Liquid-gas phase change composite material pipe as well as layering design method and preparation method thereof

Abstract

The invention discloses a liquid-gas phase change composite material pipe and a layering design method and a preparation method thereof. The preparation method comprises the following steps: S1, preparing a pipe body lining; s2, carrying out surface treatment on the pipe body lining; and S3, the spiral fiber laying layer thickness # imgabs0 # and the annular fiber laying layer thickness # imgabs1 # are obtained through the design method, the pipe body lining serves as a core mold, the reinforcing fibers are adopted for alternately conducting spiral fiber laying layer and annular fiber laying layer alternate laying layer, wet-process one-time winding forming is conducted, rotary curing is conducted after winding forming, and the reinforced fiber pipe body is formed. According to the composite pipe, the interface bonding force between the layers can be enhanced, the external load resistance of the composite pipe is improved, and the pressure bearing capacity of the composite pipe is greatly improved.

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 tube and its ply design method and preparation method. 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 at the same time has a relatively large density like a liquid, but has a smaller viscosity than a liquid, and has good mass transfer and heat transfer properties. Compress liquid carbon dioxide in a closed phase change tube, and through the combustion of chemical substances or the heat release of electric energy heating, the liquid carbon dioxide in the closed phase change tube absorbs heat and instantaneously releases impact power, which is used for explosion test simulation and aircraft launch. The tube body itself needs to bear very high pressure. High-pressure closed containers in the prior art are usually made of steel materials. In order to meet the requirements of equipment lightweight and long-term storage, lightweight and high-strength materials need to be used for weight reduction. At the same time, liquid carbon dioxide is stored in the tube, and carbon dioxide under high temperature and high pressure, especially in the supercritical state, has strong corrosiveness. Therefore, the compatibility between the inner surface material of the tube and carbon dioxide must be considered.

[0003] Chinese Patent with the authorization announcement number CN104455792B discloses a fiber-reinforced polyurethane winding sandwich composite tube and its manufacturing method. Through a glass fiber reinforced plastic inner lining layer, a glass fiber reinforced plastic inner structural layer, a fiber-reinforced polyurethane composite sandwich layer, and a glass fiber reinforced plastic outer structural layer arranged in sequence from the inside to the outside, the pre-formed Z-shaped glass fiber reinforced layer after being infiltrated with resin is transported to the upper surface and one side of a rectangular polyurethane strip for laying to obtain a fiber-reinforced polyurethane material; through a pulling device, the laid fiber-reinforced polyurethane material is synchronously and continuously wound onto the inner structural layer to form a fiber-reinforced polyurethane composite sandwich layer, so as to improve the anti-external load capacity of the composite tube. However, the high pressure generated in the tube during the liquid-gas phase change process of carbon dioxide can reach 150 MPa. The composite tubes in the prior art still cannot meet the use requirements. At the same time, due to the winding process being easily affected by various factors such as environment, equipment, and operation, the winding quality is unstable, which in turn affects the strength and durability of the pipeline; the bonding strength between the composite material winding reinforcement layer and the inner lining layer or the polyurethane layer is insufficient, which may lead to interlayer delamination and affect the comprehensive performance of the tube body. Summary of the Invention

[0004] The technical problem to be solved by the present invention is, aiming at the deficiencies of the prior art, to provide a liquid-gas phase change composite material tube and its ply design method and preparation method. The liquid-gas phase change composite material tube prepared by this method can ensure the internal pressure bearing strength of different grades, meet the requirements of long-term storage, and has good manufacturing process stability.

[0005] To solve the above technical problem, the technical solution adopted by the present invention is: The present invention discloses a method for laying a liquid-gas phase change composite material tube, comprising the following steps:

[0006] On the inner lining of the tube, alternate laying of spiral fiber layers and circumferential fiber layers is carried out using reinforcing fibers. The spiral fiber layers are laid at the spiral fiber layer angle α, and the thickness of the spiral fiber layer is , and the thickness of the circumferential fiber layer is , to obtain an alternate laying, where: ; α is the spiral fiber layer angle, is the designed strain in the fiber direction, is the designed strain value of 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 tube body of the composite material tube, is the effective elastic modulus in the fiber direction, is the thickness of the circumferential fiber layer.

[0007] The alternate laying of the spiral fiber layer and the circumferential fiber layer is carried out in the order of spiral fiber layer, circumferential fiber layer, spiral fiber layer, circumferential fiber layer... Each time, the spiral fiber layer and the circumferential fiber layer can be continuously laid in multiple layers or in a single layer.

[0008] By using the design method of the present invention to obtain the laying angle, the thickness of the spiral fiber layer and the thickness of the circumferential fiber layer, and carrying out alternate wet winding in the spiral and circumferential directions, high strength and high impact resistance performance are achieved.

[0009] In one preferred embodiment, the continuous laying of the spiral fiber layer does not exceed 4 layers, and the continuous laying of the circumferential fiber layer does not exceed 4 layers; all the alternate laying uses carbon fiber, and the outer layer of the alternate laying further includes 2 - 4 layers of glass fiber outer layer.

[0010] Alternate wet winding in the spiral and circumferential directions is carried out using carbon fiber, and the preset number of outer layers wound later uses glass fiber for alternate wet winding in the spiral and circumferential directions, so as to achieve the characteristics of hybrid reinforcement with high strength and high impact resistance.

[0011] In one preferred embodiment, when the pressure-bearing strength of the liquid-gas phase change composite material tube ≥ 150 MPa, the spiral fiber layer angle α ≤ 41.14°, and the thickness of the spiral fiber layer is 3.55 - 4.05 mm, and the thickness of the circumferential fiber layer is 1.30 - 1.80 mm.

[0012] This ply layup method can ensure that the pressure-bearing strength of the liquid-gas phase change composite material pipe is ≥150 MPa, which can meet the high-pressure requirements during the liquid-gas phase change of carbon dioxide.

[0013] The following further calculates the number of winding layers: ; ; is the number of helical windings, is the number of circumferential windings, is the thickness of the unidirectional fiber layer.

[0014] The present invention also discloses a preparation method of a liquid-gas phase change composite material pipe, comprising the following steps: S1. Prepare the inner lining of the pipe; S2. Perform surface treatment on the inner lining of the pipe; S3. Obtain the helical fiber ply thickness and the circumferential fiber ply thickness of by using the described design method, and alternately lay the helical fiber ply and the circumferential fiber ply with the inner lining of the pipe as the mandrel by wet one-time winding molding, and perform rotational curing after winding molding to form a reinforced fiber pipe body.

[0015] In one preferred embodiment, when the two end heads and the cylinder section of the inner lining of the pipe are made of titanium alloy or duplex stainless steel, the surface treatment is pickling and passivation.

[0016] Specifically, the titanium alloy is TA2 titanium alloy. When the two end heads and the cylinder section of the inner lining of the pipe are made of alloy structural steel such as Q355, the surface treatment is nitriding, carburizing or QPQ.

[0017] Preferably, after S2 performs surface treatment on the inner lining of the pipe, sandblasting treatment is further performed.

[0018] Performing surface treatment on the inner lining of the pipe enhances its compatibility with CO2. The outer surface of the cylinder section of the inner lining of the pipe and the ellipsoidal part of the end 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 perform surface treatment on the inner lining of the pipe after it is manufactured.

[0019] In one preferred embodiment, after S3, the following steps are further included: S4. Place the reinforced fiber pipe body into a casting mold for polyurethane casting, demold and take out after casting is completed to obtain a liquid-gas phase change composite material pipe.

[0020] If the product usage environment is poor and protection is required, the casting step of S4 is added.

[0021] In one preferred embodiment, before S4, the following steps are further included: Grind, clean, and dry the surface of the reinforced fiber tube body, brush the adhesive and then dry it to obtain a reinforced fiber tube body with adhesive brushed on; Uniformly brush the release agent in the pouring mold cavity.

[0022] Specifically, the surface of the reinforced fiber tube body is cleaned with acetone or ethanol, naturally dried for 5 - 10 minutes and then the adhesive is brushed, and after brushing the adhesive, it is naturally dried for 1 - 3 hours; First clean the pouring mold cavity, and then brush the release agent; preferably, wipe the pouring mold cavity with a non-woven fabric dipped in acetone or alcohol and naturally dry for 5 - 10 minutes.

[0023] In one preferred embodiment, S4 specifically includes: Assemble the reinforced fiber tube body with adhesive brushed on with the pouring mold, preheat the assembled pouring mold, add the polyurethane prepolymer and the crosslinking agent into the storage tanks of the pouring machine respectively, turn on the vacuum system for vacuum degassing; connect the pouring mold with the pouring machine and evacuate; turn on the pouring machine, open the feed port, carry out vacuum pouring, close the exhaust valve after the material comes out from the exhaust hole, and continue to evacuate after closing the feed valve after pouring is completed; cure and take out the poured pouring mold.

[0024] Preferably, the crosslinking agent uses MOCA.

[0025] Preferably, the preheating temperature of the assembled pouring mold is 50 - 70 °C and the preheating time is 1 - 2 hours.

[0026] The vacuum degree for vacuum degassing is -0.15 to -0.05 MPa and the time is 1 - 3 hours.

[0027] Connect the pouring mold with the pouring machine and evacuate, the vacuum degree is -0.15 to -0.05 MPa and the time is 10 - 20 minutes.

[0028] After pouring is completed, close the feed valve and continue to evacuate for 10 - 20 minutes, and let it stand for 10 - 20 minutes after evacuation.

[0029] The curing temperature of the poured pouring mold is 90 - 100 °C and the curing time is 1 - 3 hours.

[0030] In one preferred embodiment, take out the cured pouring mold, take out the poured tube body after demolding, and secondarily cure the tube body to obtain a liquid-gas phase change composite material tube.

[0031] Preferably, the secondary curing temperature is 90 - 100 °C and the curing time is 10 - 30 hours.

[0032] Preferably, the production of the inner lining of the pipe is specifically as follows: the two end heads and the cylinder section of the inner lining of the pipe are welded to form an integral structure, and full penetration welding is carried out by automatic laser welding.

[0033] Preferably, the inner lining of the pipe is made of titanium alloy, duplex stainless steel or high-strength steel material that meets the compatibility requirements after inner surface treatment.

[0034] The present invention also discloses a liquid-gas phase change composite material pipe prepared according to the preparation method described above, which sequentially includes an inner lining of the pipe and a reinforcing fiber layer from inside to outside.

[0035] Preferably, a polyurethane protective layer is further included outside the reinforcing fiber layer.

[0036] Preferably, the inner lining of the pipe is made of titanium alloy, duplex stainless steel, or high-strength steel material after inner surface treatment, and the reinforcing fiber layer is formed by winding a mixture of carbon fiber and glass fiber.

[0037] Through the above technical solutions, the present invention can achieve the following technical effects: the present invention performs overall and surface process treatments on the inner lining of the pipe, enhances the interfacial bonding force between layers, improves the winding quality, and prevents interlayer peeling; the present invention adopts a ply design method of winding a mixture of carbon fiber and glass fiber, accurately determines the thickness and angle of the helical fiber ply and the hoop fiber ply through quantitative calculation to ensure the internal pressure bearing strength of different grades, obtains a composite pipe with high strength and high impact resistance, combines the glass fiber layer and the polyurethane protective layer to improve the anti-external load capacity, and achieves the effect of greatly improving the service performance of the composite pipe.

[0038] According to the ply design method of the present invention, the liquid-gas phase change composite material pipe can be designed to be wound with a mixture of carbon fiber and glass fiber, achieving the characteristics of high strength and high impact resistance, and adopting a helical and circumferential alternating wet winding molding method, designing a reasonable winding structure scheme, realizing the improvement of the anti-external load capacity of the composite pipe, and greatly improving the pressure bearing and impact resistance of the composite pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of a liquid-gas phase change composite material pipe according to an embodiment of the present invention; wherein, 1 is the inner lining of the pipe; 2 is the reinforcing fiber layer; 3 is the polyurethane protective layer.

[0040] Figure 2 It is a schematic diagram of the helical fiber ply angle of a liquid-gas phase change composite material pipe according to an embodiment of the present invention; wherein r is the radial direction, Z is the axial direction, α is the helical fiber ply angle, is the circumferential direction.

[0041] Figure 3Schematic diagram of the layup thickness of the liquid-gas phase change composite material tube according to an embodiment of the present invention; wherein is the total thickness of the fiber layer, t m is the total thickness of the bladder.

[0042] Figure 4 Physical diagram of the liquid-gas phase change composite material tube according to an embodiment of the present invention. Detailed implementation manners

[0043] Example 1

[0044] An embodiment of the present invention mainly describes a preparation method of a liquid-gas phase change composite material tube, including the following steps: S1. Select a lining material and fabricate the tube inner lining.

[0045] The tube inner lining is a main component of the liquid-gas phase change composite material tube. It directly contacts with carbon dioxide, plays a sealing role, and at the same time serves as a mandrel for winding and forming the fiber-reinforced composite material, providing support for the reinforcing fibers. After winding and curing, a composite material tube structure is formed. The tube inner lining directly contacts with the internal filling medium, can play a role in sealing and sharing part of the pressure, and the tube inner lining is an important component connected to the equipment interface, and is connected to the equipment through the threads processed on the tube inner lining.

[0046] The tube inner lining is formed by connecting two end heads and a cylinder section. Therefore, the fabrication of the tube inner lining requires machining and welding of the two end heads and the cylinder section to form an integral structure. Among them, full penetration welding is carried out by automatic laser welding to ensure that the mechanical properties of the weld and the heat-affected zone after welding are consistent with those of the base material.

[0047] TA2 titanium alloy bars are selected for the two end heads of the tube inner lining, and a TA2 titanium alloy tube body is selected for the cylinder section. TA2 titanium alloy has high strength, weldability, processability and corrosion resistance. Selecting it for the fabrication of the tube inner lining is easier to process and weld, reduces the processing cost, and achieves the purpose of weight reduction and low-temperature reliability.

[0048] Alternatively, duplex stainless steel can also be selected for the two end heads of the tube inner lining, and duplex stainless steel is selected for the cylinder section at the same time; or alloy structural steel such as Q355 can be selected for the two end heads of the tube inner lining, and alloy structural steel such as Q355 is selected for the cylinder section at the same time.

[0049] S2. Perform surface treatment on the whole tube inner lining.

[0050] According to the structural characteristics of the composite material pipe, its two ends are bare alloy metals, with threaded fittings both inside and outside. The inner cavity is a space for filling liquid CO2. According to the technical requirements and the analysis of the operating conditions, the threaded ends at both ends need to meet the requirements of deep - sea environment adaptability. Considering that CO2 is an acidic gas and has corrosiveness 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.

[0051] In S2, for the two - end heads and the barrel section of the inner lining of the pipe, TA2 titanium alloy or duplex stainless steel is selected, and the whole inner lining of the pipe is pickled and passivated.

[0052] In S2, for the two - end heads and the barrel section of the inner lining of the pipe, alloy structural steels such as Q355 are selected, and the whole inner lining of the pipe is nitrided, carburized or QPQ surface - treated. After the surface treatment is completed, the winding area is sand - blasted.

[0053] For the outer surface of the barrel section of the inner lining of the pipe and the ellipsoidal part of the head, the interfacial bonding force with the fiber and resin during winding needs to be considered to prevent delamination. Therefore, considering various factors, after the inner lining of the pipe is manufactured, the surface treatment of the inner lining of the pipe is processed.

[0054] To meet the compatibility between the inner lining and carbon dioxide, the whole inner lining of the pipe is subjected to anodic oxidation surface treatment, and the thickness of the oxide film is 10 - 20um.

[0055] The winding area of the inner lining of the pipe that needs to be fiber - wound and strengthened is sand - blasted. After sand - blasting, it is cleaned with clean compressed air. After the inner lining of the pipe is sand - blasted, it is packed and protected with oil - free and dust - free pearl cotton or wrapping paper to prevent oil stains, dust, etc. from contaminating it and causing abnormalities such as delamination after winding.

[0056] S3: Using reinforcing fibers, with the inner lining of the pipe as the mandrel, alternately carry out wet spiral and circumferential one - time winding molding. After winding molding, carry out rotational curing to form a reinforced fiber pipe body;

[0057] According to the working characteristics of the composite material pipe, there are significant differences in its operating conditions during storage and use. During the filling and excitation processes, the inside of the pipe bears huge pressure. To meet the pressure requirements of the composite material pipe, reinforcing fibers can be used for winding molding. Carbon fiber has the characteristics of light weight, high strength, corrosion resistance, and high modulus, and is a good high - strength structural reinforcement and limiting material; glass fiber has good toughness, is not easy to deform, has good impact resistance, excellent corrosion resistance, good heat resistance, small thermal conductivity, and will not cause combustion. By selecting a mixture of carbon fiber and glass fiber for reinforcement, the characteristics of high strength and high impact resistance can be achieved. Therefore, the present invention adopts a carbon fiber and glass fiber hybrid winding process.

[0058] According to the technical requirements, the burst pressure of the composite material pipe shall be ≥150 MPa, and its pressure-bearing requirement is achieved through the winding reinforcement of the reinforcing fibers. In order to further improve the pressure-bearing capacity, the winding ply structure of the reinforcing fibers is designed.

[0059] Firstly, considering the matrix material, the transverse strain of the composite material pipe shall be less than the designed strain value. For the design strain in the fiber direction. For the designed strain value of the matrix. For the spiral fiber ply angle, then there is: .

[0060] Based on the grid theory and the equilibrium strain theory, the axial internal force of the composite material pipe and the circumferential internal force are: .

[0061] .

[0062] is the axial internal force of the composite material pipe, N; Determined according to the design pressure and the design space or radius; is the circumferential internal force, N; Determined according to the design pressure and the 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 ply, mm; is the thickness of the circumferential fiber ply, mm; is .

[0063] Under the action of the uniform internal pressure p, the circumferential and axial internal forces and their ratio η are designed as follows, where p is the internal pressure of the composite material pipe, Mpa; R is the radius of the composite material pipe body, mm; ; ; .

[0064] From the above equations, the thicknesses of the spiral fiber ply and the circumferential fiber ply are respectively: ; .

[0065] According to the thickness distribution of the spiral fiber ply and the circumferential fiber ply obtained above, and the thickness of the fiber monolayer (material thickness, constant), the number of spiral winding layers (Design variables) and the number of circumferential winding layers (Design variables): ; .

[0066] Further, according to the winding and laying structure such as the spiral fiber laying angle, spiral fiber laying thickness, circumferential fiber laying thickness, number of spiral winding layers, and number of circumferential winding layers designed above, wet winding is carried out alternately in a spiral and circumferential manner with the inner lining of the pipe body as the core mold using reinforcing fibers. The reinforcing fibers are carbon fibers and glass fibers. For example, carbon fibers are used for alternate wet winding in the spiral and circumferential directions during the early winding, and glass fibers are used for alternate wet winding in the spiral and circumferential directions for a preset number of outer layers during the later winding, so as to achieve hybrid reinforcement and high strength and high impact resistance.

[0067] Further, the total number of layers is calculated by the above formula; during alternate winding, in order to prevent the propagation of failure cracks in adjacent layers in the same direction, alternate winding is adopted, and the layers wound in the same direction cannot be continuously wound for more than 4 layers. For example, the maximum number of circumferential windings of the inner liner is 4 layers, and then spiral winding is carried out. The spiral layer cannot exceed 4 layers either, and then the winding method is exchanged. The number of outer layer glass fiber layers is 2 - 4 layers, mainly for anti-collision, because the toughness of glass fiber is better than that of carbon fiber.

[0068] Further, after winding and forming, rotational curing is carried out to ensure uniform heat absorption. Specifically, rotational curing is carried out in an electric heating drying oven with controllable temperature rise and fall. The curing temperature and time are executed according to the process parameters, and the curing furnace outlet temperature is strictly controlled. The furnace temperature must drop below 40°C after curing before the product can be taken out of the furnace to form a reinforcing fiber pipe body.

[0069] S4. Place the reinforcing fiber pipe body into a casting mold for polyurethane casting. After casting is completed, demold and take out to obtain a liquid-gas phase change composite material pipe.

[0070] Specifically, considering the influence of factors such as corrosion and external pressure existing in the pipe body in various natural environments, polyurethane has extremely low water absorption 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 by casting polyurethane elastomer material to achieve the purpose of self-sealing and resistance to erosion by various corrosive substances in the environment.

[0071] Further, to improve the pouring effect, before pouring: the surface of the reinforced fiber tube body is polished with 200-mesh sandpaper, scrubbed with acetone or ethanol, and naturally dried for 10 minutes, then an adhesive is brushed and naturally dried for 2 hours after brushing; the cavity of the pouring mold is wiped with non-woven fabric dipped in acetone or alcohol to clean the residual foreign matters, naturally dried for 10 minutes, and a release agent is evenly applied to the cavity of the pouring mold; the reinforced fiber tube body is assembled with the pouring mold, and during the assembly, the metal parts at both ends of the tube body are protected to prevent damage to the anodized part caused by bumps, etc.; the assembled pouring mold is placed in an oven and preheated at 60°C for 1 hour.

[0072] Further, the specific process of polyurethane pouring is as follows: the polyurethane prepolymer and the crosslinking agent MOCA are respectively added into the storage tank of the pouring machine, the vacuum system is turned on, and vacuum degassing is carried out for 1 hour with a vacuum degree of -0.09 MPa; the pouring mold is connected to the pouring machine, the vacuum pump is turned on, the vacuum degree is -0.09 MPa, and vacuum pumping is carried out for 10 minutes; the pouring machine is turned on, the feeding port is opened, and vacuum pouring is carried out. After the material comes out from the exhaust hole, the exhaust valve is closed. After pouring is completed, the feeding valve is closed and vacuum pumping is continued for 15 minutes. After vacuum pumping is completed, it is left standing for 15 minutes; the poured pouring mold is moved into the oven and cured at 95°C for 2 hours.

[0073] Further, after curing is completed, the pouring mold is taken out of the oven, the poured tube body is taken out after demolding, and the tube body is put into the oven again and cured at 95°C for 20 hours. After curing is completed, the liquid-gas phase change composite material tube is obtained.

[0074] The pouring process technology of this embodiment is a specific process formed through testing, aiming to reduce microvoids, enhance uniformity, and strengthen interfacial forces.

[0075] Example 2 (1) Calculation of spiral winding angle

[0076] As Figures 1-3 shown, based on the measured T700 fiber epoxy resin composite material, the ultimate strain in the fiber direction is 18200 microstrains, and in the matrix direction is 5482 microstrains. Then, considering the dynamic pressure-bearing safety of the high-pressure gas cylinder, a 5-fold high safety factor is designed in the fiber direction, and a 2-fold safety factor according to general materials is designed in the matrix direction. The designed strain in the fiber direction is 3640 microstrains, and the designed strain value of the matrix is 2741 microstrains.

[0077] According to the winding angle calculation formula .

[0078] The calculated winding angle α is 41.14°.

[0079] Based on the actual winding forming and for the convenience of process control, the winding angle is taken as 42° for the subsequent basic parameters of ply strength checking and ply structure design.

[0080] (2) Calculation of the fiber winding ply thickness and design of the winding ply:

[0081] In the embodiment, the effective elastic modulus of the fiber direction of the fiber-reinforced composite winding layer = 195000 MPa, the inner diameter R of the pipe body is 40 mm, and the internal pressure of the composite material pipe is taken as the design pressure of 70 MPa.

[0082] According to the grid theory, the thickness t fα of the helical winding layer and the thickness t fθ of the circumferential winding layer are calculated as follows: ; .

[0083] Thickness of the helical winding layer: 3.57 mm.

[0084] Thickness of the circumferential winding layer: 2.35 mm.

[0085] According to the above calculated thicknesses, the number of fiber winding layers is: Number of helical winding layers = Thickness of the helical winding layer / Thickness of a single fiber ply = / 0.115 = 31.04.

[0086] Number of circumferential winding layers = Thickness of the circumferential winding layer / Thickness of a single fiber ply = 1.34 / 0.115 = 20.43.

[0087] According to the winding rule, after rounding up the number of helical and circumferential winding layers respectively and considering a certain safety margin. The number of winding layers is taken as the even number closest to and meeting the load requirements. The number of helical winding layers is 34; the number of circumferential winding layers is 22.

[0088] According to the above calculation process, to ensure the pressure resistance performance of the pipe body during use and provide a certain anti-impact protection, 4 layers of glass fiber reinforced layers are wound on the outermost layer of the fiber-reinforced layer of the pipe body. According to the winding rule, to prevent fiber accumulation in the head section during the winding process, reaming is required. During winding, in accordance with the principle of decreasing tension and alternating helical and circumferential winding, the winding ply of the composite material pipe is shown in Table 1.

[0089] Comparative Example 1

[0090] The difference between Comparative Example 1 and Example 2 is that the ply is carried out according to Table 2. According to the grid theory, the strength calculation results of the helical winding layer and the circumferential winding layer are shown in Table 2 respectively:

[0091] Comparative Example 2

[0092] The difference between Comparative Example 2 and Example 2 lies in the layup according to Table 3. According to the grid theory, the strength calculation results of the helical winding layer and the circumferential winding layer are shown in Table 3 respectively:

[0093] Comparative Example 3

[0094] The difference between Comparative Example 3 and Example 2 lies in the layup according to Table 4. According to the grid theory, the strength calculation results of the helical winding layer and the circumferential winding layer are shown in Table 4 respectively:

[0095] Comparative Example 4

[0096] The difference between Comparative Example 4 and Example 2 lies in the layup according to Table 5. According to the grid theory, the strength calculation results of the helical winding layer and the circumferential winding layer are shown in Table 5 respectively:

[0097] Comparative Example 5

[0098] The difference between Comparative Example 5 and Example 2 lies in the layup according to Table 6. According to the grid theory, the strength calculation results of the helical winding layer and the circumferential winding layer are shown in Table 6 respectively:

[0099] Comparative Example 6

[0100] The difference between Comparative Example 6 and Example 2 lies in the layup according to Table 7. According to the grid theory, the strength calculation results of the helical winding layer and the circumferential winding layer are shown in Table 7 respectively. The glass fiber is not involved in the strength calculation, and the glass fiber layer only serves as damage protection caused by external drops, tool drops, etc.

[0101] After calculation, the longitudinal and circumferential burst pressures of the pipe body in Example 2 are shown in Table 8.

[0102] Check calculation conclusion: Combining the burst pressure of the inner lining (the inner layer uses a metal material with a strength much higher than 150 MPa), the longitudinal burst pressure of the pipe body is 151.539 MPa, and the circumferential burst pressure is 177.714 MPa. According to the force characteristics of the pipe body, its design scheme can meet the burst pressure bearing capacity of 150 MPa of the pipe body and can meet its use requirements.

[0103] The pressure curve of the water pressure test was increased to 84MPa and maintained for 1min, then increased to above 150MPa. After disassembly, the composite pipe was tested using ultrasonic non-destructive testing equipment. The detection results showed that there was no damage inside the composite pipe.

[0104] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0105] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for designing the layup of a liquid-gas phase change composite material tube, characterized in that It includes the following steps: On the inner lining of the pipe body, alternating layering of spiral fiber layering and circumferential fiber layering is carried out using reinforcing fibers. The spiral fiber layering is carried out at a spiral fiber layering angle α, and the thickness of the spiral fiber layering is , and the thickness of the circumferential fiber layering is , to obtain an alternating layering, where: ； α is the laying angle of the spiral fiber, is the designed strain in the fiber direction, is the designed strain value of the matrix; ； ； is the thickness of the helical fiber layer, is the internal pressure of the composite tube, and R is the radius of the composite tube body, is the effective elastic modulus in the fiber direction, is the thickness of the circumferential fiber layer.

2. The layup design method of the liquid-gas phase change composite material tube according to claim 1, wherein: The continuous layering of the spiral fiber layup does not exceed 4 layers, and the continuous layering of the circumferential fiber layup does not exceed 4 layers; all the alternating layups are made of carbon fiber, and the outer layer of the alternating layup further includes 2 - 4 layers of glass fiber outer layer.

3. The liquid-gas phase change composite material tube laying design method according to claim 2, characterized in that: When the pressure-bearing strength of the liquid-gas phase change composite material pipe ≥ 150 MPa, the spiral fiber laying angle α ≤ 41.14°, and the spiral fiber laying thickness is 2 - 2.5 mm, and the circumferential fiber laying thickness is 1.3 - 1.7 mm.

4. A method for preparing a liquid-gas phase change composite material tube, characterized in that, It includes the following steps: S1. Prepare the inner lining of the pipe. S2. Perform surface treatment on the inner lining of the pipe. S3. Obtain the spiral fiber ply thickness by using the design method described in any one of claims 1-3 and the circumferential fiber ply thickness is . With the inner liner of the pipe as the core mold, alternately lay the spiral fibers and circumferential fibers using reinforcing fibers, and perform wet winding and forming in one step. After winding and forming, perform rotational curing to form a reinforced fiber pipe body.

5. The preparation method of a liquid-gas phase change composite material tube according to claim 4, wherein: When the end heads and the barrel section of the inner lining of the pipe select titanium alloy or duplex stainless steel, the surface treatment is pickling and passivation.

6. The preparation method of the liquid-gas phase change composite material tube according to claim 4, characterized in that, After S3, the following steps are further included: S4. Place the reinforced fiber pipe body into a casting mold for polyurethane casting. After the casting is completed, demold and take it out to obtain a liquid-gas phase change composite material pipe.

7. The preparation method of a liquid-gas phase change composite material tube according to claim 6, characterized in that: Before S4, the following steps are further included: Grind, clean, and dry the surface of the reinforced fiber pipe body, brush the adhesive and then dry it to obtain a reinforced fiber pipe body with adhesive brushed on it. Uniformly apply a release agent to the cavity of the casting mold.

8. The preparation method of a liquid-gas phase change composite material tube according to claim 7, characterized in that: S4 specifically includes: Assemble the reinforced fiber pipe body with the adhesive brushed on it with the casting mold, preheat the assembled casting mold, respectively add the polyurethane prepolymer and the crosslinking agent into the storage tanks of the casting machine, turn on the vacuum system for vacuum degassing; connect the casting mold with the casting machine and evacuate; turn on the casting machine, open the feed port, perform vacuum casting, close the exhaust valve after the material comes out from the exhaust hole, continue to evacuate after closing the feed valve after the casting is completed; cure and take out the casting mold after the casting is completed.

9. The preparation method of a liquid-gas phase change composite material tube according to claim 8, characterized in that: Take out the cured casting mold, demold and take out the cast pipe body, and cure the pipe body for the second time to obtain a liquid-gas phase change composite material pipe.

10. A liquid-gas phase change composite material tube prepared by the preparation method according to any one of claims 4-8, characterized in that, It sequentially includes an inner lining (1) of the pipe and a reinforced fiber layer (2) from the inside to the outside.

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