Compressor and design method based on variable factor control polynomial membrane cavity profile

Abstract

A compressor and design method based on variable factor controlled polynomial diaphragm cavity profile, the compressor having a diaphragm cavity designed and processed based on the variable factor controlled polynomial profile, the variable factor controlled polynomial profile being formed by continuously connecting a first polynomial profile L1 and a second polynomial profile L2, defining the connection point of the first polynomial profile L1 and the second polynomial profile L2 as a profile generating point P, using the position and inclination characteristics of the profile generating point P as the generating characteristics of the diaphragm cavity profile L, and adjusting the maximum radius R of the diaphragm cavity profile L by controlling the position coordinates of the profile generating point P and the inclination angle Δθ of the profile inflection point. max and maximum deflection H max , obtaining a diaphragm compressor cavity profile that meets the set cavity volume and allowable stress conditions. This invention can enrich the optimization parameters in the profile design process, expand the optimization range, improve the design flexibility of diaphragm compressors, meet diverse market demands, enhance the reliability of diaphragm compressors, and increase the life of the diaphragm.

Description

Technical Field

[0001] The present invention relates to the technical field of diaphragm compressors, and in particular to a compressor based on variable factor control of polynomial diaphragm cavity profiles and a design method thereof. Background Art

[0002] A diaphragm compressor is a positive displacement compressor that uses a diaphragm to separate the oil and gas sides. Its operating principle is: a motor drives the crankshaft and connecting rod, driving the piston in reciprocating motion to increase and reduce the pressure of the high-pressure oil. The high-pressure oil then pushes the diaphragm to compress and discharge the gas. Due to their excellent sealing properties and high compression ratio, diaphragm compressors are widely used in the hydrogen energy industry, especially in hydrogen refueling stations. However, issues such as diaphragm life, volumetric efficiency, and diaphragm head strength are critical and difficult issues in the development of diaphragm compressors.

[0003] The diaphragm is a key component in the stable operation of a diaphragm compressor, and its performance directly affects the reliability of the compressor. Diaphragm damage can occur through various means, including collapse, distortion, wear and tear, and mechanical fatigue. Diaphragm damage can compromise the mechanical performance of the diaphragm compressor and, in severe cases, lead to significant economic losses.

[0004] The diaphragm compressor cavity profile currently widely used in China is the single-exponential, low-deflection diaphragm cavity profile. After long-term practice and verification, it has good reliability and a practical basis. However, in the development and design of new diaphragm compressor models, the traditional single-exponential diaphragm cavity profile is adjusted by three profile variables: the diaphragm cavity radius, the single exponent, and the maximum deflection. The profile optimization range is limited, and it is difficult to adjust the diaphragm stress changes caused by the change in the slope of the diaphragm cavity profile inflection point. Therefore, it cannot meet the urgent needs of diaphragm compressor technology development and the market demand for the development of new high-pressure and high-speed models. Multi-parameter diaphragm cavity profile optimization design is an effective way to improve the reliability of diaphragm compressors and reduce costs. Summary of the Invention

[0005] The purpose of the present invention is to address the problems in the above-mentioned prior art and provide a compressor and design method based on variable factor control of polynomial diaphragm cavity profile, enrich the optimization parameters in the profile design process, expand the optimization range, improve the design flexibility of diaphragm compressors, meet diverse market demands, enhance the reliability of diaphragm compressors and increase the life of the diaphragm.

[0006] In order to achieve the above object, the present invention has the following technical solutions:

[0007] A compressor based on a variable factor controlled polynomial diaphragm cavity profile, comprising a diaphragm cavity designed and processed based on a variable factor controlled polynomial profile, wherein the variable factor controlled polynomial profile is formed by continuously connecting a first polynomial profile L1 and a second polynomial profile L2, defining the connecting point of the first polynomial profile L1 and the second polynomial profile L2 as a profile generating point P, and taking the position and inclination characteristics of the profile generating point P as the generating features of the diaphragm cavity profile L, by controlling the position coordinates (x P ,y P ) and the inflection point angle Δθ of the profile, adjust the maximum radius R of the membrane cavity profile L max and maximum deflection H max , obtain the diaphragm compressor diaphragm cavity profile that sets the diaphragm cavity volume and satisfies the allowable stress conditions.

[0008] As a preferred solution, any point in the first quadrant is used as the profile generating point P in the XOY coordinate system. The inclination angle of the profile generating point P in the XOY coordinate system is the profile inflection point inclination angle Δθ. According to the maximum radius R of the membrane cavity profile L, max , maximum deflection H max , place the starting position of the first polynomial profile line L1 at the XOY coordinate origin O, and constrain the starting position of the second polynomial profile line L2 by the profile end position of the first polynomial profile line L1, then set the initial conditions for generating the membrane cavity profile line L as follows:

[0009]

[0010] Where R represents the radius of the corresponding membrane cavity line segment; x and y represent the coordinates of the corresponding membrane cavity line in the XOY coordinate system.

[0011] As a preferred solution, the expressions for defining the first polynomial profile L1 and the second polynomial profile L2 are as follows:

[0012]

[0013] Wherein, a and b are the line parameters of the first polynomial line L1 and the second polynomial line L2, respectively. The number of line parameters of the first polynomial line L1 and the second polynomial line L2 is determined according to the number of constraints.

[0014] According to the following general polynomial expression:

[0015]

[0016] Where, F polynomial is a general polynomial expression; f is the variable coefficient of the expression; n is the number of variables;

[0017] Then the first polynomial profile L1 and the second polynomial profile L2 conform to the following expressions:

[0018]

[0019] As a preferred solution, the volume of the membrane cavity enclosed by the membrane cavity line L obtained by the first polynomial line L1 and the second polynomial line L2 is solved as follows:

[0020]

[0021] According to the maximum limit volume V of the membrane cavity Lmax The maximum radius R of the membrane cavity line L max , the inflection point angle Δθ and the maximum deflection H max Positive correlation, by adjusting the membrane cavity volume V L Equal to the set membrane cavity volume.

[0022] As a preferred solution, the position coordinates (x P ,y P ) and the inflection point angle Δθ of the profile, adjust the maximum radius R of the membrane cavity profile L max and maximum deflection H max , the obtained membrane cavity line L is expressed by the following formula:

[0023] H L =F(R max ,H max ,x P ,y P ,Δθ)

[0024] According to the following formula, the set membrane cavity volume V enclosed by the membrane cavity line L under the design conditions of thermodynamic calculation is calculated. L,Set :

[0025] V Cone =ζV L,Set

[0026] Where, ζ represents the design coefficient; V Cone Represents the volume of the cone Cone;

[0027] The maximum limit volume of the membrane cavity that can be enclosed by the membrane cavity line L is the bottom angle Δθ and the bottom radius R max The cone Cone is used to describe the membrane cavity volume V that can be enclosed by the membrane cavity line L. L Meet the following conditions:

[0028]

[0029] Where: H Cone Indicates the height of the cone Cone.

[0030] As a preferred solution, let H = H L The maximum and minimum surface stresses of the diaphragm of the diaphragm compressor when it deforms close to the membrane cavity surface are calculated as follows:

[0031]

[0032] δ min =min{δ Pr ±δ Mr ,δ Pt ±δ Mt}

[0033] δ max =max{δ Pr ±δ Mr ,δ Pt ±δ Mt}

[0034] Where H represents the equation of the membrane cavity profile with respect to radius r; E is the Young's modulus of the membrane material; μ is the Poisson's ratio of the membrane material; t is the membrane thickness; ∫ represents the mathematical integral operator; d represents the mathematical differential operator; δ Pr Indicates the radial normal stress of the diaphragm; δ Pt Indicates the circumferential normal stress of the diaphragm; δ Mr represents the radial shear stress of the diaphragm; δ Mr represents the circumferential shear stress of the diaphragm; δ min Indicates the minimum stress on the diaphragm surface; δ max Indicates the maximum stress on the diaphragm surface.

[0035] As a preferred solution, by solving the line equations of the first polynomial line L1 and the second polynomial line L2, the position coordinates (x P ,y P ) and the polynomial membrane cavity profile set Ψ of the profile inflection point inclination Δθ, the expression is as follows:

[0036]

[0037] The multi-objective optimization design of the polynomial membrane cavity profile set Ψ is performed according to the following formula:

[0038]

[0039] Where H L,Best Indicates multi-objective optimization of the membrane cavity profile; Find indicates the optimization function; min indicates finding the minimum value; δ indicates the surface stress of the diaphragm compressor diaphragm using the corresponding polynomial membrane cavity profile; solve indicates the solution function;

[0040] According to the strength condition of the fourth strength theory, when the diaphragm is deformed, the multi-objective optimization of the membrane cavity line H is applied. L,Best The equivalent pressure on the diaphragm surface of the diaphragm compressor is solved by the following expression:

[0041]

[0042] Where, represents the equivalent stress of the diaphragm; Q represents the shear stress of the diaphragm; [σ] represents the allowable stress of the diaphragm material;

[0043] According to the strength condition of the first strength theory, when the diaphragm is deformed, the stress in any direction meets the following formula:

[0044]

[0045] By adding the diaphragm equivalent stress The calculation expression is substituted into the multi-objective optimization design expression, that is, the multi-objective optimization membrane cavity line H that meets the multi-objective optimization design conditions is obtained. L,Best .

[0046] A compressor design method based on variable factor control polynomial membrane cavity profile includes the following steps:

[0047] Define the maximum radius R of the membrane cavity line L max , maximum deflection H max , the inflection point angle Δθ of the profile, given the position coordinates of the profile generating point P (x P ,y P ) x P =λR max , where λ is the segmented proportional coefficient. Different segmented proportional coefficients λ are taken to calculate the polynomial membrane cavity profile set ψ;

[0048] In the polynomial membrane cavity line set ψ, the membrane cavity volume V enclosed by the membrane cavity line L under different segmented proportional coefficients λ is calculated L As the segment ratio coefficient λ increases, the membrane cavity volume V enclosed by the membrane cavity line L L Increase;

[0049] Calculate the maximum stress δ of the membrane surface corresponding to the membrane cavity line L under different segmented proportional coefficients λ max and the minimum value δ min ;

[0050] The equivalent stress of the membrane corresponding to the membrane cavity line L under different segmented proportional coefficients λ is calculated As the segmented proportional coefficient λ increases, the diaphragm equivalent stress at the center of the diaphragm Reduced, while the diaphragm equivalent stress at the edge of the diaphragm Increase;

[0051] Determine the segmented proportional coefficient λ that can obtain the target diaphragm stress distribution, and calculate the set diaphragm cavity volume V L,Set Design coefficient ζ and maximum equivalent stress corresponding to the segmented proportional coefficient λ and the membrane cavity volume V L ;

[0052] Fixed setting of membrane cavity volume V L,Set , change the inflection point angle Δθ of the profile line, and solve to obtain the maximum radius R max and maximum deflection H max , to obtain the same membrane cavity volume V L The membrane cavity line cluster, the maximum radius R max The larger the maximum deflection H is, the max The smaller;

[0053] The diaphragm compressor diaphragm cavity profile that meets the allowable stress conditions is calculated.

[0054] As a preferred solution, the maximum stress δ corresponding to the membrane surface of the membrane cavity line L under different segmented proportional coefficients λ is calculated. max and the minimum value δ min In the steps, when λ=0.1, stress concentration occurs at the center of the membrane cavity, when λ=0.9, stress concentration occurs at the edge of the membrane cavity, and when λ=0.5, the stress distribution on the diaphragm surface is uniform.

[0055] As a preferred solution, in the step of calculating the diaphragm compressor diaphragm cavity profile that meets the allowable stress condition, the equivalent radius of the diaphragm cavity is defined as The equivalent stress of the diaphragm under different inflection angles Δθ is calculated Get the equivalent stress of the diaphragm The inflection point angle Δθ of the profile that meets the allowable stress condition, and the maximum radius R of the membrane cavity profile L max and maximum deflection H max , thereby obtaining the set membrane cavity volume V L,Set The radius of the membrane cavity line under the verification is the maximum radius R of the membrane cavity line L. max and maximum deflection H max And whether the inclination angle Δθ of the inflection point of the profile meets the strength requirements and the equivalent stress of the diaphragm Evenly distributed.

[0056] Compared with the prior art, the present invention has at least the following beneficial effects:

[0057] The diaphragm compressor structure proposed in the present invention has a diaphragm cavity designed and processed based on a variable factor control polynomial profile, wherein the variable factor control polynomial profile of the present invention is formed by continuously connecting a first polynomial profile L1 and a second polynomial profile L2, and has a position coordinate (x P ,y P ), the inflection point angle Δθ of the profile, the maximum radius R of the membrane cavity profile L max and maximum deflection H max More adjustable design parameters are conducive to the membrane cavity profile design to meet diverse market demands and product requirements, and can enrich the traditional single index profile design scheme and provide more optimization options. By controlling the position coordinates of the profile generating point P (x P ,y P ) and the inflection point angle Δθ of the profile, adjust the maximum radius R of the membrane cavity profile L max and maximum deflection H max , the diaphragm compressor diaphragm cavity profile with set diaphragm cavity volume and satisfying allowable stress conditions is obtained, which has better design flexibility than the single parameter profile adjustment scheme of the traditional single exponential profile. The minimum design radius of the diaphragm cavity can be obtained through the multi-objective parameter optimization of the profile diaphragm cavity (depending on the maximum radius R of the diaphragm cavity profile L). max ), the optimal profile generating point P and the appropriate profile inflection point inclination Δθ, providing reliable suggestions for the profile development of new models of diaphragm compressors. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0059] Figure 1 Schematic diagram of polynomial membrane cavity profile calculated under different segmented proportional coefficients λ in an embodiment of the present invention;

[0060] Figure 2 Schematic diagram of the membrane cavity volume enclosed by the polynomial membrane cavity profile calculated under different segmented proportional coefficients λ in an embodiment of the present invention;

[0061] Figure 3 The maximum surface stress δ of the diaphragm calculated under different segmented proportional coefficients λ in the embodiment of the present invention is max and the minimum surface stress δ of the diaphragm min Schematic diagram of the distribution along the radial direction;

[0062] Figure 4The equivalent stress of the diaphragm calculated under different segmented proportional coefficients λ in the embodiment of the present invention is Schematic diagram of the distribution along the radial direction;

[0063] Figure 5 Schematic diagram of membrane cavity profile clusters under segmented proportional coefficient λ=0.5 and different profile inflection point inclination angles Δθ according to an embodiment of the present invention;

[0064] Figure 6 The equivalent stress of the diaphragm under the segmented proportional coefficient λ=0.5 and different profile inflection point inclination angles Δθ of the embodiment of the present invention is shown in FIG. Schematic diagram of the distribution along the radial direction. DETAILED DESCRIPTION

[0065] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0066] An embodiment of the present invention provides a compressor based on a variable factor controlled polynomial diaphragm cavity profile, which has a diaphragm cavity designed and processed based on a variable factor controlled polynomial profile. The variable factor controlled polynomial profile is formed by continuously connecting a first polynomial profile L1 and a second polynomial profile L2. The connection point of the first polynomial profile L1 and the second polynomial profile L2 is defined as a profile generating point P. The position and inclination characteristics of the profile generating point P are used as the generating features of the diaphragm cavity profile L. By controlling the position coordinates (x P ,y P ) and the inflection point angle Δθ of the profile, adjust the maximum radius R of the membrane cavity profile L max and maximum deflection H max , obtain the diaphragm compressor diaphragm cavity profile that sets the diaphragm cavity volume and satisfies the allowable stress conditions.

[0067] Specifically, in the XOY coordinate system, any point in the first quadrant is used as the membrane cavity line generation point P. The inclination angle of the line generation point P in the XOY coordinate system is the line inflection point inclination angle Δθ. According to the maximum radius R of the membrane cavity line L, max , maximum deflection H max , place the starting position of the first polynomial profile line L1 at the XOY coordinate origin O, and constrain the starting position of the second polynomial profile line L2 by the profile end position of the first polynomial profile line L1, then set the initial conditions for generating the membrane cavity profile line L as follows:

[0068]

[0069] Where R represents the radius of the corresponding membrane cavity line segment; x and y represent the coordinates of the corresponding membrane cavity line in the XOY coordinate system.

[0070] Considering that there are five equations defining the constraints of the first polynomial profile L1 and five equations defining the constraints of the second polynomial profile L2, and that the first polynomial profile L1 constrains the second polynomial profile L2, the expressions defining the first polynomial profile L1 and the second polynomial profile L2 are as follows:

[0071]

[0072] Wherein, a and b are the profile parameters of the first polynomial profile L1 and the second polynomial profile L2 respectively, and the number of profile parameters of the first polynomial profile L1 and the second polynomial profile L2 is determined according to the number of constraints.

[0073] Considering the general polynomial expression formula is defined as follows:

[0074]

[0075] Where, F polynomial is the general expression of a polynomial; f is the coefficient of the expression variable; n is the number of variables.

[0076] Therefore, the first polynomial profile L1 and the second polynomial profile L2 are defined as follows:

[0077]

[0078] Furthermore, the volume of the membrane cavity enclosed by the membrane cavity line L obtained by the first polynomial line L1 and the second polynomial line L2 is solved as follows:

[0079]

[0080] Furthermore, the maximum limit volume of the membrane cavity that can be enclosed by the polynomial membrane cavity line that meets the above conditions is the bottom angle Δθ and the bottom radius R max The cone Cone is used to describe the membrane cavity volume V that can be enclosed by the membrane cavity line L. L Meet the following conditions:

[0081]

[0082] Where H Cone Indicates the height of the cone; V Cone Represents the volume of a cone.

[0083] Similarly, the above expression can be described as:

[0084]

[0085] It can be concluded that the maximum limit volume of the membrane cavity V Lmax The maximum radius R of the membrane cavity line L max , the inflection point angle Δθ and the maximum deflection H max There is a positive correlation between the membrane cavity volume V L Equal to the set membrane cavity volume.

[0086] Furthermore, the above steps can determine the basic design parameters of the membrane cavity line L, including the position coordinates of the line generation point P (x P ,y P ) and the inflection point angle Δθ of the profile, adjust the maximum radius R of the membrane cavity profile L max and maximum deflection H max , the obtained membrane cavity line L is expressed by the following formula:

[0087] H L =F(R max ,H max ,x P ,y P ,Δθ)

[0088] Optionally, during the design of the membrane cavity profile, the set membrane cavity volume V enclosed by the membrane cavity profile L can be determined based on the thermodynamic calculation design conditions. L,Set In order to make the slope of the membrane cavity profile L change smoothly, we define:

[0089] V Cone =ζV L,Set

[0090] Where: ζ-design coefficient, preferably 2 to 6.

[0091] Let H = H L The theoretical calculation formula for the maximum and minimum surface stresses of the diaphragm compressor diaphragm using the membrane cavity profile of the embodiment of the present invention when deformed close to the membrane cavity profile is as follows:

[0092]

[0093]

[0094] δ min =min{δ Pr ±δ Mr ,δ Pt ±δ Mt}

[0095] δ max =max{δ Pr ±δ Mr ,δ Pt ±δMt}

[0096] Where H represents the equation of the membrane cavity profile with respect to radius r; E is the Young's modulus of the membrane material; μ is the Poisson's ratio of the membrane material; t is the membrane thickness; ∫ represents the mathematical integral operator; d represents the mathematical differential operator; δ Pr Indicates the radial normal stress of the diaphragm; δ Pt Indicates the circumferential normal stress of the diaphragm; δ Mr represents the radial shear stress of the diaphragm; δ Mr represents the circumferential shear stress of the diaphragm; δ min Indicates the minimum stress on the diaphragm surface; δ max Indicates the maximum stress on the diaphragm surface.

[0097] Furthermore, the line equations of the first polynomial line L1 and the second polynomial line L2 can be specifically solved, thereby obtaining a polynomial membrane cavity line set Ψ that can control the connection point position and inclination, which is defined as the following formula:

[0098]

[0099] The following multi-objective optimization design is performed on the above polynomial membrane cavity profile set Ψ:

[0100]

[0101] Where H L,Best Indicates multi-objective optimization of the membrane cavity profile; Find indicates the optimization function; min indicates finding the minimum value; δ indicates the surface stress of the diaphragm compressor diaphragm using the corresponding polynomial membrane cavity profile; solve indicates the solution function;

[0102] According to the strength condition of the fourth strength theory, when the diaphragm is deformed, the multi-objective optimization of the membrane cavity line H is applied. L,Best The equivalent pressure on the diaphragm surface of the diaphragm compressor is solved by the following expression:

[0103]

[0104] Where, Indicates the equivalent stress of the diaphragm; δ Pr represents the radial stress of the diaphragm; δ Mr represents the circumferential stress of the diaphragm; Q represents the shear stress of the diaphragm; [σ] represents the allowable stress of the diaphragm material.

[0105] According to the strength condition of the first strength theory, when the diaphragm is deformed, the stress in any direction should be less than the allowable stress of the diaphragm material, which can be described specifically as:

[0106]

[0107] Surface equivalent stress Substituting the calculation formula into δ in the above multi-objective optimization design expression, the optimized polynomial membrane cavity profile that meets the above design conditions can be solved, and then the membrane cavity of the diaphragm compressor can be designed and processed.

[0108] Another embodiment of the present invention further provides a compressor design method based on variable factor control polynomial membrane cavity profile:

[0109] Define the maximum radius R of the membrane cavity line L max =360mm, maximum deflection H max =9.4mm, inclination angle of membrane cavity line P point Given Given x P =λR max , where λ is the segmented proportional coefficient. Taking different segmented proportional coefficients λ = 0.1, 0.3, 0.5, 0.7, and 0.9, we can calculate the polynomial membrane cavity line cluster as follows: Figure 1 shown.

[0110] Furthermore, the membrane cavity volume V enclosed by the membrane cavity line L under different segmented proportional coefficients λ is calculated. L ,like Figure 2 As shown in the figure, with the increase of the segmented proportional coefficient λ, the membrane cavity volume V enclosed by the membrane cavity line L increases. L Increase.

[0111] Furthermore, the maximum stress δ corresponding to the membrane surface of the membrane cavity line L under different segmented proportional coefficients λ is calculated. max and the minimum value δ min ,like Figure 3 As shown in the figure, when λ = 0.1, stress concentration occurs at the center of the membrane cavity and the stress on the membrane surface is relatively large.

[0112] When λ=0.9, stress concentration occurs at the edge of the membrane cavity and the stress on the membrane surface is relatively large. When λ=0.5, the stress distribution on the membrane surface is the most uniform.

[0113] Furthermore, according to the fourth strength theory, the equivalent stress of the membrane corresponding to the membrane cavity line L under different segmented proportional coefficients λ is calculated: like Figure 4 As shown in the figure, with the increase of the segmented proportional coefficient λ, the diaphragm equivalent stress at the center of the diaphragm Reduced, while the diaphragm equivalent stress at the edge of the diaphragm Increase.

[0114] Preferably, according to the above calculation results, when the segmented proportional coefficient λ is 0.5, a better diaphragm stress distribution can be obtained, which is beneficial to improving the diaphragm life. The set diaphragm cavity volume V is calculated to be L,SetThe design coefficient ζ corresponding to the segment ratio coefficient λ = 0.5 is 2.23, and the maximum equivalent stress Membrane cavity volume V L =1120000mm 3 .

[0115] Furthermore, the above-mentioned set membrane cavity volume V is fixed L,Set =1120000mm 3 , change the inclination angle of the inflection point of the profile The maximum radius R is obtained by solving max and maximum deflection H max , and then obtain the same membrane cavity volume V L The membrane cavity line clusters, such as Figure 5 As shown, the maximum radius of the membrane cavity R max The larger the maximum deflection H is, the max The smaller.

[0116] Define the equivalent radius of the membrane cavity The equivalent stress of the membrane cavity under different inflection angles Δθ is calculated. ,like Figure 6 As shown, the equivalent stress Within the stress range, the maximum inclination angle of the membrane cavity line is approximately equal to The maximum radius of the membrane cavity at this membrane cavity inclination angle is R max =338mm, the maximum deflection of the membrane cavity is H max =10.7mm, thus obtaining the set membrane cavity volume V L,Set The radius of the membrane cavity line should not be less than 338mm, which verifies the above conditions. max =360mm, H max =9.4mm and The strength requirements are met and the equivalent stress is evenly distributed.

[0117] The embodiment of the present invention proposes a compressor and design method based on a polynomial diaphragm cavity profile controlled by a variable factor. The diaphragm cavity profile is continuously connected by two polynomial profiles controlled by different variable factors, including a first polynomial profile L1 and a second polynomial profile L2. The diaphragm compressor diaphragm cavity profile design conditions are met, and the diaphragm cavity profile has a maximum radius R max , maximum deflection H max 、Position coordinates of the line generation point P (x P ,y P ) and the line inflection point inclination angle Δθ and other line design parameters. More adjustable design parameters are conducive to the membrane cavity line design to meet the diverse market needs and product requirements, and can enrich the traditional single index line design scheme and provide more optimization options. The present invention controls the coordinates (xP ,y P ) and the inflection point angle Δθ of the profile, adjust the maximum radius R of the membrane cavity profile max and maximum deflection H max To obtain the set membrane cavity profile volume V L,Set The diaphragm cavity profile with the conditions of the allowable stress has better design flexibility than the single-parameter profile adjustment scheme of the traditional single-exponential profile. Through the multi-objective parameter optimization of the profile membrane cavity, the minimum design radius of the membrane cavity, the optimal profile generation point P and the appropriate profile inflection point inclination Δθ can be obtained, providing reliable suggestions for the development of the profile of new diaphragm compressors.

[0118] Although the present application has been described above with reference to specific embodiments, it should be understood by those skilled in the art that many modifications may be made to the configurations and details disclosed herein within the principles and scope of the present application. The scope of protection of the present application is determined by the appended claims, and the claims are intended to cover all modifications encompassed by the literal meaning or scope of equivalents of the technical features in the claims.

Claims

1. A compressor based on variable factor control polynomial membrane cavity profile, characterized by: The membrane cavity is designed and processed based on a variable factor controlled polynomial profile, wherein the variable factor controlled polynomial profile is formed by continuously connecting a first polynomial profile L1 and a second polynomial profile L2, defining the connection point of the first polynomial profile L1 and the second polynomial profile L2 as a profile generating point P, and taking the position and inclination characteristics of the profile generating point P as the generating features of the membrane cavity profile L, by controlling the position coordinates (x P ,y P ) and the inflection point angle Δθ of the profile, adjust the maximum radius R of the membrane cavity profile L max and maximum deflection H max , obtain the diaphragm compressor diaphragm cavity profile that sets the diaphragm cavity volume and satisfies the allowable stress conditions; The expressions defining the first polynomial profile L1 and the second polynomial profile L2 are as follows: Wherein, a and b are the line parameters of the first polynomial line L1 and the second polynomial line L2, respectively. The number of line parameters of the first polynomial line L1 and the second polynomial line L2 is determined according to the number of constraints. According to the following general polynomial expression: Where, F polynomial is a general polynomial expression; f is the variable coefficient of the expression; n is the number of variables; Then the first polynomial profile L1 and the second polynomial profile L2 conform to the following expressions:

2. The compressor according to claim 1, wherein: In the XOY coordinate system, any point in the first quadrant is taken as the profile generating point P. The inclination angle of the profile generating point P in the XOY coordinate system is the profile inflection point inclination angle Δθ. According to the maximum radius R of the membrane cavity profile L, max , maximum deflection H max , place the starting position of the first polynomial profile line L1 at the XOY coordinate origin O, and constrain the starting position of the second polynomial profile line L2 by the profile end position of the first polynomial profile line L1, then set the initial conditions for generating the membrane cavity profile line L as follows: Where R represents the radius of the corresponding membrane cavity line segment; x and y represent the coordinates of the corresponding membrane cavity line in the XOY coordinate system.

3. The compressor according to claim 2, wherein: The volume of the membrane cavity enclosed by the membrane cavity profile L obtained by the first polynomial profile L1 and the second polynomial profile L2 is solved as follows: According to the maximum limit volume V of the membrane cavity Lmax The maximum radius R of the membrane cavity line L max , the inflection point angle Δθ and the maximum deflection H max Positive correlation, by adjusting the membrane cavity volume V L Equal to the set membrane cavity volume.

4. The compressor according to claim 3, characterized in that: By controlling the line to generate the position coordinates of point P (x P ,y P ) and the inflection point angle Δθ of the profile, adjust the maximum radius R of the membrane cavity profile L max and maximum deflection H max , the obtained membrane cavity line L is expressed by the following formula: H L =F(R max ,H max ,x P ,y P ,Δθ) According to the following formula, the set membrane cavity volume V enclosed by the membrane cavity line L under the design conditions is calculated based on thermodynamics. L,Set : V Cone =ζV L,Set Where, ζ represents the design coefficient; V Cone Represents the volume of the cone Cone; The maximum limit volume of the membrane cavity that can be enclosed by the membrane cavity line L is the bottom angle Δθ and the bottom radius R max The cone Cone is used to describe the membrane cavity volume V that can be enclosed by the membrane cavity line L. L Meet the following conditions: Where: H Cone Indicates the height of the cone Cone.

5. The compressor based on variable factor control polynomial membrane cavity profile according to claim 4, characterized in that: Let H = H L The maximum and minimum surface stresses of the diaphragm of the diaphragm compressor when it deforms close to the membrane cavity surface are calculated as follows: d min =min{δ Pr ±δ Mr ,d Pt ±δ Mt } d max =max{δ Pr ±δ Mr ,d Pt ±δ Mt } Where H represents the equation of the membrane cavity profile with respect to radius r; E is the Young's modulus of the membrane material; μ is the Poisson's ratio of the membrane material; t is the membrane thickness; ∫ represents the mathematical integral operator; d represents the mathematical differential operator; δ Pr Indicates the radial normal stress of the diaphragm; δ Pt Indicates the circumferential normal stress of the diaphragm; δ Mr represents the radial shear stress of the diaphragm; δ Mr represents the circumferential shear stress of the diaphragm; δ min Indicates the minimum stress on the diaphragm surface; δ max Indicates the maximum stress on the diaphragm surface.

6. The compressor based on variable factor control polynomial membrane cavity profile according to claim 5, characterized in that: By solving the line equations of the first polynomial line L1 and the second polynomial line L2, the position coordinates (x P ,y P ) and the polynomial membrane cavity profile set Ψ of the profile inflection point inclination Δ, the expression is as follows: The multi-objective optimization design of the polynomial membrane cavity profile set Ψ is performed according to the following formula: Where H L,Best Indicates multi-objective optimization of membrane cavity profile; Find indicates optimization function; min indicates finding the minimum value; δ represents the surface stress of the diaphragm of the diaphragm compressor using the corresponding polynomial membrane cavity profile; solve represents the solution function; According to the strength condition of the fourth strength theory, when the diaphragm is deformed, the multi-objective optimization of the membrane cavity line H is applied. L,Best The equivalent pressure on the diaphragm surface of the diaphragm compressor is solved by the following expression: Where, represents the equivalent stress of the diaphragm; Q represents the shear stress of the diaphragm; [σ] represents the allowable stress of the diaphragm material; According to the strength condition of the first strength theory, when the diaphragm is deformed, the stress in any direction meets the following formula: By adding the diaphragm equivalent stress The calculation expression is substituted into the multi-objective optimization design expression, that is, the multi-objective optimization membrane cavity line H that meets the multi-objective optimization design conditions is obtained. L,Best .

7. A compressor design method based on variable factor control polynomial membrane cavity profile, characterized in that: include: Define the maximum radius R of the membrane cavity line L max , maximum deflection H max , the inflection point angle Δθ of the profile, given the position coordinates of the profile generating point P (x P ,y P ) x P =λR max , where λ is the segmented proportional coefficient. Different segmented proportional coefficients λ are taken to calculate the polynomial membrane cavity profile set Ψ; In the polynomial membrane cavity line set Ψ, the membrane cavity volume V enclosed by the membrane cavity line L under different segmented proportional coefficients λ is calculated L As the segmented proportional coefficient λ increases, the membrane cavity volume V enclosed by the membrane cavity line L L Increase; Calculate the maximum stress δ of the membrane surface corresponding to the membrane cavity line L under different segmented proportional coefficients λ max and the minimum value δ min ; The equivalent stress of the membrane corresponding to the membrane cavity line L under different segmented proportional coefficients λ is calculated As the segmented proportional coefficient λ increases, the diaphragm equivalent stress at the center of the diaphragm Reduced, while the diaphragm equivalent stress at the edge of the diaphragm Increase; Determine the segmented proportional coefficient λ that can obtain the target diaphragm stress distribution, and calculate the set diaphragm cavity volume V L,Set Design coefficient ζ and maximum equivalent stress corresponding to the segmented proportional coefficient λ and the membrane cavity volume V L ; Fixed setting of membrane cavity volume V L,Set , change the inflection point angle Δθ of the profile line, and solve to obtain the maximum radius R of the membrane cavity max and maximum deflection H max , to obtain the same membrane cavity volume V L The membrane cavity line cluster, the maximum radius R max The larger the maximum deflection H is, the max The smaller; The diaphragm compressor diaphragm cavity profile that meets the allowable stress conditions is calculated.

8. The compressor design method based on variable factor control polynomial membrane cavity profile according to claim 7, characterized in that: The calculation of the maximum stress δ of the membrane surface corresponding to the membrane cavity line L under different segmented proportional coefficients λ max and the minimum value δ min In the steps, when λ=0.1, stress concentration occurs at the center of the membrane cavity, when λ=0.9, stress concentration occurs at the edge of the membrane cavity, and when λ=0.5, the stress distribution on the diaphragm surface is uniform.

9. The compressor design method based on variable factor control polynomial membrane cavity profile according to claim 7, characterized in that: In the step of calculating the diaphragm compressor cavity profile that satisfies the allowable stress condition, the equivalent radius of the diaphragm cavity is defined as follows: The equivalent stress of the diaphragm under different inflection angles Δθ is calculated Get the equivalent stress of the diaphragm The inflection point angle Δθ of the profile that meets the allowable stress condition, and the maximum radius R of the membrane cavity profile L max and maximum deflection H max , thereby obtaining the set membrane cavity volume V L,Set The radius of the membrane cavity line under the verification is the maximum radius R of the membrane cavity line L. max and maximum deflection H max And whether the inclination angle Δθ of the inflection point of the profile meets the strength requirements and the equivalent stress of the diaphragm Evenly distributed.

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