A liquid-gas phase change composite material pipe and its lay-up design method and preparation method

Abstract

The present invention discloses a liquid-gas phase change composite material pipe and its layup design and preparation method. The preparation method comprises the following steps: S1, preparing a pipe inner lining; S2, performing surface treatment on the pipe inner lining; S3, using the design method to obtain a spiral fiber layup thickness of #imgabs0# and a hoop fiber layup thickness of #imgabs1#, using the pipe inner lining as a core mold, alternately laying spiral fiber layers and hoop fiber layers using reinforcing fibers, wet-winding in one step, and performing rotational curing after winding to form a reinforced fiber pipe body. The present invention can enhance the interfacial bonding between the layers, improve the composite pipe's ability to resist external loads, and significantly enhance the composite pipe's pressure-bearing capacity.

Description

Technical Field

[0001] The present invention relates to the field of composite material manufacturing, in particular to a liquid-gas phase change composite material pipe and a layer design method and a preparation method thereof. Background Art

[0002] In the supercritical state, carbon dioxide has the characteristics of both gas and liquid. It can be compressed or expanded like a gas, and has a relatively large density like a liquid, but its viscosity is lower than that of a liquid, and it has better mass transfer and heat transfer properties. Liquid carbon dioxide is compressed in a closed phase change tube, and the liquid carbon dioxide in the closed phase change tube absorbs heat and releases heat instantaneously through the combustion of chemical substances and the release of heat by electric energy to generate impact power. It is used for explosion test simulations and aircraft launches, and the tube itself needs to withstand very high pressure. The high-pressure sealed containers in the existing technology are usually made of steel materials. In order to meet the requirements of lightweight equipment and long-term storage, lightweight and high-strength materials need to be used to reduce weight. At the same time, liquid carbon dioxide is stored in the tube body, and carbon dioxide under high temperature and high pressure, especially in the supercritical state, is highly corrosive. Therefore, the compatibility of the inner surface material of the tube body and carbon dioxide must be considered.

[0003] A Chinese patent with authorization announcement number CN104455792B discloses a fiber-reinforced polyurethane wound sandwich composite pipe and its manufacturing method. The pipe comprises a fiberglass inner lining layer, a fiberglass inner structural layer, a fiber-reinforced polyurethane composite sandwich, and a fiberglass outer structural layer, which are sequentially arranged from the inside out. A preformed Z-shaped glass fiber reinforcement layer, impregnated with resin, is then transferred to the upper surface and one side of a rectangular polyurethane strip to form a fiber-reinforced polyurethane material. A pulling device is then used to simultaneously and continuously wind the laid fiber-reinforced polyurethane material onto the inner structural layer to form a fiber-reinforced polyurethane composite sandwich, thereby improving the composite pipe's ability to withstand external loads. However, the high pressure generated within the pipe during the liquid-gas phase transition of carbon dioxide can reach 150 MPa, and existing composite pipes still fail to meet these requirements. Furthermore, the winding process is susceptible to various factors, including environmental, equipment, and operational factors, resulting in unstable winding quality, which in turn affects the strength and durability of the pipe. Insufficient bonding strength between the composite wound reinforcement layer and the inner lining or polyurethane layer can lead to interlayer delamination, affecting the overall performance of the pipe. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a liquid-gas phase change composite material pipe and its layup design method and preparation method in response to the shortcomings of the existing technology. The liquid-gas phase change composite material pipe prepared by this method can ensure the pressure bearing strength of different levels of internal pressure, meet long-term storage requirements, and has good manufacturing process stability.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] The present invention discloses a method for designing a pipe ply of a liquid-gas phase change composite material, comprising the following steps:

[0007] The reinforcing fibers are alternately laid in spiral fiber layers and hoop fiber layers on the pipe body lining. The spiral fiber layers are laid according to the spiral fiber laying angle α. The thickness of the spiral fiber layers is , the thickness of the hoop fiber layer is , we get alternating layers, where:

[0008] ;

[0009] α is the spiral fiber ply angle, is the design strain in the fiber direction, Design strain value for the matrix;

[0010] ;

[0011] ;

[0012] is the thickness of the spiral fiber layer, is the internal pressure of the composite material tube, R is the radius of the composite material tube, is the effective elastic modulus in the fiber direction, is the hoop fiber ply thickness.

[0013] The alternating laying of spiral fiber layers and hoop fiber layers is performed in the order of spiral fiber layers, hoop fiber layers, spiral fiber layers, hoop fiber layers, etc. Each time, the spiral fiber layers and hoop fiber layers can be laid in multiple layers or in a single layer.

[0014] The design method of the present invention is used to obtain the ply angle, spiral fiber ply thickness and hoop fiber ply thickness, and to perform alternating spiral and hoop wet winding to achieve high strength and high impact resistance.

[0015] In one preferred embodiment, the continuous layers of the spiral fiber plies do not exceed 4 layers, and the continuous layers of the circumferential fiber plies do not exceed 4 layers; the alternating layers are all made of carbon fiber, and the outer layers of the alternating layers also include 2-4 layers of glass fiber outer layers.

[0016] Carbon fiber is used for alternating wet winding in spiral and hoop directions, and a preset number of outer layers wound later are used for alternating wet winding in spiral and hoop directions, thereby achieving the characteristics of mixed reinforcement, high strength and high impact resistance.

[0017] In one preferred embodiment, when the pressure strength of the liquid-gas phase change composite material pipe is ≥150 MPa, the spiral fiber layer angle α is ≤41.14°, and the spiral fiber layer thickness is 3.55~4.05mm, the thickness of the hoop fiber layer It is 1.30~1.80mm.

[0018] This laying method can ensure that the pressure strength of the liquid-gas phase change composite material pipe is ≥150MPa, which can meet the high pressure requirements during the liquid-gas phase change process of carbon dioxide.

[0019] The following further calculates the number of winding layers:

[0020] ;

[0021] ;

[0022] is the number of spiral winding layers, is the number of hoop winding layers, is the thickness of the unidirectional fiber layer.

[0023] The present invention also discloses a method for preparing a liquid-gas phase change composite material tube, comprising the following steps:

[0024] S1. Prepare the pipe lining;

[0025] S2. Surface treatment of the pipe lining;

[0026] S3. Using the design method to obtain the thickness of the spiral fiber layer and the hoop fiber layer thickness is The inner lining of the pipe body is used as the core mold, and the reinforcing fibers are alternately laid in spiral and hoop directions, and are wound in one step using a wet method. After winding, the fibers are rotary solidified to form a reinforced fiber pipe body.

[0027] In one preferred embodiment, when the end caps and barrel sections of the pipe body are lined with titanium alloy or duplex stainless steel, the surface treatment is pickling and passivation.

[0028] Specifically, the titanium alloy is TA2 titanium alloy. When the ends of the pipe body and the barrel section are lined with Q355 or other alloy structural steel, the surface treatment is nitriding, carburizing or QPQ.

[0029] Preferably, S2 performs surface treatment on the inner lining of the pipe body and then performs sandblasting.

[0030] Surface treatment of the pipe lining enhances its compatibility with CO2. The outer surface of the pipe lining barrel and the ellipsoidal portion of the head need to consider the interfacial bonding strength with the fiber and resin during winding to prevent delamination. Therefore, considering various factors, it is planned to perform surface treatment on the pipe lining after it is manufactured.

[0031] In one preferred embodiment, S3 further includes the following steps:

[0032] S4. Place the reinforced fiber tube body into a casting mold for polyurethane casting, and remove the tube from the mold after casting to obtain a liquid-gas phase change composite material tube.

[0033] If the product is used in a bad environment and needs protection, add the pouring step of S4.

[0034] In one preferred embodiment, before S4, the following steps are further included:

[0035] The surface of the reinforced fiber tube body is polished, cleaned, and dried, and then an adhesive is applied and dried to obtain the reinforced fiber tube body applied with the adhesive;

[0036] Apply release agent evenly on the casting mold cavity.

[0037] Specifically, the surface of the reinforced fiber tube body is cleaned with acetone or ethanol, and after natural drying for 5-10 minutes, the adhesive is applied, and the adhesive is naturally dried for 1-3 hours.

[0038] First clean the casting mold cavity, then apply the release agent; preferably, wipe the casting mold cavity with a non-woven cloth dipped in acetone or alcohol and let it dry naturally for 5 to 10 minutes.

[0039] In one preferred embodiment, S4 specifically includes:

[0040] Assemble the reinforced fiber tube body brushed with adhesive with the casting mold, preheat the assembled casting mold, add the polyurethane prepolymer and cross-linking agent into the storage tank of the casting machine respectively, and start the vacuum system for vacuum degassing; connect the casting mold to the casting machine and evacuate the air; start the casting machine, open the feed port, and perform vacuum casting; close the exhaust valve after the exhaust hole discharges the material; after the casting is completed, close the feed valve and continue to evacuate the air; solidify and remove the casting mold after casting.

[0041] Preferably, the cross-linking agent is MOCA.

[0042] Preferably, the assembled casting mold is preheated to a temperature of 50-70° C. for 1-2 hours.

[0043] The vacuum degree of vacuum degassing is -0.15~-0.05 MPa, and the time is 1~3 hours.

[0044] Connect the casting mold to the casting machine and evacuate the mold to a vacuum degree of -0.15~-0.05 MPa for 10~20 minutes.

[0045] After pouring is completed, close the feed valve and continue to vacuum for 10 to 20 minutes. After vacuuming, let it stand for 10 to 20 minutes.

[0046] The temperature of curing the cast mold after casting is 90-100°C and the curing time is 1-3 hours.

[0047] In one preferred embodiment, the solidified casting mold is taken out, the cast tube body is taken out after demoulding, and the tube body is secondary solidified to obtain a liquid-gas phase change composite material tube.

[0048] Preferably, the secondary curing temperature is 90-100° C., and the curing time is 10-30 hours.

[0049] Preferably, the manufacturing of the pipe body lining is specifically as follows: the end caps and the barrel section of the pipe body lining are welded to form an integral structure, and the welding is performed by fully automatic laser welding to perform full penetration welding.

[0050] Preferably, the pipe body is lined with titanium alloy, duplex stainless steel or high-strength steel that has undergone internal surface treatment to meet compatibility requirements.

[0051] The present invention also discloses a liquid-gas phase change composite material tube prepared according to the preparation method, which comprises a tube inner lining and a reinforcing fiber layer from the inside to the outside.

[0052] Preferably, the outer layer of the reinforced fiber layer further includes a polyurethane protective layer.

[0053] Preferably, the inner lining of the pipe body is made of titanium alloy, duplex stainless steel, or high-strength steel with inner surface treatment, and the reinforcing fiber layer is formed by winding a mixture of carbon fiber and glass fiber.

[0054] Through the above technical scheme, the present invention can achieve the following technical effects: the present invention performs overall and surface processing on the pipe body lining to enhance the interface bonding force between the layers, improve the winding quality, and prevent interlayer peeling; the present invention adopts a ply design method of mixed winding of carbon fiber and glass fiber, and accurately determines the thickness and angle of the spiral fiber ply, and the thickness and angle of the circumferential fiber ply through quantitative calculation to ensure the bearing strength of different levels of internal pressure, thereby obtaining high strength and high impact resistance of the composite pipe, and combining the glass fiber layer and the polyurethane protective layer to improve the resistance to external loads, thereby greatly improving the performance of the composite pipe.

[0055] According to the ply design method of the present invention, the liquid-gas phase change composite material pipe can be designed to adopt a mixed winding of carbon fiber and glass fiber to achieve the characteristics of high strength and high impact resistance, and adopt spiral and circumferential alternating wet winding molding, and design a reasonable winding structure scheme to achieve the improvement of the composite pipe's resistance to external loads, thereby greatly improving the composite pipe's pressure-bearing and impact resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 Schematic diagram of a liquid-gas phase change composite material tube according to an embodiment of the present invention; 1 is the tube body lining; 2 is the reinforcing fiber layer; and 3 is the polyurethane protective layer.

[0057] Figure 2 Schematic diagram of the spiral fiber layer angle of the liquid-gas phase change composite material tube according to one embodiment of the present invention; wherein r is the radial direction, Z is the axial direction, α is the spiral fiber layer angle, The circular direction.

[0058] Figure 3 Schematic diagram of the ply thickness of a liquid-gas phase change composite material tube according to an embodiment of the present invention; is the total thickness of the fiber layer, t m is the total gallbladder thickness.

[0059] Figure 4 This is a physical picture of a liquid-gas phase change composite material tube according to an embodiment of the present invention. DETAILED DESCRIPTION

[0060] Example 1

[0061] An embodiment of the present invention mainly describes a method for preparing a liquid-gas phase change composite material tube, comprising the following steps:

[0062] S1. Select lining materials and make the inner lining of the pipe.

[0063] The pipe body lining is the main component of the liquid-gas phase change composite material pipe. It is in direct contact with carbon dioxide and plays a sealing role. At the same time, it serves as a core mold for the winding molding of fiber-reinforced composite materials, supporting the reinforcing fibers. After winding molding and curing, a composite pipe structure is formed. The pipe body lining is in direct contact with the internal filling medium, which can play a role of sealing and sharing part of the pressure. Moreover, the pipe body lining is an important component connected to the equipment interface, and is connected to the equipment through the threads processed by the pipe body lining.

[0064] The pipe lining is made up of two end heads and a barrel section. Therefore, the production of the pipe lining requires machining and welding the end heads and barrel sections to form an integral structure. The welding uses fully automatic laser welding for full penetration welding to ensure that the mechanical properties of the weld and the heat-affected zone after welding remain consistent with those of the parent material.

[0065] The ends of the pipe lining are made of TA2 titanium alloy rods, and the barrel section is made of TA2 titanium alloy pipe. TA2 titanium alloy has high strength, welding performance, processing performance and corrosion resistance. It is easier to process and weld for the pipe lining, which reduces processing costs and achieves the purpose of weight reduction and low-temperature reliability.

[0066] Alternatively, the ends of the pipe lining may be made of duplex stainless steel, while the barrel section may be made of duplex stainless steel; alternatively, the ends of the pipe lining may be made of Q355 or other alloy structural steel, while the barrel section may be made of Q355 or other alloy structural steel.

[0067] S2. Perform surface treatment on the entire inner lining of the pipe body.

[0068] Due to its structural characteristics, the composite pipe has exposed alloy metal at both ends, with mounting threads inside and outside. The inner cavity is a space filled with liquid CO2. According to technical requirements and operating conditions, the threaded ends at both ends need to meet the adaptability requirements of the deep-sea environment. The inner wall needs to consider that CO2 is an acidic gas, which is corrosive under high temperature and high pressure, especially in the supercritical state. The inner wall needs to be surface treated to enhance its compatibility with CO2.

[0069] In S2, the ends of the pipe lining and the barrel section are made of TA2 titanium alloy or duplex stainless steel, and the entire pipe lining is pickled and passivated.

[0070] In S2, the ends of the pipe lining and the barrel section are made of alloy structural steel such as Q355. The entire pipe lining is subjected to nitriding, carburizing or QPQ surface treatment. After the surface treatment is completed, the winding area is sandblasted.

[0071] The outer surface of the inner lining barrel section of the pipe body and the ellipsoidal part of the head need to consider the interfacial bonding force with the fiber and resin during winding to prevent delamination. Therefore, considering various factors, it is planned to carry out surface treatment of the inner lining of the pipe body after the inner lining of the pipe body is completed.

[0072] In order to ensure the compatibility between the lining and carbon dioxide, the entire inner lining of the pipe is subjected to anodized surface treatment, and the oxide film thickness is 10 to 20 μm.

[0073] The inner lining of the pipe body needs to be sandblasted in the winding area where the fiber winding is enhanced. After sandblasting, it is cleaned with clean compressed air. The inner lining of the pipe body after sandblasting is wrapped and protected with oil-free and dust-free pearl cotton or wrapping paper to prevent it from being contaminated by oil, dust, etc., which may cause abnormalities such as delamination after winding.

[0074] S3, using the reinforced fiber to perform spiral and circumferential wet winding molding alternately with the pipe body lining as the core mold, and then performing rotational curing after winding molding to form a reinforced fiber pipe body;

[0075] According to the working characteristics of composite pipes, there are significant differences in their working conditions during storage and use. During the filling and excitation process, the inside of the pipe body is subjected to enormous pressure. In order to meet the pressure requirements of composite pipes, reinforcing fibers can be used for winding molding. Carbon fiber has the characteristics of light weight, high strength, corrosion resistance, and high modulus. It is a good high-strength structural reinforcement limiting material; glass fiber has good toughness, is not easy to deform, has good impact resistance, excellent corrosion resistance, good heat resistance, low thermal conductivity, and will not cause combustion. By selecting carbon fiber and glass fiber for mixed reinforcement, high strength and high impact resistance can be achieved. Therefore, the present invention adopts a mixed winding process of carbon fiber and glass fiber.

[0076] According to technical requirements, the bursting pressure of the composite pipe is ≥150MPa, and its pressure-bearing requirement is achieved by reinforcing the reinforcing fibers by winding. In order to further improve the pressure-bearing capacity, the winding and laying structure of the reinforcing fibers is designed.

[0077] First, considering the matrix material, the transverse strain of the composite tube should be less than the design strain value. is the design strain in the fiber direction, is the design strain value of the matrix, is the spiral fiber ply angle, then: .

[0078] Based on the grid theory and equilibrium strain theory, the axial internal force of the composite tube and circumferential internal force for:

[0079] .

[0080] .

[0081] is the axial internal force of the composite tube, N; Determined by design pressure and design space or radius; is the hoop internal force, N; Determined by design pressure and design space or radius; is the effective elastic modulus in the fiber direction, MPa; E is the modulus, which is a constant; is the thickness of the spiral fiber layer, mm; is the thickness of the hoop fiber layer, mm; for .

[0082] Under the action of uniform internal pressure p, the annular and axial internal forces and their ratio η are designed as follows, where p is the internal pressure of the composite tube, MPa; R is the radius of the composite tube body, mm;

[0083] ;

[0084] ;

[0085] .

[0086] From the above formulas, the thickness of the spiral fiber layer and the thickness of the hoop fiber layer can be obtained as follows:

[0087] ;

[0088] .

[0089] According to the distribution of spiral fiber ply thickness and hoop fiber ply thickness obtained above, as well as the fiber unidirectional layer thickness (Material thickness, constant), calculate the number of spiral winding layers (design variable) and the number of hoop winding layers (Design variables):

[0090] ;

[0091] .

[0092] Furthermore, based on the winding layup structure such as the spiral fiber layup angle, spiral fiber layup thickness, hoop fiber layup thickness, spiral winding layer number, hoop winding layer number and the like designed above, the reinforcing fiber is adopted to perform spiral and hoop wet winding molding alternately with the inner lining of the pipe body as the core mold, and the reinforcing fiber adopts carbon fiber and glass fiber. For example, in the early winding, carbon fiber is adopted to perform spiral and hoop wet winding alternately, and in the later winding, a preset number of outer layers are adopted to perform spiral and hoop wet winding alternately, so as to achieve the characteristics of mixed reinforcement to realize high strength and high impact resistance.

[0093] Furthermore, the total number of layers is calculated using the above formula. During alternating winding, to prevent crack propagation in adjacent unidirectional layers, alternating winding is used. Furthermore, no more than four layers of unidirectional winding are allowed. For example, the liner can be wound circumferentially for a maximum of four layers, followed by spiral winding, which cannot exceed four layers. The winding pattern is then reversed. The outer glass fiber layer has two to four layers, primarily for collision protection, as glass fiber has greater toughness than carbon fiber.

[0094] Furthermore, after winding molding, rotation curing is carried out to ensure uniform heating. Specifically, rotation curing is carried out in an electric drying oven with controllable rising and falling temperatures. The curing temperature and time are carried out according to the process parameters, and the curing oven temperature is strictly controlled. After curing, the oven temperature drops below 40°C before it can be taken out of the oven to form a reinforced fiber tube body.

[0095] S4. Place the reinforced fiber tube body into a casting mold for polyurethane casting, and remove the tube from the mold after casting to obtain a liquid-gas phase change composite material tube.

[0096] Specifically, considering the influence of factors such as corrosion and external pressure on the pipe body in various natural environments, polyurethane has an ultra-low water absorption rate and can meet the requirements of self-sealing and resistance to erosion by various corrosive substances in the environment. A protective layer is formed on the outer layer of the pipe body by pouring polyurethane elastomer material to achieve the purpose of self-sealing and resistance to erosion by various corrosive substances in the environment.

[0097] Furthermore, in order to improve the pouring effect, before pouring: the surface of the reinforced fiber tube body is polished with 200-grit sandpaper, scrubbed with acetone or ethanol, and brushed with adhesive after natural drying for 10 minutes, and then naturally dried for 2 hours; the casting mold cavity is wiped with acetone or alcohol with a non-woven cloth to clean the remaining foreign matter, and naturally dried for 10 minutes, and the mold release agent is evenly applied to the casting mold cavity; the reinforced fiber tube body is assembled with the casting mold, and the metal parts at both ends of the tube body are protected during assembly to prevent damage to the anodized area due to bumps and the like; the assembled casting mold is placed in an oven and preheated at 60°C for 1 hour.

[0098] Furthermore, the specific process of polyurethane pouring is as follows: add the polyurethane prepolymer and the cross-linking agent MOCA into the storage tank of the pouring machine respectively, turn on the vacuum system, vacuum degassing for 1 hour, vacuum degree -0.09MPa; connect the pouring mold to the pouring machine, turn on the vacuum pump, vacuum degree -0.09MPa, and vacuum for 10 minutes; turn on the pouring machine, open the feed port, and perform vacuum pouring. After the exhaust hole is discharged, close the exhaust valve. After the pouring is completed, close the feed valve and continue to vacuum for 15 minutes. After vacuuming, let it stand for 15 minutes; move the poured pouring mold into the oven and cure at 95°C for 2 hours.

[0099] Furthermore, after curing is completed, the casting mold is taken out from the oven, and the cast tube body is taken out after demoulding. The tube body is put into the oven again and further cured at 95°C for 20 hours. After curing is completed, a liquid-gas phase change composite material tube is obtained.

[0100] The casting process of this embodiment is a specific process formed through testing, the purpose of which is to reduce microscopic gaps, enhance uniformity, and strengthen interface forces.

[0101] Example 2

[0102] (1) Calculation of spiral winding angle

[0103] like Figure 1-3As shown, according to the measured T700 fiber epoxy resin composite material, the ultimate strain in the fiber direction is 18200 microstrain, and the ultimate strain in the matrix direction is 5482 microstrain. Then, considering the dynamic pressure safety of the high-pressure gas cylinder, a 5-fold safety factor is designed in the fiber direction, and a 2-fold safety factor is used in the matrix direction according to the general material, to obtain the design strain in the fiber direction. The strain value of the matrix is ​​3640 microstrain. It is 2741 microstrain.

[0104] According to the winding angle calculation formula .

[0105] The calculated winding angle α is 41.14°.

[0106] According to the actual winding forming and to facilitate process control, the winding angle is taken as 42° for subsequent laminate strength verification and basic parameters for laminate structure design.

[0107] (2) Calculation of fiber winding layer thickness and winding layer design:

[0108] Effective elastic modulus in the fiber direction of the fiber reinforced composite winding layer in the embodiment =195000MPa, the inner diameter of the pipe R=40mm, and the internal pressure of the composite material pipe is the design pressure of 70MPa.

[0109] According to the grid theory, the thickness of the spiral winding layer t fα and the thickness of the hoop winding layer t fθ The calculations are as follows:

[0110] ;

[0111] .

[0112] Thickness of spiral winding layer: 3.57mm.

[0113] Thickness of hoop wrapping layer: 2.35mm.

[0114] According to the above calculated thickness, the number of fiber winding layers is:

[0115] Number of spiral winding layers = thickness of spiral winding layer / thickness of fiber single layer = / 0.115=31.04.

[0116] Number of hoop winding layers = hoop winding layer thickness / fiber single layer thickness = 1.34 / 0.115 = 20.43.

[0117] According to the winding rules, the number of helical and hoop winding layers is rounded off separately, with a certain safety margin. The number of winding layers is the closest even number that meets the load requirements. The number of helical winding layers is 34; the number of hoop winding layers is 22.

[0118] Based on the above calculations, to ensure the pipe's pressure resistance and provide a certain degree of impact protection during use, four layers of glass fiber reinforcement are wound around the outermost fiber reinforcement layer of the pipe body. According to the winding rules, to prevent fiber accumulation in the end cap during the winding process, expansion is required. Winding is performed according to the principle of decreasing tension and alternating spiral and circumferential winding. The composite pipe winding layup is shown in Table 1.

[0119] Comparative Example 1

[0120] The difference between Comparative Example 1 and Example 2 is that the layers are laid according to Table 2. According to the grid theory, the strength calculation results of the spiral winding layer and the hoop winding layer are shown in Table 2:

[0121]

[0122] Comparative Example 2

[0123] The difference between Comparative Example 2 and Example 2 is that the layers are laid according to Table 3. According to the grid theory, the strength calculation results of the spiral winding layer and the hoop winding layer are shown in Table 3:

[0124]

[0125] Comparative Example 3

[0126] The difference between Comparative Example 3 and Example 2 is that the layers are laid according to Table 4. According to the grid theory, the strength calculation results of the spiral winding layer and the hoop winding layer are shown in Table 4:

[0127]

[0128] Comparative Example 4

[0129] The difference between Comparative Example 4 and Example 2 is that the layers are laid according to Table 5. According to the grid theory, the strength calculation results of the spiral winding layer and the hoop winding layer are shown in Table 5:

[0130]

[0131] Comparative Example 5

[0132] The difference between Comparative Example 5 and Example 2 is that the layers are laid according to Table 6. According to the grid theory, the strength calculation results of the spiral winding layer and the hoop winding layer are shown in Table 6:

[0133]

[0134] Comparative Example 6

[0135] The difference between Comparative Example 6 and Example 2 is that the layers were laid according to Table 7. Based on grid theory, the strength calculation results for the spirally wound layer and the hoop wound layer are shown in Table 7. The glass fiber was not included in the strength calculation; the glass fiber layer only served to protect against damage from external drops, tool drops, and so on.

[0136] After calculation, the longitudinal and circumferential bursting pressures of the pipe body in Example 2 are shown in Table 8.

[0137] Verification calculations concluded that, considering the lining blast pressure (the inner layer is made of metal with a strength far exceeding 150 MPa), the longitudinal blast pressure of the pipe body is 151.539 MPa, and the circumferential blast pressure is 177.714 MPa. Based on the stress characteristics of the pipe body, the design solution can meet the pipe body's 150 MPa blast pressure bearing capacity and meet its operational requirements.

[0138] The water pressure test pressure curve is as follows: the pressure is increased to 84MPa and maintained for 1 minute, and then increased to above 150MPa. After disassembly, the composite pipe is inspected using ultrasonic non-destructive testing equipment. The detection results show that there is no damage inside the composite pipe.

[0139] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0140] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for designing a liquid-gas phase change composite pipe layup, characterized in that: The following steps are involved: The reinforcing fibers are alternately laid in spiral fiber layers and hoop fiber layers on the pipe lining. The spiral fiber layers are laid according to the spiral fiber laying angle α. The thickness of the spiral fiber layers is t fa , the thickness of the hoop fiber layer is t fθ , we get alternating layers, where: ； α is the spiral fiber ply angle, is the design strain in the fiber direction, Design strain value for the matrix; ； ； is the thickness of the spiral fiber layer, is the internal pressure of the composite material tube, R is the radius of the composite material tube, is the effective elastic modulus in the fiber direction, is the hoop fiber ply thickness; The continuous plies of the spiral fiber ply do not exceed 4 layers, and the continuous plies of the hoop fiber ply do not exceed 4 layers; the alternating plies are all made of carbon fiber, and the outer layers of the alternating plies further include 2-4 layers of glass fiber outer layers; When the pressure bearing strength of the liquid-gas phase change composite material pipe is ≥150 MPa, the spiral fiber layer angle α is ≤41.14°, and the spiral fiber layer thickness is 2~2.5mm, the thickness of the hoop fiber layer It is 1.3~1.7mm.

2. A method for preparing a liquid-gas phase change composite material tube, characterized in that: The following steps are involved: S1. Prepare the pipe lining; S2. Surface treatment of the pipe lining; S3. The spiral fiber layer thickness is obtained by the design method described in claim 1. and the hoop fiber layer thickness is The inner lining of the pipe body is used as the core mold, and the reinforcing fibers are alternately laid in spiral and hoop directions, and are wound in one step using a wet method. After winding, the fibers are rotary solidified to form a reinforced fiber pipe body.

3. The method for preparing a liquid-gas phase change composite material tube according to claim 2, characterized in that: When the ends and barrel sections of the pipe body are lined with TA2 titanium alloy or duplex stainless steel, the surface treatment is pickling and passivation; When the ends of the pipe body and the barrel section are lined with Q355 alloy structural steel, the surface treatment is nitriding, carburizing or QPQ.

4. The method for preparing a liquid-gas phase change composite material tube according to claim 2, characterized in that: S3 also includes the following steps: S4. Place the reinforced fiber tube body into a casting mold for polyurethane casting, and remove the tube from the mold after casting to obtain a liquid-gas phase change composite material tube.

5. The method for preparing a liquid-gas phase change composite material tube according to claim 4, characterized in that: Before S4, the following steps were also included: The surface of the reinforced fiber tube body is polished, cleaned, and dried, and then an adhesive is applied and dried to obtain the reinforced fiber tube body applied with the adhesive; Apply release agent evenly on the casting mold cavity.

6. The method for preparing a liquid-gas phase change composite material tube according to claim 5, characterized in that: S4 specifically includes: Assemble the reinforced fiber tube body brushed with adhesive with the casting mold, preheat the assembled casting mold, add the polyurethane prepolymer and cross-linking agent into the storage tank of the casting machine respectively, and start the vacuum system for vacuum degassing; connect the casting mold to the casting machine and evacuate the air; start the casting machine, open the feed port, and perform vacuum casting; close the exhaust valve after the exhaust hole discharges the material; after the casting is completed, close the feed valve and continue to evacuate the air; solidify and remove the casting mold after casting.

7. The method for preparing a liquid-gas phase change composite material tube according to claim 6, characterized in that: The solidified casting mold is taken out, the cast tube body is taken out after demoulding, and the tube body is secondary solidified to obtain a liquid-gas phase change composite material tube.

8. A liquid-gas phase change composite material tube prepared according to the preparation method according to any one of claims 2 to 6, characterized in that: From the inside to the outside, it includes a pipe inner lining (1) and a reinforcing fiber layer (2).

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