A long-time running gain generator with adjustable gain spatial distribution

Abstract

The application relates to a long-time running gain generator with adjustable gain space distribution, which is provided with a secondary diluent nozzle and a secondary fuel nozzle on both sides of a vane outlet section; the two ends of the secondary fuel nozzle are respectively communicated with a secondary fuel supply cavity and a vane outlet end slope, and are used for spraying secondary fuel; the two ends of the secondary diluent nozzle are respectively communicated with a secondary diluent supply cavity and a vane outlet end slope, and are used for spraying mixed gas of the secondary fuel and the secondary diluent; by adjusting the proportion of the secondary fuel and the secondary diluent in the mixed gas, different length gain areas can be formed in a lasing cavity; a gas cooling structure for circulating cooling liquid and a liquid cooling structure for main diluent are embedded in the side wall of a combustion section, the gas cooling structure is communicated with a gas collection cavity and the inside of the combustion section, and the main diluent flows into the inside of the combustion section through a gas distribution hole to form a cooling gas film. The application realizes directional regulation of the length of the gain space, adopts a composite cooling mode of a gas film and a gas-liquid nested phase, and guarantees long-time stable work.

Description

Technical Field

[0001] This invention relates to the field of HF / DF chemical laser technology, and more particularly to HF / DF lasers capable of operating at tens to hundreds of watts per hour. It discloses a long-term operating gain generator with adjustable gain spatial distribution. Background Technology

[0002] Mid-infrared lasers, ranging from tens to hundreds of watts and capable of operating for extended periods (hours), have broad and significant application prospects in fields such as spectroscopy, medicine, communications, environmental monitoring, remote sensing, and infrared countermeasures. Among them, HF lasers cover the output wavelength range of 2.5–3.3 μm, and DF lasers cover the output wavelength range of 3.5–4.2 μm; both are indispensable core laser sources in the mid-infrared frequency band. The gain generator, as a core functional component of HF / DF chemical lasers, directly determines the laser gain generation effect and the overall output performance of the system.

[0003] Compared to large HF / DF lasers with power ratings of tens of thousands of watts or more, smaller HF / DF lasers with power ratings of hundreds of watts have a compact structure, but it is difficult to improve the laser gain extraction efficiency of the optical resonator. Furthermore, HF / DF lasers generally operate in a combustion-driven mode, where the chemical reaction of the feed gas continuously releases a large amount of heat energy during the gain generator's operation, creating a high-temperature, high-pressure region inside the cavity. Traditional high-power HF / DF lasers are designed for short-duration operation of a few seconds to tens of seconds, before the heat transfer process reaches a steady state, resulting in relatively low difficulty in thermal protection design and an inability to meet the requirements for continuous operation on an hourly basis. When the laser enters a long-term steady-state operating state, conventional cooling structures are insufficient, easily leading to performance degradation and reduced reliability of the gain generator, making it difficult to simultaneously achieve efficient laser gain extraction and long-term steady-state safe operation. Summary of the Invention

[0004] In view of this, the present invention provides a long-term operating gain generator with adjustable gain spatial distribution, which can realize directional control of the gain spatial length. At the same time, it adopts a composite cooling method combining gas film and gas-liquid nesting to ensure stable operation of the device for a long time and effectively improve the laser gain extraction efficiency of the optical resonator.

[0005] This invention is achieved through the following technical solution: A long-term gain generator with adjustable gain spatial distribution includes an injector, a combustion section, a nozzle array, and a lasing chamber connected in sequence. The nozzle array includes several linearly arranged blades, with the gap between two adjacent blades forming a main nozzle. The fluorinated gas flow generated in the combustion section is ejected from the main nozzle and injected into the lasing chamber. Secondary diluent nozzles and secondary fuel nozzles are sequentially arranged on both sides of the blade exit section along the fluorinated gas flow direction. The two ends of the secondary fuel nozzles are respectively connected to a secondary fuel supply chamber and a sloped end of the blade exit, for ejecting secondary fuel. The two ends of the secondary diluent nozzles are respectively connected to a secondary diluent supply chamber and a sloped end of the blade exit. The jet chamber is used to inject a mixture of auxiliary fuel and auxiliary diluent. By adjusting the ratio of auxiliary fuel to auxiliary diluent in the mixture, gain zones of different lengths can be formed in the jet chamber. Several layers of air-cooled structures and several layers of liquid-cooled structures are embedded circumferentially in the side wall of the combustion section. The air-cooled structures and liquid-cooled structures are arranged alternately. Circulating coolant is introduced into the liquid-cooled structures, and the main diluent is introduced into the air-cooled structures. The air-cooled structures are connected to the gas collection chamber located in the side wall of the inlet end of the combustion section. The gas collection chamber is connected to the interior of the combustion section through several gas distribution holes. The main diluent flows into the interior of the combustion section through the gas distribution holes and forms a cooling gas film along the side wall of the combustion section.

[0006] Furthermore, the ratio of secondary fuel to secondary diluent in the mixed gas is A:1, where A ranges from 0 to 2.5. The gain region length L and the ratio A satisfy a linear relationship using the formula L=b. k×A; where b and k are constants related to the blade design parameters.

[0007] Furthermore, the blade period of the nozzle array is 6-8 mm.

[0008] Furthermore, several auxiliary fuel nozzles are uniformly arranged along the blade height direction, and several auxiliary diluent nozzles are uniformly arranged along the blade height direction; the auxiliary fuel nozzles and auxiliary diluent nozzles located on the same side of the same blade have the same arrangement height for each layer along the blade height direction; the auxiliary fuel nozzles located on opposite sides of the same blade have different arrangement heights for each layer along the blade height direction.

[0009] Furthermore, both the auxiliary fuel nozzle and the auxiliary diluent nozzle are conical nozzles, and the outlet end of the auxiliary fuel nozzle is connected to the outlet end of the main nozzle.

[0010] Furthermore, both the inner sides of the top and bottom side walls of the combustion section inlet are provided with bosses, and two gas collection chambers are respectively provided in the inner sides of the top and bottom side walls of the combustion section inlet, corresponding to the bosses; each boss is provided with several gas distribution holes with axes parallel to the combustion section axis.

[0011] Furthermore, both the liquid-cooled structure and the gas-cooled structure are annular channels, arranged at intervals along the thickness direction of the combustion section sidewall; all gas-cooled structures are connected to the air intake pipe located on the top sidewall of the combustion section to achieve air intake; all gas-cooled structures are connected to the air outlet pipe located on the bottom sidewall of the combustion section for the gas within the gas-cooled structure to flow into the gas collection chamber.

[0012] Compared with existing technologies, the beneficial effects of this invention are: 1. This invention achieves gain spatial distribution control through adjustable ratio of auxiliary fuel and auxiliary diluent, and, in conjunction with a composite thermal protection structure of gas-liquid nested composite cooling and inner wall cooling gas film, enhances the heat dissipation and thermal protection capabilities of the combustion section, ensuring that the gain generator is stable and reliable under output conditions of tens to hundreds of watts, and can achieve long-term operation for hours.

[0013] 2. This invention achieves a linear correlation between the ratio of secondary fuel and secondary diluent and the length of the gain region, allowing for precise control of the gain distribution as needed, resulting in more concentrated gain and effectively improving the gain extraction efficiency of the optical resonator.

[0014] 3. The nozzle array period of the present invention is 6-8 mm, which, compared with the conventional array period, can compress the length of the gain region and make the gain more concentrated.

[0015] 4. The present invention, through the structure of the air distribution hole and the air collection cavity, enables the cooling air film to form uniformly and stably, thereby further improving the thermal protection effect of the combustion section.

[0016] 5. The present invention uses a multi-layered arrangement of secondary diluent nozzles and secondary fuel nozzles along the blade height, with staggered arrangement on both sides, to make the airflow mix more fully and the injection more stable, which is conducive to the uniform generation of gain. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the gain generator of the present invention.

[0018] Figure 2 for Figure 1 Side view.

[0019] Figure 3 This is a schematic diagram of the nozzle array structure of the present invention.

[0020] Figure 4 This is a cross-sectional view of the nozzle array of the present invention.

[0021] Figure 5 This is a schematic diagram of the gas-liquid nested structure of the combustion section.

[0022] Figure 6 This is a cross-sectional view of the combustion section.

[0023] Figure 7 This is a schematic diagram of the air distribution pore structure.

[0024] Among them, 1-injector, 2-combustion section, 3-nozzle array, 4-jet chamber, 5-blade, 6-main nozzle, 7-secondary diluent nozzle, 8-secondary fuel nozzle, 9-blade outlet end slope, 10-annular gas cooling channel, 11-annular liquid cooling channel, 12-gas distribution hole, 13-gas collection chamber. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0026] This invention provides a long-term operating gain generator with adjustable gain spatial distribution, such as... Figure 1 , 2 As shown, the gain generator includes an injector 1, a combustion section 2, a nozzle array 3, and a lasing cavity 4 connected in sequence. The injector 1 is a component for conveying and mixing the raw material gas, used to uniformly inject the main fuel, oxidant, and other raw material gas into the combustion section 2 according to the specified ratio. The combustion section 2 is the core region of the chemical reaction, where the raw material gas undergoes a combustion reaction, releasing heat and generating a high-temperature, high-pressure gas flow containing fluorine. The nozzle array 3 is a gas flow expansion and acceleration component, which can expand and accelerate the high-temperature, high-pressure fluorine-containing gas flow generated in the combustion section 2 to supersonic speed, and then eject it from the tail end of the nozzle array 3 and inject it into the lasing cavity 4. The lasing cavity 4 is a cavity for generating and amplifying laser gain, where the fluorine-containing gas flow and the auxiliary fuel react in the cavity to generate excited-state molecules, forming laser gain and realizing optical amplification output.

[0027] In this embodiment, the combustion section 2 is located between the injector 1 and the nozzle array 3, and its ends are welded to the injector 1 and the nozzle array 3 respectively. The lasing cavity 4 is located at the outlet of the nozzle array 3 and is connected to the flange of the nozzle array 3. The injector 1, combustion section 2, and lasing cavity 4 are made of stainless steel, which has good structural strength and corrosion resistance; the nozzle array 3 is made of high-temperature alloy GH3039, which can withstand the high-temperature and high-speed airflow environment inside the nozzle. The lasing cavity 4 is formed by 3D printing of stainless steel powder, which can realize the integrated molding of complex internal cavity structures and adapt to the flow field requirements of laser gain generation; the inner wall of the lasing cavity 4 can be provided with water cooling channels.

[0028] The connection direction between the injector 1 and the lasing cavity 4 is along the length direction of the gain generator, such as... Figure 3 As shown, the nozzle array 3 includes several blades 5 arranged linearly along the width direction of the gain generator. The blades 5 are divided into an inlet section, a throat section and an outlet section in sequence along the flow direction of the fluorine-containing gas. The two sides of the outlet section (the two sides along the width direction of the gain generator) are inclined surfaces, which are the blade outlet end inclined surfaces 9.

[0029] The gap between two adjacent blades 5 forms the main nozzle 6. The inlet section of the main nozzle 6 is between the adjacent blades 5, and the throat of the main nozzle 6 is between the adjacent blades 5. The outlet section of the blades 5 corresponds to the expansion section of the main nozzle 6. The main nozzle 6 is a two-dimensional planar nozzle. The fluorine-containing gas flow generated by the reaction in the combustion section 2 is expanded and accelerated through the main nozzle 6 and then injected into the lasing chamber 4.

[0030] In this embodiment, as Figure 4 As shown, the nozzle array 3 has an exit size of 146 mm × 25 mm, and the blades 5 have a period of 6 mm, with a total of 24 blades 5 arranged linearly. Traditional high-power HF / DF lasers have strong gain, and in order to reduce power density, the gain region length usually needs to be lengthened, with the blade 5 period typically greater than 12 mm. However, the present invention is used in a small gain generator for ultra-long-term operation at the hundreds of watts level. The 6 mm ultra-short period blades 5, unlike the long period of traditional high-power lasers, can effectively compress the gain region length, making the laser gain more concentrated and improving the gain extraction efficiency of the optical resonator.

[0031] Both sides of the exit section of blade 5 are provided with secondary diluent nozzles 7 and secondary fuel nozzles 8 in sequence along the direction of fluorine-containing gas flow. The two ends of the secondary fuel nozzle 8 are connected to the secondary fuel supply chamber and the blade exit end inclined surface 9, respectively, for spraying secondary fuel. The two ends of the secondary diluent nozzle 7 are connected to the secondary diluent supply chamber and the blade exit end inclined surface 9, respectively, for spraying a mixture of secondary fuel and secondary diluent. By adjusting the ratio of secondary fuel to secondary diluent in the mixture, gain zones of different lengths can be formed in the lasing chamber 4.

[0032] The auxiliary fuel nozzles 8 located on both sides of the exit section of blade 5 have inlets connected to auxiliary fuel supply chambers arranged along the blade height, and outlets connected to the inclined surface 9 at the exit end of the blade on the same side. Auxiliary fuel from the auxiliary fuel supply chambers is injected into the expansion section of the main nozzle 6 through the auxiliary fuel nozzles 8. Similarly, the auxiliary diluent nozzles 7 located on both sides of the exit section of blade 5 have inlets connected to auxiliary diluent supply chambers arranged along the blade height, and outlets connected to the inclined surface 9 at the exit end of the blade on the same side. The mixed gas from the auxiliary diluent supply chambers is injected into the expansion section of the main nozzle 6 through the auxiliary diluent nozzles 7.

[0033] More specifically, several auxiliary fuel nozzles 8 are evenly distributed along the height of the blade 5 on each side of the blade exit section, and several auxiliary diluent nozzles 7 are also evenly distributed along the height of the blade 5 on each side of the blade exit section. The exits of all auxiliary fuel nozzles 8 and auxiliary diluent nozzles 7 are located on the inclined surface 9 at the blade exit end. Among them, the auxiliary diluent nozzles 7 are close to the throat of the main nozzle 6, and the auxiliary fuel nozzles 8 are close to the exit end of the main nozzle 6.

[0034] The auxiliary fuel nozzle 8 and auxiliary diluent nozzle 7, located on the same side of the same blade 5, are arranged at the same height along the blade 5 layer by layer, ensuring the synchronization of auxiliary fuel and mixed gas injection on one side and making the airflow mixing more uniform. The auxiliary fuel nozzles 8, located on opposite sides of the same blade 5, are arranged at different heights along the blade 5 layer by layer, which can avoid mutual interference between the airflow on both sides, ensure the stability of airflow injection, and provide a flow field basis for the stable generation of laser gain.

[0035] In this embodiment, both the auxiliary fuel nozzle 8 and the auxiliary diluent nozzle 7 are conical nozzles. The outlet end of the auxiliary fuel nozzle 8 is connected to the outlet end of the main nozzle 6. The axes of both the auxiliary fuel nozzle 8 and the auxiliary diluent nozzle 7 form a 25° angle with the axis of the main nozzle 6. The distance between the intersection of the axis of the auxiliary fuel nozzle 8 and the inclined surface 9 at the blade outlet end, and the intersection of the axis of the auxiliary diluent nozzle 7 and the inclined surface 9 at the blade outlet end, is 4 mm.

[0036] The blade 5 of the nozzle array 3 of the present invention has a blade period (referring to the blade width) of 6-8 mm, which can compress the gain region length. At the same time, by using a mixture of N2 or He with a certain proportion of auxiliary fuel as a mixed gas to be ejected from the auxiliary diluent nozzle 7, the gain region length and spatial distribution of gain can be further controlled. For DF lasers, the following combinations can be used: (1) the auxiliary fuel ejected from the auxiliary fuel nozzle 8 is D2, and the mixed gas ejected from the auxiliary diluent nozzle 7 is D2 and He; (2) the auxiliary fuel ejected from the auxiliary fuel nozzle 8 is D2, and the mixed gas ejected from the auxiliary diluent nozzle 7 is D2 and N2.

[0037] For HF lasers, the following combinations can be used: (1) the auxiliary fuel ejected from the auxiliary fuel nozzle 8 is H2, and the mixed gas ejected from the auxiliary diluent nozzle 7 is H2 and He; (2) the auxiliary fuel ejected from the auxiliary fuel nozzle 8 is H2, and the mixed gas ejected from the auxiliary diluent nozzle 7 is H2 and N2.

[0038] The ratio of secondary fuel to secondary diluent (N2 or He) in the mixed gas is A:1, where the ratio coefficient A ranges from 0 to 2.5. The gain region length L and the ratio coefficient A satisfy a linear relationship formula: L = b k×A, where b and k are constants related to the design parameters of blade 5. In this embodiment, the value of b ranges from 18 to 22, and the value of k ranges from 3.6 to 5.6. By adjusting the ratio of auxiliary fuel to auxiliary diluent in the mixed gas, the reaction rate and reaction range between the fluorine-containing gas flow and the auxiliary fuel can be changed, thereby achieving directional and linear control of the gain region length within the lasing cavity 4. This adapts to the gain concentration requirements of small HF / DF lasers and improves the extraction efficiency of laser gain by the optical resonator. For example, this gain generator uses an NF3+C2H4+N2+D2 reaction system to output a 3.5-4.2μm DF laser. The mixed gas uses D2 / N2 with a ratio of 2:1, and the gain region length can be controlled to around 10mm.

[0039] like Figure 5 As shown, the sidewall of combustion section 2 is embedded with several layers of air-cooled structures and several layers of liquid-cooled structures along the circumferential direction. The air-cooled structure is an annular gas cooling channel 10, and the liquid-cooled structure is an annular liquid cooling channel 11. The air-cooled and liquid-cooled structures are arranged at intervals along the thickness direction of the sidewall of combustion section 2, forming a gas-liquid nested composite cooling structure. The circulating coolant in the annular liquid cooling channel 11 is room temperature deionized water with a liquid pressure of 0.2-0.5 MPa and a liquid flow rate of 8-15 m / s. The main diluent in the annular gas cooling channel 10 is room temperature N2 with a gas pressure of 0.3-0.5 MPa. The dual gas-liquid cooling method achieves efficient cooling of combustion section 2, meeting the thermal protection requirements for long-term operation at the hour level.

[0040] At the same time, such as Figure 6 As shown, the air-cooled structure is connected to the gas collection chamber 13 located in the side wall of the inlet end of the combustion section 2. The gas collection chamber 13 is connected to the internal chamber (combustion chamber) of the combustion section 2 through several gas distribution holes 12. The main diluent flows into the combustion chamber through the gas distribution holes 12 and forms a cooling gas film along the side wall of the combustion section 2.

[0041] Specifically, such as Figure 7 As shown, protrusions are provided on the inner sides of the top and bottom sidewalls of the inlet end of combustion section 2. Two gas collecting chambers 13 are respectively located on the inner sides of the top and bottom sidewalls of the inlet end of combustion section 2, corresponding to the protrusions. Each protrusion has several gas distribution holes 12 evenly arranged along the width direction of the gain generator. The axis of the gas distribution holes 12 is parallel to the axis of combustion section 2, that is, the gas distribution holes 12 are arranged along the length direction of the gain generator. The axis of the gas distribution holes 12 is 0.5 mm away from the inner sidewall of the sidewall of combustion section 2, the diameter of the gas distribution holes 12 is 0.6 mm, and the spacing between adjacent gas distribution holes 12 is 3 mm. One end of the gas distribution hole 12 passes through the gas collecting chamber 13, and the other end is connected to the interior of combustion section 2, so that the main diluent inside the gas collecting chamber 13 flows evenly into the interior of combustion section 2.

[0042] In specific implementation, the distance between the axis of the air distribution hole 12 and the inner side wall of the combustion section 2 can be 0.5mm to 1mm, the diameter of the air distribution hole 12 can be 0.5mm to 1mm, and the spacing between adjacent air distribution holes 12 can be 2 to 5mm.

[0043] In this embodiment, all air-cooled structures are connected to the intake pipe located on the top sidewall of combustion section 2 to achieve stable intake of the main diluent. All air-cooled structures are also connected to the outlet pipe located on the bottom sidewall of combustion section 2. The main diluent N2 in the air-cooled structure cools combustion section 2 through an annular gas cooling channel 10. After absorbing heat, the N2 then flows into the gas collection chamber 13 through the outlet pipe, and then flows evenly into the combustion chamber inside combustion section 2 through the gas distribution hole 12. The outlet velocity of the gas distribution hole 12 is 100-150 m / s.

[0044] After being sprayed through the gas distribution hole 12, the main diluent N2 forms a continuous cooling gas film along the side wall of the combustion section 2. This cooling gas film isolates the high-temperature gas from the inner wall of the combustion section 2 to control the temperature of the inner wall of the combustion section 2 and further improve the cooling and protection effect. At the same time, the main diluent can also participate in the airflow regulation in the cavity, optimize the reaction environment, avoid the thermal damage caused by the high-temperature gas directly contacting the side wall of the combustion section 2, and ensure the stable operation of the combustion section 2 for a long time.

[0045] This invention achieves linear control of the gain region length and optimization of the gain spatial distribution within the lasing cavity 4 through the ultra-short cycle blade 5 and the adjustable ratio of auxiliary fuel / diluent, effectively improving the gain extraction efficiency of the optical resonator of a small HF / DF laser. Simultaneously, it employs a thermal protection structure combining gas-liquid nested composite cooling and an inner wall cooling gas film, ensuring that the gain generator can achieve stable operation for hours at output levels ranging from tens to hundreds of watts. The overall structure is compact, reliable, and flexible in control, fully meeting the long-term, high-efficiency, and highly stable operating requirements of mid-infrared chemical laser systems.

[0046] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A long-term operating gain generator with adjustable gain spatial distribution, the gain generator comprising an injector, a combustion section, a nozzle array, and a lasing chamber connected in sequence, the nozzle array comprising a plurality of linearly arranged blades, the gap between two adjacent blades forming a main nozzle, and the fluorine-containing gas flow generated in the combustion section being ejected from the main nozzle and injected into the lasing chamber, characterized in that: Both sides of the blade exit section are provided with a secondary diluent nozzle and a secondary fuel nozzle in sequence along the direction of the fluorine-containing gas flow. The two ends of the secondary fuel nozzle are respectively connected to the secondary fuel supply chamber and the inclined surface of the blade exit end, and are used to spray out secondary fuel. The two ends of the secondary diluent nozzle are respectively connected to the secondary diluent supply chamber and the inclined surface of the blade exit end, and are used to spray out a mixed gas of secondary fuel and secondary diluent. By adjusting the ratio of secondary fuel to secondary diluent in the mixed gas, gain zones of different lengths can be formed in the lasing chamber. Several layers of air-cooled structures and several layers of liquid-cooled structures are embedded circumferentially inside the sidewall of the combustion section. The air-cooled structures and liquid-cooled structures are arranged alternately. Circulating coolant is introduced into the liquid-cooled structures, and the main diluent is introduced into the air-cooled structures. The air-cooled structures are connected to the gas collection chamber located in the sidewall of the inlet end of the combustion section. The gas collection chamber is connected to the interior of the combustion section through several gas distribution holes. The main diluent flows into the interior of the combustion section through the gas distribution holes and forms a cooling gas film along the sidewall of the combustion section.

2. The gain generator with adjustable gain spatial distribution for long-term operation as described in claim 1, characterized in that, The ratio of secondary fuel to secondary diluent in the mixed gas is A:1, where A ranges from 0 to 2.

5. The gain region length L and the ratio A satisfy a linear relationship using the formula L=b. k×A; where b and k are constants related to the blade design parameters.

3. The gain generator with adjustable gain spatial distribution for long-term operation as described in claim 1 or 2, characterized in that, The blade period of the nozzle array is 6-8 mm.

4. The gain generator with adjustable gain spatial distribution for long-term operation as described in claim 1, characterized in that, Several auxiliary fuel nozzles are evenly distributed along the blade height direction, and several auxiliary diluent nozzles are evenly distributed along the blade height direction; The auxiliary fuel nozzles and auxiliary diluent nozzles located on the same side of the same blade are arranged at the same height for each layer along the blade height direction; The auxiliary fuel nozzles, located on both sides of the same blade, have different installation heights for each layer along the blade height direction.

5. The gain generator with adjustable gain spatial distribution for long-term operation as described in claim 1, characterized in that, Both the auxiliary fuel nozzle and the auxiliary diluent nozzle are conical nozzles, and the outlet end of the auxiliary fuel nozzle is connected to the outlet end of the main nozzle.

6. The gain generator with adjustable gain spatial distribution for long-term operation as described in claim 4 or 5, characterized in that, The inner sides of the top and bottom side walls of the combustion section inlet are provided with protrusions, and two gas collection chambers are respectively provided in the inner sides of the top and bottom side walls of the combustion section inlet, corresponding to the protrusions; each protrusion is provided with several gas distribution holes with the axis parallel to the axis of the combustion section.

7. The gain generator with adjustable gain spatial distribution for long-term operation as described in claim 6, characterized in that, Both the liquid cooling structure and the gas cooling structure are annular channels, and they are arranged at intervals along the thickness direction of the combustion section sidewall. All gas cooling structures are connected to the air intake pipe located on the top sidewall of the combustion section to achieve air intake. All gas cooling structures are connected to the air outlet pipe located on the bottom sidewall of the combustion section for the gas inside the gas cooling structure to flow into the gas collection chamber.

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