parameters to the gas-liquid nozzle at the rear end, where the thermal parameters include the temperature, density and components of the oxygen-rich gas. Preferably, the included angle between the secondary injection holes 14 and the inner side wall of the liquid injection ring is 30° to 75°. In this embodiment, the number of the secondary injection holes 14 is 12, and the included angle between the secondary injection holes 14 and the inner side wall of the liquid injection ring is 45°.

[0052] In the present invention, the first oxidant and the second oxidant usually adopt the same oxidant. In this embodiment, both the first oxidant and the second oxidant are liquid oxygen, and the fuel is liquid kerosene. In other embodiments of the present invention, both the first oxidant and the second oxidant can also adopt oxidants such as dinitrogen tetroxide, and the fuel can adopt fuels such as hydrazine. Among them, the oxidant and the fuel can be normal-temperature propellants (i.e., hypergolic propellants), or low-temperature propellants.

[0053] If the first oxidant, the fuel and the second oxidant are all low-temperature propellants, a torch igniter 17 is arranged on the side wall of the primary mixing combustion part 8 at a position corresponding to the downstream of the liquid-liquid injector 3, for igniting the propellants entering the primary mixing combustion part 8. If the first oxidant, the fuel and the second oxidant are all normal-temperature propellants, the torch igniter 17 can be not arranged for ignition.

[0054] At the same time, in order to accelerate and rectify the generated oxygen-rich gas, the position near the outlet inside the secondary mixing combustion part 13 is set as a transition contraction section 15.

[0055] At the positions corresponding to the first oxidizer inlet 7 and the fuel inlet 5 in the liquid-liquid injector 3, there are two annular channels respectively. A first oxidizer pre-injection pressure monitoring device 4 and a fuel pre-injection pressure monitoring device 6 are respectively installed on the two annular channels. A second oxidizer pre-injection pressure monitoring device is installed on the channel of the second oxidizer inlet 9. The first oxidizer pre-injection pressure monitoring device 4, the fuel pre-injection pressure monitoring device 6 and the second oxidizer pre-injection pressure monitoring device are used to monitor the pre-injection pressures of the first oxidizer, the fuel and the second oxidizer respectively, and determine whether the propellant flow rates at the inlets of each propellant are in a normal state through the actually monitored pre-injection pressures. A chamber pressure monitoring device 10 is installed at the position on the side wall of the secondary mixing and combustion section 13 corresponding to the lower part of the secondary injection annular cavity 12, which is used to monitor the actual chamber pressure of the secondary mixing and combustion section 13, and compare the actual chamber pressure with the target preset chamber pressure to judge whether there is pulsation in the secondary mixing and combustion section 13. In this embodiment, the joints of the first oxidizer inlet 7, the fuel inlet 5, the first oxidizer pre-injection pressure monitoring device 4 and the fuel pre-injection pressure monitoring device 6 are respectively connected to the liquid-liquid injector 3 by welding.

[0056] Based on the above-mentioned oxygen-rich gas generator with a wide-range adjustable mixing ratio, the present invention also provides an oxygen-rich gas generation method with a wide-range adjustable mixing ratio, which specifically includes the following steps:

[0057] Step 1, preset the flow rate and thermodynamic parameters of the oxygen-rich gas, and obtain the flow rates of the fuel and the oxidizer required for the combustion organization of the oxygen-rich gas generator through thermodynamic calculation.

[0058] Step 2, preset the propellant mixing ratio of the liquid-liquid injector 3, and determine the flow rate of the first oxidizer according to the propellant mixing ratio of the liquid-liquid injector 3; then, in combination with the flow rate of the oxidizer required for the combustion organization of the oxygen-rich gas generator obtained in Step 1 and the flow rate of the first oxidizer, determine the flow rate of the second oxidizer;

[0059] Determine the target pre-injection pressures of the first oxidizer, the second oxidizer and the fuel respectively according to the flow rate of the first oxidizer, the flow rate of the second oxidizer, the flow rate of the fuel and the target chamber pressure of the oxygen-rich gas generator.

[0060] Step 3, calculate the internal aperture of the throat 11 according to the flow rate of the first oxidizer, the flow rate of the second oxidizer fuel, the flow rate of the fuel obtained in Step 1, the target outlet pressure of the throat 11 and the target chamber pressure of the oxygen-rich gas generator.

[0061] Step 4, select the corresponding throat 11 according to the internal aperture of the throat 11 calculated in Step 3, and then build the above-mentioned oxygen-rich gas generator with a wide-range adjustable mixing ratio.

[0062] Step 5: Input the first oxidizer and fuel with a given flow rate. After the first oxidizer and fuel are mixed in the liquid-liquid injector 3, they are burned in the primary mixing combustion section 8. Input the second oxidizer with a given flow rate, which is mixed and burned with the first oxidizer and fuel in the secondary mixing combustion section 13 to form oxygen-rich gas. The oxygen-rich gas flows out through the throat 11 and enters other downstream test components.

[0063] When the propellants are mixed and burned in the oxygen-rich gas generator, the actual pre-injection pressures of the corresponding ones are monitored respectively through the first oxidizer pre-injection pressure monitoring device 4, the fuel pre-injection pressure monitoring device 6, and the second oxidizer pre-injection pressure monitoring device. Read the actual pre-injection pressures of the first oxidizer, the second oxidizer, and the fuel monitored, and compare them with the target pre-injection pressures of the first oxidizer, the second oxidizer, and the fuel respectively to determine whether the flow rate inputs of the first oxidizer, the second oxidizer, and the fuel are normal.

[0064] In addition, the actual chamber pressure of the oxygen-rich gas generator is monitored through the chamber pressure monitoring device 10. Read the actual chamber pressure of the oxygen-rich gas generator monitored and compare it with the target chamber pressure of the oxygen-rich gas generator to determine whether there is pulsation in the oxygen-rich gas generator, so as to confirm the combustion stability state of the oxygen-rich gas generator.

[0065] As described above, it is only used to illustrate the technical solution of the present invention, rather than to limit it. For those of ordinary professional skills in the art, the specific technical solution recorded in the above embodiments can be modified, or some of the technical features can be equivalently replaced. These modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution protected by the present invention.

Claims

1. An oxygen-rich gas generator with a wide-range adjustable mixing ratio, characterized in that: It includes a generator body part (1) and a secondary mixing part (2) of the generator; the generator body part (1) includes a liquid-liquid injector (3) and a primary mixing and combustion part (8), and the secondary mixing part (2) of the generator includes a secondary mixing and combustion part (13) and a throat (11); Both the primary mixing and combustion part (8) and the secondary mixing and combustion part (13) are cavity structures; The outer side wall of the liquid-liquid injector (3) is hermetically connected to the upper end of the primary mixing and combustion part (8), and the lower end extends into the primary mixing and combustion part (8); the lower end of the primary mixing and combustion part (8) is fixedly connected to the upper end of the secondary mixing and combustion part (13); the throat (11) is coaxially installed at the lower end of the secondary mixing and combustion part (13); The side wall of the liquid-liquid injector (3) is provided with a first oxidant inlet (7) and a fuel inlet (5); A liquid injection ring is circumferentially arranged at a position near the upper end inside the secondary mixing and combustion part (13); an annular groove is circumferentially opened in the middle section of the outer side wall of the liquid injection ring, and the annular groove and the inner side wall of the secondary mixing and combustion part (13) at the corresponding position form a secondary injection ring cavity (12); a second oxidant inlet (9) is opened on the side wall of the secondary mixing and combustion part (13) corresponding to the secondary injection ring cavity (12); a plurality of downwardly inclined secondary injection holes (14) are circumferentially arranged on the side wall of the liquid injection ring corresponding to the secondary injection ring cavity (12).

2. The oxygen-rich gas generator with a wide-range adjustable mixing ratio according to claim 1, characterized in that: A torch igniter (17) is arranged on the side wall of the primary mixing and combustion part (8) at a position corresponding to the downstream of the liquid-liquid injector (3).

3. The oxygen-rich gas generator with a wide-range adjustable mixing ratio according to claim 1 or 2, characterized in that: The included angle between the secondary injection hole (14) and the inner side wall of the liquid injection ring is 30° - 75°.

4. The oxygen-rich gas generator with a wide-range adjustable mixing ratio according to claim 3, characterized in that: The included angle between the secondary injection hole (14) and the inner side wall of the liquid injection ring is 45°; The number of the secondary injection holes (14) is 12.

5. The oxygen-rich gas generator with a wide-range adjustable mixing ratio according to claim 4, characterized in that: The position near the outlet inside the secondary mixing and combustion part (13) is set as a transition contraction section (15); The liquid-liquid injector (3) is a liquid-liquid double centrifugal injector; The throat (11) is a subsonic throat or a sonic throat.

6. The oxygen-rich gas generator with a wide-range adjustable mixing ratio according to claim 5, characterized in that: A first oxidant pre-injection pressure monitoring device (4) is installed on the annular channel of the liquid-liquid injector (3) corresponding to the first oxidant inlet (7); A fuel pre-injection pressure monitoring device (6) is installed on the annular channel of the liquid-liquid injector (3) corresponding to the fuel inlet (5); A second oxidant pre-injection pressure monitoring device is installed on the channel of the second oxidant inlet (9); A chamber pressure monitoring device (10) is installed at a position on the side wall of the secondary mixing combustion part (13) corresponding to the lower part of the secondary injection annular cavity (12).

7. The oxygen-rich gas generator with a wide-range adjustable mixing ratio according to claim 6, characterized in that: A stepped groove is circumferentially formed at a position near the upper end inside the secondary mixing combustion part (13); The liquid injection ring is installed in the stepped groove of the secondary mixing combustion part (13) by means of clearance fitting or welding fitting.

8. The oxygen-rich gas generator with a wide-range adjustable mixing ratio according to claim 1, characterized in that: A first sealing flange is circumferentially arranged on the outer side wall near the lower end of the liquid-liquid injector (3), a second sealing flange is arranged at the upper end of the primary mixing combustion part (8), a third sealing flange is arranged at the lower end thereof, and a fourth sealing flange is arranged at the top of the secondary mixing combustion part (13); The first sealing flange and the second sealing flange are axially fixed by a plurality of fixing screws; The third sealing flange and the fourth sealing flange are axially fixed by a plurality of fixing screws; The throat (11) is coaxially installed at the lower end of the secondary mixing combustion part (13) through a throat flange (16).

9. A method for generating oxygen-rich gas with a wide-range adjustable mixing ratio, based on the oxygen-rich gas generator with a wide-range adjustable mixing ratio according to any one of claims 1-8, characterized in that, It includes the following steps: Step 1, preset the flow rate and thermodynamic parameters of the oxygen-rich gas, and obtain the flow rates of the fuel and oxidant required for the combustion organization of the oxygen-rich gas generator through thermodynamic calculation; Step 2, preset the propellant mixing ratio of the liquid-liquid injector (3), and determine the flow rate of the first oxidant according to the propellant mixing ratio of the liquid-liquid injector (3); Then, combine the flow rate of the oxidant obtained in Step 1 and the flow rate of the first oxidant to determine the flow rate of the second oxidant; Step 3, calculate the internal aperture of the throat (11) according to the flow rate of the first oxidant, the flow rate of the second oxidant, the flow rate of the fuel obtained in Step 1, the target outlet pressure of the throat (11), and the target chamber pressure of the oxygen-rich gas generator; Step 4, select the corresponding throat (11) according to the internal aperture of the throat (11) calculated in Step 3, and then build the oxygen-rich gas generator with a wide-range adjustable mixing ratio according to any one of claims 1-9; Step 5, input the first oxidant and fuel with a given flow rate. After the first oxidant and fuel are mixed in the liquid-liquid injector (3), they burn in the primary mixing combustion part (8); input the second oxidant with a given flow rate, and it is mixed and burned with the first oxidant and fuel in the secondary mixing combustion part (13) to form an oxygen-rich gas; the oxygen-rich gas flows out through the throat (11) and enters other downstream test components.

10. The method for generating an oxygen-rich gas with a wide-range adjustable mixing ratio according to claim 9, characterized in that: In Step 2, it further includes: respectively determining the target pre-injection pressures of the first oxidant, the second oxidant, and the fuel according to the flow rate of the first oxidant, the flow rate of the second oxidant, the flow rate of the fuel, and the target chamber pressure of the oxygen-rich gas generator. In step 5, the actual pre-injection pressures are respectively monitored by the first oxidant pre-injection pressure monitoring device (4), the fuel pre-injection pressure monitoring device (6), and the second oxidant pre-injection pressure monitoring device, and are respectively compared with the target pre-injection pressures of the first oxidant, the second oxidant, and the fuel to determine whether the flow inputs of the first oxidant, the second oxidant, and the fuel are normal; The actual chamber pressure of the oxygen-rich gas generator is monitored by the chamber pressure monitoring device (10) and compared with the target chamber pressure of the oxygen-rich gas generator to determine whether there is pulsation in the oxygen-rich gas generator.

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