Construction and application of diaphragm head cavity curve model of diaphragm compressor of hydrogen refueling station

Abstract

The invention provides a construction method and application of a hydrogen refueling station diaphragm compressor diaphragm head cavity type curve model, and the method comprises the following steps: (1) obtaining a curve model of the diaphragm head cavity type curve model of a diaphragm compressor based on a single-index generatrix equation representing the contours of a gas cavity and an oil cavity of a diaphragm compressor diaphragm head and boundary conditions of the single-index generatrix equation; (2) taking the adjusting parameters corresponding to the three-index generatrix equation as variables, establishing a corresponding objective function taking the radial bending stress of the diaphragm and the volume of the diaphragm cavity as optimization objectives, and solving an optimal combination of the adjusting parameters based on the objective function to obtain a three-index generatrix equation; therefore, the radial bending stress of the diaphragm is minimum and the volume of the diaphragm cavity is maximum. According to the construction method and application of the diaphragm head cavity curve model of the diaphragm compressor of the hydrogen refueling station, the maximum diaphragm cavity volume is achieved while the minimum radial bending stress of the diaphragm is achieved, the service life of the diaphragm compressor can be prolonged, and the compression efficiency of the diaphragm compressor can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of new energy equipment, and in particular to the construction and application of a cavity curve model of a diaphragm compressor of a hydrogen refueling station. Background Art

[0002] Hydrogen energy is a secondary clean energy with the advantages of high energy density, high combustion calorific value, wide source, storability, renewable, zero pollution, zero carbon emission, etc. It helps to solve energy crisis and environmental pollution. In the field of hydrogen energy application, there is a technical development path from low pressure to high pressure and from gaseous state to multiphase state for the storage, transportation and filling of hydrogen energy. The compressor, as the core equipment of the hydrogen refueling station, plays a pivotal role in the entire hydrogen refueling station. Among them, the commonly used compressor is the diaphragm compressor. The diaphragm compressor is a positive displacement compressor, which includes a diaphragm cavity and a diaphragm arranged in the diaphragm cavity. The diaphragm separates the diaphragm cavity into an air cavity and an oil cavity. The movement of the diaphragm in the diaphragm cavity will cause the volume of the air cavity and the oil cavity to change, thereby compressing and transporting the hydrogen. Since the diaphragm can effectively isolate the air cavity and the oil cavity, it ensures that the hydraulic oil in the oil cavity will not contaminate the hydrogen due to leakage. Therefore, the diaphragm compressor has become the preferred compressor for the construction of hydrogen refueling stations.

[0003] The existing diaphragm compressor diaphragm cavity curve profile is usually a profile characterized by a single exponential generatrix equation. Under the influence of this diaphragm cavity curve profile, the diaphragm is deformed greatly during the hydrogen compression process, resulting in a large radial bending stress of the diaphragm, which makes the diaphragm easily damaged, causing hydrogen or hydraulic oil leakage, and also shortening the service life of the diaphragm and the diaphragm compressor. Moreover, the diaphragm cavity volume of this diaphragm cavity curve profile is small, resulting in low compression efficiency, that is, to compress the same volume of hydrogen, more compression times and longer working time are required, which aggravates diaphragm damage and increases the operating cost of the hydrogen refueling station. Therefore, there is an urgent need for a diaphragm compressor that can avoid diaphragm damage and increase compression efficiency to solve the above problems.

[0004] The information disclosed in this background technology section is only used to deepen the understanding of the background technology of the present disclosure, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art known to those skilled in the art. Summary of the invention

[0005] In view of the above problems, a method for constructing and applying a diaphragm head cavity curve model for a diaphragm compressor at a hydrogen refueling station is provided. The method for constructing and applying the diaphragm head cavity curve model for a diaphragm compressor at a hydrogen refueling station can achieve a maximum diaphragm cavity volume while having minimum bending radial stress of the diaphragm, thereby improving the service life and compression efficiency of the diaphragm compressor.

[0006] Specifically, the present application provides a method for constructing a cavity curve model of a diaphragm compressor of a hydrogenation station, comprising the following steps: (1) Based on the single exponential generatrix equation and its boundary conditions that characterize the contours of the air cavity and oil cavity of the diaphragm compressor, the following triple exponential generatrix equation is established: ; in, H（r） The curve equation that characterizes the contour of the air cavity and / or oil cavity, m The first index, n is the second index, k The third index, a To control the parameters, H 0 is the deflection at the center of the air cavity, R is the distance between the center of the air cavity and the edge of the air cavity, r is the distance from the center of the air cavity to any position between the center of the air cavity and the edge of the air cavity; r is the independent variable parameter, m、n、k、a、H 0 All are adjustment parameters; (2) Taking the adjustment parameters corresponding to the three-exponential generatrix equation as variables, a corresponding objective function with the radial bending stress of the diaphragm and the membrane cavity volume as optimization targets is established, and based on the objective function, the optimal combination of the adjustment parameters is solved to minimize the radial bending stress of the diaphragm and maximize the membrane cavity volume.

[0007] Optionally, the objective function includes: Characterize the arc length of the diaphragm profile L The first objective function is: ; Characterize the cross-sectional area of ​​the air cavity or oil cavity S The second objective function is: .

[0008] Optionally, in step (2), the membrane cavity structure is optimized using Matlab in conjunction with Isight software, that is, the three-exponential generatrix equation is imported into the Matlab component in Isight, and its independent variable parameters, adjustment parameters and the objective function are added to Isight, and then the minimum value of the first objective function and the maximum value of the second objective function are taken as target values, and a multi-island genetic algorithm is used to calculate and output the optimal value combination of the adjustment parameters.

[0009] Optionally, the boundary conditions include: Geometric boundary conditions: ; in, i The three-exponential generatrix equation is r The first derivative of represents the slope at that location; The three-exponential generatrix equation is r The second derivative of represents the deflection angle at that location; Stress boundary conditions: ; in, R 1 is the position radius of the exhaust holes of the air side membrane head, s r is the radial stress of the diaphragm, [ s a ]for R > r ≥ R 1 The corresponding allowable radial stress of the diaphragm is, s c ]for R 1 > r The allowable radial stress of the diaphragm corresponding to ≥0.

[0010] Optionally, the initial value range of the adjustment parameter is: .

[0011] Optionally, the diaphragm radial bending stress is: ; in, t is the diaphragm thickness, E is the elastic modulus, m is Poisson's ratio.

[0012] Optionally, the expression of the control parameter is: ; in, s MR for r = R The corresponding s Mr Value, that is, the radial bending stress at the edge of the diaphragm.

[0013] Optionally, the diaphragm compressor diaphragm head includes an air side diaphragm head provided with the air cavity, an oil side diaphragm head provided with the oil cavity and the diaphragm sandwiched between the air side diaphragm head and the oil side diaphragm head; the contours of the air cavity and the oil cavity are symmetrically arranged; and the diaphragm is correspondingly fitted with the air cavity or the oil cavity in the maximum deformation state.

[0014] The present application also provides a method for preparing a diaphragm compressor membrane head, comprising the following steps: Based on the above-mentioned hydrogen station diaphragm compressor diaphragm head cavity curve model, the optimal combination of various adjustment parameters is solved to determine the cavity contours of the air cavity and oil cavity of the diaphragm compressor diaphragm head, and the corresponding diaphragm head is manufactured or processed accordingly.

[0015] In the construction and application of the diaphragm head cavity curve model of the hydrogen refueling station diaphragm compressor of the present application, the contour curves of the air cavity and the oil cavity are optimized from a single-exponential generatrix equation to a three-exponential generatrix equation. On the one hand, the maximum radial bending stress of the diaphragm is reduced to avoid damage to the diaphragm during the compression of hydrogen, thereby avoiding leakage of hydrogen or hydraulic oil, and also extending the service life of the diaphragm and the diaphragm compressor; on the other hand, the volume of the air cavity and the oil cavity is increased, and the compression efficiency is improved. That is, to compress the same volume of hydrogen, fewer compression times and shorter working time are required, thereby avoiding damage to the diaphragm and reducing the operating cost of the hydrogen refueling station.

[0016] Furthermore, the present application replaces the radial stress of the diaphragm with the arc length of the diaphragm contour and replaces the mold cavity volume with the cross-sectional area of ​​the diaphragm, which can simplify the first objective function and the second objective function and facilitate software calculation and solution.

[0017] Based on the detailed description of the specific embodiments of the present application in combination with the accompanying drawings below, those skilled in the art will become more aware of the above and other objects, advantages and features of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic structural diagram of the diaphragm compressor membrane head in an embodiment of the present application.

[0019] Figure 2 It is a schematic cross-sectional view of the diaphragm compressor diaphragm head in an embodiment of the present application.

[0020] Figure 3 It is a schematic structural diagram of the air side membrane head in the embodiment of the present application.

[0021] Figure 4 Schematic diagram of the structure of the diaphragm in the embodiment of the present application when it is in the maximum deformation state.

[0022] In the above figures, 100 is the diaphragm compressor diaphragm head, 110 is the air side diaphragm head, 111 is the air inlet hole, 112 is the exhaust hole, 113 is the air groove, 120 is the oil side diaphragm head, and 130 is the diaphragm. DETAILED DESCRIPTION

[0023] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "top", "bottom", "inside", "outside", "vertical", "horizontal", "clockwise", "counterclockwise", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0024] Figure 1 Schematic diagram of the structure of the diaphragm compressor 100 in the embodiment of the present application, as shown in FIG. Figure 1 As shown, and refer to Figure 2 to Figure 4 The embodiment of the present application provides a method for constructing a cavity curve model of a diaphragm compressor diaphragm head of a hydrogen refueling station. The diaphragm compressor diaphragm head 100 includes an air-side diaphragm head 110 provided with an air cavity, an oil-side diaphragm head 120 provided with an oil cavity, and a diaphragm 130 sandwiched between the air-side diaphragm head 110 and the oil-side diaphragm head 120. The contours of the air cavity and the oil cavity are symmetrically arranged. The diaphragm 130 is correspondingly fitted with the air cavity or the oil cavity in the maximum deformation state. The cavity curve model of the air cavity and the oil cavity is constructed by the following steps: S1. The contours of the air cavity and the oil cavity are respectively represented as single exponential generatrix equations, and according to the single exponential generatrix equations and boundary conditions, the code of the triple exponential generatrix equation is edited in Matlab; S2. Import the code of the three-exponential generatrix equation into the Matlab component in Isight, and add the input parameters and the objective function of the three-exponential generatrix equation into Isight; wherein the input parameters include independent variable parameters and adjustment parameters; the objective function includes a first objective function for characterizing the arc length of the contour of the diaphragm 130 and a second objective function for characterizing the cross-sectional area of ​​the air cavity or the oil cavity; S3. Input the initial value range of the input parameters into Isight, and take the minimum value of the first objective function and the maximum value of the second objective function as the target value, and use the multi-island genetic algorithm to calculate and output the optimal combination of each adjustment parameter.

[0025] The method for constructing the cavity curve model of the diaphragm compressor of the hydrogen refueling station in the present application is as follows: the original single-exponential generatrix equation of the air cavity or oil cavity contour is edited in Matlab to obtain the optimized three-exponential generatrix equation, and the input parameters and objective function are imported. According to the initial value range of the input parameters and the target value of the objective function, a multi-island genetic algorithm is used to obtain the optimal value of the adjustment parameter.

[0026] In the method for constructing the diaphragm head cavity curve model of the diaphragm compressor of the hydrogen refueling station of the present application, the contour curves of the air cavity and the oil cavity are optimized from a single-exponential generatrix equation to a three-exponential generatrix equation. On the one hand, the maximum radial bending stress of the diaphragm 130 is reduced, thereby avoiding damage to the diaphragm 130 during the compression of hydrogen, thereby avoiding leakage of hydrogen or hydraulic oil, and also extending the service life of the diaphragm 130 and the diaphragm compressor; on the other hand, the volume of the air cavity and the oil cavity is increased, and the compression efficiency is improved. That is, to compress the same volume of hydrogen, fewer compression times and shorter working time are required, thereby avoiding damage to the diaphragm 130 and reducing the operating cost of the hydrogen refueling station.

[0027] Furthermore, since the deformation of the diaphragm 130 is positively correlated with the arc length of the diaphragm 130 and the radial bending stress of the diaphragm 130, and when the deformation of the diaphragm 130 is the largest, the arc length of the diaphragm 130 is also the longest, and the radial bending stress of the diaphragm 130 is also the largest, at this time, the diaphragm 130 is attached to and overlaps with the air cavity, so the arc length of the diaphragm 130 is used to replace the radial bending stress of the diaphragm 130, which can simplify the first objective function and facilitate software calculation and solution. Similarly, the cross-sectional area of ​​the diaphragm 130 is also positively correlated with the compressed volume of the diaphragm 130, and when the cross-sectional area of ​​the diaphragm 130 is the largest, the volume of the diaphragm 130 is also the largest, so the cross-sectional area of ​​the diaphragm 130 is used to replace the compressed volume of the diaphragm 130, which can simplify the second objective function and facilitate software calculation and solution. Among them, the compressed volume of the diaphragm 130 is the volume of the air cavity or oil cavity, which can also be called the diaphragm cavity volume.

[0028] In some embodiments of the present application, Isight is a comprehensive software that quickly couples various simulation and analysis software in a building block manner, such as CAD software: UG, Pro Engineer, CAE software: Abaqus / CAE, ANSYS Solver, numerical analysis software: Excel, Matlab, etc. Isight organizes the design process, optimization algorithm, and approximate model into a unified framework, automatically runs the simulation software, and completes the entire process of "analysis-optimization-model correction-re-analysis and re-optimization", thereby eliminating the "bottleneck" in the traditional design process and making the entire design process fully digital and fully automated. Isight can replace engineering designers to perform repetitive and error-prone digital and design processing work, so Isight is called a "software robot". Isight can shorten the product design cycle, reduce product costs, and improve product quality.

[0029] In some embodiments of the present application, the multi-island genetic algorithm is a multi-objective optimization algorithm. By introducing the concept of multiple sub-populations, the ability of the genetic algorithm to solve complex problems is enhanced, especially in terms of global optimization, parallel processing and diversity maintenance, so that the results calculated by the multi-island genetic algorithm are of higher quality. Of course, the present application can also use a multi-objective particle swarm algorithm, which can save computing resources and has a faster computing efficiency.

[0030] In some embodiments of the present application, the single exponential generatrix equation is: ; The three-exponential generatrix equation is: ;in z For a single index, m The first index, n is the second index, k The third index, a To control the parameters, H 0 is the deflection at the center of the air cavity, R is the distance between the center of the air cavity and the edge of the air cavity, r is the distance from the center of the air cavity to any position between the center of the air cavity and the edge of the air cavity; r is the independent variable parameter, m、n、k、a、H 0 These are adjustment parameters.

[0031] In the embodiment of the present application, the five parameters of the three-exponential generatrix equation are m、n、k、a、H 0 As variables, an objective function with the radial bending stress of the diaphragm (replaced by the arc length of the diaphragm 130 contour) and the membrane cavity volume (replaced by the cross-sectional area of ​​the membrane cavity) as optimization targets was established, and the membrane cavity structure was optimized using Matlab and Isight software. Based on the multi-objective optimization algorithm, iterative optimization was performed to determine the above five parameters after optimization, and then an optimal combination of parameters was found, which minimized the radial bending stress of the membrane cavity and maximized the volume of the membrane cavity.

[0032] In some embodiments of the present application, the boundary conditions include geometric boundary conditions and stress boundary conditions. The geometric boundary conditions are: ; in, i is the three-exponential generatrix equation pair r The first derivative of represents the slope at that location; is the three-exponential generatrix equation pair rThe second derivative of represents the deflection angle at that location. In the embodiment of the present application, it can be seen from the above geometric boundary conditions that the slopes at the center of the air cavity and the edge of the air cavity are both 0, and the deflection angle at the center of the air cavity ≤ 0 indicates that the function at the center of the air cavity is a convex function.

[0033] In some embodiments of the present application, Figure 3 As shown, the air side membrane head 110 also includes an air inlet hole 111, an exhaust hole 112 and an air groove 113. The air inlet hole 111 and the exhaust hole 112 are both used to connect the air cavity and the outside of the air side membrane head 110. The exhaust hole 112 is located at the center of the air side membrane head 110 and is evenly distributed along the circumference of the air side membrane head 110. The air inlet hole 111 is located on the air side membrane head 110 away from the exhaust hole 112. The air grooves 113 are evenly distributed along the circumference of the air side membrane head 110 and are respectively connected to the corresponding exhaust holes 112.

[0034] In the embodiment of the present application, when the diaphragm compressor is working, the diaphragm 130 moves downward, so that hydrogen enters the air cavity through the air inlet 111, and the diaphragm 130 moves upward, so that the hydrogen is compressed and then discharged through the air groove 113 and the exhaust hole 112. The provided air groove 113 has a guiding function, which facilitates the discharge of hydrogen.

[0035] In some embodiments of the present application, the stress boundary condition is: ; in, R 1 is the location radius of the exhaust holes 112 distribution, such as Figure 3 As shown, s r is the radial stress of the diaphragm 130, [σ a ]for R>r≥R 1 The corresponding allowable radial stress of the diaphragm 130, [σ c ]for R 1 >r≥0 The corresponding allowable radial stress of the diaphragm 130 is R 1 When it is 22mm, [σ a ] is 200Mpa, [σ c ] is 170Mpa.

[0036] In the embodiment of the present application, the stress boundary condition takes into account the actual working condition that the air side diaphragm head 110 has the air groove 113 and the exhaust hole 112, and fully simulates the influence of the additional stress caused by the air groove 113 and the exhaust hole 112 on the diaphragm 130. Therefore, it can truly reflect the stress condition of the diaphragm 130, and the numerical value obtained by calculation is more accurate and the result is more reliable.

[0037] In some embodiments of the present application, the first objective function is: .

[0038] In the present application, the first objective function is the arc length of the contour of the diaphragm 130 . By using the arc length instead of the radial bending stress of the diaphragm 130 , the first objective function can be simplified, which facilitates software calculation and solution.

[0039] In some embodiments of the present application, the second objective function is: .

[0040] In the present application, the second objective function is the cross-sectional area of ​​the air cavity or the oil cavity. By using the cross-sectional area instead of the compressed volume of the diaphragm 130 (ie, the diaphragm cavity volume), the second objective function can be simplified and the software calculation and solution can be facilitated.

[0041] In some embodiments of the present application, the initial value range of the adjustment parameter is: .

[0042] In the embodiment of the present application, m、n、k The initial value range of can be obtained through pilot testing. Specifically, taking parameter m as an example, we first roughly set the parameter based on experience. m range, such as m = [2, 20], substituting into the three-exponential generatrix equation, we find that when m >9:00, m The change of has little effect on the curve profile, so you can set m The initial range of is [2, 9]. H 0 The initial value range of can be obtained through experience. a The initial value range can be obtained by m、n、k、H 0 The initial value range of is determined. Through optimization calculation, it can be obtained m =2.8, n =3, k =2.1, a =-0.53, H 0=4, the maximum radial stress of the diaphragm 130 can be minimized, and the compressed volume of the diaphragm 130 can be maximized. According to calculations, the maximum radial stress of the diaphragm 130 before optimization is 139MPa, and the maximum radial stress of the diaphragm 130 after optimization is 131MPa, which is reduced by 6.1%; the maximum equivalent stress of the diaphragm 130 before optimization is 133MPa, and the maximum equivalent stress of the diaphragm 130 after optimization is 127MPa, which is reduced by 4.7%; the volume of the diaphragm cavity before optimization is 133799.760 cubic millimeters, and the volume of the diaphragm cavity after optimization is 136840.880 cubic millimeters, which is increased by 2.3%. Therefore, the diaphragm compressor diaphragm head 100 of the embodiment of the present application can significantly reduce the maximum radial stress of the diaphragm 130, and can increase the volume of the diaphragm cavity.

[0043] In some embodiments of the present application, radial stress refers to stress applied along a radial direction, which is usually a stress component considered in a cylindrical or spherical structure. Radial stress consists of radial bending stress and radial tensile stress. Because radial bending stress is the main factor affecting fatigue damage of the diaphragm 130, simulation can only display radial stress, but cannot specifically display radial bending stress. However, radial bending stress can also reflect the magnitude of radial stress. Conversely, the radial stress result obtained by simulation can also reflect the optimized target radial bending stress.

[0044] Equivalent stress, also known as Mises stress, is used to represent the comprehensive stress state of a material under specific loading conditions. It is usually used to compare the safety of materials under different stress states and is often used for fatigue analysis based on the material's yield standard (such as the von Mises standard). Under the same conditions, the smaller the equivalent stress and radial stress, the higher the fatigue life.

[0045] In some embodiments of the present application, the radial bending stress of the diaphragm ,in, t is the thickness of the diaphragm 130, E is the elastic modulus, m is Poisson's ratio. The radial bending stress at any position of the diaphragm 130 can be obtained by using the radial bending stress formula of the diaphragm 130, and the optimized radial bending stress can be obtained by substituting the optimal parameters into the formula. The compression volume of the diaphragm 130 The compressed volume of the diaphragm 130 can be obtained by using the compressed volume formula of the diaphragm 130 , and the optimized compressed volume of the diaphragm 130 , that is, the maximum value of the compressed volume of the diaphragm 130 , can be obtained by substituting the optimal parameters into the formula.

[0046] In the embodiment of the present application, the maximum bending radial stress of the diaphragm 130 under the load of the optimized diaphragm cavity is theoretically calculated, and the maximum bending radial stress of the diaphragm 130 in the diaphragm cavity before and after optimization is verified by finite element simulation comparison, so as to ensure that the diaphragm 130 in the optimized diaphragm cavity has a smaller radial bending stress during the process of compressing gas. At the same time, the volume of the diaphragm cavity is theoretically calculated, that is, it is ensured that the volume of the diaphragm cavity is increased while reducing the maximum bending stress of the diaphragm 130.

[0047] In some embodiments of the present application, the control parameters ,in, s MR for r=R The corresponding σ Mr The value is the radial bending stress at the edge of the diaphragm 130. In the embodiment of the present application, when R =165.5mm, t =0.4mm, E =200000Mpa, m =0.3, s MR The value range is [60, 90]Mpa, from which we can get a The initial value range of .

[0048] The present application also provides a method for preparing a diaphragm compressor membrane head, comprising the following steps: Based on the cavity curve model of the hydrogenation station diaphragm compressor diaphragm head established in the above embodiment, the optimal combination of each adjustment parameter is solved to determine the cavity profile of the air cavity and the oil cavity of the diaphragm compressor diaphragm head, and the corresponding diaphragm head is manufactured or processed accordingly. The diaphragm head in this embodiment has the largest diaphragm cavity volume while having the minimum radial bending stress, so the service life of the diaphragm compressor diaphragm head can be extended and the compression efficiency can be improved.

[0049] Although some preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0050] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the inventive concept. Thus, if these modifications and variations to the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for constructing a cavity curve model of a diaphragm compressor of a hydrogenation station, characterized in that: The steps include: (1) Based on the single exponential generatrix equation and its boundary conditions that characterize the contours of the air cavity and oil cavity of the diaphragm compressor, the following triple exponential generatrix equation is established: ； in, H（r） The curve equation that characterizes the contour of the air cavity and / or oil cavity, m The first index, n is the second index, k The third index, a To control the parameters, H 0 is the deflection at the center of the air cavity, R is the distance between the center of the air cavity and the edge of the air cavity, r is the distance from the center of the air cavity to any position between the center of the air cavity and the edge of the air cavity; r is the independent variable parameter, m, n, k, a, H 0 All are adjustment parameters; (2) Taking the adjustment parameters corresponding to the three-exponential generatrix equation as variables, a corresponding objective function with the radial bending stress of the diaphragm and the membrane cavity volume as optimization targets is established, and based on the objective function, the optimal combination of the adjustment parameters is solved to minimize the radial bending stress of the diaphragm and maximize the membrane cavity volume.

2. The construction method according to claim 1, characterized in that: The objective function includes: Characterize the arc length of the diaphragm profile L The first objective function is: ； Characterize the cross-sectional area of ​​the air cavity or oil cavity S The second objective function is: 。 3. The construction method according to claim 2, characterized in that: In the step (2), the membrane cavity structure is optimized by using Matlab and Isight software, that is, the three-exponential generatrix equation is imported into the Matlab component in Isight, and its independent variable parameters, adjustment parameters and the objective function are added to Isight, and then the minimum value of the first objective function and the maximum value of the second objective function are taken as target values, and a multi-island genetic algorithm is used to calculate and output the optimal value combination of the adjustment parameters.

4. The construction method according to claim 1, characterized in that: The boundary conditions include: Geometric boundary conditions: ； in, θ The three-exponential generatrix equation is r The first derivative of represents the slope at that location; The three-exponential generatrix equation is r The second derivative of represents the deflection angle at that location; Stress boundary conditions: ； in, R 1 is the position radius of the exhaust holes of the air side membrane head, σ r is the radial stress of the diaphragm, [ σ a ]for R > r ≥ R 1 The corresponding allowable radial stress of the diaphragm is, σ c ]for R 1 > r The allowable radial stress of the diaphragm corresponding to ≥0.

5. The construction method according to claim 1, characterized in that: The initial value range of the adjustment parameter is: 。 6. The construction method according to claim 1, characterized in that: The radial bending stress of the diaphragm is: ;in, t is the diaphragm thickness, E is the elastic modulus, μ is Poisson's ratio.

7. The construction method according to claim 6, characterized in that: The expression of the control parameter is: ;in, σ MR for r = R The corresponding σ Mr Value, that is, the radial bending stress at the edge of the diaphragm.

8. The construction method according to claim 1, characterized in that: The diaphragm compressor diaphragm head includes an air side diaphragm head provided with the air cavity, an oil side diaphragm head provided with the oil cavity and the diaphragm sandwiched between the air side diaphragm head and the oil side diaphragm head; the contours of the air cavity and the oil cavity are symmetrically arranged; and the diaphragm is correspondingly fitted with the air cavity or the oil cavity in the maximum deformation state.

9. A method for preparing a diaphragm compressor membrane head, characterized in that: The steps include: Based on the cavity curve model of the diaphragm compressor diaphragm head of the hydrogen refueling station established in claim 1, the optimal combination of various adjustment parameters is solved to determine the cavity contours of the air cavity and oil cavity of the diaphragm compressor diaphragm head, and the corresponding diaphragm head is manufactured or processed accordingly.

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