Diffuser and fuel gas cooling device

Abstract

The invention provides a diffuser and a fuel gas cooling device, and relates to the technical field of aerospace, the diffuser is mainly composed of a plurality of diffuser units which are connected end to end in a sealed mode, the diffuser can provide a vacuum environment for a vacuum cabin of an engine, the diffuser units are of tubular structures, and when fuel gas is injected to the diffuser units, the fuel gas is cooled through the diffuser units. The pressure intensity of the vacuum chamber is reduced, a vacuum environment is achieved, the diffuser units located at the two ends are installed inside and outside the vacuum chamber at the same time, the diffuser unit located in the middle is installed at an outlet of the vacuum chamber, and therefore the diffuser units of different sections can be replaced according to needs. The different diffuser units located in the vacuum cabin can adapt to engines of different ranges and models, any section of diffuser unit can be independently replaced in time when damaged, the narrow space of the vacuum cabin and the cabin passing flange of the vacuum cabin can be fully utilized, and the cost of the diffuser can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of aerospace technology, and in particular to a diffuser and a gas cooling device. Background Art

[0002] When developing a new attitude and orbit control rocket engine, determining the high-altitude characteristics of the rocket engine is one of the important tasks during the engine ground test. The thrust of the rocket engine increases with the increase of altitude until it reaches the maximum thrust in a vacuum environment. The ambient pressure of the attitude and orbit control rocket engine is very low when it is working. During the ground test, a low-pressure vacuum environment at the corresponding altitude must be established to truly simulate the high-altitude characteristics of the rocket engine. In order to reduce the load on the vacuum equipment, a diffuser is generally used to establish the low-pressure environment required for the test.

[0003] In high-altitude simulation tests, the diffuser is the simplest way to evacuate air. Its typical structure is to connect a supersonic diffuser to the engine nozzle. One end of the diffuser is connected to the vacuum chamber of the test, and the other end is connected to the evacuation equipment (or the atmosphere). The gas from the nozzle is sprayed to the inlet of the diffuser. The high-speed flowing gas has an induced effect on the surrounding gas, so that a low-pressure environment lower than the diffuser outlet is generated and maintained at the engine of the test vacuum chamber.

[0004] However, the traditional diffuser is an integral structure, with one end of the diffuser installed inside the vacuum chamber and the other end installed outside the vacuum chamber. However, this type of diffuser can only adapt to a small range of engine models. At the same time, when part of the diffuser is damaged, the entire diffuser needs to be replaced, resulting in increased costs. Summary of the invention

[0005] In view of this, one of the objects of the present invention is to provide a diffuser to solve the technical problems that the diffuser in the prior art is an integral structure, when a part of the section is damaged, the whole diffuser needs to be replaced, resulting in increased costs, and the integral diffuser can only adapt to a small range of engine models.

[0006] A second object of the present invention is to provide a fuel gas cooling device containing a novel diffuser.

[0007] In order to achieve one of the above-mentioned purposes, the present invention provides a diffuser for providing a vacuum environment for a vacuum chamber of an engine, comprising a plurality of diffuser units sealed at both ends, wherein the diffuser units are tubular structures, and the diffuser units located at both ends are installed at the inside and outside of the vacuum chamber at the same time, and the diffuser unit located in the middle is installed at the outlet of the vacuum chamber.

[0008] Optionally, the outer layer of the diffuser unit is provided with an interlayer water cooling structure.

[0009] Optionally, the interlayer water-cooling structure is an annular structure, which is sleeved on the outer wall of the diffuser unit.

[0010] Optionally, a spiral baffle is provided in the interlayer water cooling structure.

[0011] Optionally, the interlayer water-cooling structure comprises a water inlet pipe and a water outlet pipe, the water inlet pipe is located below the interlayer water-cooling structure, and the water outlet pipe is located above the interlayer water-cooling structure.

[0012] Optionally, the diffuser unit includes three sections, namely a first diffuser unit, a second diffuser unit and a third diffuser unit. The first diffuser unit, the second diffuser unit and the third diffuser unit are sealed and connected end to end in sequence. The first diffuser unit is located inside the vacuum chamber, the second diffuser unit is located at the outlet of the vacuum chamber, and the third diffuser unit is located outside the vacuum chamber.

[0013] Optionally, the first-stage diffuser unit is cylindrical or conical, and is connected to the second-stage diffuser unit by a slip-on flange.

[0014] Optionally, the interlayer water-cooling structure of the first-stage diffuser unit and the third-stage diffuser unit are both single-layered, and the interlayer water-cooling structure of the second-stage diffuser unit is double-layered.

[0015] Optionally, the side wall of the third-section diffuser unit is corrugated.

[0016] In order to achieve the second objective above, the present invention provides a gas cooling device, comprising any of the diffusers described above, and also comprising a gas cooler, wherein the tail end of the diffuser is connected and communicated with the head end of the gas cooler.

[0017] The diffuser provided by the present invention has the following technical effects:

[0018] This type of diffuser is mainly composed of several sections of diffuser units sealed at the ends, which can provide a vacuum environment for the vacuum chamber of the engine. The diffuser unit is a tubular structure. When the fuel gas is injected into the diffuser unit, the pressure of the vacuum chamber is reduced to achieve a vacuum environment. The diffuser units at both ends are installed inside and outside the vacuum chamber at the same time, and the diffuser unit in the middle is installed at the outlet of the vacuum chamber. In this way, different sections of diffuser units can be replaced as needed. Different diffuser units in the vacuum chamber can adapt to different types of engines, and if any section of the diffuser unit is damaged, it can be replaced separately in time, which can fully utilize the narrow space of the vacuum chamber and its through-chamber flange and reduce the cost of the diffuser. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 is a schematic structural diagram of diffuser embodiment 1 of the present invention;

[0021] Figure 2 Contains Figure 1 A schematic diagram of the structure of the gas cooling device of the middle diffuser;

[0022] Figure 3 yes Figure 2 A schematic diagram of the structure of the elbow pipe of the gas cooling device;

[0023] Figure 4 is a schematic structural diagram of a diffuser embodiment 2 of the present invention;

[0024] Figure 5 is the cabin pressure during the pulse ignition of the engine with a gas flow rate of 4 g / s in Example 1;

[0025] Figure 6 It is the cabin pressure during the pulse ignition of the engine with a gas flow rate of 10g / s in Example 1.

[0026] in, Figure 1-Figure 6 :

[0027] 1. First diffuser unit; 11. First water inlet pipe; 12. Second water outlet pipe;

[0028] 2. The second diffuser unit; 21. The second water inlet pipe; 22. The second water outlet pipe;

[0029] 3. The third diffuser unit; 31. The third water inlet pipe; 32. The third water outlet pipe;

[0030] 4. Spiral baffles;

[0031] 5. Loop flange structure; 51. Loop flat bearing; 52. Spring snap ring; 53. Loop flange;

[0032] 6. Sandwich water cooling structure; 7. Vacuum chamber; 8. Water inlet pipeline; 9. Water outlet pipeline;

[0033] 100. Diffuser;

[0034] 200, gas cooler; 201, inlet section; 202, center section; 203, outlet section; 204, elbow. DETAILED DESCRIPTION

[0035] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0036] The following is combined with specific Figure 1-6 The diffuser and the gas cooling device of the present invention are described in detail with Examples 1-2.

[0037] Embodiment 1:

[0038] like Figure 1 , which is a schematic diagram of the structure of a diffuser provided in this embodiment. The diffuser 100 utilizes the exhaust process of the engine to evacuate the vacuum chamber 7, so as to achieve the purpose of simulating the high vacuum working environment of the engine.

[0039] The diffuser of this embodiment is cylindrical and is suitable for engines with a flow rate of 0.4 to 16 g / s.

[0040] Specifically, the diffuser 100 includes a plurality of diffuser units that are sealed and connected end to end. The diffuser units are all tubular structures, and the gas can pass through the tube cavity of the diffuser unit. The present embodiment preferably includes three diffuser units, such as Figure 1 As shown, the three-section diffuser unit is respectively a first-section diffuser unit 1, a second-section diffuser unit 2 and a third-section diffuser unit 3. The first-section diffuser unit 1, the second-section diffuser unit 2 and the third-section diffuser unit 3 are sealed and connected end to end in sequence. The first-section diffuser unit 1 is located inside the vacuum chamber 7, the second-section diffuser unit 2 is located at the outlet of the vacuum chamber 7, and the third-section diffuser unit 3 is located outside the vacuum chamber 7. Since the diffuser units are spliced, when one of the diffuser units is damaged, it is sufficient to disassemble the diffuser unit separately without replacing the entire diffuser, thereby reducing the cost.

[0041] The first-stage diffuser unit 1 of this embodiment is in a columnar structure and is connected to the second-stage diffuser unit 2 via a slip-on flange 53 .

[0042] Since the first-stage diffuser unit 1 of the present embodiment has a cylindrical structure, this diffuser can adapt to engines with a fuel gas flow rate of 0.4 to 16 g / s.

[0043] The modified diffuser 100 (the first diffuser unit 1 is a cylindrical structure) was used to conduct several engine ignition tests. During the test, the pressure in the vacuum chamber 7 met the technical index requirements. After the diffuser 100 was modified, the vacuum degree of the vacuum chamber 7 during the engine ignition process was better than that before the diffuser 100 was modified. The test data are shown in FIG. Figure 5 and Figure 6 shown.

[0044] like Figure 5 As shown, before the diffuser 100 was modified, when the cabin pressure had not reached equilibrium, the cabin pressure was already close to 100 Pa and had an upward trend. After the diffuser was modified, the cabin pressure was stabilized within 20 Pa during the pulse ignition of the engine with a flow rate of 4 g / s.

[0045] like Figure 6 As shown, during the 10g / s flow rate engine test, the stable pressure in the cabin was about 200Pa before the modification and about 80Pa after the modification, which greatly improved the vacuum degree in the cabin during the test.

[0046] In this embodiment, the first-stage diffuser unit 1 and the second-stage diffuser unit 2 are connected by a slip-on flange 53 structure 5 , and the second-stage diffuser unit 2 and the third-stage diffuser unit 3 are also connected by a slip-on flange 53 structure 5 .

[0047] In detail, the slip-on flange 53 structure 5 includes a slip-on flat support 51, a spring snap ring 52 and a slip-on flange 53. The slip-on flat support 51 and the slip-on flange 53 are both provided with grooves corresponding to the spring snap ring 52, and the groove edges are both provided with smooth fillets to facilitate the installation of the slip-on flange 53. When not in operation, the slip-on flange 53 can be pressed down, and the spring snap ring 52 is compressed and retracted due to the force, and the slip-on flange 53 slides out of the groove as the force acts. When in operation, the slip-on flange 53 is lifted up, and the spring snap ring 52 is compressed and retracted in the groove until the groove of the slip-on flange 53 matches the spring snap ring 52, and then the installation is in place.

[0048] Continue to see Figure 1 As shown, the outer layers of the first-stage diffuser unit 1, the second-stage diffuser unit 2 and the third-stage diffuser unit 3 all have a sandwich water-cooling structure 6, which is an annular structure and is sleeved on the outer wall of the diffuser unit.

[0049] The sandwich water-cooling structure 6 of the first-stage diffuser unit 1 of the present embodiment includes a first water inlet pipe 11 and a first water outlet pipe 12. The first water inlet pipe 11 and the first water outlet pipe 12 enter and exit the vacuum chamber 7 through a chamber flange plate. The inlet and outlet water pipe interfaces are preferably of nozzle type. The first water inlet pipe 11 is located below the sandwich water-cooling structure 6, and the first water outlet pipe 12 is located above the sandwich water-cooling structure 6. At the same time, the sandwich water-cooling structure 6 also has a spiral baffle 4. The spiral baffle and the water-cooling pipe are used in a bottom-in and top-out manner to ensure that the cooling water can flow fully in the sandwich water-cooling structure 6, thereby improving the cooling effect.

[0050] The interlayer water cooling structure 6 inside the vacuum chamber 7 and the interlayer water cooling structure 6 outside the vacuum chamber 7 operate relatively independently. Figure 1 As shown, the interlayer water cooling structure 6 of the second-stage diffuser unit 2 is double-layered, and a spiral baffle 4 is arranged inside the interlayer water cooling structure 6 , which is also an annular structure and is sleeved on the outer wall of the second-stage diffuser unit 2 .

[0051] The interlayer water cooling structure 6 of the second-stage diffuser unit 2 also includes a second water inlet pipe 21 and a second water outlet pipe 22. The second water inlet pipe 21 is located below the second-stage diffuser unit 2 and is connected to the inner layer of the interlayer water cooling structure 6. The second water outlet pipe 22 is located above the second-stage diffuser unit 2 and is connected to the outer layer of the interlayer water cooling structure 6. The spiral baffle 4 is passed to ensure the cooling effect of the second-stage diffuser unit 2 when the gas passes through.

[0052] Similarly, the third-section diffuser unit 3 also includes a sandwich water-cooling structure 6, which is a single-layer structure having a third water inlet pipe 31 and a third water outlet pipe 32. The third water inlet pipe 31 is located below the sandwich water-cooling structure 6, and the third water outlet pipe 32 is located above the sandwich water-cooling structure 6. The purpose is also to ensure that the cooling water can flow fully in the sandwich water-cooling structure 6, thereby improving the cooling effect.

[0053] In addition, the third-stage diffuser unit 3 of this embodiment adopts a corrugated structure, on the one hand to prevent deformation caused by alternating hot and cold, and on the other hand to facilitate installation with the second-stage diffuser unit 2 and the gas cooler 200.

[0054] This embodiment also provides a gas cooling device, such as Figure 2 As shown, the gas cooling device includes the above-mentioned diffuser 100 and also includes a gas cooler 200. The tail end of the diffuser 100 is connected and communicated with the head end of the gas cooler 200. The gas cooler 200 can reduce the high-temperature gas generated by the engine from 3000K to below 370K to reduce the heat capacity of the engine gas and reduce the ejector exhaust load.

[0055] like Figure 3As shown, the gas cooler 200 includes an inlet section 201, a center section 202 and an outlet section 203. A water inlet conveying pipe 8 and a water outlet conveying pipe 9 are provided below the diffuser 100 and the gas cooler 200. The water inlet conveying pipe 8 and the water outlet conveying pipe 9 are both laid horizontally. The water inlet conveying pipe 8 is located above the water outlet conveying pipe 9. The water inlet conveying pipe 8 is connected to the water inlet pipe of the diffuser 100 and the water inlet pipe of the gas cooler 200. The water outlet conveying pipe 9 is connected to the water outlet pipe of the diffuser 100 and the water outlet pipe of the gas cooler 200.

[0056] Inlet section 201: The inlet is connected to the diffuser 100 by a slip-on flange 53, the diameter is DN550mm, the inlet section 201 is designed as a conical structure, the cooling form of the flange and the conical section is a sandwich water cooling structure 6, and the spiral plate and other methods are used to ensure that there is no dead angle in the cooling.

[0057] Central section 202: The main cooling structure is a tube bundle type. Figure 4 The elbow joint 204 shown is connected, the gas flow is the pipe layer, the cooling water flow is the shell layer, the recommended specification of the cooling pipe is Φ38×3mm, and the tube bundle inlet adopts the following methods: setting a guide cone, a high-temperature resistant baffle, spraying a high-temperature resistant coating, etc. to ensure the uniformity of the gas and improve the ablation resistance of the equipment. The central section 202 cylinder adopts a sandwich water-cooling structure 6, and ensures that there is no dead angle in cooling through spiral plates and other methods. An exhaust port is set on the top, and the inlet section 201 and the central section 202 are connected by a flange.

[0058] Outlet section 203: Designed as a single-wall conical structure, the outlet is connected to the gas channel by welding, and the diameter is DN650mm.

[0059] Embodiment 2:

[0060] like Figure 4 , which is a schematic diagram of the structure of a diffuser provided in this embodiment. The diffuser 100 utilizes the exhaust process of the engine to evacuate the vacuum chamber 7, so as to achieve the purpose of simulating the high vacuum working environment of the engine.

[0061] The diffuser of this embodiment is of a secondary throat type, which can adapt to engines with a fuel gas flow rate of 16 to 40 g / s.

[0062] Specifically, the diffuser 100 includes a plurality of diffuser units that are sealed and connected end to end. The diffuser units are all tubular structures, and the gas can pass through the tube cavity of the diffuser unit. The present embodiment preferably includes three diffuser units, such as Figure 4As shown, the three-section diffuser unit is respectively a first-section diffuser unit 1, a second-section diffuser unit 2 and a third-section diffuser unit 3. The first-section diffuser unit 1, the second-section diffuser unit 2 and the third-section diffuser unit 3 are sealed and connected end to end in sequence. The first-section diffuser unit 1 is located inside the vacuum chamber 7, the second-section diffuser unit 2 is located at the outlet of the vacuum chamber 7, and the third-section diffuser unit 3 is located outside the vacuum chamber 7. Since the diffuser units are spliced, when one of the diffuser units is damaged, it is sufficient to disassemble the diffuser unit separately without replacing the entire diffuser, thereby reducing the cost.

[0063] The first-stage diffuser unit 1 of the present embodiment is of a secondary throat-like structure and is connected to the second-stage diffuser unit 2 by a slip-on flange 53 .

[0064] Since the first-stage diffuser unit 1 of the present embodiment is a secondary throat-like structure, this type of diffuser can adapt to engines with a larger flow rate, for example, 16 to 40 g / s.

[0065] In this embodiment, the first-stage diffuser unit 1 and the second-stage diffuser unit 2 are connected by a slip-on flange 53 structure 5 , and the second-stage diffuser unit 2 and the third-stage diffuser unit 3 are also connected by a slip-on flange 53 structure 5 .

[0066] In detail, the slip-on flange 53 structure 5 includes a slip-on flat support 51, a spring snap ring 52 and a slip-on flange 53. The slip-on flat support 51 and the slip-on flange 53 are both provided with grooves corresponding to the spring snap ring 52, and the groove edges are both provided with smooth fillets to facilitate the installation of the slip-on flange 53. When not in operation, the slip-on flange 53 can be pressed down, and the spring snap ring 52 is compressed and retracted due to the force, and the slip-on flange 53 slides out of the groove as the force acts. When in operation, the slip-on flange 53 is lifted up, and the spring snap ring 52 is compressed and retracted in the groove until the groove of the slip-on flange 53 matches the spring snap ring 52, and then the installation is in place.

[0067] Continue to see Figure 4 As shown, the outer layers of the first-stage diffuser unit 1, the second-stage diffuser unit 2 and the third-stage diffuser unit 3 all have a sandwich water-cooling structure 6, which is an annular structure and is sleeved on the outer wall of the diffuser unit.

[0068] The sandwich water-cooling structure 6 of the first-stage diffuser unit 1 of the present embodiment includes a first water inlet pipe 11 and a first water outlet pipe 12. The first water inlet pipe 11 and the first water outlet pipe 12 enter and exit the vacuum chamber 7 through a chamber flange plate. The inlet and outlet water pipe interfaces are preferably of nozzle type. The first water inlet pipe 11 is located below the sandwich water-cooling structure 6, and the first water outlet pipe 12 is located above the sandwich water-cooling structure 6. At the same time, the sandwich water-cooling structure 6 also has a spiral baffle 4. The spiral baffle and the water-cooling pipe are used in a bottom-in and top-out manner to ensure that the cooling water can flow fully in the sandwich water-cooling structure 6, thereby improving the cooling effect.

[0069] The interlayer water cooling structure 6 inside the vacuum chamber 7 and the interlayer water cooling structure 6 outside the vacuum chamber 7 operate relatively independently. Figure 4 As shown, the interlayer water cooling structure 6 of the second-stage diffuser unit 2 is double-layered, and a spiral baffle 4 is arranged inside the interlayer water cooling structure 6 , which is also an annular structure and is sleeved on the outer wall of the second-stage diffuser unit 2 .

[0070] The interlayer water cooling structure 6 of the second-stage diffuser unit 2 includes a second water inlet pipe 21 and a second water outlet pipe 22. The second water inlet pipe 21 is located below the second-stage diffuser unit 2 and is connected to the inner layer of the interlayer water cooling structure 6. The second water outlet pipe 22 is located above the second-stage diffuser unit 2 and is connected to the outer layer of the interlayer water cooling structure 6. The spiral baffle 4 is passed to ensure the cooling effect of the second-stage diffuser unit 2 when the gas passes through.

[0071] Similarly, the third-section diffuser unit 3 also includes a sandwich water-cooling structure 6, which is a single-layer structure having a third water inlet pipe 31 and a third water outlet pipe 32. The third water inlet pipe 31 is located below the sandwich water-cooling structure 6, and the third water outlet pipe 32 is located above the sandwich water-cooling structure 6. The purpose is also to ensure that the cooling water can flow fully in the sandwich water-cooling structure 6, thereby improving the cooling effect.

[0072] In addition, the third-stage diffuser unit 3 of this embodiment adopts a corrugated structure, on the one hand to prevent deformation caused by alternating hot and cold, and on the other hand to facilitate installation with the second-stage diffuser unit 2 and the gas cooler 200.

[0073] In the description of the present invention, it should be noted that, unless otherwise specified, "multiple" means two or more than two; the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0074] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0075] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A diffuser, used to provide a vacuum environment for a vacuum chamber of an engine, characterized in that: The diffuser unit comprises a plurality of sections of diffuser units which are sealed and connected end to end. The diffuser units are tubular structures. The diffuser units at both ends are installed inside and outside the vacuum chamber at the same time. The diffuser unit at the middle position is installed at the outlet of the vacuum chamber.

2. The diffuser according to claim 1, characterized in that The outer layer of the diffuser unit is provided with an interlayer water cooling structure.

3. The diffuser according to claim 2, characterized in that The interlayer water cooling structure is an annular structure and is sleeved on the outer wall of the diffuser unit.

4. The diffuser according to claim 3, characterized in that The sandwich water cooling structure is provided with a spiral baffle.

5. The diffuser according to claim 3, characterized in that The interlayer water-cooling structure comprises a water inlet pipe and a water outlet pipe, wherein the water inlet pipe is located below the interlayer water-cooling structure, and the water outlet pipe is located above the interlayer water-cooling structure.

6. The diffuser according to claim 3, characterized in that The diffuser unit includes three sections, namely a first diffuser unit, a second diffuser unit and a third diffuser unit. The first diffuser unit, the second diffuser unit and the third diffuser unit are sealed and connected end to end in sequence. The first diffuser unit is located inside the vacuum chamber, the second diffuser unit is located at the outlet of the vacuum chamber, and the third diffuser unit is located outside the vacuum chamber.

7. The diffuser according to claim 6, characterized in that The first-stage diffuser unit is cylindrical or conical, and is connected to the second-stage diffuser unit by a slip-on flange.

8. The diffuser according to claim 6, characterized in that The sandwich water cooling structure of the first-stage diffuser unit and the third-stage diffuser unit are both single-layer, and the sandwich water cooling structure of the second-stage diffuser unit is double-layer.

9. The diffuser according to claim 6, characterized in that The side wall of the third-stage diffuser unit is corrugated.

10. A gas cooling device, characterized in that: It comprises the diffuser according to any one of claims 1 to 9, and also comprises a gas cooler, wherein the tail end of the diffuser is connected and communicated with the head end of the gas cooler.

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