Large-size ultra-light low-temperature storage tank

Abstract

The application belongs to the technical field of aerospace, and discloses a large-size ultra-light low-temperature storage tank. The large-size ultra-light low-temperature storage tank comprises a metal inner container, a composite material outer shell, an insulation structure and an anti-sway structure. The metal inner container comprises a cylindrical barrel section and a tank bottom. The cylindrical barrel section is spirally coiled from a metal thin strip with a certain thickness and width, and the two ends of the cylindrical barrel section are connected to the tank bottom. The composite material outer shell is located outside the metal inner container, and the insulation structure is arranged between the metal inner container and the composite material outer shell. The insulation structure is uniformly coated outside the metal inner container. The large-size ultra-light low-temperature storage tank is provided with a liquid filling pipe at one end, an exhaust pipe at the other end, a liquid level meter and a pressure instrument on the side. The large-size ultra-light low-temperature storage tank can greatly reduce the mass under the conditions of maintaining the required strength, rigidity and density, and can ensure a certain pressure resistance.

Description

TECHNICAL FIELD

[0001] The application relates to the field of aerospace technology, and in particular to a large-size ultra-light low-temperature storage tank. BACKGROUND

[0002] The low-temperature storage tank is an important component of a spacecraft and is used for storing low-temperature fuels such as liquid hydrogen, liquid oxygen and kerosene. The low-temperature storage tank has a large overall structure size and a large mass proportion, and therefore, optimization of the structure and mass of the low-temperature storage tank is a key to realizing the lightweight of the spacecraft, improving the structural efficiency and the carrying capacity. It is pointed out in "Chen Z G, Jiao W C, Yan M L, et al. Research progress of carbon fiber reinforced resin matrix composite low-temperature tank leak resistance [J]. Glass Steel / Composites, 2018(11): 109-116." that, taking a launch vehicle as an example, the structural weight of the low-temperature storage tank accounts for more than 50% of the total weight of the vehicle structure, and the lightweight of the storage tank has always been one of the important ways to improve the carrying efficiency of the rocket. For a new generation of aerospace aircraft, the demand for lightweight of the storage tank is more urgent, and the lightweight index is more demanding. For example, such a storage tank requires an equivalent surface density of not more than 9 kg / m 2 When the tank body is made of aluminum alloy or stainless steel, the equivalent thickness of the tank body cannot exceed 3.3 mm and 1.15 mm, which is obviously unreasonable. More importantly, the strength requirement of the tank body material for a large-size storage tank is getting higher and higher. For example, for a storage tank with a diameter-thickness ratio (D / t) greater than 1000 and a pressure not less than 0.5 MPa, the yield strength of the tank body material is required to be not less than 350 MPa (taking a safety factor of 1.5), and the strength of the existing aluminum alloy plate and stainless steel plate cannot meet the requirement. Therefore, traditional metal structural materials such as aluminum alloy and stainless steel cannot be used for the manufacture of new large-size lightweight storage tanks.

[0003] Composite material is one of the important ways to realize the lightweight of the tank, and relevant research has been carried out at home and abroad and important progress has been made. By using carbon fiber composite material continuous winding, NASA and Boeing Company of the United States prepared a composite material tank with a wall thickness of about 2.0 mm and a diameter of 5 m or even larger. However, due to the compatibility problem between composite material and liquid oxygen, the resin matrix in the composite material will crack or have holes at low temperature, and the liquid oxygen tank made of composite material has the risk of microcracks and liquid leakage, which to a large extent limits the practical application of the composite material low temperature tank. At the same time, the low temperature tank made of full composite material also has the following problems: (1) the processability of the composite material is poor, and it is difficult to directly connect and seal the shell of the full composite material tank with other structures such as fuel delivery pipeline and measuring instrument; (2) the winding of the composite material is discontinuous, and the structural stiffness of the full composite material tank is low, and the compression instability resistance is poor, which needs to increase additional reinforcing frames or rib plates inside and outside the shell, resulting in complex structure; (3) the low temperature tank needs to use complex heat insulation structure, anti-slosh structure and the like, and it is difficult to set or connect such structures on the full composite material tank.

[0004] The large size low temperature tank of the new generation aerospace aircraft, heavy launch vehicle and other aircraft has extremely harsh requirements for structural lightweight, and the traditional metal material tank cannot meet the equivalent surface density requirement, and the yield strength is low and cannot meet the pressure bearing requirement, and the full composite material tank has the risk of liquid leakage and the defects of difficult connection, sealing and assembly with other structures. Therefore, a new ultra-lightweight large size low temperature tank structure needs to be put forward. SUMMARY

[0005] In order to improve the carrying efficiency of the aerospace vehicle, meet the harsh lightweight requirement, and ensure safety, the application provides a large size ultra-lightweight low temperature tank structure, so as to solve the problems of large equivalent surface density of the existing metal tank, overweight structure, insufficient pressure bearing capacity, and liquid leakage of the full composite material tank and difficult connection and sealing with other structures, thereby providing basic guarantee for the design and manufacture of the new generation aerospace aircraft, heavy launch vehicle and other advanced aircraft.

[0006] In order to achieve the above object, the technical scheme of the present application is as follows: a large-size ultra-light low-temperature storage tank, comprising a metal inner container 3, a composite material outer shell 5, an insulating structure 4 and an anti-sloshing structure 6; the metal inner container 3 is in a spherical columnar structure, comprising a cylindrical barrel segment 13 and a hemispherical tank bottom 14; the cylindrical barrel segment 13 is spirally coiled from a metal thin strip with a certain thickness and width, and the two ends thereof are connected with the hemispherical tank bottom 14 respectively; the two sides of the coiled cylindrical barrel segment 13 are formed into curved bites through rolling; the two bite edges are mutually buckled during the coiling process, and the mutually buckled bites are pressed tightly by the buckling wheels which roll oppositely in the coiling equipment; the composite material outer shell 5 is located outside the metal inner container 3, and the insulating structure 4 is arranged between the two; the insulating structure 4 is uniformly coated outside the metal inner container 3; the large-size ultra-light low-temperature storage tank is provided with a liquid filling pipe 8 at one end and an exhaust pipe 2 at the other end, and is provided with a liquid level meter 11 and a pressure instrument 12 on the side surface; the liquid filling pipe 8 and the exhaust pipe 2 both extend into the large-size ultra-light low-temperature storage tank; the liquid filling pipe 8 is provided with a filling stop valve 9 and a discharge stop valve 10; the filling stop valve 9 and the discharge stop valve 10 are connected with the liquid filling pipe through a three-way joint at one end; the hemispherical tank bottom 14 is manufactured by stamping or deep drawing, and is connected with the cylindrical barrel segment 13 in a welding or flange connection mode.

[0007] The exhaust pipe 2 is provided with a pressure regulating valve 1; the liquid level meter 11 and the pressure instrument 12 extend into the large-size ultra-light low-temperature storage tank through connecting pipelines; vertical sliding grooves 7 are arranged on the two sides in the metal inner container 3 for mounting the anti-sloshing structure 6. The sliding grooves 7 are made of aluminum alloy.

[0008] The anti-sloshing structure 6 is in a cylindrical shape, comprising a floating plate 17, a transmission ring 15 and a prestressed elastic device 16; the transmission ring 15 moves on the sliding groove 7, and the inner side thereof is connected with the floating plate 17 through four prestressed elastic devices 16; the floating plate 17 is located in the middle of the transmission ring 15. The thickness of the floating plate 17 and the transmission ring 15 is 30 mm.

[0009] The metal inner container 3 is an aluminum alloy thin strip; the composite material outer shell 5 is a carbon fiber reinforced composite material; and the insulating structure 4 is a flexible thermal insulation material.

[0010] The flexible thermal insulation material is one of a polyimide film, a polyamide fiber felt and a silicone rubber.

[0011] The metal inner container 3, the insulating structure 4 and the composite material outer shell 5 are connected in a gluing or hot pressing mode.

[0012] The adhesive for the gluing connection is one of an epoxy resin adhesive, a polyamino acid glue, an acrylic acid glue and a silicone rubber glue.

[0013] The present application has the following beneficial effects:

[0014] (1) The application adopts the structure of combining metal inner can and composite material shell, the spiral structure of the cylindrical section of the metal inner can has higher strength than the traditional straight seam pipe structure, and the cylindrical section of the metal inner can of the storage tank only needs to change the forming angle when forming, so that the same width of aluminum alloy thin strips can be used to produce cylindrical sections with different diameters, and because of the continuous bending forming, the length of the cylindrical section is not limited, which can effectively meet the production needs of large-size storage tanks.

[0015] (2) The application adopts the structure of combining metal inner can and composite material shell, the spiral structure of the cylindrical section of the metal inner can has certain axial and circumferential expansion and contraction, which can absorb the thermal expansion and contraction deformation caused by filling and discharging low-temperature propellant to a certain extent, improve the impact resistance, and make the structure more stable.

[0016] (3) The application adopts the structure of combining metal inner can and composite material shell, and the low-temperature storage tank needs to adopt heat insulation structure and anti-slosh structure, etc., compared with the connection of such structures on the composite material storage tank, the anti-slosh structure arranged in the metal inner can is simpler, and can effectively inhibit the sloshing of the liquid, and the flexible heat insulation material connected outside the metal inner can can adapt to the thermal expansion and contraction of the internal metal inner can, thereby reducing the stress between the inner and outer layers, and the flexible heat insulation material can further improve the sealing performance and durability of the low-temperature storage tank.

[0017] (4) The composite material shell is lighter in quality, compared with the traditional metal storage tank, the use of the composite material shell can greatly reduce the quality of the storage tank and improve the operation efficiency of the storage tank. The composite material shell has excellent properties such as high strength, high rigidity, low density, etc., and also has good fatigue resistance, compared with the traditional metal storage tank, the use of the composite material shell can improve the structural strength of the storage tank and improve the load capacity of the storage tank.

[0018] (5) On the one hand, the metal inner can has good sealing performance, and a perfect sealing design is adopted at the joint of the metal inner can and the composite material shell, which can effectively prevent liquid leakage, and on the other hand, the metal inner can is compatible with liquid oxygen and has good corrosion resistance, which can ensure the sealing performance and protection performance of the storage tank. The metal inner can has good processability, and fuel delivery pipelines, measuring instruments and other structures can be directly connected to the inner wall of the metal inner can, and the adhesive is used to connect the metal inner can and the composite material shell, which can ensure the connection performance of the fuel delivery pipelines and the measuring instruments while ensuring the sealing performance.

[0019] (6) The metal inner can serves as the supporting structure of the composite material shell and has certain strength and rigidity, which can effectively improve the pressure resistance and stability of the storage tank and avoid problems such as instability of the storage tank structure, and has high mechanical performance, which can effectively improve the service life and reliability of the storage tank. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1is a large size ultra-lightweight low-temperature storage tank structure described in the present application;

[0021] Figure 2 is a metal liner structure in the large size ultra-lightweight low-temperature storage tank described in the present application;

[0022] Figure 3 is a anti-sway structure structure diagram in the large size ultra-lightweight low-temperature storage tank described in the present application.

[0023] In the figure, 1 is a pressure regulating valve, 2 is an exhaust pipe, 3 is a metal liner, 4 is an adiabatic structure, 5 is a composite material shell, 6 is an anti-sway structure, 7 is a sliding groove, 8 is a liquid filling pipe, 9 is a filling stop valve, 10 is a discharge stop valve, 11 is a liquid level gauge, 12 is a pressure instrument, 13 is a cylindrical cylinder segment, 14 is a tank bottom, 15 is a transmission ring, 16 is a prestressed elastic device, and 17 is a floating plate. DETAILED DESCRIPTION

[0024] The specific embodiments of the present application are further described below in combination with the drawings and technical solutions.

[0025] Example 1, as shown in Figure 1 and Figure 2 The present application provides a large size ultra-lightweight low-temperature storage tank, which comprises: a metal liner 3, a composite material shell 5 and other internal and external auxiliary structures; the metal liner is made of aluminum alloy thin strips with low density and good low-temperature performance, and the composite material shell is made of carbon fiber reinforced composite material; other internal and external auxiliary structures, including: pressure regulating valve 1, exhaust pipe 2, adiabatic structure 4, anti-sway structure 6, sliding groove 7, liquid filling pipe 8, filling stop valve 9, discharge stop valve 10, liquid level gauge 11, pressure instrument 12; the adiabatic structure 4 is uniformly coated on the outside of the metal liner 3 shell; the anti-sway structure 6 includes: floating plate 17, transmission ring 15, elastic device 16; one end of the inside of the metal liner 3 is provided with a liquid filling pipe 8; the liquid filling pipe 8 penetrates out of the adiabatic structure 4, the composite material shell 5 and the port on the outside is provided with a filling stop valve 9 and a discharge stop valve 10; the other end of the inside of the metal liner 3 is provided with an exhaust pipe 2; the exhaust pipe 2 penetrates out of the adiabatic structure 4, the composite material shell 5 and the port on the outside is provided with the pressure regulating valve 1; the side end of the inside of the metal liner 3 is provided with the liquid level gauge pipeline and the pressure gauge pipeline; the liquid level gauge pipeline and the pressure gauge pipeline penetrate out of the adiabatic structure 4, the composite material shell 5 and the port on the outside are respectively provided with the liquid level gauge 11 and the pressure instrument 12. The storage tank metal liner 3 is a spherocylindrical structure composed of a cylindrical cylinder segment 13 and two hemispherical tank bottoms 14; the cylindrical cylinder segment 13 is obtained by spiral winding of metal thin strips with certain thickness and width, and the cylinder segment with a certain diameter is obtained, and the hemispherical tank bottom 14 is manufactured by stamping or deep drawing, and is connected with the cylindrical cylinder segment 13 in a welding or flange connection manner.

[0026] Preferably, the thermal insulation structure 4 is made of a flexible thermal insulation material such as polyimide film, polyamide fiber felt, or silicone rubber.

[0027] Preferably, in the aforementioned large-size ultra-lightweight cryogenic storage tank, the metal inner liner 3 of the storage tank is connected to the insulation structure 4, and the insulation structure 4 is connected to the composite material outer shell 5, by means of adhesive bonding or hot pressing. The adhesive bonding agent is one of epoxy resin adhesive, polyurethane glue, acrylic glue, or silicone rubber glue.

[0028] Example 2, as Figure 2 As shown, the present invention provides a large-size ultra-lightweight cryogenic storage tank, comprising: a metal inner liner 3, a composite material outer shell 5, and other internal and external auxiliary structures; the metal inner liner 3 is made of aluminum alloy strip with low density and good low-temperature performance, and the composite material outer shell 5 is made of carbon fiber reinforced composite material; the other internal and external auxiliary structures include: a pressure regulating valve 1, an exhaust pipe 2, a heat insulation structure 4, an anti-sway structure 6, a sliding groove 7, a liquid filling pipe 8, a filling shut-off valve 9, a discharge shut-off valve 10, a level gauge 11, and a pressure gauge 12; the heat insulation structure 4 is uniformly covered on the outside of the metal inner liner 3 shell; the anti-sway structure 6 includes: a float 17, a transmission ring 15, and an elastic device 16. One end of the metal inner liner 3 of the storage tank is provided with a liquid filling pipe 8; the liquid filling pipe 8 passes through the heat insulation structure 4 and the composite material shell 5, and the outer port is provided with a filling stop valve 9 and a discharge stop valve 10; the other end of the metal inner liner 3 of the storage tank is provided with an exhaust pipe 2; the exhaust pipe 2 passes through the heat insulation structure 4 and the composite material shell 5, and the outer port is provided with a pressure regulating valve 1; the side end of the metal inner liner 3 of the storage tank is provided with a level gauge pipe and a pressure gauge pipe; the level gauge pipe and the pressure gauge pipe pass through the heat insulation structure 4 and the composite material shell 5, and the outer ports are respectively provided with a level gauge 11 and a pressure gauge 12. The spiral structure of the cylindrical section 13 of the metal inner liner of the storage tank has higher strength than that of the traditional straight seam pipe section. When the inner wall of the spiral section is compressed, the principal stress is circumferential stress. The spiral weld is at a 45-degree angle to the axis, avoiding the principal stress. In contrast, the principal stress of the straight seam pipe is perpendicular to the weld, and its strength is generally lower than that of the spiral structure. When the cylindrical section 13 is formed, the impact toughness is the greatest along the rolling direction and the least along the straight rolling direction. The difference between the two is several times. The spiral shape of the spiral structure can effectively avoid the effect of the principal stress along the rolling direction when the traditional straight seam pipe is rolled, and reduce the impact on the weak links of the spiral structure.

[0029] Example 3, as Figure 1 and Figure 3As shown, the present application provides a large size ultra-light low-temperature tank, comprising: a metal liner 3, a composite material shell 5 and other internal and external auxiliary structures; the metal liner 3 is made of aluminum alloy thin strip with low density and good low-temperature performance, and the composite material shell 5 is made of carbon fiber reinforced composite material; the other internal and external auxiliary structures include: a pressure regulating valve 1, an exhaust pipe 2, an adiabatic structure 4, a anti-slosh structure 6, a sliding groove 7, a liquid filling pipe 8, a filling stop valve 9, a discharge stop valve 10, a liquid level meter 11 and a pressure instrument 12; the adiabatic structure 4 is uniformly coated on the outside of the metal liner 3 shell; the anti-slosh structure 6 includes: a floating plate 17, a transmission ring 15 and an elastic device 16; one end of the tank metal liner 3 is provided with the liquid filling pipe 8; the liquid filling pipe 8 penetrates through the adiabatic structure 4 and the composite material shell 5, and the port on the outside is provided with the filling stop valve 9 and the discharge stop valve 10; the other end of the tank metal liner 3 is provided with the exhaust pipe 2; the exhaust pipe 2 penetrates through the adiabatic structure 4 and the composite material shell 5, and the port on the outside is provided with the pressure regulating valve 1; the side end of the tank metal liner 3 is provided with the liquid level meter pipe and the pressure gauge pipe; the liquid level meter pipe and the pressure gauge pipe penetrate through the adiabatic structure 4 and the composite material shell 5, and the ports on the outside are respectively provided with the liquid level meter 11 and the pressure instrument 12. The anti-slosh structure 6 is cylindrical, the thickness of the floating plate 17 and the transmission ring 15 is 30mm, and the transmission ring 15 is connected with the tank metal liner inner wall by two vertical sliding grooves 7. The floating plate 17 is located in the middle of the transmission ring 15, and the two are connected by four prestressed elastic devices 16, which is to prevent the floating plate 17 from hitting the tank metal liner inner wall during movement. Two vertical sliding grooves 7 are opened on the tank metal liner inner wall, which plays a restraining role, so that the transmission ring can only move along the slender axis of the tank; the sliding groove 7 is made of aluminum alloy.

[0030] The operation mode of a large size ultra-light low-temperature tank in Example 1 is as follows:

[0031] The adiabatic structure 4 is installed on the outside of the low-temperature tank metal liner, which is used to prevent the low-temperature propellant from exchanging heat with the outside world, maintain the temperature stability of the low-temperature liquid, ensure the quality and safety of storage, and reduce the evaporation and loss of the propellant. At the same time, in order to avoid the tank pressure being too high when the low-temperature propellant in the low-temperature tank evaporates and exceeds the design pressure, an exhaust pipe 2 is arranged at the top of the tank, one end of the exhaust pipe 2 is connected with a pressure regulating valve 1, when the internal pressure of the tank rises to the design pressure, the pressure regulating valve 1 opens, and the excess gas is discharged outside the tank; when the internal pressure of the tank drops to a certain value, the pressure regulating valve 1 closes, avoiding the outside gas entering the tank; by controlling the internal pressure change of the tank through the pressure regulating valve, the problem of tank structure deformation or liquid leakage caused by excessive internal pressure of the tank is avoided.

[0032] When the low-temperature propellant is filled and discharged, the filling port of the filling stop valve 9 is connected with the low-temperature propellant tank truck, the filling stop valve 9 is opened, the low-temperature propellant is filled into the low-temperature storage tank, and the liquid is collected through the liquid filling pipe 8. At the same time, the filling and discharging conditions of the low-temperature propellant in the storage tank are observed through the liquid level meter 11 and the pressure instrument 12. The following functions are realized through the sliding groove 7 installed on the inner wall of the metal inner container of the storage tank and the anti-slosh structure 6 connected with the sliding groove 7: during the flight mission period, the liquid in the storage tank is always positioned above the liquid filling pipe 8 due to the action of the anti-slosh structure 6, so that the sloshing of the liquid propellant in the storage tank is reduced.

Claims

1. A large-size, ultra-lightweight cryogenic storage tank, characterized in that, The large-size ultra-lightweight cryogenic storage tank includes: a metal inner liner (3), a composite material outer shell (5), a heat insulation structure (4), and an anti-sway structure (6); the metal inner liner (3) is a spherical structure, which includes a cylindrical section (13) and a hemispherical bottom (14); the cylindrical section (13) is made of a metal strip of a certain thickness and width spirally rolled, and its two ends are respectively connected to the hemispherical bottom (14); the thin strip of the rolled cylindrical section (13) is rolled to form a curved seam on both sides; during the rolling process, the seam edges on both sides interlock with each other, and the interlocking wheels that roll up and down in the rolling equipment further press the interlocking seam tightly; the composite material outer shell (5) is located outside the metal inner liner (3), and a heat insulation structure is provided between the two. Structure (4); The insulation structure (4) is uniformly wrapped around the outside of the metal inner liner (3); One end of the large-size ultra-lightweight cryogenic tank is provided with a liquid filling pipe (8), and the other end is provided with an exhaust pipe (2). A liquid level gauge (11) and a pressure gauge (12) are provided on the side; The liquid filling pipe (8) and the exhaust pipe (2) both extend into the large-size ultra-lightweight cryogenic tank; The liquid filling pipe (8) is provided with a filling stop valve (9) and an exhaust stop valve (10) respectively through a three-way connector; The exhaust pipe (2) is provided with a pressure regulating valve (1); The liquid level gauge (11) and the pressure gauge (12) extend into the large-size ultra-lightweight cryogenic tank through connecting pipes; Sliding grooves (7) are provided on both sides of the metal inner liner (3) for installing anti-sway structures (6).

2. The large-size ultra-lightweight cryogenic storage tank according to claim 1, characterized in that, The anti-sway structure (6) includes a float plate (17), a transmission ring (15), and a prestressed elastic device (16); the transmission ring (15) moves on the sliding groove (7), and its inner side is connected to the float plate (17) through the prestressed elastic device (16); the float plate (17) is located in the middle of the transmission ring (15).

3. The large-size ultra-lightweight cryogenic storage tank according to claim 1 or 2, characterized in that, The metal inner liner (3) is an aluminum alloy strip; the composite material outer shell (5) is a carbon fiber reinforced composite material; and the heat insulation structure (4) is a flexible heat insulation material.

4. The large-size ultra-lightweight cryogenic storage tank according to claim 3, characterized in that, The flexible thermal insulation material is one of polyimide film, polyamide fiber felt, and silicone rubber.

5. The large-size ultra-lightweight cryogenic storage tank according to any one of claims 1-4, characterized in that, The metal inner liner (3) and the heat insulation structure (4) are connected by adhesive or hot pressing.

6. The large-size ultra-lightweight cryogenic storage tank according to claim 5, characterized in that, The adhesive bonding method uses an adhesive, which is one of epoxy resin adhesive, polyurethane glue, acrylic glue, or silicone rubber glue.

Images