A heat-insulating and load-bearing integrated all-composite liquid hydrogen tank

Abstract

The present invention provides an insulated, load-bearing, integrated, all-composite liquid hydrogen tank, comprising an anti-leakage shell, an anti-mechanical shell and a coordination ring; the anti-leakage shell forms a space for accommodating cryogenic propellants, and comprises a front connector, a sealing shell and a rear connector from front to back, the front connector and the rear connector are interconnected with a detachable core to form a core mold, and a sealing shell is prepared by prepreg plying on the outer surface of the core mold; the anti-mechanical shell comprises an inner coordination layer, a high-rigidity layer and an outer protective layer fixedly connected in sequence outside the sealing shell; the coordination ring is located at the front and rear ends of the liquid hydrogen tank, seals the two ends of the anti-leakage shell and is connected to the anti-mechanical shell, so that a vacuum state is maintained between the sealing shell and the outer protective layer. The insulated, load-bearing, integrated composite liquid hydrogen tank of the present invention has a simple structure, and has the characteristics of good thermal insulation, high rigidity and low weight through structural and material design, and can be applied to high-efficiency low-temperature upper stage transportation, and can also be applied to low-temperature spacecraft for deep space exploration.

Description

Technical Field

[0001] The present invention belongs to the technical field of liquid hydrogen tanks, and in particular relates to an insulated and load-bearing integrated all-composite material liquid hydrogen tank and a preparation method thereof, which is suitable for large high-performance spacecraft such as cryogenic propulsion aircraft, cryogenic lander and cryogenic upper stage. Background Art

[0002] Liquid hydrogen / liquid oxygen and other cryogenic propellant combinations are the preferred propellants for deep space exploration due to their high specific impulse, non-toxicity and pollution-free nature. Since the boiling point of liquid hydrogen is as low as -253°C and its latent heat is low, in actual engineering applications, the complex and harsh thermal and mechanical environments such as ground convection and space radiation bring great difficulties to the application of liquid hydrogen. At the same time, the mass density of liquid hydrogen is only 71kg / m 3 Therefore, the volume and weight of the liquid hydrogen tank are the main components of the aircraft. Therefore, reducing the weight of the liquid hydrogen tank while ensuring insulation, strength and rigidity has always been one of the key issues that plague large cryogenic aircraft. Summary of the invention

[0003] In order to overcome the deficiencies in the prior art, the inventors have conducted intensive research and provided an insulated, load-bearing integrated all-composite material liquid hydrogen tank and a preparation method thereof. Through structural and material design, the liquid hydrogen tank has the characteristics of good thermal insulation, high strength and rigidity, and low weight, thereby completing the present invention.

[0004] The technical solution provided by the present invention is as follows:

[0005] An insulated and load-bearing integrated all-composite liquid hydrogen tank, comprising an anti-leakage shell, a mechanical resistance shell and a coordination ring; the anti-leakage shell forms a space for accommodating cryogenic propellants, and comprises a front connector, a sealing shell and a rear connector from front to back, the front connector and the rear connector are connected to a detachable core to form a core mold, and a sealing shell is obtained by laying prepreg on the outer surface of the core mold;

[0006] The mechanical resistance shell comprises an inner coordination layer, a high stiffness layer and an outer protective layer which are fixedly connected in sequence outside the sealing shell, wherein the inner coordination layer is used to coordinate the deformation of the sealing shell and the high stiffness layer, the high stiffness layer is used to enhance the composite liquid hydrogen tank's ability to withstand external loads and provide vacuum insulation, and the outer protective layer is used to coordinate the deformation of the high stiffness layer and form vacuum insulation, while protecting the tank from external mechanical damage;

[0007] The coordination ring is located at the upper and lower ends of the liquid hydrogen storage tank, seals the two ends of the anti-leakage shell and is connected to the mechanical resistance shell, so that a vacuum state is maintained between the sealing shell and the outer protective layer.

[0008] The heat-insulating and load-bearing integrated all-composite material liquid hydrogen tank provided by the present invention has the following beneficial effects:

[0009] (1) The heat-insulating and load-bearing integrated composite liquid hydrogen tank of the present invention fully utilizes the designability of the mechanical properties of composite materials in different directions, and reduces the weight by more than 30% compared with the traditional aluminum alloy tank;

[0010] (2) The combined design of the inner coordination layer, the high stiffness layer and the outer protective layer in the mechanical resistance shell of the composite liquid hydrogen tank of the present invention realizes the integration of heat insulation and load bearing; at the same time, a corrugated cylindrical high stiffness layer is arranged between the inner coordination layer and the outer protective layer to effectively resist the bending moment and torque on the front and rear ends of the liquid hydrogen tank;

[0011] (3) The anti-leakage shell of the composite material liquid hydrogen storage tank in the present invention comprises a front connector, a sealing shell and a rear connector. The sealing shell is formed by laying a layer on the core mold composed of the front connector, the detachable core and the rear connector, thereby realizing high-precision preparation of the anti-leakage shell and reducing the processing difficulty of the special-shaped anti-leakage shell. The connection strength of the three parts meets the requirements of the anti-leakage shell for accommodating liquid hydrogen.

[0012] (4) The sealing shell of the composite liquid hydrogen tank of the present invention is divided into an inner layer, an intermediate layer and an outer layer, which effectively meets the sealing requirements of liquid hydrogen;

[0013] (5) The coordination rings of the composite liquid hydrogen tank of the present invention are located at the upper and lower ends of the liquid hydrogen tank, sealing the two ends of the anti-leakage shell and connecting to the mechanical shell, which is conducive to ensuring the vacuum degree between the sealed shell and the outer protective layer, and the curved structure and connection method of the coordination ring reduce the internal and external connection stress of the liquid hydrogen tank;

[0014] (6) The heat-insulating load-bearing integrated composite liquid hydrogen tank of the present invention has a simple appearance and structure, does not require outer foam spraying, can effectively reduce convective heat transfer, and can be used for high-efficiency low-temperature upper stage transportation;

[0015] (7) The heat-insulating load-bearing integrated composite liquid hydrogen tank of the present invention has a simple external structure and does not require composite variable-density multi-layer insulation on the outer wall of the tank, which can significantly reduce radiation heat exchange and can be applied to deep space exploration missions of space orbit transfer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of the heat-insulating and load-bearing integrated all-composite material liquid hydrogen tank of the present invention. Figure 1 (A) is a longitudinal cross-sectional view, Figure 1 (B) is a top view;

[0017] Figure 2 It is a schematic diagram of the layer structure of the anti-leakage shell and the mechanical resistance shell in the liquid hydrogen storage tank of the present invention;

[0018] Figure 3 Schematic diagram of the structure of the high rigidity layer in the liquid hydrogen tank of the present invention. Figure 3 (A) is an enlarged view of the corrugated cylinder in the shape of a “X”. Figure 3 (B) is a transverse cross-sectional view;

[0019] Figure 4 It is a structural schematic diagram of the coordination ring in the liquid hydrogen tank of the present invention, Figure 4 (A) is the coordination ring structure, Figure 4 (B) is the position connection relationship of the coordination ring in the tank.

[0020] Description of Figure Numbers

[0021] 1-front connector; 2-sealing shell; 3-coordination ring; 301-first connection surface; 302-second connection surface; 303-third connection surface; 304-transition section; 4-inner coordination layer; 5-high stiffness layer; 6-outer protective layer; 7-rear connector. DETAILED DESCRIPTION

[0022] The following detailed description of the present invention will make the features and advantages of the present invention more clear and explicit.

[0023] The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise noted.

[0024] According to a first aspect of the present invention, there is provided a heat-insulating and load-bearing integrated all-composite liquid hydrogen tank, such as Figure 1 As shown, it includes: an anti-leakage shell, an anti-mechanical shell and a coordination ring 3; the anti-leakage shell forms a space for accommodating liquid hydrogen, which includes a front connector 1, a sealing shell 2 and a rear connector 7 from front to back, the front connector 1 and the rear connector 7 are connected to each other with a detachable core to form a core mold, and the sealing shell 2 is formed by automatically laying prepreg on the outer surface of the core mold; the anti-mechanical shell includes an inner coordination layer 4, a high stiffness layer 5 and an outer protective layer 6 fixedly connected to the outside of the sealing shell 2 in sequence, the inner coordination layer 4 is used to coordinate the deformation of the sealing shell 2 and the high stiffness layer 5, the high stiffness layer 5 is used to bear the external load of the composite liquid hydrogen tank, and the outer protective layer 6 is used to coordinate the deformation of the high stiffness layer 5, and form vacuum insulation, while protecting the tank from external mechanical damage; the coordination ring 3 is located at the upper and lower ends of the liquid hydrogen tank, seals the two ends of the anti-leakage shell and is connected to the anti-mechanical shell, so that a vacuum state is maintained between the sealing shell 2 and the outer protective layer 6.

[0025] In the present invention, the front connector 1 adopts a three-dimensional woven composite material, and a manhole is opened at the top (preferably at the center position) thereof, the diameter of the manhole is not less than 450 mm, and the rear end is connected to the sealing shell 2 by a slope. The wall thickness gradually becomes thinner along the direction of increasing diameter, and the wall thickness of the sealing shell 2 at the connection point gradually becomes thicker. Through this gradual design, the contact area between the sealing shell 2 and the front connector 1 is increased, and the bonding strength is improved.

[0026] Furthermore, the front connector 1 is obtained by curing a composite material having a fiber volume content of not less than 70%. The three-dimensional woven dry preform in the composite material is woven by carbon fibers, and the elastic modulus of the carbon fibers is not less than 276 GPa; and the resin is a thermosetting epoxy resin.

[0027] In the present invention, the rear connector 7 is made of a three-dimensional woven composite material, and a drainage port can be provided at its bottom. The rear connector 7 is connected to the sealing shell 2 by a slope surface, and the wall thickness gradually becomes thinner along the direction of increasing diameter, and the wall thickness of the sealing shell 2 at the connection point becomes thicker accordingly, thereby increasing the contact area between the sealing shell 2 and the rear connector 7.

[0028] Furthermore, the rear connector 7 is cured from a composite material having a fiber volume content of not less than 70%. The three-dimensionally woven dry preform in the composite material is woven from carbon fibers, the elastic modulus of the carbon fibers is not less than 276 GPa, and the resin is a thermosetting epoxy resin.

[0029] Preferably, the composite material of the rear connecting head 7 is the same as that of the front connecting head 1 .

[0030] In the present invention, Figure 2 As shown, the sealing shell 2 includes an inner layer, an intermediate layer and an outer layer, which are connected to the front connector 1 and the rear connector 7 in sequence by automatic prepreg laying, and form a complete anti-leakage shell with the front connector 1 and the rear connector 7 after curing; specifically, the inner layer is automatically laid on a core mold consisting of the front connector 1, the detachable core and the rear connector 7 connected to each other using prepreg, the number of laid layers is not less than 7 layers, the thickness of each layer is not more than 0.14 mm (preferably 0.1-0.14 mm), and the laying angle is symmetrical with the laying angle of the outer layer. Taking the characteristic laying of 6 layers as an example, the laying angles are 12°, -12°, -45°, 45°, 65°, and -65°.

[0031] The middle layer is automatically laid on the outside of the inner layer using the impregnation material, the number of layers laid is not less than 5, the thickness of each layer is not more than 0.07mm (preferably 0.05-0.07mm), the laying angle is symmetrical, taking the characteristic laying of 5 layers as an example, the laying angles are 60°, -60°, 0, -60°, 60°, to reduce the leakage of small hydrogen molecules;

[0032] The outer layer is automatically laid on the outside of the middle layer using prepreg, the number of laid layers is not less than 6, the layer thickness is not more than 0.14mm (preferably 0.1-0.14mm), and the laying angle is symmetrical with the laying angle of the inner layer. Taking the characteristic laying of 6 layers as an example, the laying angles are -65°, 65°, 45°, -45°, -12°, and 12°. The laying angle of the outer layer is symmetrical with the laying angle of the inner layer to reduce the manufacturing stress caused by laying. The detachable core can be taken out through the manhole of the front connector 1 after being split.

[0033] Furthermore, the prepreg used in the inner layer and the outer layer includes the following mass ratio components: high modulus carbon fiber is used as the reinforcement, the fiber volume content is not less than 70%, the elastic modulus of the carbon fiber is not less than 276GPa, and the resin is a thermosetting epoxy resin.

[0034] Furthermore, the prepreg used in the middle layer includes the following mass ratio components: fine filament bundle high modulus PBO fiber is used as reinforcement, the fiber volume content is not less than 70%, the elastic modulus of the PBO fiber is not less than 270GPa, and the resin is thermosetting epoxy resin.

[0035] The middle layer of the sealing shell 2 uses fine-filament bundle PBO fibers as reinforcement, which reduces the generation of pores in the composite material at a higher volume ratio and improves the liquid hydrogen sealing performance; the inner layer and the outer layer are symmetrical in thickness and laying angle to ensure that the middle layer is evenly stressed and minimizes local stress concentration in the middle layer to cause leakage.

[0036] In the present invention, the thickness of the sealing shell 2 is not less than 2.07 mm, wherein the thickness of the inner layer is not less than 0.86 mm, the thickness of the middle layer is not less than 0.35 mm, and the thickness of the outer layer is not less than 0.86 mm. The sealing shell 2 can withstand a pressure of not less than 0.4 MPa, and the pressure at the connection with the front connector 1 and the connection with the rear connector 7 is not less than 0.4 MPa.

[0037] In the present invention, the inner coordination layer 4 is fixedly connected to the sealing shell 2 by automatic placement using high modulus carbon fiber prepreg. Specifically, the prepreg includes the following mass ratio components: high modulus carbon fiber is used as a reinforcement, the volume content of carbon fiber is not less than 70%, the elastic modulus of carbon fiber is not less than 276GPa, and the resin is a thermosetting epoxy resin.

[0038] In the present invention, the high rigidity layer 5 is a corrugated cylinder with a continuous "X"-shaped cross section. During the preparation, a high modulus carbon fiber prepreg corrugated board is firstly manufactured by laying, then rolled and bent to form a corrugated cylinder, which is finally connected to the inner coordination layer 4.

[0039] Specifically, the prepreg includes the following components in mass ratio: high modulus carbon fiber is used as reinforcement, the volume content of carbon fiber is not less than 70%, the elastic modulus of carbon fiber is not less than 276GPa, and the resin is thermosetting epoxy resin.

[0040] In the present invention, the outer protective layer 6 includes two sublayers, an inner sublayer and an outer sublayer. Figure 2 The inner sublayer high modulus carbon fiber prepreg is connected to the high stiffness layer 5 through automatic placement, and the outer sublayer is connected to the inner sublayer through automatic placement using glass fiber prepreg. The glass fiber outer sublayer protects the liquid hydrogen tank from external mechanical load collision.

[0041] Specifically, the prepreg for the inner sublayer includes the following mass ratio components: high modulus carbon fiber is used as the reinforcement, the volume content of the carbon fiber is not less than 70%, the elastic modulus of the carbon fiber is not less than 276GPa, and the resin is a thermosetting epoxy resin.

[0042] The prepreg for the outer sublayer includes the following mass ratio components: high modulus glass fiber is used as reinforcement, the volume content of glass fiber is not less than 70%, the elastic modulus of glass fiber is not less than 72GPa, and the resin is thermosetting epoxy resin

[0043] In the present invention, the thickness of the inner coordination layer 4 is not less than 0.86 mm; the thickness of the outer protection layer 6 is not less than 0.86 mm.

[0044] The thickness of the high rigidity layer 5 is the distance between the inner coordination layer 4 and the outer protective layer 6, which is 30 to 32 mm; the wall thickness of the corrugated cylinder forming the high rigidity layer 5 is 0.5 mm to 0.7 mm, and the corrugation turning angle of the corrugated cylinder is 60° to 65°. Figure 3 After extensive research, the inventors found that the corrugation turning angle of 60° to 65° minimizes the stress on the corrugated cylinder, and minimizes the spacing between the inner coordination layer 4 and the outer protective layer 6. The high rigidity layer thickness of 30 to 32 mm can effectively withstand external loads such as bending moment and torque of the cryogenic storage tank under the premise of optimizing weight.

[0045] In the present invention, Figure 4As shown, the upper and lower parts of the liquid hydrogen tank are both installed with coordination rings 3; the coordination ring 3 includes a first connection surface 301, a second connection surface 302, a transition section 304 and a third connection surface 303, the first connection surface 301 is connected to the inner side surface of the outer protective layer 6, after vacuum degassing, the second connection surface 302 is sealed and connected to the high rigidity layer 5 and the inner coordination layer 4, the third connection surface 303 is connected to the outer side surface of the sealing shell 2 head, the transition section 304 is an arc surface section, located between the second connection surface 302 and the third connection surface 303, reducing the stress concentration at the connection corner point of the anti-leakage shell and the mechanical resistance shell; through the structural form and connection method of the coordination ring 3, the vacuum degree requirement between the outer protective layer 6 and the sealing shell 2 is guaranteed, and the heat transfer is reduced.

[0046] Furthermore, the coordination ring 3 is manufactured by a manual laying process; high-strength carbon fiber is used as a reinforcement, the volume content of the carbon fiber is not less than 70%, the tensile strength of the carbon fiber is not less than 2410 MPa, and the resin is epoxy resin.

[0047] The present invention has been described in detail above in conjunction with specific embodiments, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements can be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

[0048] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A heat-insulating and load-bearing integrated all-composite material liquid hydrogen tank, characterized in that: It includes an anti-leakage shell, a mechanical resistance shell and a coordination ring (3); The anti-leakage shell forms a space for accommodating cryogenic propellants, and comprises, from front to back, a front connector (1), a sealing shell (2) and a rear connector (7), wherein the front connector (1) and the rear connector (7) are connected to a detachable core to form a core mold, and the sealing shell (2) is manufactured by laying prepreg on the outer surface of the core mold; The sealing shell (2) comprises an inner layer, an intermediate layer and an outer layer, which are connected to the front connector (1) and the rear connector (7) in sequence by automatic prepreg laying, and after curing, form a complete anti-leakage shell with the front connector (1) and the rear connector (7); the inner layer is automatically laid on a core mold consisting of the front connector (1), the detachable core and the rear connector (7) connected to each other by using prepreg, the number of laid layers is not less than 7 layers, the thickness of each layer is not more than 0.14 mm, and the laying angle is symmetrical with the laying angle of the outer layer; the intermediate layer is automatically laid on the outer side of the inner layer by using prepreg, the number of laid layers is not less than 5 layers, the thickness of each layer is not more than 0.07 mm, and the laying angle is symmetrical; the outer layer is automatically laid on the outer side of the intermediate layer by using prepreg, the number of laid layers is not less than 6 layers, the layer thickness is not more than 0.14 mm, and the laying angle is symmetrical with the laying angle of the inner layer; The mechanical resistance shell comprises an inner coordination layer (4), a high rigidity layer (5) and an outer protective layer (6) which are fixedly connected in sequence outside the sealing shell (2); the inner coordination layer (4) is used to coordinate the deformation of the sealing shell (2) and the high rigidity layer (5); the high rigidity layer (5) is used to bear the external load of the composite liquid hydrogen tank; the high rigidity layer (5) is a corrugated cylindrical tube with a continuous "X"-shaped cross section; the outer protective layer (6) is used to coordinate the deformation of the high rigidity layer (5) and form vacuum insulation, while protecting the tank from external mechanical damage; The coordination ring (3) is located at the front and rear ends of the liquid hydrogen storage tank, seals the two ends of the anti-leakage shell and is connected to the mechanical resistance shell, so that a vacuum state is maintained between the sealing shell (2) and the outer protective layer (6).

2. The heat-insulating and load-bearing integrated all-composite material liquid hydrogen tank according to claim 1, characterized in that: The front connector (1) is made of a three-dimensional braided composite material, a manhole is provided on the top, the rear end is connected to the sealing shell (2) with a slope, the wall thickness gradually becomes thinner along the direction of increasing diameter, and the wall thickness of the sealing shell (2) at the connection point gradually becomes thicker; and / or The rear connecting head (7) is made of a three-dimensional woven composite material, and a drainage port can be provided at its bottom. The rear connecting head (7) and the sealing shell (2) are connected with each other via a slope, and the wall thickness gradually becomes thinner along the direction of increasing diameter, and the wall thickness of the sealing shell (2) at the connection point becomes thicker accordingly.

3. The heat-insulating and load-bearing integrated all-composite material liquid hydrogen tank according to claim 2, characterized in that: The front connector (1) is obtained by curing a composite material having a fiber volume content of not less than 70%, wherein the three-dimensionally woven dry preform in the composite material is woven by carbon fibers, and the elastic modulus of the carbon fibers is not less than 276 GPa; the resin is a thermosetting epoxy resin; and / or The rear connector (7) is obtained by curing a composite material having a fiber volume content of not less than 70%, wherein the three-dimensionally woven dry preform in the composite material is woven by carbon fibers, and the elastic modulus of the carbon fibers is not less than 276 GPa; and the resin is a thermosetting epoxy resin.

4. The heat-insulating and load-bearing integrated all-composite material liquid hydrogen tank according to claim 1, characterized in that: The prepreg used in the inner layer and the outer layer includes the following mass ratio components: high modulus carbon fiber is used as a reinforcement, the fiber volume content is not less than 70%, the elastic modulus of the carbon fiber is not less than 276GPa, and the resin is a thermosetting epoxy resin; The prepreg used in the middle layer includes the following mass ratio components: fine filament bundle high modulus PBO fiber is used as reinforcement, the fiber volume content is not less than 70%, the elastic modulus of the PBO fiber is not less than 270GPa, and the resin is thermosetting epoxy resin.

5. The heat-insulating and load-bearing integrated all-composite material liquid hydrogen tank according to claim 1, characterized in that: The thickness of the sealing shell (2) is not less than 2.07 mm; wherein the thickness of the inner layer is not less than 0.86 mm, the thickness of the middle layer is not less than 0.35 mm, and the thickness of the outer layer is not less than 0.86 mm.

6. The heat-insulating and load-bearing integrated all-composite material liquid hydrogen tank according to claim 1, characterized in that: The thickness of the high-rigidity layer (5) is the distance between the inner coordination layer (4) and the outer protective layer (6), which is 30 to 32 mm; the wall thickness of the corrugated cylinder forming the high-rigidity layer (5) is 0.5 to 0.7 mm, and the corrugation turning angle of the corrugated cylinder is 60° to 65°.

7. The heat-insulating and load-bearing integrated all-composite material liquid hydrogen tank according to claim 1, characterized in that: The outer protective layer (6) comprises two sub-layers, an inner sub-layer and an outer sub-layer. The inner sub-layer is connected to the high stiffness layer (5) by automatic placement using high modulus carbon fiber prepreg, and the outer sub-layer is connected to the inner sub-layer by automatic placement using glass fiber prepreg.

8. The heat-insulating and load-bearing integrated all-composite material liquid hydrogen tank according to claim 1, characterized in that: The upper and lower parts of the liquid hydrogen tank are both installed with a coordination ring (3); the coordination ring (3) comprises a first connection surface (301), a second connection surface (302), a transition section (304) and a third connection surface (303); the first connection surface (301) is connected to the inner side surface of the outer protective layer (6); after vacuum degassing, the second connection surface (302) is sealed and connected to the high rigidity layer (5) and the inner coordination layer (4); the third connection surface (303) is connected to the outer side surface of the sealing head of the sealing shell (2); the transition section (304) is a curved surface section, which is located between the second connection surface (302) and the third connection surface (303) to reduce stress concentration at the corner point where the anti-leakage shell and the mechanical resistance shell are connected.

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