Cryogenic fuel tank and method for manufacturing same

Abstract

The invention provides a low-temperature fuel storage tank and a manufacturing method thereof. The storage box comprises an inner box, an outer box, a supporting structure, a penetrating pipe and a pipeline. The inner box body is composed of a lining and a composite material winding layer, a storage cavity and a center vacuum cavity are formed, and two flexible nesting pipes connected through a pull rod are symmetrically distributed in the center vacuum cavity. The outer box is composed of a shell and a pipeline distributor. The supporting structure is composed of a communicating base, a connecting ring and a supporting frame. The pipeline is composed of a liquid adding pipe, a liquid discharging pipe and an exhaust pipe. The two ends of the inner box are connected with the outer box through supporting structures based on flexible nested pipes, and an annular vacuum cavity is formed. The annular vacuum cavity is filled with the coating layer, and the storage cavity and the pipeline distributor are connected in a sealed mode through the pipeline. According to the low-temperature fuel storage tank, the problems that an existing low-temperature fuel storage tank is low in storage density, short in dormancy time, high in heat leakage and low in mechanical environment adaptability are solved on the premise that the weight is not increased.

Description

Technical Field

[0001] The present invention belongs to the field of aerospace and basic traffic power technology, and specifically relates to a low-temperature fuel tank and a manufacturing method thereof, especially a low-temperature high-pressure fuel tank and a manufacturing method thereof. Background Art

[0002] As one of the core systems of aerospace vehicles and basic transportation vehicles, the development direction of fuel power system in recent years includes:

[0003] 1. In order to meet the long-range exploration requirements of aerospace vehicles and the long-range endurance requirements of basic transportation vehicles, the power system needs to carry more fuel. Considering that the volume and weight of the tank are limited by the entire system and cannot be increased indefinitely, increasing the storage density becomes the only way.

[0004] 2. Considering the increasingly serious problems of energy consumption and environmental pollution, the fuel of the power system is gradually changing from toxic and non-renewable fuel to non-toxic and renewable fuel.

[0005] 3. The power system needs to adapt to more complex and extreme service conditions.

[0006] Based on the above development direction, the power systems of aerospace vehicles are gradually changing from traditional propellant propulsion to liquid oxygen and liquid hydrogen / liquid oxygen and methane / liquid oxygen and kerosene propulsion, and the power systems of basic transportation vehicles are gradually changing from gasoline power to LNG / liquid hydrogen power.

[0007] Patent document CN107270120B discloses a vehicle-mounted lightweight high-pressure metal hydride composite hydrogen storage tank, including a tank-shaped metal liner, on the outside of which a fiber reinforcement layer and an outer fiber winding layer are sequentially wound; left and right end plugs are respectively provided at both ends of the metal liner, and a plurality of gas-conducting metal isolation filter plates are arranged at intervals along the axial direction of the tank body in the inner cavity of the tank body, and a plurality of hydrogen storage metal matrices arranged along the axial direction of the tank body are distributed between adjacent gas-conducting metal isolation filter plates, and the hydrogen storage metal is deposited on the metal matrix of conductive metal material to form an alloy sheet structure; the gas-conducting metal isolation filter plate supports the alloy sheet structure and divides the alloy sheet structure into two parts; a plurality of groups of heat-conducting pipes are evenly distributed in the gaps between the hydrogen storage metal matrices, and are connected to external pipelines through the right end plug.

[0008] However, there are still some problems with the tanks currently used to store cryogenic liquid fuels. For example, the storage density is still limited and cannot meet the current service time requirements; the thermal insulation performance is limited, resulting in a short dormancy time, and the steam leakage for safety will cause fuel loss; the current low-temperature fuel tank has limited mechanical environmental resistance and is prone to structural failure. Therefore, it is necessary to propose a low-temperature high-pressure fuel tank with high storage density, low heat leakage, and high mechanical environmental adaptability. Summary of the invention

[0009] In view of the defects in the prior art, an object of the present invention is to provide a cryogenic fuel storage tank and a manufacturing method thereof.

[0010] A cryogenic fuel storage tank according to the present invention comprises: an inner box 1, an outer box 2, a support structure 3, a through pipe 4 and a pipeline 5;

[0011] The inner box 1 is connected to the outer box 2 through the supporting structures 3 at both ends to form an annular vacuum chamber 6;

[0012] A sealed through-tube 4 is embedded in the center of the inner box 1, dividing the inner cavity of the inner box 1 into a storage cavity 7 and a central vacuum cavity 8;

[0013] After the pipeline 5 enters the head of the outer box 2, it spirally wraps around the inner box 1 for multiple turns along the axial outer side of the inner box 1 in the annular vacuum chamber 6 of the outer box 2, enters the central vacuum chamber 8 of the penetrating tube 4 from the tail of the inner box 1, and then enters the storage chamber 7 through the axial center position of the penetrating tube 4.

[0014] Preferably, it further comprises: a flexible nested tube 9 installed in the through-tube 4;

[0015] The flexible nested tube 9 includes an outer tube 91, a semicircular segment 92, and an inner tube 93 which are connected in sequence; the inner tube 93 is located inside the outer tube 91;

[0016] The free end 911 of the outer cylinder is connected to the inner box 1, and the free end 931 of the inner cylinder is connected to the support structure 3; the non-free end 912 of the outer cylinder is connected to the non-free end 932 of the inner cylinder through the semicircular segment 92;

[0017] There is a heat insulating gap I 94 between the outer wall of the outer cylinder 91 and the inner wall of the through tube 4;

[0018] There is a heat insulation gap II 95 between the inner wall of the outer cylinder 91 and the outer wall of the inner cylinder 93;

[0019] The two flexible nested tubes 9 have the same length and are symmetrical about the axial center of the through tube 4;

[0020] The non-free ends of the two flexible nested tubes 9 are arranged opposite to each other and connected by a connecting rod 96 .

[0021] Preferably, the heat conduction path comprises:

[0022] The first path: starting from the inner box 1, passing through the outer cylinder free end 911, the outer cylinder non-free end 912, the semicircular segment 92, the inner cylinder non-free end 932, the inner cylinder free end 931, the support structure 3, and reaching the outer box 1;

[0023] The second path: starting from the inner box 1, passing through the pipeline 5, and reaching the outer box 1.

[0024] Preferably, the pipeline 5 includes a liquid adding pipe 51, a liquid discharging pipe 52 and an exhaust pipe 53, the length of the liquid adding pipe 51 extending from the outer box 2 to the storage chamber 7 is equal to the length of the liquid discharging pipe 52 / exhaust pipe 53 extending from the storage chamber 7 to the outer box 2, and the inner and outer diameters of each pipeline are constant.

[0025] Preferably, the through-tube 4 has the same axial length as the inner box 1, and a plurality of ribs are arranged at equal intervals on the outer wall thereof.

[0026] Preferably, the thermal insulation gap I 94 and the thermal insulation gap II 95 of the flexible nested tube 9 are radial gaps, and in the radial gaps, a plurality of permanent magnet block groups with opposite magnetic properties are arranged at equal intervals along the axial direction on the inner wall of the outer tube and the outer wall of the inner tube.

[0027] Preferably, the support structure 3 comprises: a connecting seat 31, a connecting ring 32 and a support frame 33 connected in sequence;

[0028] The connecting ring 32 is an open ring structure composed of a plurality of fan-shaped blocks; the outer wall of the connecting seat 31 and the inner wall of the supporting frame 33 are provided with an annular inward groove, and the upper end of the baffle plate outside the groove is provided with an opening consistent with the fan-shaped block surface of the connecting ring 32;

[0029] The support frame 33 is a radial structure, consisting of a number of circumferentially distributed "I"-shaped spokes;

[0030] The free end of the inner cylinder of the flexible nested tube 9 is connected to the communication seat 31 via a corrugated ring structure.

[0031] Preferably, the inner box 1 comprises an inner liner 11 and a composite material winding layer 12, and the composite material winding layer 12 is laid on the outer surface of the inner liner 11;

[0032] The outer box 2 includes a shell 21 and a pipeline distributor 22 . The pipeline distributor 22 is sealedly connected to the storage chamber 7 via a pipeline 5 .

[0033] The annular vacuum chamber 8 is filled with a “fiber cloth-fiber mesh-reflection screen” coating layer 81 .

[0034] A spacecraft provided according to the present invention comprises the cryogenic fuel tank.

[0035] A method for manufacturing a cryogenic fuel tank according to the present invention comprises the following steps:

[0036] Step 1: Assemble and weld the storage chamber section and the central vacuum chamber section of the pipeline 5 to the through pipe 4 respectively to form an assembly 1;

[0037] Step 2: Assemble and weld the assembly 1 with the upper head, cylindrical section, and lower head of the liner 11 in sequence to form the assembly 2;

[0038] Step 3: Assemble two flexible nested tubes 9 at both ends of the inner cavity of the through tube 4 in the second assembly, and weld them to the liner 11 to form the third assembly;

[0039] Step 4: Laying a composite material winding layer 12 on the outer surface of the inner lining 11 of the assembly three to form an assembly four;

[0040] Step 5: Assemble the annular vacuum chamber section of pipeline 5 with assembly 4, and weld it with the central vacuum chamber section of pipeline 5 to form assembly 5;

[0041] Step 6: Laying the coating layer 81 on the assembly 5 to form the assembly 6;

[0042] Step 7: Assemble each sector of the connecting ring 32 in the groove through the openings of the connecting seat 31 and the supporting frame 33 in sequence, and glue the three together to form the supporting structure 3;

[0043] Step 8: Assemble and weld the support structure 3, the assembly 6 and the cylindrical section of the shell 21 to form the assembly 7;

[0044] Step 9: Assemble and weld the assembly 7 with the pipeline distributor 22, the upper head and the lower head of the shell 21 in sequence to finally form a storage tank.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] 1. The storage tank provided by the present invention solves the problems of low storage density, short dormancy time, high heat leakage and low mechanical environment adaptability of the current low-temperature fuel storage tank without increasing the weight.

[0047] 2. The present invention adopts a metal lining combined with a composite material winding layer structure to replace the all-metal structure of the inner box of the current traditional cryogenic fuel storage tank, thereby increasing the storage pressure of the cryogenic fuel and effectively increasing the storage density and dormancy time.

[0048] 3. The present invention adopts a supporting structure in which inner and outer tubes are connected in sequence with flexible nested tubes, metal connecting seats, composite connecting rings, and I-shaped spokes, and a pipeline in which a U-shaped section of the storage cavity, a straight section of the central vacuum cavity, and an annular vacuum spiral section are connected in sequence, thereby greatly extending the heat conduction path, reducing the heat conduction area, increasing the thermal resistance, and ultimately achieving a significant reduction in the total heat leakage;

[0049] 4. The present invention can realize the deformation and displacement compensation of the inner box under pressure changes and mechanical environment by arranging the magnetic ring group and the corrugated ring in the flexible nested tube, thereby improving the reliability of the storage tank;

[0050] 5. The tank of the present invention has no increase in weight compared to the existing cryogenic fuel tanks through the lightweight design of each component;

[0051] 6. In the present invention, the length of the input pipeline and the output pipeline of the pipeline are equal, so that the thermal resistance of the two is equal, and the length of the heat conduction path formed by the two flexible nested tubes is equal, and the full penetration tube is used as much as possible to form a longer heat conduction path. In this way, by avoiding the difference in thermal resistance between the conduction paths, the heat is conducted more from the path with lower thermal resistance, thereby greatly reducing heat leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0053] Figure 1 A schematic diagram of the structure of the low-temperature and high-pressure fuel storage tank provided by the present invention for reference from multiple angles;

[0054] Figure 2 A schematic diagram of the flexible nested tube structure provided by the present invention;

[0055] Figure 3 A schematic diagram of the support structure provided by the present invention.

[0056] The figure shows:

[0057]

[0058] DETAILED DESCRIPTION

[0059] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0060] The present invention provides a low-temperature high-pressure fuel tank, which is suitable for a launch vehicle. Figure 1 This is a schematic structural diagram of a low-temperature high-pressure fuel storage tank provided by the present invention, which includes an inner box 1, an outer box 2, two sets of support structures 3, a through pipe 4 and a pipeline 5;

[0061] The inner box 1 adopts a structure of a metal lining 11 and a composite material winding layer 12;

[0062] The outer box 2 includes a metal shell 21 and a pipeline distributor 22 for gas and liquid inlet and outlet;

[0063] The supporting structure 3 includes a metal connecting seat 31, a composite material connecting ring 32 with low thermal conductivity, and a metal supporting frame 33;

[0064] The pipeline 5 includes a liquid adding pipe 51, a liquid discharging pipe 52 and an exhaust pipe 53;

[0065] The inner box 1 is located in the inner cavity of the outer box 2, and its two ends are connected to the outer box 2 through the supporting structure 3 to form an annular vacuum chamber 6;

[0066] A sealed through-tube 4 is embedded in the center of the inner box 1, dividing the inner cavity of the inner box 1 into a storage cavity 7 and a central vacuum cavity 8; two flexible nested tubes 9 are embedded in the central vacuum cavity 8 and are symmetrically distributed, and the two tubes are connected by a tie rod;

[0067] After the pipeline 5 enters the head of the outer box 2, it spirally wraps around the inner box 1 for multiple turns along the axial outer side of the inner box 1 in the annular vacuum chamber 6 of the outer box 2, enters the central vacuum chamber 8 of the penetrating tube 4 from the tail of the inner box 1, and then enters the storage chamber 7 through the axial center position of the penetrating tube 4.

[0068] The annular vacuum chamber 6 is filled with a coating layer 61, and the pipeline 5 seals and connects the storage chamber 7 with the pipeline distributor 22;

[0069] In order to achieve high storage density, low heat leakage and high structural reliability of cryogenic liquid, the relevant components of this tank have the following characteristics:

[0070] (1) The inner box 1 adopts a metal lining combined with a composite material winding layer structure, which increases the working pressure, i.e., high pressure, and thus increases the storage density and dormancy period of the cryogenic liquid;

[0071] (2) The outer wall of the through-tube 4 is provided with a plurality of ribs at equal intervals of 10% to 20% of its length, which can improve its ability to resist instability due to working pressure and prevent the through-tube 13 from being crushed when the tank is working;

[0072] (3) The flexible nested tube 9 is mainly composed of an outer tube 91, a semicircular segment 92, and an inner tube 93; the inner tube 93 is located inside the outer tube 91; the free end 911 of the outer tube is connected to the inner box 1, and the free end 931 of the inner tube is connected to the support structure 3; the non-free end 912 of the outer tube is connected to the non-free end 932 of the inner tube through the semicircular segment 92; there is a heat insulation gap I 94 between the outer wall of the outer tube 91 and the inner wall of the through tube 4, and there is a heat insulation gap II 95 between the inner wall of the outer tube 91 and the outer wall of the inner tube 93; the two flexible nested tubes 9 have the same length and are symmetrical about the axial center position of the through tube 4; the non-free ends of the two flexible nested tubes 9 are arranged oppositely and connected by a connecting rod 96. This long heat conduction path can reduce the amount of heat leakage. Among them, the long heat conduction path is specifically: low temperature fuel → inner box 1 → flexible nested tube 9 (outer tube 91 → semicircular segment 92 → inner tube 93) → support structure 3 → shell 21 → external environment. The symbol → indicates the direction of heat conduction; at the same time, permanent magnet blocks with opposite magnetic properties are arranged at equal intervals along the axial direction in the heat insulation gap I 94 and the heat insulation gap II 95 to prevent the heat conduction path from being short-circuited due to elastic deformation contact between the inner and outer cylinders under a mechanical environment; in addition, a plurality of corrugated rings are arranged at the free end 931 of the inner cylinder to compensate for the axial deformation and displacement of the inner box 1 under the pressure change and mechanical environment, so as to improve the structural reliability;

[0073] (4) The connecting ring 32 is composed of a plurality of low thermal conductivity composite fan-shaped blocks to form an open ring structure, so as to increase the thermal resistance value on the heat conduction path of the supporting structure 3 and reduce the heat leakage; the outer wall of the connecting seat 31 and the inner wall of the supporting frame 33 are provided with an annular inward groove, and the upper end of the baffle plate outside the groove is provided with an opening consistent with the profile of the fan-shaped block of the connecting ring 32, so as to achieve reliable connection of the supporting structure 3;

[0074] (5) The support frame 33 is a radial structure, which is composed of a plurality of circumferentially distributed I-shaped spokes. The radial structure can reduce the heat conduction area and reduce the heat leakage. At the same time, the I-shaped spokes have high rigidity and can achieve reliable fixation of the inner box 1.

[0075] (6) Pipeline 5 is spirally wound along the outer axial direction of inner box 1 for multiple turns from pipeline distributor 22, and then enters central vacuum chamber 8 from the tail, and then enters storage chamber 7 at the axial center position of penetrating tube 4; the super-long heat conduction path is: low-temperature fuel → pipeline 5 (liquid addition pipe 51 / liquid discharge pipe 52 / exhaust pipe 53) → external environment of distributor 22. The symbol → indicates the direction of heat conduction, which can reduce the amount of heat leakage.

[0076] The present invention will be described in more detail below.

[0077] The above-mentioned low-temperature high-pressure fuel tank manufacturing method comprises the following steps:

[0078] Step 1: Assemble and weld the storage chamber section of the pipeline 5 to be located in the storage chamber 7 and the central vacuum chamber section to be located in the central vacuum chamber 8 to the through pipe 4 respectively to form a first assembly;

[0079] Step 2: Assemble and weld the assembly 1 with the upper head, cylindrical section, and lower head of the liner 11 in sequence to form the assembly 2;

[0080] Step 3: Assemble two flexible nested tubes 9 at both ends of the inner cavity of the through tube 4 in the second assembly, and weld them to the liner 11 to form the third assembly;

[0081] Step 4: Laying a composite material winding layer 12 on the outer surface of the inner lining 11 of the assembly three to form an assembly four;

[0082] Step 5: Assemble the annular vacuum chamber section of the pipeline 5 to be located in the annular vacuum chamber 6 with the assembly 4, and weld it with the central vacuum chamber section of the pipeline 5 to form the assembly 5;

[0083] Step 6: Laying the coating layer 4 on the assembly 5 to form the assembly 6;

[0084] Step 7: Assemble each sector of the connecting ring 32 in the groove through the openings of the connecting seat 31 and the supporting frame 33 in sequence, and glue the three together to form the supporting structure 3;

[0085] Step 8: Assemble and weld the support structure 3, the assembly 6 and the cylindrical section of the shell 21 to form the assembly 7;

[0086] Step 9: Assemble and weld the assembly 7 with the pipeline distributor 22, the upper head and the lower head of the shell 21 in sequence to finally form a storage tank.

[0087] The basic embodiments of the present application are described above. The present application will be described in more detail below in combination with preferred examples and / or variations of the basic embodiments.

[0088] like Figure 1 As shown, a low-temperature high-pressure fuel storage tank comprises an inner box 1, an outer box 2, two sets of support structures 3, a through pipe 4 and a pipeline 5;

[0089] The inner box 1 is mainly composed of an inner liner 11 and a composite material winding layer 12; the outer box 2 is mainly composed of a shell 21 and a pipeline distributor 22; each group of supporting structures 3 is mainly composed of a connecting seat 31, a connecting ring 32 and a supporting frame 33; the pipeline 5 is mainly composed of a liquid adding pipe 51, a liquid discharging pipe 52 and an exhaust pipe 53; the flexible nested pipe 9 is composed of an outer tube 91, a semicircular segment 92 and an inner tube 93;

[0090] A sealed through-tube 4 is embedded in the center of the inner box 1, dividing the inner cavity of the inner box 1 into a storage cavity 7 and a central vacuum cavity 8; two flexible nested tubes 9 are embedded in the central vacuum cavity 8 and are symmetrically distributed;

[0091] The inner box 1 is located in the inner cavity of the outer box 2, and its two ends are connected to the outer box 2 through the support structure 3 based on the flexible nested tube 9, and form an annular vacuum cavity 6; the pipeline 5 seals and connects the storage cavity 7 with the pipeline distributor 22;

[0092] Specifically, in this embodiment, the liner 11 and the shell 21 are both stainless steel welded structures in which the upper head, the cylindrical section, and the lower head are connected in sequence; the coating layer 61 is a multilayer structure in which fiber cloth, fiber screen, and reflective screen are connected in sequence; the pipeline 5 is a stainless steel welded structure in which the storage cavity section, the central vacuum cavity section, and the annular vacuum section are connected in sequence; the composite material winding layer 12 is mainly made of carbon fiber T800 and low-temperature resin; the through pipe 4, the flexible nested pipe 9, the pipeline distributor 22, the connecting seat 31, the support frame 33, and the pipeline 5 are all made of stainless steel; the connecting ring 32 is made of glass fiber reinforced plastic with low thermal conductivity;

[0093] Specifically, in this embodiment, the wall thickness of the liner 11 is 5 mm determined by the fatigue performance of the tank, and its inner diameter and axial length are 360 ​​mm and 800 mm respectively determined by the storage volume of the tank; the wall thickness of the composite winding layer 12 is 2 mm determined by the working pressure (35 MPa) of the inner box 1;

[0094] Specifically, in this embodiment, ribs are arranged at equal intervals through the outer wall of the tube 4, and the spacing is 10% of its length (800*10%=80mm);

[0095] Specifically, in this embodiment, the length of the outer tube 91 of the flexible nested tube 9 is 40% (800*40%=320 mm) of the axial length of the liner 11, and the length of the inner tube 93 is 350 mm;

[0096] Specifically, in this embodiment, radial heat insulation gaps I 94 and II 95 with a width of 20 mm are provided between the outer wall of the outer tube 91 of the flexible nested tube 9 and the inside of the through tube 4, and between the inside of the outer tube 91 and the outer wall of the inner tube 93, and 7 groups of permanent magnet blocks with opposite magnetic properties are provided in the gaps at equal intervals of 50 mm along the axial direction.

[0097] Specifically, in this embodiment, a corrugated ring is provided at the free end 931 of the inner tube of the flexible nested tube 9, with a width of 10 mm and a wave height of 10 mm;

[0098] Specifically, in this embodiment, the connecting ring 32 is composed of 11 30° sector blocks forming an open ring structure, the outer wall of the connecting seat 31 and the inner wall of the supporting frame 33 are provided with an annular inward groove, and the upper end of the baffle plate outside the groove is provided with a 30° opening;

[0099] Specifically, in this embodiment, the support frame 33 is a spoke-shaped structure, consisting of four circumferentially distributed I-shaped spokes;

[0100] Specifically, in this embodiment, the pipeline 5 is spirally wound 10 times along the outer axial direction of the inner box 1 from the pipeline distributor 22 and enters the central vacuum chamber 8 from the tail, and then enters the storage chamber 7 at the axial center position of the penetrating tube 13.

[0101] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0102] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A cryogenic fuel tank, characterized in that: include: An inner box (1), an outer box (2), a supporting structure (3), a through-tube (4) and a pipeline (5); The inner box (1) is connected to the outer box (2) via the supporting structures (3) at both ends to form an annular vacuum chamber (6); A sealed through-tube (4) is embedded in the center of the inner box (1) to divide the inner cavity of the inner box (1) into a storage cavity (7) and a central vacuum cavity (8); After the pipeline (5) enters the head of the outer box (2), it spirally wraps around the inner box (1) multiple times along the axial direction of the outer side of the inner box (1) in the annular vacuum chamber (6) of the outer box (2), enters the central vacuum chamber (8) of the through-tube (4) from the tail of the inner box (1), and then enters the storage chamber (7) through the axial center position of the through-tube (4).

2. The cryogenic fuel tank according to claim 1, characterized in that: Also includes: A flexible nested tube (9) installed in the through-tube (4); The flexible nested tube (9) comprises an outer tube (91), a semicircular segment (92), and an inner tube (93) which are connected in sequence; the inner tube (93) is located inside the outer tube (91); The free end (911) of the outer cylinder is connected to the inner box (1), and the free end (931) of the inner cylinder is connected to the supporting structure (3); the non-free end (912) of the outer cylinder is connected to the non-free end (932) of the inner cylinder via the semicircular segment (92); There is a heat insulating gap I (94) between the outer wall of the outer cylinder (91) and the inner wall of the through-tube (4); There is a heat insulation gap II (95) between the inner wall of the outer cylinder (91) and the outer wall of the inner cylinder (93); The two flexible nested tubes (9) have the same length and are symmetrical about the axial center of the through tube (4); The non-free ends of the two flexible nested tubes (9) are arranged opposite to each other and connected by a connecting rod (96).

3. The cryogenic fuel tank according to claim 2, characterized in that: The heat conduction paths include: A first path: starting from the inner box (1), passing through the outer cylinder free end (911), the outer cylinder non-free end (912), the semicircular segment (92), the inner cylinder non-free end (932), the inner cylinder free end (931), the support structure (3), and reaching the outer box (1); The second path starts from the inner box (1), passes through the pipeline (5), and reaches the outer box (1).

4. The cryogenic fuel tank according to claim 1, characterized in that: The pipeline (5) comprises a liquid adding pipe (51), a liquid discharging pipe (52) and an exhaust pipe (53); the length of the liquid adding pipe (51) extending from the outer box (2) to the storage chamber (7) is equal to the length of the liquid discharging pipe (52) / exhaust pipe (53) extending from the storage chamber (7) to the outer box (2), and the inner and outer diameters of each pipeline are constant.

5. The cryogenic fuel storage tank according to claim 1, characterized in that: The through-tube (4) has the same axial length as the inner box (1), and a plurality of ribs are arranged at equal intervals on its outer wall.

6. The cryogenic fuel tank according to claim 2, characterized in that: The thermal insulation gap I (94) and the thermal insulation gap II (95) of the flexible nested tube (9) are radial gaps, and within the radial gaps, a plurality of permanent magnet block groups with opposite magnetic properties are arranged at equal intervals along the axial direction on the inner wall of the outer tube and the outer wall of the inner tube.

7. The cryogenic fuel storage tank according to claim 3, characterized in that: The support structure (3) comprises: a connecting seat (31), a connecting ring (32) and a support frame (33) which are connected in sequence; The connecting ring (32) is an open ring structure composed of a plurality of fan-shaped blocks; the outer wall of the connecting seat (31) and the inner wall of the supporting frame (33) are provided with an annular inward groove, and the upper end of the baffle plate outside the groove is provided with an opening consistent with the fan-shaped block surface of the connecting ring (32); The support frame (33) is a radial structure, consisting of a plurality of circumferentially distributed I-shaped spokes; The free end of the inner cylinder of the flexible nested tube (9) is connected to the connecting seat (31) via a corrugated ring structure.

8. The cryogenic fuel tank according to claim 1, characterized in that: The inner box (1) comprises an inner liner (11) and a composite material winding layer (12), wherein the composite material winding layer (12) is arranged on the outer surface of the inner liner (11); The outer box (2) comprises a shell (21) and a pipeline distributor (22), and the pipeline distributor (22) is sealedly connected to the storage chamber (7) via a pipeline (5); The annular vacuum chamber (8) is filled with a coating layer having a fiber cloth, a fiber screen and a reflective screen structure.

9. A spacecraft, characterized in that: A cryogenic fuel storage tank comprising the cryogenic fuel storage tank as claimed in any one of claims 1 to 8.

10. A method for manufacturing a cryogenic fuel tank, characterized in that: The following steps are involved: Step 1: Assemble and weld the storage chamber section and the central vacuum chamber section of the pipeline (5) to the through-tube (4) respectively to form a first assembly; Step 2: Assemble and weld the first assembly with the upper head, the cylindrical section, and the lower head of the liner (11) in sequence to form the second assembly; Step 3: Assemble the two flexible nested tubes (9) at the two ends of the inner cavity of the through tube (4) in the second assembly respectively, and weld them to the inner liner (11) to form the third assembly; Step 4: Laying the composite material winding layer (12) on the outer surface of the inner lining (11) of the assembly three to form an assembly four; Step 5: Assemble the annular vacuum chamber section of the pipeline (5) and the assembly four, and weld them to the central vacuum chamber section of the pipeline (5) to form an assembly five; Step 6: Laying a coating layer on the assembly 5 to form the assembly 6; Step 7: Assemble each sector of the connecting ring (32) in the groove through the opening of the connecting seat (31) and the supporting frame (33) in turn, and glue the three together to form the supporting structure (3); Step 8: Assembling and welding the support structure (3), the assembly six and the cylindrical section of the shell (21) to form an assembly seven; Step 9: Assemble and weld the assembly 7 with the pipeline distributor (22), the upper head and the lower head of the shell (21) in sequence to finally form a storage tank.

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